Sustainable Biomass-Derived Catalysts and Hybrid Materials for the Removal of Emerging Pharmaceuticals and Personal Care Products from Aquatic Environments

Abstract

Pharmaceutical compounds, emerging medicinal residues, and personal care products (PPCPs) are ubiquitous in aquatic environments and are causing a serious global environmental problem because of their persistence, bioaccumulation, and harmful effects on the environment and human health. Conventional wastewater treatment technologies are sometimes not capable of removing them completely, causing persistent releases of biologically active micropollutants to surface water, groundwater, and drinking water systems. In this context, biomass-derived catalysts are a promising class of advanced materials for environmental remediation because of their sustainable and cost-efficient nature. The catalysts are composed of bio-residues, such as agricultural residues, forestry wastes, and other bioresources, that have tunable surface chemistry, high porosity, and can be activated and functionalized to increase their catalytic activity. This review summarizes recent advances in biomass-derived catalysts for the removal of pharmaceuticals and PPCPs from water. Special attention is given to synthesis methods, such as pyrolysis, hydrothermal carbonization, chemical activation, heteroatom doping, and metal or metal-oxide hybridization. The catalytic mechanisms of pollutant degradation, including adsorption, radical-based advanced oxidation processes, and non-radical electron-transfer mechanisms, are critically discussed. Moreover, the effect of key operating parameters, catalyst stability, and real wastewater test performance are studied. Sustainability aspects such as green synthesis routes, integration of circular bioeconomy, and life-cycle aspects are also emphasized. Finally, current issues like catalyst deactivation, scaling-up, and the lack of a full mechanistic understanding are identified, and future research avenues are suggested to enable the implementation of efficient, durable, and environmentally friendly catalytic systems for large-scale wastewater treatment applications.