Concurrent elimination of arsenic and nitrate from aqueous environments through a novel nanocomposite: Fe3O4-ZIF8@eggshell 3 O 4-ZIF8@eggshell membrane matrix

The high concentration of nitrate and arsenic as potentially toxic elements (PTEs) with carcinogenic properties in many groundwater sources worldwide is a concern for health and the environment. This work checked the capacity of a novel nanocomposite, Fe3O4-ZIF8@eggshell 3 O 4-ZIF8@eggshell membrane matrix (F-ZIF8@EMM) for concurrently eliminating arsenic and nitrate, two of the most encountered hazardous pollutants in drinking water. Contact time (30-120 min), pH (3-10), initial arsenic concentration (25-100 mu g/L), initial nitrate concentration (60-120 mg/L) and adsorbent dose (0.25-5 mg/L) as various operating influences were investigated on the co-adsorption of arsenic and nitrate from water by a new nanocomposite thru diverse experimental tests. Characteristics of FZIF8@EMM were determined through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) analyses. Taguchi model was used to determine the optimal co-adsorption conditions. The results revealed that the optimal conditions for the simultaneous adsorption of 94.32 % of these two elements were at pH = 7, adsorbent dose 1 mg/L, primary nitrate concentration 120 mg/L, initial arsenic concentration 100 mu g/L, and contact time 90 min. Correspondingly, the simultaneous adsorption of arsenic and nitrate best fit the Langmuir isotherm, and the pseudo-second-order (PSO) model was the best model that fitted with experimental kinetic data (R2 2 = 1). The maximum experimental adsorption capacity of F-ZIF8@EMM was 128.5 mg/g. This study indicated that the efficiency of nanocomposite F-ZIF8@EMM in the co-adsorption of arsenic and nitrate was promising.