Remediation of lead-contaminated groundwater by oyster shell powder-peanut shell biochar mixture

Abstract

Groundwater pollution caused by lead ions has become a widespread issue worldwide due to the ever-increasing development of industrial activities. Such pollution poses significant threats to both humans and the environment. Oyster shell powder-peanut shell biochar mixture (OSP-PSB mixture) was used for lead-contaminated groundwater treatment by permeable reactive barrier (PRB) technology. Basic characteristics of materials proved that OSP-PSB mixture has good adsorption properties; OSP with particle sizes ranging from 0.85 to 1.18 mm was used in this research; according to engineering and adsorption characteristics, OSP-PSB mixture (5:1) showed excellent permeability (4.35 × 10^-4 cm/s) and lead adsorption capacity(27 mg/g); long-term permeability of the OSP-PSB mixture slightly decreased over time and met the permeability requirements for PRB; the removal mechanisms of lead ions by OSP-PSB mixture include precipitation, surface complexation, ion exchange, and physical adsorption. The experiment results showed that the OSP-PSB mixture fulfills the actual project requirements of PRB.

Keywords: Adsorption; Lead-contaminated groundwater; Oyster shell powder; Peanut shell biochar; Permeable reactive barrier.