Chromium Removal from Contaminated Water Using Thiourea-Modified Biochar and Zinc Nanoparticle-Enhanced Biochar

Chromium (Cr) is a heavy metal that is one of the most dangerous and is a Group A carcinogen as determined by the U.S Environmental Protection Agency (EPA) because it is highly toxic and carcinogenic.Its hexavalent Cr (VI) is much more toxic than trivalent Cr (III) due to its high solubility, mobility and bioavailability.The primary sources of chromium pollution are anthropogenic activities, e.g., steel production, leather tanning, electroplating, and inappropriate disposal of industrial waste.The paper compares the applicability of thioureamodified biochar and zinc nanoparticle-modified biochar as effective adsorbents in the removal of Cr (VI) in contaminated water.Experiments in batch were aimed to test the impact of pH, contact time, initial concentration and sorbent dosage.The adsorption behaviour was explained by adsorption kinetics and isotherm models (Langmuir, Freundlich, pseudo-first-order, and pseudo-second-order).The surface functionalization of the modified biochar shown to have an increased redox interactions and active-site availability suggested that surface functionalization enhances the sorption capacity of the modified biocarbon.The research suggests a green, inexpensive, and affordable remedial strategy in chromium waters.