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

Abstract

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

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“…The ow rate is another important factor. 27,28 As presented in Fig. 2c, the ammonia conversion efficiency increased with ow rate from 2 to 4 mL min À1 .…”

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“…The function here accelerate the rate of sludge treatment, and its active oxidation process into the tank are being calculated and demonstrated a pathway that H2O2 flow is very much effective to disinfect the biowaste by the electrode and the cathode potential in order to achieve the content of biowaste pH, flow rate, and oxygen dissolved into a normal clean biomaterial form (37,39,50). Hence, the maximum flow of H2O2 is being accounted for 1.38 mol L - Once the sludge is disinfected, then the product is being placed into the closed bioreactor tank to allow for anaerobic co-digestion process (5,7,61). Thereafter, the product is being heated for 95 O F for 15 days which will stimulate the growth of anaerobic bacteria of Desulfovivrio, Methanecoccus, which engulf organic material of the sludge and to produce biogas through biosynthesis process (Figure 3).…”

A Bifunctional Electroactive Ti4O7-Based Membrane System for Highly Efficient Ammonia Decontamination

“…The doped SnO 2 electrode demonstrated good performance and acceptable cost, but with limited service life [6]. While the CNT electrode possesses superior conductivity and a high specific surface area, the potential release of nanoscale CNT powders may cause secondary pollution [7]. Alternatively, sub-stoichiometric titanium oxide materials have attracted much recent interest from the scientific community for electrocatalytic applications due to their high conductivity, low cost, strong corrosion resistance, and excellent stability [8].…”