As a green remediation technology for complete remediation of contaminated soil, the combination of easily recoverable adsorbents and washing still faces challenges such as low remediation efficiency and unclear remediation mechanisms. Hence, the bis Schiff base functional group comprising sulfhydryl groups was loaded into the UiO-66 calcium alginate spheres (UiO-66-AMB-ACPs) to obtain efficient selective adsorption. The results of response surface optimization showed that the maximum removal of Pb and Cd from soil reached 69.73% and 82.63% by the combination of UiO-66-AMB-ACPs with acetic acid, of which about 95.55% and 60.31% were attributed to the adsorption. Factor interaction analysis demonstrated that solid-liquid ratio combined with either adsorbent dosage or acetic acid concentration significantly affected Cd adsorption rates. In the above system, Schiff bases,-SH, and carboxylic acids in UiO-66-AMB-ACPs compete for the Pb and Cd captured by acetic acid through chelation, ion exchange, and complexation, which assisted in maintaining the high desorption rate to further enhance the resolution process of acid-soluble and reduced Pb and Cd. The release of free acetic acid will again participate in the resolution of heavy metals, thus constituting an internal cycle of acetic acid. UiO-66-AMB-ACPs were maintained in a stable state during each of the 18 cycles. The remediated soil retained most of the plant nutrients, while the mobility of residual heavy metals was greatly inhibited. This technique showed promise for the total removal and recovery of Pb and Cd from contaminated soils with low damage and short time while immobilizing the residual heavy metals.

来源平台：CHEMICAL ENGINEERING JOURNAL