Arsenic Removal from Water Using Novel Zeolite Imidazole Framework (ZIF-8)@MXene

With the rapid advance of industry and agriculture in developing countries, arsenic-containing wastewater is becoming increasingly prevalent and serious, which has caused public health issues. In this study, a novel adsorbent ZIF-8@MXene was proposed using a straightforward approach for the in-depth treatment of As(III/V). The synthesized ZIF-8@MXene was thoroughly characterized before and after the treatment process by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Brunauer−Emmett−Teller (BET) analysis, Fourier-transform infrared (FTIR), point of zero charge (pHpzc), and scanning electron microscopy (SEM). The results showed that ZIF-8@MXene had abundant functional groups and a high BET surface area of 1374.51 m2/g. Studies of dynamics and thermodynamics showed that adsorption of As(III/V) followed pseudo-second-order kinetics and the Langmuir adsorption model. During batch adsorption experiments, the optimum conditions were: pH 6–7, equilibrium time 2 h, initial concentrations set of 1 mg/L each for As(III) and As(V), and an adsorbent dosage of 0.1 g/L at 25°C. The maximum removal efficiency of As(III) and As(V) were 90.00 and 85.62%, respectively, with adsorption capacities of 41.20 and 38.96 mg/g. The adsorption process primarily involved complexation reactions and electrostatic interactions, as confirmed by FTIR/XRD analyses. The coordination between ZIF-8 functional groups (Zn2+, –OH, –NH2) and As(III/V) played a critical role in adsorption, while the –OH and –O groups on the MXene surface enhanced interfacial affinity, further improving adsorption efficiency. These results provide insights for constructing ZIF-8-based adsorbents with high BET surface area and multiple functional groups, effective for removing heavy metals and organic pollutants from wastewater.