Integrated biochar and Lemna minor system for sustainable remediation of Benzophenone-3 from wastewater

Benzophenone-3 is an Emerging Pollutant having significant ecotoxicological effects on aquatic organisms, owing to its widespread use as a UV filter and stabilizer to prevent photodegradation of commercial products, and has a ubiquitous presence. The present study entails an investigation of the bioremediation potential of an integrated system of biochar and Lemna minor against Benzophenone-3 from aqueous solution through batch studies. This integration in spiked distilled and municipal wastewater yielded a total removal of 73.82% and 80.46% of Benzophenone-3, respectively. Quantitative analysis of the FTIR spectra showed Benzophenone-3 adsorption onto the sugarcane bagasse biochar in a similar trend, comparable with its experimental removal efficiency. The reactions followed pseudo-second-order and intraparticle diffusion kinetics and the Freundlich isotherm modelling. Metabolites of Benzophenone-3, namely 2,4-Dihydroxybenzophenone and the first report of 2,3,4-Trihydroxybenzophenone in plants, were observed in tissues of Lemna minor. Cation exchange and pore-filling in the case of biochar and plant uptake and metabolism in the case of Lemna minor were the major removal mechanisms. Physicochemical analysis of the municipal wastewater pre- and post-treatment revealed an improvement in its overall quality, rendering the water suitable for reuse. The study provides baseline data about the potential of biochar and Lemna minor in an integrated system for the remediation of Benzophenone-3. It finds potential application in constructed wetlands for the efficient, cost-effective and eco-friendly remediation of Emerging Contaminants upon further research.