Intimately Coupled Photocatalysis and Biodegradation for Wastewater Treatment

Intimately coupled photocatalysis and biodegradation (ICPB) is an emerging hybrid approach that integrates light-driven advanced oxidation processes with microbial degradation to achieve efficient removal of refractory organic pollutants from wastewater. Photocatalysts such as titanium dioxide or graphitic carbon nitride absorb photons to generate reactive oxygen species that partially oxidise contaminants, producing intermediate compounds that are more amenable to microbial breakdown. By embedding photocatalysts within biocompatible carriers or biofilms, reactive radicals are generated in situ alongside robust microbial communities, which mineralise oxidation products and prevent accumulation of toxic intermediates. This synergistic operation enhances overall removal efficiency, reduces energy consumption compared with standalone ultraviolet or chemical treatments, and mitigates the formation of persistent by-products. Applications span textile dye effluents, pharmaceutical residues and persistent chlorinated aromatics, with modular reactor designs demonstrating scalability for industrial and municipal settings. The global significance of ICPB lies in its potential to meet tightening discharge regulations, minimise chemical usage and deliver sustainable water reuse solutions.

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Intimately Coupled Photocatalysis and Biodegradation for Wastewater Treatment publication trend

The graph below shows the total number of articles in intimately coupled photocatalysis and biodegradation for wastewater treatment across all publications each year (not limited to Nature Index journals).

Technical terms

Photocatalysis: A process in which a semiconductor material absorbs light to generate electron–hole pairs that drive oxidation and reduction reactions, producing reactive species that degrade pollutants.

Biodegradation: The microbial metabolism of organic compounds into simpler molecules such as carbon dioxide, water and biomass, often following partial chemical or photochemical oxidation.

Reactive Oxygen Species (ROS): Highly reactive intermediates—such as hydroxyl radicals, superoxide anions and singlet oxygen—formed during photocatalysis that attack and oxidise contaminant molecules.

Composite Carrier: A structured support, often composed of biopolymers or porous cellulosic materials, designed to immobilise both photocatalysts and microbial communities for simultaneous oxidative and biological treatment.

Chemical Oxygen Demand (COD): A measure of the total quantity of oxygen required to chemically oxidise organic compounds in water, used as an indicator of water quality and treatment efficiency.

References

1. Simultaneous photocatalytic and microbial degradation of dye-containing wastewater by a novel g-C3N4-P25/photosynthetic bacteria composite. PLOS ONE (2017).
2. Preparation and Photocatalytic Properties of a Bagasse Cellulose-Supported Nano-TiO2 Photocatalytic-Coupled Microbial Carrier. Materials (2020).
3. Study on Degradation of 1,2,4-TrCB by Sugarcane Cellulose-TiO2 Carrier in an Intimate Coupling of Photocatalysis and Biodegradation System. Polymers (2022).