# Solar-powered bioelectrochemical system for efficient cadmium remediation and recovery of reusable solids

## TL;DR

A solar-powered system efficiently removes and recovers cadmium from water using a bioelectrochemical process that favors solid Cd–O formation.

## Contribution

Integrating photovoltaics with bioanodes enables reagent-free cadmium immobilization and recovery under mild conditions.

## Key findings

- The PV-BES achieved 62.3% removal of dissolved Cd2+ in batch experiments.
- Solar-driven bias promotes crystalline Cd–O solid formation over metallic Cd plating.
- PV-assisted BES offers a sustainable, low-energy approach for heavy metal remediation.

## Abstract

Cadmium (Cd) is a persistent industrial pollutant that poses severe environmental risks, necessitating remediation technologies that balance efficiency with energy sustainability. This study investigates a solar-powered bioelectrochemical system (PV-BES) as a low-energy strategy for Cd recovery, addressing limitations associated with conventional energy-intensive processes. In batch experiments, the PV-BES achieved 62.3% removal of dissolved Cd2+, outperforming the 53.8% efficiency of a self-biased microbial fuel cell. Electrochemical measurements combined with solid-phase characterization indicate that the solar-driven bias is consistent with localized interfacial alkalization, which favors the formation of crystalline Cd–O solids rather than continuous metallic Cd plating under near-neutral bulk pH conditions. These results suggest that coupling photovoltaics with bioanodes provides a synergistic, reagent-free pathway for cadmium immobilization and recovery. Overall, this work supports the potential of PV-assisted BES as a sustainable, low-energy approach for heavy metal remediation under mild aqueous conditions.

A solar-powered bioelectrochemical system integrates a photovoltaic bias with a bioanode to enable cadmium remediation and recovery under mild aqueous conditions, favoring precipitation of Cd–O solids over metallic deposition.