Natural deep eutectic solvents-assisted asymmetrical alternating current electrochemistry for heavy metals reduction...

Heavy metal contamination in livestock and poultry manure (LPM) restricts its resource utilization. This study proposes a novel natural deep eutectic solvents-assisted asymmetrical alternating current electrochemistry (NADES-AACE) process to efficiently removal multiple heavy metals from LPM. Under optimal conditions, the removal rates of Zn, Cu and Pb reached 81%, 69%, and 67%, with total nitrogen and phosphorus retention exceeding 83%. Mechanism analysis showed NADES pretreatment disrupted the cellulose and lignin structures, promoting heavy metal release and speciation transformation. During AACE treatment, metal-EDTA chelates migrated toward the amidoxime-modified electrode under positive bias, and heavy metals were reduced to zero-valent particles and deposited on the electrode under negative bias, enabling metal removal and EDTA regeneration. The scaled-up process exhibited stable performance and electrode reusability. Compared with conventional methods, energy consumption per unit heavy metal removal decreased 40-79%. The findings indicate that the NADES-AACE process is an effective and sustainable method for LPM heavy metal control and safe utilization.