Removal of As(V) in the presence of Cr(VI) in contaminated water from the Bajio region of Mexico using ferrihydrite-functionalized graphene oxide (GOFH): A case study

The presence of heavy metals such as arsenic (As) and chromium (Cr) can be considered one of the most toxic heavy metals. This study aims to develop and evaluate a graphene oxide (GO) based material functionalized with ferrihydrite for the removal of As(V) in the presence of Cr(VI). The adsorbent ferrihydrite-functionalized graphene oxide (GOFH) was characterized by SEM, FTIR, XRD, XPS, surface charge, BET and TGA. Individual adsorption capacities for As(V) and Cr(VI) were 160 and 66 mg g−1 respectively at pH 4 and 298 K, fitting the Langmuir model. In binary systems, GOFH adsorbed As(V) with an adsorption capacity of 137 mg g−1 in the presence of 20 mg L−1 Cr(VI) at room temperature. Thermodynamic analysis revealed an exothermic and spontaneous process. Additionally, GOFH effectively removed several coexisting anions from groundwater, including SO42−, CO32− and Cl−. This work evidences the potential of GOFH for competitive adsorption of priority pollutants from complex matrices. The GOFH material represents a technically and economically viable technology for application in groundwater decontamination, as it requires inexpensive precursors and ambient conditions during synthesis and operation