Ultra-efficient sorption of Cu²⁺ and Pb²⁺ ions by light biochar derived from Medulla tetrapanacis

A novel mesoporous biochar (PBC) was facilely prepared from Medulla tetrapanacis. PBC exhibited high efficiency for the sorption of Cu²⁺ (458.72 mg/g) and Pb²⁺ (1031.23 mg/g) ions, and these values were higher than that of reported literatures. In the multi-metal system, the maximum sorption capacity for Cu²⁺, Pb²⁺, Cr³⁺, and Fe³⁺ were 430.88 mg/g, 701.63 mg/g, 696.67 mg/g, and 697.01 mg/g, respectively, and the removal efficiencies of those ions were more than 80% at a metal ion concentration of 200 mg/L. Furthermore, the PBC was effective for the treatment of industrial effluent wastewater. The ash content (45.46%) of the PBC was higher than that of most other biochar derived from lignocellulosic biomass. Complexation, precipitation, π-π interactions, ion exchange, and physical sorption were the main sorption mechanisms. Overall, PBC is an inexpensive product, which is simply synthesized and an excellent adsorbent for heavy metal ion removal.