Hydrogel-Based Adsorption Techniques for Dye Removal in Aqueous Solutions

Hydrogel-based adsorbents have emerged as versatile materials for the efficient removal of organic dyes from contaminated water. These three-dimensional, crosslinked polymer networks swell in aqueous environments to expose abundant active sites for dye capture. Tailoring of polymer chemistry—through incorporation of charged monomers, aromatic functionalities or inorganic fillers—enhances electrostatic attraction, π-π stacking and hydrogen-bonding interactions with common pollutants such as methylene blue and methyl orange. Key performance metrics include adsorption capacity, kinetics and recyclability, which together define practical applicability in textile effluent treatment and industrial wastewater management. Recent advances focus on biopolymer–synthetic hybrids, nanocomposite scaffolds and super-adsorbent architectures, aiming to balance high uptake with mechanical stability, facile recovery and repeated use. These innovations carry significant global impact for low-cost, decentralised water purification technologies.

Research from Nature Portfolio

Researchers have developed a three-dimensional polyacrylamide–phytic acid–polydopamine hydrogel exhibiting over 350 mg g⁻¹ adsorption capacity for both anionic and cationic dyes. The porous network enables rapid uptake through combined π-π stacking and ion-exchange interactions, following pseudo-second-order kinetics. The free-standing hydrogel can be easily separated post-adsorption and regenerated by simple pH adjustments, demonstrating robust reusability without significant loss of efficiency. This work establishes a conductive, mechanically stable hydrogel platform that can be tuned for a broad spectrum of water-soluble dyes.

Hydrogel-Based Adsorption Techniques for Dye Removal in Aqueous Solutions publication trend

The graph below shows the total number of articles in hydrogel-based adsorption techniques for dye removal in aqueous solutions across all publications each year (not limited to Nature Index journals).

Technical terms

Hydrogel: Three-dimensional polymer network capable of absorbing large volumes of water and swelling to expose functional adsorption sites.

Adsorption isotherm: Model describing equilibrium distribution of a solute between liquid phase and adsorbent surface (e.g. Langmuir for monolayer binding, Freundlich for heterogeneous multilayer adsorption).

Pseudo-second-order kinetics: Rate law assuming chemisorption controls uptake, often applied to dye adsorption by hydrogel materials.

Swelling ratio: Dimensionless measure of water uptake (mass of water absorbed per mass of dry polymer), reflecting network porosity and crosslink density.

Crosslinking: Junctions—covalent or physical—between polymer chains that stabilise the network and define mechanical strength and pore architecture.

References

1. Polyacrylamide-Phytic Acid-Polydopamine Conducting Porous Hydrogel for Efficient Removal of Water-Soluble Dyes. Scientific Reports (2017).
2. Novel Superadsorbent Highly Porous Hydrogel Based on Arabic Gum and Acrylamide Grafts for Fast and Efficient Methylene Blue Removal. Polymers (2020).
3. Preparation and Characterization of Sodium Alginate-Based Oxidized Multi-Walled Carbon Nanotubes Hydrogel Nanocomposite and its Adsorption Behaviour for Methylene Blue Dye. Frontiers in Chemistry (2021).