Microwave-assisted chemical modification method for surface regulation of biochar and its application for estrogen removal

Estrogenic hormones have become an emerging and serious concern in the recent years, owing to their adverse effects on ecosystems and human health. It is necessary to explore green, effective and sustainable technologies to remove these contaminants. Biochar derived from biomass residue has been recognized as an effective adsorbent for removing pollutants from aqueous solutions. Objective of this study was to investigate the influence of microwave-assisted chemical modification method on the property of biochar and evaluate its application for 17 beta-estradiol (E2) removal. Biochar derived from rice husk biomass waste were modified by acid (sulfuric acid and phosphoric acid), alkali (sodium hydroxide and sodium bicarbonate) and oxidizing agent (hydrogen peroxide), respectively. Various characterization techniques and adsorption experiments were carried out to investigate the property and the adsorption performance of biochar. The results showed that alkali modified biochar have higher adsorption capacity for E2 than other modified biochar. And the maximum adsorption capacity was 44.9 mg/g obtained from the Langmuir model at 298 K, which can be attributed to its higher surface area and superior hydrophobic property. This study not only provides useful information for E2 removal from aquatic environment, but also gives insight into the reuse of biomass waste. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.