Interfacial interaction mechanism between Mn doped highly conjugated biochar and berberine hydrochloride

MnSO₄-modified biochar (Mn-BC) was synthesized to remove berberine hydrochloride (BH) from wastewater by utilizing tea waste as raw material and MnSO₄ as modifier. Brunel Emmett Taylor (BET) analysis reveals that the specific surface area (SSA) and average pore size (D_ave) of Mn-BC are 1.4 and 7 times higher than those of pristine biochar apart, attributing to the dissociation effect can promote the dispersion of MnSO₄ in the pores of the biochar. Meanwhile, the doping of Mn not only introduces additional oxygen-containing functional groups (OCFGs), but also modulates the π electron density. Furthermore, Response surface method (RSM) analysis reveals that Mn-BC dosage has the most significant effect on BH removal, followed by BH concentration and pH value. Kinetic and isothermal studies reveal that the BH adsorption process of Mn-BC was mainly dominated by chemical and monolayer adsorption. Meanwhile, density functional theory (DFT) calculations confirm the contribution of Mn doping to the conjugation effect in the adsorption system. Originally proposed Mn-BC is one potentially propitious material to eliminate BH from wastewater, meanwhile this also provides a newfangled conception over the sustainable utilization of tea waste resources.