Properties and mechanism of Cr(VI) removal by a ZnCl 2 -modified sugarcane bagasse biochar-supported nanoscale iron sulfide composite

• Published in: Environmental science and pollution research international Vol. 30; no. 10; p. 26889
• Main Authors: Jiang, Chunlu, Zhou, Shijia, Li, Chang, Yue, Fengdie, Zheng, Liugen
• Format: Journal Article
• Language: English
• Published: Germany 01.02.2023
• Subjects: Adsorption; Cellulose; Charcoal - chemistry; Chromium - chemistry; Iron - chemistry; Kinetics; Saccharum; Water Pollutants, Chemical - analysis; Chemical reduction; Adsorption; Chromium; Biochar; Nanoscale iron sulfide

A ZnCl -modified biochar-supported nanoscale iron sulfide composite (FeS-ZnBC) was successfully prepared to address the easy oxidization of FeS and enhance Cr(VI) removal from water. The material was characterized by SEM, XRD, FTIR, and XPS. The effects of FeS:ZnBC mass ratio, FeS-ZnBC dosage, solution pH, initial Cr(VI) concentration, and reaction time on the adsorption performance were investigated. The results revealed that the optimum adsorption capacity of FeS-ZnBC (FeS:ZnBC = 1:2) for Cr(VI) was 264.03 mg/g at 298 K (pH = 2). A Box-Behnken design (BBD) was applied to optimize the input variables that affected the adsorption of Cr(VI) solution. The results revealed that the highest removal (99.52%) of Cr(VI) solution was achieved with a Cr(VI) initial concentration of 150.59 mg/L, FeS-ZnBC adsorbent dosage of 2 g/L, and solution pH of 2. The sorption kinetics could be interpreted using a pseudo-second-order kinetic model. The isotherms were simulated using the Redlich-Peterson isotherm model, indicating that Cr(VI) removal by the FeS-ZnBC composites was a hybrid chemical reaction-sorption process. The main mechanisms of Cr(VI) removal by FeS-ZnBC were adsorption, chemical reduction, and complexation. This study demonstrated that FeS-ZnBC has potential application prospects in Cr(VI) removal.