Enhanced Arsenite Removal Using Bifunctional Electroactive Filter Hybridized with La( OH) 3

• Published in: 东华大学学报（英文版） Vol. 39; no. 3; pp. 239 - 250
• Main Authors: ZHANG Shujing, FANG Xiaofeng, LIU Yanbiao
• Format: Journal Article
• Language: English
• Published: Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection,College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China%Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection,College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China 2022; Shanghai Institute of Pollution Control and Ecological Security,Shanghai 200092,China
• Subjects: electrochemical filtration; carbon nanotube; arsenite; adsorption-oxidation; La ( OH )3
• ISSN: 1672-5220
• DOI: 10.19884/j.1672-5220.202105005

X523; A bifunctional electroactive filter was rationally fabricated for simultaneous oxidation and sequestration of toxic trivalent arsentic As ( Ⅲ). A novel nanoscale La(OH)3 modified electrochemical carbon nanotube ( CNT ) network filter was prepared by a facile electrodeposition strategy. The As (Ⅲ) decontamination kinetics and adsorption capacity were both found to increase with the flow rate (1.5-6.0 mL/min) and the applied voltage (0-2.5 V). The CNT filter hybridized with La (OH)3 (CNT-La(OH)3) has demonstrated the ultra-high adsorption capacity of 750.2 mg/g for As(Ⅲ), which is ascribed to the combined role of sufficient adsorption sites, flow-through filtration and electric field. XPS analysis revealed that the As ( Ⅲ) decontamination mechanism involved a two-step adsorption-oxidation process. The formation of inner-sphere La-O-As complexes, ligand exchange and electro-adsorption are all parts of the As(Ⅲ) adsorption process. The adsorbed neutrally-charged As(Ⅲ) was further oxidized to negatively-charged As(V) when aided by an electric field, which could be effectively sequestrated by La(OH)3. The CNT-La(OH)3 filter shows high stability under alkaline conditions and can be regenerated with dilute NaOH solution. In this study, all experiment results have demonstrated a promising and effective CNT-La(OH)3 electrochemical filter for As(Ⅲ) pollution minimization.