CHENHaoyu,SHIZhou,ZHOUShiqing,et al.Effectiveness and Mechanism of Ferric Sulfate Enhanced Coagulation for Synergistic Removal of Cr(Ⅵ) and Ni(Ⅱ)[J].China Water & Wastewater,2026,42(9):24-31.
Effectiveness and Mechanism of Ferric Sulfate Enhanced Coagulation for Synergistic Removal of Cr(Ⅵ) and Ni(Ⅱ)
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第42卷
Number:
第9期
Page:
24-31
Column:
Date of publication:
2026-05-01
- Keywords:
- ferrous sulfate; Cr(Ⅵ); Ni(Ⅱ); coagulation mechanism
- Abstract:
- Ferrous sulfate (FeSO4) is widely used as a reducing agent, coagulant, and precipitant in wastewater treatment. Compared to other coagulants, FeSO4 offers advantages such as low toxicity, environmental friendliness, and cost-effectiveness, demonstrating excellent application potential. However, due to the poor coagulation effect of traditional ferrous sulfate process, the treated water has a color and is usually only used to treat single heavy metal wastewater, which also limits the further promotion and practical application of ferrous sulfate in coagulation removal of heavy metals technology. In response to the aforementioned technical bottlenecks, this study proposed a triple mechanisms of Cr(Ⅵ)/Ni(Ⅱ) removal by ferrous sulfate-enhanced coagulation: reduction, co-precipitation, and net trapping.The synergistic treatment mechanism of FeSO4 for heavy metal wastewater containing Cr(Ⅵ) and Ni(Ⅱ) was systematically investigated. By adjusting key parameters including FeSO4 dosage, Cr(Ⅲ) concentration, and pH, and employing multi-scale characterization techniques such as SEM, XRD, XPS, and FTIR, the triple synergistic mechanism of “reduction-co-precipitation-net trapping” was elucidated. Experimental results showed that under optimal conditions [pH=7, mass concentration ratio of Fe(Ⅱ) to total Cr at 1∶1], the removal efficiencies of total Cr, Ni(Ⅱ), and total Fe reached 98.6%, 97.4%, and 99.0%, respectively. Mechanistic analysis revealed that Fe(Ⅱ) first reduces Cr(Ⅵ) to Cr(Ⅲ), followed by the formation of stable co-precipitates between Cr(Ⅲ) and Fe(Ⅲ). These precipitates further enhance heavy metal removal through hydroxyl coordination and net trapping effects.
Last Update:
2026-05-01