EDTA functionalized magnetic biochar for Pb(II) removal: Adsorption performance, mechanism and SVM model prediction

It is beneficial to establish a rapid prediction approach of sorption by considering various operating variables that can greatly reduce workload and minimize operational costs. In the present study, Pb(II) sorption onto synthetic biochar (BC), magnetic biochar (M-BC) and EDTA functionalized magnetic biochar (EDTA-M-BC) were comparative investigated in view of adsorption factors, adsorption kinetics and adsorption isotherm. Support vector machine (SVM) model was proposed to predict the adsorption performance by considering various operating variables. It was found that the BET surface areas of BC, M-BC and EDTA-M-BC was 499.2, 255.7 and 57.5 m(2)/g, respectively, and the majority of pores in the BC samples were mesoporous. The Pb(II) sorption processes by three kinds of BCs were well fitted to pseudo-second-order kinetic model and Langmuir model. According to zeta potential and X-ray photoelectron spectroscopy (XPS) analysis, the adsorption mechanism for Pb(II) adsorbed onto BCs were mainly attributed to electrostatic interaction and chemical complexation. The 10-fold cross-validation was performed to estimate SVM validity. The predication results showed approximately 99.4% accuracy for test datasets and 100% accuracy for experiment data. Thus, SVM could be a reliable accurate estimation method to predict adsorption performance.