Microwave-assisted one-pot synthesis of β-cyclodextrin modified biochar for stabilization of Cd and Pb in soil

Ethylenediaminetetraacetic acid crosslinked β-cyclodextrin modified biochar (BC-CDMW) was fast prepared by microwave-assisted one-pot process, and was applied to remediation of Cd and Pb contaminated soil. Batch adsorption studies showed that the BC-CDMW possessed superior adsorption performance with maximal monolayer Cd(II)/Pb(II) uptake of 39.56 or 208.36 mg/g spanning broad pH range of 2.0–6.0. Furthermore, by applying BC-CDMW dosage of 5%, labile Cd and Pb portions in soil were reduced from 74.91% to 56.61%–30.65% and 28.30% after simulated remediation of 30 days at 40% moisture content. In comparison with BC, the stable residue state content increased by 30.84% and 18.91% for Cd and Pb, respectively, by BC-CDMW treatment. Besides, the BC-CDMW was identified to implement Cd and Pb stabilization in soil via combined roles of electrostatic attraction, complexation and pore filling. Overall, this work suggested BC-CDMW as a high-performance amendment for heavy metals stabilization in soil.