Removal of co-present chromate and arsenate by zero-valent iron in groundwater with humic acid and bicarbonate

Mechanism insights into enhanced Cr(VI) removal using nanoscale zerovalent iron supported on the pillared bentonite by macroscopic and spectroscopic studies

“…Zerovalent iron (ZVI) has been extensively investigated over the past decades as an environmentally benign chemical reductant for remediation of a variety of contaminants including chlorinated organics [1,2], nitroaromatics [3], radionuclides [4,5] and heavy metals [6][7][8]. Because the reduction of contaminants occurs on the solid iron surface, the smaller size of ZVI particles means larger specific surface area, and consequently results in higher reactivity.…”

Comparison of Cr(VI) and As(V) removal in single and binary mixtures with Fe(III)-treated Staphylococcus xylosus biomass: Thermodynamic studies

“…Liu et al [12] have studied the removal of co-present chromate and arsenate at lower concentrations (up to 10 mg/L) by zero valent iron with humic acid and bicarbonate, and the results showed that As(V) displayed little inhibitory effects on Cr(VI) removal whereas Cr(VI) itself could compete for adsorption sites with As(V), resulting in decreased As(V) uptake by iron corrosion products. Such unusual influences between Cr(VI) and As(V) may be due to originate of their distinct removal mechanisms and the different biosorbents used in each study.…”

“…More specifically, use and disposal of chromated copper arsenate-treated wood is a widespread problem that affects many countries due to the presence of toxic elements as the primary wood preservative [10]. Among the three metal ions used, copper ions remained in soil by adsorption and precipitation, whereas chromate and arsenate ions are relatively mobile in soil, ending to groundwater [11,12]. Therefore, the simultaneous removal of chromate and arsenate species from contaminated water also needs to be considered.…”

“…Iron(III) has been used in many studies for the modification of biomass or other materials, since it possesses a natural affinity towards chromium and arsenic species. In addition, iron and its compounds, as well as iron modified biomass have been used to remove Cr(VI) and As(V) from wastewater elsewhere [12,20,22].…”

“…Although single toxic metallic species rarely exist in natural and wastewater, much research has been focused on the removal of single species, whereas very little attention has been drawn to remove the many metals simultaneously [26]. The only report on the simultaneous sorption of Cr(VI) and As(V) at low concentrations using zero-valent iron with humic acid and bicarbonate has been published recently by Liu et al [12]. In this study, the biosorption ability of Fe(III)-treated S. xylosus biomass towards Cr(VI) and As(V) in single and binary mixtures was investigated and compared.…”