Arsenic Removal from Groundwater Using Recycled Iron Nanoparticles: Development and Evaluation of a Low-Cost Filter for Rural Communities

Author(s): Juan Simón Torres Espada, Yrene Romina Lazcano Cruz

The presence of geogenic arsenic in groundwater poses a serious threat to public health in regions such as the Lake Poopó basin in Oruro, Bolivia. This study developed and evaluated a low-cost experimental filter using metallic iron (Fe⁰) and iron oxide (Fe₃O₄) nanoparticles obtained from recycled iron shavings using top-down and bottom-up filtration technologies. The nanoparticles were integrated into a homemade filtration system along with readily available materials such as sand, charcoal, and ground brick. Kinetic and adsorption tests were performed under controlled conditions, achieving arsenic removal rates exceeding 97% with Fe⁰ nanoparticles and 91% with Fe₃O₄. These results best fit the Freundlich isotherm model and second-order kinetics, which describe the arsenate adsorption behavior on both nanoparticles. The filter proved effective for up to 13 consecutive treatment cycles, reducing arsenic concentrations to levels ≤ 0.01 mg/L. This approach represents a sustainable, economical, and technically viable alternative for rural communities affected by this contaminant.