The surface flat pristine biochar provides limited adsorption sites for Cd(II) adsorption. To address this issue, a novel sludge-derived biochar (MNBC) was prepared by NaHCO3 activation and KMnO4 modification. The batch adsorption experiments illustrated that the maximum adsorption capacity of MNBC was twice that of pristine biochar and reached equilibrium more quickly. The pseudo-second order and Langmuir model were more suitable for analyzing the Cd(II) adsorption process on MNBC. Na+, K+, Mg2+, Ca2+, Cl− and NO−3 had no effect on the Cd(II...
