Adsorption and recovery of berberine hydrochloride from wastewater by a novel magnesium-modified biochar: Toward resource utilization of waste dander

At present, China produces 1.4 million tons of waste dander annually, and if they are directly incinerated, about 2.3 million tons of CO₂ will be generated, leading to the aggravation of the greenhouse effect. In order to realize the resource utilization of waste dander, Mg²⁺-modified biochar (MBC) was prepared via Mg²⁺ impregnation and pyrolysis. And the generated MgO nanoparticles were in-situ immobilized on its surface, which effectively increased the specific surface area of the biochar and provided more active sites for the adsorption of the macromolecular organic pollutant berberine hydrochloride (BBH). In addition, the introduction of Mg²⁺ not only effectively reduced the release of small molecules such as SO₂ and CO₂, but also generated C-O-Mg bond and more conjugated structures. As a result, MBC is endowed with greater adsorption capacity and stability. Meanwhile, mechanistic analyses indicated that the superior adsorption capacity of MBC for BBH may be related to electrostatic and π-π interactions. Finally, density functional theory (DFT) was employed to confirm the formation of C-O-Mg bonds and verify that BBH was adsorbed on different adsorption sites of MBC. Therefore, the resource utilization of waste dander can be achieved with MBC.