Influence of iron, phosphate, and silicate on arsenic removal from groundwater using a low-cost ceramic filter.

Abstract

The ceramic filter amended with iron (Fe) has proven to be a potential low-cost method for arsenic (As) removal from groundwater. The presence of Fe, phosphate (P), and silicate (Si) significantly affects the As removal efficiency of the ceramic filter, which has not been passably investigated. The present research aimed to examine the effect of Fe, P, and (or) Si presence as single or in combination on As (III) removal from synthetics groundwater by a low-cost iron amended ceramic filter (IACF). Laboratory-scale filtration experiments at different compositions of Fe, P, Si, and As (III) were conducted by the IACF fabricated with a ceramic candle and iron netting box. Fe (II) in synthetic groundwater positively impacted As (III) removal. At a concentration of 2mg/L of Fe (II), the As levels in the effluent decreased to less than the maximum contamination level (MCL) of 50 μg/L. Groundwater P concentration needed less than 3mg/L or Si concentrations required less than 35 mg/L to effectively reduce As (III) to below the MCL at 5mg/L of groundwater Fe (II). The cumulative effect of P and Si on As removal was found to be more significant than distinct contributions. The presence of 2mg/L P and 35 mg/L or higher Si in the groundwater cumulatively reduced the As removal performance from 92% to 63%, and the MCL was not met. The negative impact of P and Si on As (III) removal followed the order of (P + Si) > P > Si. P competed with As for adsorption sites during the process, while Si inhibited the Fe release and floc formation, significantly reducing As removal performance. The study findings can potentially contribute to optimizing IACF as a low-cost method for As removal from groundwater.