A primary battery for efficient cadmium contamination remediation and electricity generation

In this work, two kinds of primary batteries, both of which included a Zn anode, C rod cathode, copper wire and electrolyte composed of Cd²⁺-contaminated water or soil, were constructed in the first attempt to both remove Cd²⁺ and generate electricity. Unlike traditional technologies such as electrokinetic remediation with high energy consumption, this technology could realize Cd²⁺ migration to aggregation and solidification and generate energy at the same time through simultaneous galvanic reactions. The passive surface of Zn and C was proven via electrochemical measurements to be porous to maintain the relatively active galvanic reactions for continuous Cd²⁺ precipitation. Cd²⁺ RE (removal efficiency) and electricity generation were investigated under different conditions, based on which two empirical models were established to predict them successfully. In soil, KCl was added to desorb Cd²⁺ from soil colloids to promote Cd²⁺ removal. These systems were also proven to remove Cd²⁺ efficiently when their effects on plants, zebrafish, and the soil bacterial community were tested. LEDs could be lit for days by utilizing the electricity produced herein. This work provides a novel, green, and low-cost route to remediate Cd²⁺ contamination and generate electricity simultaneously, which is of extensive practical significance in the environmental and energy fields.