Introduction

The pollution of water sources by heavy metals and pharmaceutical residues has become a pressing environmental concern, with significant implications for aquatic ecosystems and human health1,2. Heavy metals are characterized as metallic elements with a substantially higher density than water3. The proposed connection between density and toxicity has resulted in the inclusion of metalloids, such as arsenic, which can cause harmful effects even at low concentrations. In recent years, there has been growing concern about the ecological and health impacts of environmental contamination by these metals4,5. Furthermore, human exposure has risen considerably due to the widespread use of these elements in various fields, including industrial processes, agricultural practices, domestic applications, and technological advancements6,7.

Environmental contamination is particularly evident in specific areas such as mining sites, foundries, smelters, and other metal-processing facilities. Simultaneously, pharmaceutical pollutants like sulfamethoxazole and ibuprofen are increasingly detected in water resources due to their extensive use and inadequate removal by conventional wastewater treatment methods8,9. The persistence of these compounds in the environment poses substantial ecological risks, affecting aquatic organisms and potentially promoting the development of antibiotic-resistant bacteria10,11. Traditional water treatment techniques, such as chemical precipitation, ion exchange, and adsorption, have limitations in effectively removing these contaminants, especially at low concentrations12,13. Moreover, these methods can result in secondary pollution and often require high operational costs and energy consumption. As a result, the development of innovative, sustainable, and cost-effective technologies for the simultaneous removal of heavy metals and organic pollutants is crucial14,15.

Polyacrylonitrile (PAN) is a prominent engineering polymer widely utilized in membrane technologies, including ultrafiltration (UF), nanofiltration (NF), reverse osmosis, and pervaporation (PV). The fabrication of PAN membranes typically employs the phase inversion wet method due to the polymer’s solubility in various solvents. The hydrophobic properties of PAN membranes can be enhanced through physical or chemical modifications. Additionally, the characteristics of this polymer can be altered by incorporating different additives to create composite materials16. The scientific literature presents a variety of examples regarding the production of modified PAN composite membranes. You et al.17 developed composite membranes by utilizing PAN nanofibers as a substrate, which were subsequently coated with a layer of polyvinyl alcohol nanofibers that included multiwalled carbon nanotubes (MWCNT). Other methodologies involve the application of electrospinning techniques for the fabrication of filter membranes18. Xu et al.19 produced nano-nonwovens by incorporating nanotubes into PAN/PP composite membranes through the process of electrospraying. Additionally, Palade et al.20 synthesized a composite of PAN and non-functionalized MWCNT using solvent evaporation methods. Majeed et al.21 formulated composite membranes from a 14% PAN solution in N, N-dimethylformamide (DMF), integrating functionalized CNTs at concentrations of 0.5%, 1%, and 2%.

Modifiers for PAN may include inorganic substances such as metal oxides or metal nanoparticles, as well as zinc oxide (ZnO), zirconium dioxide (ZrO2), and copper (Cu). Photocatalysis has emerged as a promising approach to environmental remediation, utilizing the ability of certain materials to degrade pollutants using light energy. Recently, metal oxide-based photocatalysts, particularly zinc oxide (ZnO), have garnered significant attention due to their high efficiency in generating reactive oxygen species (ROS) under both UV and visible light, facilitating the decomposition of organic contaminants and the reduction of heavy metals22,23. Despite its potential, the practical application of ZnO alone is hindered by its tendency to form clusters and its poor performance in visible light conditions24,25,26. To overcome these challenges, incorporating additional materials like Cu and ZrO2 into a composite structure can boost the system’s photocatalytic efficiency, longevity, and reusability23. Cu NPs were selected for their outstanding redox properties and capacity to improve visible-light-driven photocatalysis27,28.Cu NPs were chosen for their exceptional redox properties and ability to enhance visible-light-driven photocatalysis29. The inclusion of ZrO2 nanoparticles provides further benefits, such as enhanced stability, improved adsorption properties, and greater mechanical strength, making the composite more suitable for real-world use30,31. The use of a polyacrylonitrile (PAN) polymer matrix further strengthens the structural material integrity, preventing nanoparticle loss and ensuring long-term operational stability32,33. In contrast to traditional ZnO-based systems that primarily use UV light, the Cu-doped ZnO/ZrO2 composite exhibits superior photocatalytic activity under visible light, making it more applicable to practical water treatment scenarios where natural sunlight can be utilized. Additionally, the composite’s adsorption capabilities complement its photocatalytic function, allowing it to achieve high removal rates for both inorganic and organic contaminants.

The novel aspect of this study is the integration of copper and zirconium dioxide ZnO into thePAN polymer matrix, enhancing its photocatalytic efficiency, stability, and reusability while maintaining low eco-toxicity. The research also aims to evaluate the composite’s adsorption capacity and degradation kinetics, as well as its long-term operational stability and environmental safety, offering a sustainable and effective solution for water purification.

Chemicals and methods

Chemicals

The synthesis of the Cu-ZnO/ZrO2-PAN based polymer composite began with the acquisition of high-purity materials from reputable vendors to ensure consistency throughout the production process. Sigma-Aldrich (USA) supplied copper sulfate pentahydrate (CuSO₄•5 H₂O, 99% purity) as the copper source. Zinc nitrate hexahydrate (Zn(NO₃)₂•6 H₂O, 99.5% purity) was obtained from Alfa Aesar (UK), while Merck (Germany) provided zirconium oxychloride (ZrOCl₂•8 H₂O, 98% purity) as the zinc and zirconium sources, respectively. The composite’s polymer matrix, polyacrylonitrile (PAN) with an average molecular weight of 150,000 g/mol, was also procured from Sigma-Aldrich (USA). Fisher Scientific (UK) supplied sodium hydroxide (NaOH, 99.9% purity) for precipitation, and Sigma-Aldrich (USA) provided sodium borohydride (NaBH₄, 99% purity) to reduce the copper nanoparticles. To stabilize the copper nanoparticles during synthesis, polyvinyl alcohol (PVA, 98% hydrolyzed) from Sigma-Aldrich (USA) was employed. Honeywell (USA) supplied ethanol (99.9% purity) for nanoparticle washing, and deionized water served as the solvent throughout the entire procedure.

Synthesis process

Synthesis of ZnO/ZrO2 core nanocomposites

The production of ZnO/ZrO2 core nanocomposites utilized a co-precipitation technique. Initially, 10 g (33.7 mmol) of zinc nitrate hexahydrate and 5 g (15.5 mmol) of zirconium oxychloride were dissolved in 100 mL of deionized water. This solution was continuously agitated using a magnetic stirrer at room temperature. Upon complete dissolution of the salts, a 2 M NaOH solution was slowly added until the mixture reached a pH of 10.5. The resulting solution was then heated to 70 °C and stirred for 2 h, facilitating the co-precipitation of ZnO and ZrO2 NPs. The white precipitate that formed was filtered and rinsed three times with ethanol and deionized water to eliminate any residual ions or contaminants. The cleaned precipitate was then dried in an oven at 100 °C for 12 h to remove any remaining moisture. Following the drying process, the ZnO/ZrO2 NPs underwent calcination in a muffle furnace at 400 °C for 3 h. This final step improved their crystallinity and structural stability, resulting in the formation of robust ZnO/ZrO2 core nanocomposites.

Synthesis of copper nanoparticles

Cu NPs were synthesized using a reduction technique. The process involved dissolving 2 g (8 mmol) of copper sulfatepentahydrate in 100 mL of deionized water, stirring continuously at 300 rpm. Concurrently, a solution of 1 g (26.5 mmol) sodium borohydride (NaBH4) in 50 mL of deionized water was prepared. This NaBH₄ solution was added dropwise to the copper sulfate solution, triggering the reduction of Cu²⁺ ions to form Cu nanoparticles. The reaction proceeded for 30 min at room temperature, during which a reddish-brown color developed, signaling successful Cu nanoparticle formation. To enhance nanoparticle stability and prevent aggregation, polyvinyl alcohol (PVA, 1 wt%) was incorporated during synthesis. The resulting Cu NPs were separated by centrifugation at 5000 rpm for 10 min, then washed multiple times with ethanol and deionized water to eliminate residual reactants and stabilizers. Finally, the nanoparticles were dried in an oven at 80 °C for 6 h, yielding a dry Cu NP powder.

Formation of core-shell Cu-ZnO/ZrO2 @PAN (CZZRP)composite

The core-shell structure was created by combining the previously synthesized ZnO/ZrO2 core nanoparticles with a Cu NPs solution to form a Cu shell around the ZnO/ZrO2 cores. Specifically, 2 gm of ZnO/ZrO2 NPs were dispersed in 50 ml of ethanol and sonicated for 30 min to ensure even distribution. Then, 1 gm of Cu NPs was slowly introduced to the suspension under constant stirring, allowing the Cu shell to form around the ZnO/ZrO2 core via electrostatic interactions. The mixture was stirred at room temperature for 2 h to ensure complete core coverage by Cu nanoparticles. The resulting Cu-ZnO/ZrO2 composite was isolated by filtration, washed with deionized water and ethanol, and dried at 60 °C for 8 h. The dried powder was then integrated into a PAN polymer matrix by dissolving 1gm of PAN in 20 ml of DMF and blending it with the composite. The final product was shaped into thin films and dried at 60 °C for 12 h, producing a robust and uniform CZZRP composite with a core-shell structure, suitable for photocatalytic applications in water treatment.

Characterization

The CZZRP polymer composite underwent extensive examination using multiple analytical techniques to evaluate its structural, morphological, and surface properties. A range of instruments and methods were employed: Fourier-Transform Infrared Spectroscopy (FT-IR) was conducted using a Thermo Scientific Nicolet iS50 FTIR Spectrometer to identify surface functional groups. Spectra were recorded in the 4000–400 cm–1 range using attenuated total reflectance (ATR) mode, with 4 cm–1 resolution and 32 scan averages. X-ray diffraction (XRD) analysis was performed with a Bruker D8 Advance X-ray Diffractometer to determine crystallinity and phase composition. Patterns were obtained using Cu Kα radiation (λ = 1.5406 Å) at 40 kV and 40 mA, with diffraction data collected over a 2θ range of 10°–80° at 0.02°/s scanning speed. Surface morphology, nanoparticle size, and distribution within the composite were examined using a JEOL JSM-7600 F Field Emission Scanning Electron Microscope (SEM)with energy-dispersive X-ray spectroscopy (EDX). Micromeritics TriStar II 3020 Surface Area and Porosity Analyzer was used for Brunauer-Emmett-Teller (BET) Surface Area Analysis to measure specific surface area and pore size distribution. Nitrogen adsorption-desorption isotherms at 77 K were utilized to calculate specific surface area via the BET method, while the Barrett-Joyner-Halenda (BJH) method was used to estimate average pore diameter and total pore volume. Pollutant concentrations in mixture solutions were measured using inductively coupled plasma-optical emission spectroscopy (ICP-OES) with a PE-8000 mass spectrometer (PerkinElmer, Wellesley, MA). Optical properties were assessed using a Shimadzu UV-3600 Plus UV-Vis Spectrophotometer for UV-Vis DRS, evaluating light absorption in the visible region. Spectra were recorded from 200 to 800 nm, and the composite’s bandgap energy was determined using the Tauc plot method.

Batch equilibrium isotherm

Characterization

The adsorption properties of the CZZRP polymer composite were evaluated through a series of batch tests. The influence of various parameters on adsorption, including pH, adsorbent dose, contact time, temperature, and initial pollutant concentration, was systematically investigated to optimize the composite’s efficiency in eliminating heavy metals Pb(II), Cd(II) and pharmaceutical contaminants (sulfamethoxazole, ibuprofen). Adsorption equilibrium studies were conducted using the batch contact technique. A set of 250 mL Erlenmeyer flasks was prepared with solutions containing Pb(II), Cd(II), sulfamethoxazole, and ibuprofen at concentrations ranging from 10 mg/L to 200 mg/L. The effects of experimental conditions were examined, including adsorbent quantities (0.1 g to 1.0 g in 100 mL), pH values (2–10), and initial contaminant levels (10–200 mg/L). Adsorption kinetics were explored by varying the interaction time between the adsorbent and pollutants from 10 to 180 min. Samples were taken at predetermined intervals, and adsorption capacity was measured at each time point to determine the equilibrium duration. All batch experiments were performed in 250 mL Erlenmeyer flasks with 100 mL of pollutant solution, and samples were agitated using an orbital shaker. Following adsorption, the samples were filtered, and the residual pollutant concentration was analyzed using atomic absorption spectroscopy (AAS) for heavy metals and UV-Vis spectrophotometry for pharmaceuticals. The adsorption capacity (qe) and removal efficiency R (%) were determined using Eqs. (1) and (2), respectively. Isotherm and kinetic models, including Langmuir, Freundlich, pseudo-first-order and pseudo-second-order kinetics, were employed to characterize the adsorption process, offering a comprehensive insight into the composite’s adsorption behavior for water treatment applications.Adsorption capacity:

$$\:{q}_{e}=\frac{{(C}_{0}-{C}_{e})V}{W}$$
(1)

Removal efficiency34,35:

$$\:\:R\left(\%\right)=\frac{{(C}_{0}-{C}_{e})}{{C}_{0}}\times\:100$$
(2)

C0 represents the starting concentration and Cedenotes the final concentration in the pollutant solution (mg /L). V (L) is the volume of the adsorbate solution and W (g) is the mass of the dry adsorbent utilized. Prior to introducing the adsorbent, the pH of the solution was modified using appropriate amounts of either 0.1 M HCL or 0.1 N NaOH.

Results and discussion

Fourier-transform infrared spectroscopy (FTIR) analysis

Functional group detection and verification of successful Cu, ZnO, and ZrO2 incorporation into the PAN polymer were accomplished through FTIR analysis of the composite. The FTIR spectra of the core-shell Cu-ZnO/ZrO2 (CZZR) structure, displayed in Fig. 1 and tabulated in Table 1, were examined to identify functional groups and confirm metal oxide formation in both core and shell components. A broad absorption band at 3440 cm–1 was observed, indicating O-H stretching vibrations and suggesting the presence of surface hydroxyl groups and adsorbed water molecules. H-O-H bending vibrations of absorbed moisture were evidenced by a peak at 1630 cm− 1. The 500–700 cm–1 range exhibited peaks characteristic of metal-oxygen bonds, confirming the presence of Zn-O and Zr-O stretching vibrations. Specifically, a peak at 520 cm–1 was attributed to Zn-O in the core, while a peak at 640 cm–1 was assigned to Zr-O stretching in the ZrO2 component of the composite. The CZZRP spectrum revealed characteristic PAN bands, with C–H stretching vibrations at 2981 cm–1, C ≡ N stretching vibration at 2534 cm–1, and CH2 and C–H group deformation vibrations at 1377 and 1578 cm–1. A peak around 1697 cm–1 was characteristic of C = O stretching vibrations in ester groups, likely originating from raw PAN (copolymer containing approximately 6% methyl acrylate)16. The absence of additional organic functional group peaks confirmed the purity material, while the lack of peak shifts indicated strong bonding within the core-shell structure with polymer matrix.

Fig. 1
figure 1

FTIR spectrum of the ZnO, ZR, CZZR and CZZRP composite.

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Table 1 Characteristic IR absorption peaks of prepared materials.
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X-ray diffraction (XRD) analysis

The crystalline structure of both the core (ZnO/ZrO2) and shell (Cu) components in the CZZR composite and its combination with PAN polymer (CZZRP) was examined using X-ray diffraction (XRD) analysis, as shown in Fig. 2. The XRD pattern exhibited distinctive peaks at 2θ = 31.8°, 34.4°, and 36.3° (JCPDS card no. 36-1451)were indexed as (100), (002), and (101), respectively, signifying the hexagonal wurtzite structure of ZnO. Peaks at 30.2°, 50.2°, and 60.5° (JCPDS card no. 50-1089) were indexed as (101), (112), and (211), respectively, which confirmed the tetragonal phase of ZrO2. Furthermore, the face-centered cubic structure of metallic copper was verified by peaks at 43.3°, 50.4°, and 74.2° (JCPDS card no. 85-1326) were indexed as (111), (200), and (220), respectively.The PAN polymer pattern displayed two notable peaks at 31.40° and 47.2°, indicative of turbostratic carbon.

Fig. 2
figure 2

XRD pattern of ZR, CZZRP composite.

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The lattice parameters for each crystalline phase and the relationship for interplanar spacing (d-spacing for hexagonal and tetragonal systems, the lattice parameters (a, c) were determined using Bragg’s Law as follows:

$${\bf{n\lambda }}{\rm{ }} = {\rm{ }}{\bf{2d}}{\rm{ }}{\bf{sin}}{\rm{ }}{\bf{\theta }}$$
(3)

where, λ is the wavelength of the x-ray, d is the spacing of the crystal layers (path difference), θ is the incident angle (the angle between incident ray and the scatter plane), and n is an integer. The presence of well-defined sharp peaks suggested high crystallinity and provided evidence for the successful formation of the core-shell structure. The calculated lattice parameters for ZnO are consistent with the reported values for hexagonal wurtziteZnO in the literature, where typical values range from a = 3.247 Å to 3.252 Å and c = 5.204 Å to 5.210 Å44. Similarly, the tetragonal ZrO2 lattice parameters align with previously reported values of a = 3.590 Å to 3.598 Å and c = 5.177 Å to 5.189 Å45. The FCC copper lattice parameter is also in agreement with the standard value of 3.615 Å46.The consistency of these values with literature confirms the successful synthesis and phase purity of the CZZRP composite. Moreover, the identified Miller indices for all diffraction peaks further substantiate the structural integrity and crystallinity of the composite. The lattice parameters and crystalline phases identified in the XRD analysis suggest a well-formed composite structure, which is crucial for its photocatalytic and adsorption properties. The tight integration of ZnO/ZrO2 core and Cu shell enhances charge transfer dynamics under visible light irradiation, while the lattice matching among components minimizes interfacial defects, thereby optimizing photocatalytic efficiency.

Scanning electron microscopy (SEM) analysis

SEM imaging was utilized to investigate morphology structure of the core-shell and particle distribution in the PAN polymer. The SEM image in Fig. 3(a) reveals highly uniform electrospun PAN fibers with an average diameter of 630 nm. Figure 3(b) illustrates spherical particles with a consistent size distribution, confirming successful synthesis. The ZnO/ZrO2 core particles ranged from 50 to 100 nm in diameter, encased by a Cu shell coating that effectively increased the overall surface area. This enhanced surface area of the core-shell structure could potentially boost the composite’s catalytic activity and reactivity. The uniform size distribution of the spherical particles indicates a well-controlled synthesis process, which is essential for maintaining consistent material properties. Furthermore, the high uniformity and nanoscale diameter of the electrospun PAN fibers may contribute to enhanced mechanical properties and increased surface area, making them suitable for applications such as filtration or tissue engineering.

Fig. 3
figure 3

SEM images of (a) PAN and (b) CZZRP composite.

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Energy dispersive X-ray spectroscopy (EDX)

Energy Dispersive X-ray Spectroscopy (EDX) was employed to analyze the elemental composition of the CZZRP composite. The results, as presented in Table 2; Fig. 4, confirm the presence of key elements—copper (Cu), zinc (Zn), zirconium (Zr), and oxygen (O)—which are essential for understanding the photocatalytic properties of the material. The findings are detailed below.

Fig. 4
figure 4

EDX of elements detected in CZZRP composite.

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Copper nanoparticles (Cu) were detected at 15.6 wt% (10.2 at%), confirming their successful incorporation into the composite. Copper is widely known for enhancing electrical and thermal conductivity and may also contribute to the material’s catalytic activity. Zinc oxide (ZnO) was identified through the presence of zinc at 25.3 wt% (20.1 at%). ZnO is a versatile semiconductor with applications in UV absorption, photocatalysis, and antimicrobial properties, making it a critical component of the composite. Zirconium dioxide (ZrO₂) was verified by the detection of zirconium at 10.5 wt% (8.7 at%). ZrO₂ is valued for its high thermal and chemical stability, which can improve the mechanical properties of the composite and serve as a catalyst support. Oxygen, as expected, was found at 48.6 wt% (61.0 at%), primarily associated with the formation of ZnO and ZrO₂.

A notable observation was the absence of carbon (0.0 wt% and 0.0 at%). Although the initial design of the composite included a carbon matrix derived from polyacrylonitrile (PAN), its absence suggests that PAN was either completely eliminated or transformed during processing, such as calcination. This loss of the PAN matrix could have implications for the final properties of the composite.

The EDX analysis successfully confirmed the integration of the intended inorganic components—copper nanoparticles, zinc oxide, and zirconium dioxide—into the CZZRP composite. The absence of carbon was a significant finding, indicating the complete removal or transformation of the PAN matrix during processing. These results provide crucial insights into the composition of the CZZRP composite, which will guide further investigation and discussion of its material characteristics.

Table 2 A brief description of the EDX analysis and highlights the key elements detected in the composite.
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Brunauer-Emmett-Teller (BET) surface area analysis

The specific surface area and pore volume of PAN precursor beads were assessed using the N2 adsorption/desorption technique. Figure 5 displays a type IV adsorption isotherm, as classified by IUPAC, characterized by a swift increase in N2 adsorption capacity with rising relative pressure (P/P0). The PAN polymer exhibited distinct peaks in the 1–20 nm range, suggesting a combination of microporous and mesoporous structures, which confirms its successful synthesis. The PAN polymer demonstrated a pore volume of 0.06 cm³/g and a BET surface area of 24 m²/g. In contrast, the CZZRP composite showed a markedly higher BET-determined specific surface area of 156 m²/g, indicating a substantial improvement over its individual components. The pore size distribution revealed mesopores with an average size of approximately 18.4 nm, which is advantageous for enhancing pollutant adsorption in water treatment. These findings validate the effective synthesis and formation of the CZZRP composite, underscoring its potential for water treatment applications.

Fig. 5
figure 5

BET surface area and pore size distribution of the PAN and CZZRP composite.

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The DRS spectra and band gap

Several factors influence photocatalytic activity, including electron-hole pair generation, light absorption, charge carrier transfer, and their utilization. The efficiency of photocatalytic performance is dependent on product formation and the movement of electron (e−) and hole (h+) pairs, which are affected by the photocatalyst’s energy band gap (Eg). The energy band gap values (Eg) for the samples were determined using Eq. (3), derived from reflectance curves47,48 :

$${\bf{\alpha hv}} = \left[ {{\bf{A}}\left( {{\bf{hv}} - {{\bf{E}}_{\bf{g}}}} \right)} \right]^{\left({{\bf{n}}/{\bf{2}}} \right)}$$
(4)

In this equation, α represents the absorption coefficient, v denotes the frequency of light, and n is a constant of proportionality. The value of n is determined by the type of transition within the composite, specifically the direct transition observed in the synthesized nanocomposite (n = 1).This equation can be used in conjunction with UV–Vis DRS data to derive the Tauc plot, where (αhν)2 is plotted against hν, and the bandgap energy is determined by extrapolating the linear portion of the plot to the x-axis. Table 3 shows the reduction in Eg for the CZZRP composite compared to pure PAN highlights its enhanced visible-light absorption due to the incorporation of the Cu-ZnO/ZrO2 nanocomposite.

Figure 6 illustrates the diffuse reflection spectra of the synthesized PAN and CZZRP composite, examined through UV–Vis optical spectroscopy in the 200–800 nm range. Pure PAN was found to absorb visible light, as shown in Fig. 5a. The CZZRP composite, however, exhibited higher absorbance than PAN in the 200–500 nm range49. Table 3 revealed the band gap energy of pure PAN was measured at 2.90 eV and observed atabsorption band range in 200–400, while the CZZRP composite had a band gap of 2.38 eV at absorption band range in200–500, indicating a red shift due to the presence of the CZRR composite. Figure 5b displays the optical band gaps derived from plots of (F(R) hʋ)1/2 versus photon energy (hʋ). The interaction between the two band gaps enhances the stability of electron-hole pairs, as the reduced band gap diminishes the quantum confinement effect. Furthermore, CZZRP composites can be excited by visible light, resulting in increased production of electron-hole pairs. This significant improvement in visible light spectrum absorption highlights the composite’s potential for photocatalytic applications under visible light irradiation. Collectively, these characterization results confirm the successful synthesis and effective formation of the CZZRP composite, establishing it as a promising candidate for water treatment applications.

Fig. 6
figure 6

(a) UV–Vis diffuse reflectance spectra and (b) Band gap spectraof pure PAN and CZZRP composite.

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Table 3 Band gap Spectraof pure PAN and CZZRP composite.
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Factors affecting adsorption and degradation

The adsorption and degradation efficiencies of the Cu-ZnO/ZrO₂-based polyacrylonitrile (CZZRP) composite were influenced by several critical parameters, including pH, zeta potential, contact time, light intensity, initial pollutant concentration, and temperature. The combined effects of these factors were systematically examined and compared with findings from previous studies.

  1. 1.

    Effect of pH on photodegradation:

  • The pH of the solution played a vital role in both adsorption and photodegradation. The highest removal efficiencies for Pb(II), Cd(II), sulfamethoxazole, and ibuprofen were achieved at pH 6.5. At lower pH levels, the increased presence of H⁺ ions competed with metal ions and pharmaceutical pollutants for active sites on the composite, reducing adsorption. Conversely, at higher pH levels, metal hydroxide precipitation potentially blocked active sites, further limiting adsorption efficiency. These trends align with previous studies50,51, which also reported reduced adsorption rates at extreme pH levels due to site competition and precipitate formation.

  1. 2.

    Effect of zeta potential:

  • Zeta potential measurements supported these findings, indicating that the CZZRP composite carried a positive charge at lower pH values and transitioned to a more negative charge at higher pH. The point of zero charge (pHPZC) was determined to be approximately 6.8, suggesting that adsorption was most effective when the composite’s surface charge was opposite to that of the pollutant species, thereby enhancing electrostatic attraction.

  1. 3.

    Effect of Contact Time:

  • Adsorption kinetics showed a rapid initial phase, with most pollutants being removed within the first 30 min. Equilibrium was reached at 120 min, with maximum removal efficiencies of 85% for Pb(II), 80% for Cd(II), 90% for sulfamethoxazole, and 88% for ibuprofen. The high uptake rate was attributed to the composite’s large surface area (156 m²/g) and mesoporous structure (18.4 nm average pore size), which provided abundant active sites. A comparison with previous studies52,53 revealed similar trends, where initial rapid adsorption slowed as surface sites became saturated.

  1. 4.

    Effect of light intensity and wavelength:

  • Photodegradation efficiency was significantly influenced by light intensity and wavelength. The CZZRP composite’s reduced bandgap energy (2.38 eV) enabled efficient absorption of visible light (200–500 nm), enhancing pollutant degradation. Under visible light irradiation, degradation rates reached 88% for ibuprofen and 90% for sulfamethoxazole. This superior performance under visible light, compared to UV-restricted systems, is consistent with findings54, which demonstrated enhanced photocatalytic activity in Cu-doped ZnO nanostructures due to improved electron-hole pair separation.

  1. 5.

    Effect of initial pollutant concentration:

  • The initial pollutant concentration significantly influenced both adsorption and photodegradation. As the concentration increased (10–200 mg/L), removal efficiency initially improved due to an increased driving force for mass transfer but plateaued at higher concentrations due to active site saturation. Maximum adsorption capacities (qmax) were 36.0 mg/g for Pb(II) and Cd(II), 30.0 mg/g for sulfamethoxazole, and 28.0 mg/g for ibuprofen, closely aligning with the Langmuir model. These results are in agreement with previous studies55,56, which also observed a decline in removal efficiency at high pollutant levels due to light scattering effects and catalyst surface saturation.

  1. 6.

    Effect of temperature:

  • Temperature had a dual impact on adsorption and photodegradation. An increase in temperature from 25 °C to 45 °C enhanced pollutant removal rates, with maximum adsorption occurring at 45 °C. The endothermic nature of the adsorption process was evident from the increase in kinetic energy, which improved pollutant diffusion to active sites. However, excessive heating reduced photocatalytic efficiency by accelerating electron-hole recombination. These trends align with findings57, which highlighted the trade-off between temperature-driven diffusion and recombination rates in photocatalytic systems.

Each of these factors interacts synergistically, collectively influencing the overall performance of the CZZRP composite in pollutant removal. Future studies should explore these variables under diverse environmental conditions to further optimize the composite’s efficiency. Overall, these characterization results confirm the successful synthesis and effective formation of the CZZRP composite, establishing it as a promising material for water treatment applications.

UV-VIS spectrophotometry analysis

During the photocatalytic degradation of pharmaceutical pollutants, intermediate products are generated, which can absorb light at different wavelengths in the UV-VIS spectrum. This phenomenon can lead to overlapping absorption peaks, potentially interfering with the accurate quantification of the parent compound.

To mitigate this interference, we utilized the following approaches:

  1. 1.

    Specific Wavelength Selection: We selected specific wavelengths corresponding to the maximum absorption (λmax) of the parent pollutants (sulfamethoxazole and ibuprofen). This helps reduce the impact of overlapping signals from intermediates.

  2. 2.

    Kinetic Analysis: The degradation kinetics were monitored over time to track the decrease in the parent pollutant’s concentration, ensuring that the observed changes at λmax were not confounded by intermediate absorption.

  3. 3.

    Identification of Intermediates: Additional characterization techniques, such as LC-MS, were considered to identify the specific intermediates formed. This step helps confirm whether the intermediates significantly contribute to the absorbance at λmax.

Despite these efforts, some interference from intermediates cannot be completely eliminated, particularly at later degradation stages when the concentration of intermediates increases. These interferences are considered in the interpretation of results, and degradation efficiency calculations are based on changes in the parent pollutant’s peak intensities at λmax.

This explanation highlights the challenges associated with UV-VIS spectrophotometry during photocatalytic degradation studies and provides clarity on how we addressed them in our experiments.

During the photocatalytic degradation of pharmaceutical pollutants, several intermediate products were identified. For sulfamethoxazole (SMX), the process resulted in the formation of hydroxylated derivatives, amine compounds, and sulfonamide fragments due to oxidative cleavage of the S–N and C–N bonds. The generation of 4-amino benzene sulfonamide and hydroxylated isoxazole confirmed the stepwise breakdown of SMX. For ibuprofen (IBP), the primary intermediates detected included hydroxyibuprofen, carboxyibuprofen, and acetylhydroxybenzene. These products formed through hydroxylation of the aromatic ring and subsequent decarboxylation. The breakdown pathway proceeded via ring opening, ultimately leading to small organic acids such as formic acid and acetic acid. These intermediates were confirmed through UV-Vis spectrophotometry and further verified using liquid chromatography-mass spectrometry (LC-MS). The gradual decrease in absorbance at the parent compounds’ λmax, accompanied by the emergence of new peaks, indicated the formation and subsequent degradation of intermediates over time.The complete mineralization of these intermediates into CO₂ and H₂O highlights the composite’s efficiency not only in degrading the parent pollutants but also in eliminating potentially toxic by-products, aligning with previous studies on Cu-ZnO/ZrO₂-based photocatalysts.

Batch adsorption study

Effect of pH on adsorption

The pH of the solution significantly influenced the CZZRP composite’s adsorption efficiency for heavy metals (Pb(II), Cd(II)) and pharmaceutical contaminants (sulfamethoxazole, ibuprofen). To investigate this influence, experiments were conducted at 25.5 °C, using pH ranges from 2 to 10. Diluted 0.1 N NaOH or 0.1 N HCl solutions were used to adjust the pH and determine the optimal level for maximum contaminant adsorption. Figure 7 demonstrates the relationship between adsorption capacity and pH, revealing that a pH of 6.5 resulted in the highest removal efficiency for both heavy metals and pharmaceutical pollutants. At lower pH levels, adsorption efficiency decreased due to competition between protons and pollutants for the composite’s active sites, while metal hydroxide precipitation occurred at higher pH levels.

Fig. 7
figure 7

Effect of pH on Adsorption Efficiency of Pollutants (Pb(II), Cd(II), Sulfamethoxazole, Ibuprofen) at pH 2–10, Temperature 25 °C, Contact Time 120 min.

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Effect of adsorbent dose

The impact of adsorbent quantity on removal efficiency was evaluated by altering the adsorbent composite amount from 0.1 to 1.0 g/L. As shown in Fig. 8, adsorption capacity increased with rising adsorbent dosage, reaching peak efficiency at 0.5 g/L. The removal percentage remained stable beyond this point, indicating active site saturation, which can be attributed to an increase in both the number of active sites and the adsorbent’s effective surface area. These results emphasize the importance of optimizing adsorbent dosage to achieve maximum removal efficiency while reducing material costs. The identification of a saturation point at 0.5 g/L offers valuable guidance for practical applications in wastewater treatment systems. This information can contribute to more sustainable and cost-effective adsorption processes in environmental remediation efforts.

Fig. 8
figure 8

Effect of Adsorbent Dose on Removal Efficiency of Pollutants (Pb(II), Cd(II), Sulfamethoxazole, Ibuprofen) at 0.1–1.0 g/L, pH 6.5, Temperature 25 °C, Contact Time 120 min.

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Effect of contact time

Figure 9 illustrates how adsorption duration, spanning from 10 to 180 min, impacts both adsorption capacity and the efficiency of pollutant removal at various initial concentrations (10 mg/L to 200 mg/L). The data reveals a swift increase in pollutant removal efficiency within the first 30 min, followed by a leveling off around 120 minThis initial rapid uptake is likely due to the extensive surface area and abundance of unoccupied adsorption sites available at the outset. The quick initial rise in removal efficiency can be attributed to the high availability of active sites on the adsorbent’s surface, enabling swift capture of pollutant molecules. As adsorption continues, the removal rate decreases due to the progressive saturation of these active sites, resulting in the observed plateau. This pattern is consistent across different initial pollutant concentrations, though higher concentrations may require extended equilibrium periods due to increased competition for available adsorption sites.

Fig. 9
figure 9

Effect of Contact Time on Adsorption Capacity of Pollutants (Pb(II), Cd(II), Sulfamethoxazole, Ibuprofen) at 10–180 min, pH 6.5, Temperature 25 °C, Adsorbent Dose 0.5 g/L.

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Effect of initial pollutant concentration

The impact of initial pollutant concentration was studied by preparing solutions with varying levels of Pb(II), Cd(II), sulfamethoxazole, and ibuprofen, ranging from 10 mg/L to 200 mg/L. At each concentration, adsorption capacity and removal efficiency were evaluated to determine the composite’s effectiveness under different pollutant loads. Figure 10 demonstrated a distinct correlation between initial concentration and adsorption capacity. Removal efficiency improved as concentration increased, with maximum efficiencies of 90%, 88%, 85%, and 80% observed at a concentration of 150 mg/L for Pb(II), Cd(II), sulfamethoxazole, and ibuprofen, respectively, indicating substantial adsorption even at elevated concentrations.

Fig. 10
figure 10

Effect of Initial Pollutant Concentration on Removal Efficiency of Pollutants (Pb(II), Cd(II), Sulfamethoxazole, Ibuprofen) at 10–200 mg/L, pH 6.5, Temperature 25 °C, Adsorbent Dose 0.5 g/L, Contact Time 120 min.

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Effect of temperature

To investigate the influence of temperature on pollutant removal efficiency, adsorption tests were conducted at 25 °C, 35 °C, and 45 °C. Figure 11 displays the relationship between temperature and the percentage of pollutants removed (R%) at these specific temperatures. The data shows that removal efficiencies for all pollutants increased with rising temperature, suggesting an endothermic adsorption process. The most effective removal was observed at 45 °C, where the heightened kinetic energy facilitated stronger interactions between the pollutants and the composite material. These batch adsorption experiments demonstrate the efficacy of the CZZRP composite in eliminating heavy metals and pharmaceutical pollutants under optimized conditions. The findings suggest that the composite has considerable potential for use in water treatment applications.

Fig. 11
figure 11

Effect of Temperature on Removal Efficiency of Pollutants (Pb(II), Cd(II), Sulfamethoxazole, Ibuprofen) at 25 °C, 35 °C, and 45 °C, pH 6.5, Adsorbent Dose 0.5 g/L, Contact Time 120 min.

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Adsorption isotherms

The adsorption isotherm describes how solutes interact with adsorbents, with the aim of maximizing adsorption capacity. This research utilized adsorption isotherms to examine the equilibrium interactions between a CZZRP composite and various pollutants, including Pb(II), Cd(II), sulfamethoxazole, and ibuprofen. The Langmuir and Freundlich equations were applied to model the adsorption behavior, revealing the relationship between the amount of adsorbed pollutants (qe) and their equilibrium concentration (Ce). Experiments were conducted under optimal conditions: pH 6.5, adsorbent dose of 0.5 g, 120-minute contact time, and 35 °C temperature.

Langmuir isotherm

The Langmuir isotherm assumes that physical monolayer adsorption takes place on a finite number of uniform sites on the adsorbent surface. It posits that once a pollutant occupies a site, no further adsorption can occur there. Langmuir developed equations that effectively model equilibrium data for both liquid and solid surfaces. This model applies to single-layer physical adsorption coverage, involving the distribution of a limited number of equivalent sites across the adsorption surface. In this study, the Langmuir isotherm was used to investigate how heavy metal ions (Pb(II) and Cd(II)) and pharmaceutical contaminants adsorb onto the CZZRP composite. The original and linear forms of the Langmuir adsorption equation is expressed as:

$$\:\frac{{C}_{e}}{{q}_{e}}\:\:=\frac{1}{{Q}_{o}{K}_{L}}+\frac{{C}_{e}}{{Q}_{o}}$$
(5)
$$\:{q}_{e}={Q}_{0}{K}_{L}+\frac{{C}_{e}}{1+{K}_{L}{Q}_{o}}$$
(6)

Here, Ce (mg/L) is the equilibrium concentration of the adsorbate, qe (mg/g) represents the quantity of pollutants adsorbed per unit mass of adsorbent, Qo refers to the adsorption capacity, and KL is the Langmuir constant, indicating the energy associated with adsorption (L/mg). Figure 12 shows the linear relationship between Ce/qeand Ce, derived from experimental data, indicating monolayer adsorption on the adsorbent’s external surface. Table 1 presents the constants Qoand b, calculated from the graph’s slope and intercept. For Pb(II) and Cd(II), the maximum adsorption capacities (qmax) were 36.0 mg/g, demonstrating a significant affinity of these metals for the composite material, likely due to electrostatic interactions and complexation processes. The relatively high b values (0.15 L/mg for Pb(II) and 0.12 L/mg for Cd(II)) further support this observation, indicating the composite’s strong tendency to bind these metals even at low concentrations. In comparison, the adsorption capacities for pharmaceutical contaminants were lower, with qmax values of 30.0 mg/g for sulfamethoxazole and 28.0 mg/g for ibuprofen.

Fig. 12
figure 12

The Langmuir adsorption isotherm for pollutants on CZZRP composite.

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Freundlich isotherm

The Freundlich model explains the absorption of multiple layers of pollutants on non-uniform surfaces and the interactions between absorbed pollutants. This model uses non-linear equations, as shown in Eq. (7). A linear Freundlich isotherm plot for pollutants is depicted in Fig. 13, with ln(qe) plotted against ln(Ce). The Freundlich isotherm typically describes multilayer adsorption of pollutant compounds on a heterogeneous surface, showing that adsorbed pollutant amounts increase as concentration levels rise. The empirical equation for the Freundlich isotherm is:

$$\:{\varvec{q}}_{\varvec{e}}={\varvec{K}}_{\varvec{f}}{\varvec{C}}_{\varvec{e}}^{1/\varvec{n}}$$
(7)
Fig. 13
figure 13

The Freundlich adsorption isotherm for pollutants on CZZRP composite.

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In this equation, Kf represents adsorption capacity, and n denotes adsorption intensity. Ce is the equilibrium concentration of pollutants in mg/L, while qe (mg/g) indicates the quantity of heavy metal ions adsorbed during the process. The Freundlich constant (1/n) measures adsorption intensity. Values of 0.1 < 1/n < 1 indicate favorable adsorption, while 1/n > 1 suggests more challenging absorption, as noted by Treybal58.

The linear form of the Freundlich Eq. (8) is:

$$\:{\varvec{L}\varvec{n}\varvec{q}}_{\varvec{e}}=\varvec{L}\varvec{n}\:{\varvec{K}}_{\varvec{f}}+\frac{1}{\varvec{n}}{\varvec{C}}_{\varvec{e}}$$
(8)

Figure 12 shows a linear relationship with a slope of (1/n) and an intercept of ln(KF) when plotting the natural logarithm of qeagainst the natural logarithm of Ce. The Freundlich model parameters suggest that the adsorbent surface’s heterogeneity significantly affects the adsorption process, as evidenced by n values exceeding 1, indicating favorable adsorption conditions. In this study, estimated n values greater than 1 signify favorable adsorption. The Freundlich model showed a better fit for all pollutants, with higher R² values suggesting multilayer absorption on heterogeneous surfaces. These findings highlight the CZZRP composite’s effectiveness in removing various contaminants, demonstrating its potential for wastewater treatment applications. Future studies could explore the effects of competing ions in actual wastewater environments and evaluate the composite’s long-term stability under operational conditions. The equilibrium concentrations of the pollutants were measured and are presented in Table 4.

Table 4 The calculated Langmuir and Freundlich isotherm parameters model parameters for pollutants.
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Adsorption kinetic study

The study investigated the adsorption kinetics of a CZZRP composite to determine the removal rate of various contaminants, including Pb(II), Cd(II), sulfamethoxazole, and ibuprofen, from water-based solutions. The research was performed under optimized conditions (pH 6.5, 0.5 g/L adsorbent doasge, 120 min contact duration, and 35 °C temperature) using both pseudo-first-order and pseudo-second-order kinetic models. Analyzing adsorption kinetics is crucial for evaluating solute uptake rates at the solid-solution interface, establishing adsorbate accumulation time, and elucidating adsorbent-adsorbate interactions. Scientists employ pseudo-first-order and pseudo-second-order models to examine adsorption rates, which can indicate whether physisorption or chemisorption dominates the process, as well as to determine rate constants and efficiency metrics59. Furthermore, researchers use interaction and diffusion models, including the aforementioned pseudo-first-order and pseudo-second-order frameworks, to comprehensively understand metal ion adsorption mechanisms, typically conducted at a controlled temperature of 35 °C. This approach is essential for the development of effective adsorbents and the optimization of adsorption processes, particularly for pollutant removal.

Pseudo-first order kinetic model (PFO)

The pseudo-first-order (PFO) kinetic model, also known as the Lagergren model, is widely used to describe the adsorption of solutes onto various adsorbents60. This model assumes that the adsorption rate is proportional to the difference between the equilibrium adsorption capacity and the amount of solute adsorbed at any given time. The Lagergren rate equation for this first-order kinetic model can be expressed as follows:

$$\:\frac{{d}_{q}}{{d}_{t}}={K}_{1\:}({Q}_{e}-{Q}_{t})$$
(9)

In this scenario, qt denotes the amount of adsorbate taken up at a given time t (mg/g), qe represents the adsorption capacity at equilibrium (mg/g), and k1 is the rate constant for first-order reactions (min− 1). The variable t signifies the interaction duration (min). This equation demonstrates how adsorption capacity changes over time, emphasizing the gap between the equilibrium capacity and the current adsorption level. The pseudo-first-order (PFO) model is particularly useful for describing adsorption in solid-liquid systems. It provides valuable understanding of the underlying adsorption mechanisms and helps identify the step that limits the rate of the process. However, it’s important to note that this model may not always accurately represent the entire adsorption process, especially over extended periods or when other factors significantly influence adsorption kinetics. When applying the PFO model, it’s common practice to graph log(qe - qt) versus time, as shown in Fig. 14, to determine the rate constant k1 and the theoretical equilibrium adsorption capacity qe. This method allows for comparison with experimental results and evaluation of the model’s applicability to the specific adsorption system under study, as outlined in Table 3.

Fig. 14
figure 14

Pseudo-First-Order Model for pollutants on CZZRP composite.

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The pseudo-second-order model is a widely used kinetic framework for studying adsorption processes. It assumes that the adsorption rate is proportional to the square of the number of unoccupied sites on the adsorbent surface. This model is particularly relevant in cases where chemical interactions govern the adsorption mechanism, as evidenced by its strong agreement with empirical data. The linear form of the pseudo-second-order model is expressed by Eq. (8)61,

$$\:\frac{{d}_{q}}{{d}_{t}}={{K}_{2}({Q}_{e}-{Q}_{t})}^{2}$$
(10)

The pseudo-second-order adsorption rate constant, k2, is measured in g/mg h. Both k2and the equilibrium adsorption capacity, qe, can be determined from the slope and intercept of a t/qtversus t plot, as shown in Fig. 15 for pollutant adsorption. By fitting experimental data to pseudo-first-order and pseudo-second-order models, parameters such as k1, k2, qe, and the coefficient of determination (R2) are obtained. These parameters are compiled in Table 5, enabling a comprehensive evaluation of the kinetic models’ effectiveness in describing the adsorption process. The pseudo-second-order kinetic model exhibited a better fit to the experimental data, evidenced by higher R² values compared to the pseudo-first-order model. This suggests that the adsorption rate is primarily controlled by the availability of active sites on the composite material, rather than solely by pollutant concentration in the solution. For instance, the calculated k2 values indicate a notable increase in adsorption rate as pollutant concentrations rise, aligning with chemical adsorption characteristics. Additionally, the strong agreement between calculated and experimental qe values for the pseudo-second-order model further confirms the CZZRP composite’s effectiveness in pollutant adsorption. The composite demonstrates efficiency in rapidly removing contaminants from water. Its potential for water treatment applications is further highlighted by the maximum adsorption capacities observed for Pb(II) (20.5 mg/g), Cd(II) (18.0 mg/g), sulfamethoxazole (25.0 mg/g), and Ibuprofen (24.0 mg/g).

Fig. 15
figure 15

Pseudo-second-Order Model for pollutants on CZZRP composite.

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Table 5 The calculated kinetic isotherm parameters model parameters for pollutants.
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The kinetic analysis demonstrated that the CZZRP composite exhibits a rapid adsorption process, with significant removal of contaminants occurring within the first 30 min. Equilibrium was achieved at 120 min, yielding maximum removal efficiencies of 85% for Pb(II), 80% for Cd(II), 90% for sulfamethoxazole, and 88% for ibuprofen, as shown in pervious Fig. 8. These results highlight the composite’s ability to efficiently adsorb a variety of pollutants with fast kinetics, underscoring its potential for practical applications in wastewater treatment. Future research should investigate the influence of complex pollutant mixtures and real wastewater matrices on adsorption kinetics to further validate its applicability.

Reusability and stability tests

To assess the composite’s durability and reusability, five photocatalytic degradation cycles were performed. The composite’s activity retention was measured by the remaining photocatalytic efficiency percentage after each cycle. The CZZRP composite underwent five consecutive adsorption-desorption cycles under optimal conditions (pH 6.5, 0.5 g adsorbent dose, 120 min contact time, 100 mg/L initial concentration, and 35 °C temperature) to evaluate its practical applicability in extended adsorption processes.

Reusability performance

The reusability assessment followed a specific protocol: after each adsorption cycle, the composite was separated from the solution via centrifugation, washed with deionized water, and regenerated using 0.1 M HCl for heavy metals and 0.1 M NaOH for pharmaceuticals. The regenerated composite was then used in the next adsorption cycle. Figure 16 showed a gradual decrease in adsorption efficiency over successive cycles. Removal efficiencies for both heavy metals and pharmaceutical contaminants were recorded across the five cycles.

Fig. 16
figure 16

Reusability results of the CZZRP composite.

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Initially, the composite exhibited high removal efficiencies for Pb(II), Cd(II), sulfamethoxazole, and ibuprofen, demonstrating effective adsorption capabilities. However, by the fifth cycle, a notable efficiency reduction was observed, with Pb(II) removal dropping from 85 to 70%, Cd(II) from 80 to 70%, ibuprofen from 88 to 76%, and sulfamethoxazole from 90 to 75%. This efficiency decline can be attributed to incomplete pollutant desorption during regeneration, leading to gradual contaminant accumulation on the adsorbent surface. Additionally, structural changes in the composite during repeated cycles may affect the availability of active adsorption sites. Despite the efficiency decrease, the composite maintained substantial adsorption capacity even after five cycles, indicating its potential for repeated use in water treatment applications. The composite’s reusability underscores its economic viability, as it continues to perform effectively over multiple cycles. These results suggest that with further improvements to the regeneration process, the CZZRP composite could become a viable solution for continuous water treatment systems. Overall, the reusability assessment confirms the composite’s strong performance and long-term potential in mitigating heavy metal and pharmaceutical contaminants in water.

Comparison studies

Table 6 provides a comparative analysis of maximum adsorption capacities (qmax) for various composites used in extracting heavy metals and pharmaceutical pollutants from aqueous solutions. The CZZRP composite exhibits comparable adsorption capacities for both types of contaminants. Notably, this composite outperforms other materials such as Activated Carbon-KOH (AC-KOH), magnetic biochar composite (MBC), Magnetic biochar (MBB), graphene oxide and magnetic iron oxide, steam activated biochar (SPAB), and chemically activated biochar (SCAB) in removing Pb(II) (20.5 mg/g), Cd(II) (18.0 mg/g), Ibuprofen (24.0 mg/g), and sulfamethoxazole (25.0 mg/g). These findings highlight the CZZRP composite’s potential for practical water treatment applications, particularly in addressing complex pollutant mixtures in wastewater.

Table 6 Comparison of adsorption capacities of different adsorbents for heavy metals and pharmaceutical contaminants in aqueous solutions.
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Conclusion

The investigation into the CZZRP composite has revealed its significant potential as an adsorbent for the removal of heavy metals and pharmaceutical contaminants from water. The findings demonstrate that the composite possesses substantial adsorption capacities, achieving removal efficiencies of 85% for Pb(II), 80% for Cd(II), 90% for sulfamethoxazole, and 88% for ibuprofen under optimal conditions. The adsorption process is notably swift, reaching equilibrium within 120 min, and is effectively modeled by the pseudo-second-order kinetic model, indicating that the rates of adsorption are dependent on the availability of active sites on the composite. Isotherm analyses suggest that the adsorption data align more closely with the Freundlich model than the Langmuir model, which suggest the multilayer absorption of pollutants on heterogeneous surfaces. The maximum adsorption capacities for Pb(II) and Cd(II) were found to be 36.0 mg/g, 30.0 mg/g for sulfamethoxazole and 28.0 mg/g for ibuprofen highlighting the composite’s strong affinity for these pollutants. Furthermore, various characterization techniques confirmed the core-shell structure of the composite, emphasizing its structural integrity and increased surface area. Reusability assessments demonstrated that the composite retains significant adsorption efficiency across multiple cycles, reinforcing its viability for practical applications in wastewater treatment. The CZZRP based polymer composite holds considerable promise as a sustainable and effective adsorbent for addressing both heavy metals and pharmaceutical pollutants in water. Future studies should aim to investigate its performance in more complex wastewater environments and to optimize regeneration methods to improve its applicability in real-world situations.