Efficient removal of arsenic species by green rust sulfate (GRSO4)

The interfacial reactivity between green rust sulfate (GR_SO4) and arsenic (As) species were investigated using batch adsorption experiments. GR_SO4 is capable of adsorbing up to 155 and 88 mg g⁻¹ of As(III) and As(V), respectively. The value of pH greatly affects adsorption, with As(III) removal 2.5 times higher at alkaline pH, while As(V) removal higher at circum-neutral conditions. Competing groundwater species such as magnesium (Mg²⁺) or phosphate ( https://www.w3.org/1998/Math/MathML"> PO 4 3 − https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781351046633/1b195dff-f254-4eb3-aa20-efaa8e66f26f/content/eq133.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> ) reduce removal efficiency. Our results show that GR_SO4 is a stable, efficient and environmentally-relevant mineral substrate for As sequestration in anoxic groundwater systems.