Synthesis of Magnesium Modified Biochar for Removing Copper, Lead and Cadmium in Single and Binary Systems from Aqueous Solutions: Adsorption Mechanism

Biochar modification can enhance the properties associated with porosity and functional groups has been identified as an effective way to improve adsorption capacity. Modified corncob biochars pretreated by different contents of MgCl2 are obtained through slow pyrolysis; then, this work explores abilities towards heavy metals. After modification, mainly impregnate carbon surface Mg(OH)2 MgO particles. The best mass ratio magnesium (Mg)/feedback is 15% for modified biochar, 15%Mg-BC much higher (2.36–9.34 times) metal sorption capacity than pristine biochar. Batch experiments show that copper (Cu(II)) lead (Pb(II)) on adsorbents follow a pseudo-second-order model cadmium (Cd(II)) follows intraparticle diffusion model. isotherm Cu(II) fits well Langmuir model, Pb(II) Cd(II) fit Freundlich In binary system, biochar still effectively removes metals, but metals decreases rapidly because competitive sorption. main mechanisms include precipitation, cation π-banding, complexation, ion exchange. results Mg-modified may be environmentally friendly material reducing water pollution