This study proposes an innovative and environment-friendly method for recycling spent lead-acid batteries without SO 2 generation. Iron-containing waste was employed as a sulfur-fixing agent to retain sulfur as ferrous matte, which eliminated the generation and emissions of gaseous SO 2 . This work investigated the thermodynamic and experimental feasibility and conversion mechanism of the method, and evaluated its industrial applicability. A bench-scale test showed direct recoveries of 93.5% and 97.7% in crude lead and ferrous matte for lead and sulfur, respectively. The phase transformation mechanism study indicated that metallic lead from the lead paste was extracted mainly through the sequence of PbSO 4 → C / C O PbS → F e 3 O 4 PbO → C / C O Pb. Sulfur in PbSO 4 was thus first transferred to PbS and finally fixed as FeS. An industrial-scale pilot campaign was also conducted to confirm the feasibility and reliability of the new process.
Every year, billions of tons of iron-rich waste are generated globally, presenting a valuable resource for synthesizing iron-based catalysts. In this study, we synthesized iron oxide-biochar (Iron Oxide@Biochar) nanocomposites by ball milling a combination of tea leaves and iron-rich waste. These nanocomposites were found to be highly efficient activators of peroxymonosulfate (PMS) for degrading tetracycline (TC). Particularly, biochar-encapsulated disposable instant hot packs (DHP/BC) achieved a TC removal efficiency of 94.7% under optimal conditions, exhibiting excellent stability and strong anti-interference capabilities. Our analysis revealed that TC degradation predominantly occurred via a non-radical pathway involving singlet oxygen ( 1 O 2 ) and electron transfer , with free radicals (·OH and SO 4 ·- ) playing a secondary role. This research not only offers an economical and efficient solution for recycling solid waste and reusing natural biochar but also introduces a sustainable and environmentally friendly method for preparing catalysts for pollutant degradation, thus achieving the dual goals of “resource recycling” and “treating waste with waste."
危险品化学品经营许可证（带存储）