Synthesis of mesoporous bismuth-impregnated aluminum oxide for arsenic removal: Adsorption mechanism study and application to a lab-scale column

• Published in: Journal of environmental management Vol. 211; pp. 73 - 82
• Main Authors: Zhu, Ningyuan, Qiao, Jun, Ye, Yanfang, Yan, Tingmei
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-04-2018
• Subjects: Adsorption mechanism; Aluminum oxide; Arsenic removal; Bismuth; Impregnation; Practical application; Bismuth; Impregnation; Arsenic removal; Practical application; Adsorption mechanism; Aluminum oxide
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2018.01.049

High mobility and toxicity of arsenic [As (III)] limit its removal from an aquatic environment and pose a threat to human health. In this work, batch adsorption experiments were conducted to investigate the adsorption capacity of bismuth-impregnated aluminum oxide (BiAl). Continuous application of As (III) removal was achieved via a lab-scale column reactor. Bismuth impregnation decreased the specific surface area of aluminum oxide and affected its pore size distribution. However, because of its abundant and well-proportioned mesoporous character, it also enhanced its adsorption capacity through the surface complexation of As (III). Batch adsorption experiments demonstrated a suitable Freundlich model and a fitted pseudo-second-kinetic model for As (III) adsorption. The main mechanism was chemisorption with both bismuth and aluminum atoms; however, physisorption also contributed to arsenic adsorption at the initial stage of the reaction. The Adams-Bohart model better described the breakthrough curves than the Thomas model. BiAl exhibited efficient As (III) adsorption over a wide pH range and could be applied to As (III) removal from wastewater. A high As (III) removal efficiency (91.6%) was obtained at an initial As (III) concentration of 5 mg L−1 at a flow rate of 1 mL min-1. This study indicates the potential for the practical application of BiAl in As (III) removal.
•Bismuth impregnated aluminum oxide showed a strong ability for arsenic (III) removal.•Bismuth inclusion optimized the pore size distribution of aluminum oxide.•The chemisorption made the main contribution to arsenic (III) adsorption.•BiO bond played an important role in arsenic (III) adsorption.