TiO2 pillared montmorillonite in-situ growth of CeOx/MnOy nanoparticles for effective arsenic (III) adsorption in wastewater

Compared with As(V), As(III) is a tricky issue worldwide for its higher toxicity and more difficult to remove in aqueous solution. In present study, a novel CeO x /MnO y nanoparticles anchored layered structural TiO 2 pillared montmorillonite (TiO 2 -Mt-Ce-Mn) was fabricated and applied as an efficient absorbent for As(III) removal. Under the condition of the initial As(III) concentration = 20 mg/L and adsorbent dose = 0.4 g/L, TiO 2 -Mt-Ce-Mn with a high specific surface area (148.099 m 2 /g) has an outstanding adsorption capacity (46.58 mg/g) for As(III) at pH 4.2, and the effect of oxy-anions on adsorption efficiency is slight except for H 2 PO 4 − . Interestingly, the layered structure provides sufficient attachment space for CeO x /MnO y nanoparticles, while CeO x /MnO y nanoparticles in turn endows TiO 2 -Mt a high redox potential, which further facilitates the oxidation of As(III), and this significantly reduces the toxicity of wastewater. The adsorption mechanism includes the oxidation of As(III) to As(V) by both CeO x /MnO y nanoparticles and TiO 2 and effective adsorption of the residual As(III) and the formed As(V) subsequently. In addition, the adsorption efficiency of TiO 2 -Mt-Ce-Mn can still maintain 79.6% after five cycles through a facile regeneration method. Thus, the nanocomposite with low-cost synthesis process, high adsorption capacity, and regenerability is a promising candidate for As(III) treatment of wastewater.