Comparison of As removal efficiency and health risks from aqueous solution using as-synthesized Fe 0 and Cu 0 : modelling, kinetics and reusability.

Batch scale removal of arsenic (As) from aqueous media was explored using nano-zero valent iron (Fe 0 ) and copper (Cu 0 ) particles. The synthesized particles were characterized using a Brunauer-Emmett-Teller (BET) surface area analyzer, a scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). The BET result showed that the surface area (31.5 m 2 /g) and pore volume (0.0415 cm 3 /g) of synthesized Fe 0 were higher than the surface area (17.56 m 2 /g) and pore volume (0.0287 cm 3 /g) of Cu 0 . The SEM results showed that the morphology of the Fe 0 and Cu 0 was flowery microspheres and highly agglomerated with thin flakes. The FTIR spectra for Fe 0 showed broad and intense peaks as compared to Cu 0 . The effects of the adsorbent dose (1-4 g/L), initial concentration of As (2 mg/L to 10 mg/L) and solution pH (2-12) were evaluated on the removal of As. Results revealed that effective removal of As was obtained at pH 4 with Fe 0 (94.95%) and Cu 0 (74.86%). When the dosage increased from 1 to 4 g L -1 , the As removal increased from 70.59 to 93.02% with Fe 0 and from 67 to 70.59% with Cu 0 . However, increasing the initial As concentration decreased the As removal significantly. Health risk indices, including estimated daily intake (EDI), hazard quotient (HQ), and cancer risk (CR) were employed and a significant decline (up to 99%) in risk indices was observed in As-treated water using Fe 0 /Cu 0 . Among the adsorption isotherm models, the values of R 2 showed that isothermal As adsorption by Fe 0 and Cu 0 was well explained by the Freundlich adsorption isotherm model (R 2  > 0.98) while the kinetic experimental data was well-fitted with the Pseudo second order model. The Fe 0 showed excellent stability and reusability over five sorption cycles, and it was concluded that, compared to the Cu 0 , the Fe 0 could be a promising technology for remediating As-contaminated groundwater.