Enhancing Soil Remediation of Copper-Contaminated Soil through Washing with a Soluble Humic Substance and Chemical Reductant

The bioavailability and mobility of copper (Cu) in soil play a crucial role its toxicity impact on organisms. Humic substances, with their abundant functional groups unique pore structure, have demonstrated the ability to effectively mitigate toxic effects heavy metals soil. This study explores potential soluble humic substance (HS) derived from leonardite for Cu removal contaminated soils. various washing conditions, such as concentration cycles, efficiency were assessed. results showed that single HS solution achieved an optimal 37.5% soil, subsequent reuse achieving over 30.5%. To further enhance efficiency, two-step approach using chemical reductant NH2OH·HCl coupled (NH2OH·HCl + HS) was employed, resulting increased 53.0%. Furthermore, this significantly reduced plant availability bioaccessibility by 13.6% 11.4%, respectively. Compared NH2OH·HCl, both pH organic matter content. These findings suggest soil-washing removed polluted demonstrates substances environmentally friendly materials remediating metal-polluted promoting green sustainable applications remediation practices.