In situ treatment of arsenic contaminated groundwater by aquifer iron coating: Experimental study

摘要: In situ arsenic removal from groundwater by an aquifer iron coating method has great potential to be a cost effective and simple remediation technology, especially in rural remote areas where is used as the main water source for drinking. The technology was first optimized simulating various quartz sand columns under anoxic conditions. effectiveness then evaluated actual high-arsenic environment. mechanism coated oxide/hydroxide investigated different conditions using scanning electron microscopy (SEM)/X-ray absorption spectroscopy, probe microanalysis, Fourier transformation infrared spectroscopy. Aquifer developed via 4-step alternating injection of oxidant, salt oxygen-free water. A continuous 5.0 mmol/L FeSO4 2.5 NaClO 96 h can form uniform goethite on surface without causing clogging. At flow rate 7.2 mL/min reagents, (as Na2HAsO4) tracer fluorescein sodium pass through iron-coated column were approximately at 126 7 pore volumes, respectively. retardation factor 23.0, adsorption capacity 0.11 mol As per Fe. achieved simultaneous injections As(V) Fe(II) reagents. Arsenic fixation resulted process adsorption/co-precipitation with fine particles way bidentate binuclear complexes. Therefore, study results indicate that high efficiency likely expanded specific area small particles, which enhanced sorption capability and/or co-precipitation particles.