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

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. Graphical Abstract