Zinc Exchanged Carbonate Minerals: Application for in situ Treatment of Arsenic Contaminated Groundwater

摘要

While over 140 million people worldwide are at risk of drinking arsenic contaminated groundwater above the WHO guideline of 10 μg/L, the need for an efficient treatment scheme in actual groundwater conditions is growing. This study examines the use of zinc carbonate minerals for in situ removal of As(V) from contaminated groundwater. Batch adsorption isotherms compare the adsorption of As(V) to reagent grade ZnCO 3 and freshly precipitated ZnCO 3 minerals on calcite particles in buffered electrolyte solution and real groundwater. Column studies examine the exchange of calcite particles for zinc-carbonate minerals through injection of a zinc chloride solution and the subsequent removal of As(V). While arsenic adsorption in batch studies is greatly reduced in actual groundwater relative to synthetic solution, As(V) mobility is significantly impeded in column studies with R greater than 12,000 for both synthetic and actual groundwater. Plausible explanations for arsenic removal mechanisms are discussed.