The Fenton-like reaction for Arsenic removal from groundwater: Health risk assessment

In this paper, the heterogeneous Fenton like-reaction for Arsenic-contaminated groundwater remediation based on the performance of FeSO4 as an efficient and green catalyst and CaO2 as a source of H2O2 was investigated. To intensify the heterogeneous Fenton process, three oxidants were tested: sodium percarbonate (SPC), sodium persulfate (SPS), and calcium peroxide (CP). The results showed that CP and SPC had a synergetic effect on the rate of Arsenic degradation, while SPS had an antagonistic effect. On the other hand, inorganic ions such as Na+, Mg2+ have a very low impact on the Arsenic removal efficiency, while the anions Cl- and NO3- exhibited significant inhibition of Arsenic degradation. This effect may be imputed to the reaction and conversion of hydroxyl (HO center dot) radicals to less reactive. Thus, HCO3- and humic acid dramatically raised the degradation rate. Also, the response Surface method based on Box-Behnken design was applied to examine the suitable modeling, and optimized condition of the Fenton like-reaction process, the maximum Arsenic removal efficiency of 94.91% is obtained when [Fe3+](0) = 1.97 mM, [CaO2](0) = 1.74 mM and initial pH = 4.67. The obtained results showed that the Fenton-like reaction is an effective and reliable process for arsenic removal from groundwater with low non carcinogenic risk (HQ) and carcinogenic risk (CR) values.