Electroactive Modified Carbon Nanotube Filter for Simultaneous Detoxification and Sequestration of Sb(III)

• DOI: 10.1021/acs.est.8b05936
• Publication Date: 2019-01-09T01:34:54Z
• Authors: Yanbiao Liu; Peng Wu; Fuqiang Liu; Fang Li; Xiaoqiang An; Jianshe Liu; Zhiwei Wang; Chensi Shen; Wolfgang Sand
• Keywords: Kinetics; Nanotubes, Carbon; Adsorption; 01 natural sciences; Water Pollutants, Chemical; 6. Clean water; Water Purification; 0105 earth and related environmental sciences

Herein, we rationally designed a dual-functional electroactive filter system for simultaneous detoxification and sequestration of Sb(III). Binder-free nanoscale TiO2-modified carbon nanotube (CNT) filters were fabricated. Upon application an external electrical field, in situ transformation Sb(III) to less toxic Sb(V) can be achieved, which is further sequestered by TiO2. removal kinetics capacity increase with applied voltage flow rate. This explained the synergistic effects filter's flow-through design, electrochemical reactivity, small pore size, increased number exposed sorption sites. STEM characterization confirms that Sb mainly XPS, AFS, XAFS results verify conversion process was accelerated field. The proposed technology works effectively across wide pH range. presence sulfate, chloride, carbonate ions negligibly inhibited removal. Exhausted TiO2-CNT regenerated using NaOH solution. At 2 V, 100 μg/L Sb(III)-spiked tap water generated ∼1600 bed volumes effluent >90% efficiency. Density functional theory calculations suggest adsorption energy onto TiO2 increases (from -3.81 eV -4.18 eV) becomes more positively charged upon