Adsorption behavior and mechanism of Pb(II) and complex Cu(II) species by biowaste-derived char with amino functionalization

This work aimed to develop a feasible technology to reuse dead pig biowaste for heavy metals removal , which was first carbonized into pig bone char (PBC) after pyrolysis and further functionalized with amino ( NH 2 ) to improve its affinity with heavy metals. The application of PBC after NH 2 -functionalization for aqueous heavy metals removal was explored, including Pb 2+ , Cu 2+ , and different complex Cu(II) species. PBC@SiO 2 -NH 2 showed comparable performance with AC@SiO 2 -NH 2 . The adsorption capacity of Pb 2+ and Cu 2+ by PBC@SiO 2 -NH 2 was 120 and 30 mg g −1 , respectively. The NH 2 functionalization enhanced the adsorption of complex Cu(II) species, and PBC@SiO 2 -NH 2 exhibited good performance under a wide pH range and coexisting ions. The adsorption of Cu(II) EDTA species with an EDTA/Cu(II) molar ratio of 1.0 by PBC would be enhanced ~3 times and ~6 times after NH 2 functionalization and further addition of Fe 3+ , respectively. The results of EDX , elemental mapping, and XPS confirmed the adsorption of Cu(II) species. The adsorption kinetics , isotherm, and thermodynamics of different Cu(II) species by PBC@SiO 2 -NH 2 were investigated. The regeneration of PBC@SiO 2 -NH 2 was easily performed via acidic wash. These results suggested the application potential of the reuse of biowaste, which could be a promising adsorbent for aqueous heavy metals after specific functionalization.