不同水质灌溉下土壤吸附Cu2+、Zn2+特性:多因素耦合效应OA

To address agricultural water scarcity in northern arid regions and ensure the safety of unconventional water irrigation,this study investigates the retention characteristics of Cu2+and Zn2+in soil under irrigation with different water qualities,along with key influencing factors.Using sandy soil as the research subject,isothermal adsorption experiments,single-factor experiments(pH,salinity,dissolved organic matter—DOM),and multi-factor coupling experiments were conducted.The adsorption characteristics were analyzed using Langmuir,Freundlich,and Temkin models,and the interactions among multiple factors were examined using the Box – Behnken response surface methodology.The soil Zn2+retention capacity under different water quality irrigation was in the following order:brackish water>pure water>reclaimed water>tap water;for Cu2+,the order was:reclaimed water>brackish water>tap water>pure water.pH was the key factor dominating the adsorption process,with Cu2+achieving a removal rate of 99.99%at pH=7,while Zn2+approached complete removal at pH=9.Salinity exhibited a slight promoting effect on adsorption within the range of 200~3 000 mg/L.The removal rates of Zn2+and Cu2+from the soil by DOM generally showed a tendency to decrease;however,at low concentrations of Dissolved Organic Matter(DOM),the removal rate of Cu2+from the soil increased.Multi-factor coupling analysis indicated that the order of influence of the three factors was:pH>DOM>salinity.The findings of this study provide a theoretical basis and decision-making support for risk assessment and water quality regulation in unconventional water irrigation.