Abstract:

Electrochemical method was used to reduce Fe³⁺ to Fe²⁺ in the refractory iron-rich sludge that were produced in the Fenton oxidation process of pulp and paper wastewater for its subsequent reuse. The results indicated that the stainless steel cathode could significantly reduce the overpotential of Fe³⁺ reduction. When the concentration of Fe³⁺ was 2 000 mg/L, auxiliary electrolyte was not needed. After two hours of the electrochemical reduction under the condition that the ratio of cathode area to water volume was 0.48 cm²/mL and current density was 0.65 mA/cm², the Fe²⁺ regeneration rate reached 60.1%, and the corresponding current efficiency was 92.1%. The acid-treated iron-rich sludge solution was also reduced under this condition for three hours. The Fe²⁺ regeneration rate could reach 68.8%, and the current efficiency was close to 100%. The electrochemical reduction is a feasible method for the recovery of Fe³⁺ in iron-rich sludge.

Key words: iron-rich sludge, electrochemical reduction, pulp and paper, Fenton oxidation

摘要：

采用电化学法将制浆造纸厂废水Fenton氧化产生的难处理富铁污泥中的Fe³⁺还原为Fe²⁺，以便于其再利用。研究表明，以不锈钢为阴极材料可较大幅度降低Fe³⁺还原的过电位；当Fe³⁺质量浓度为2 000 mg/L时无需辅助电解质，在极水比为0.48 cm²/mL，电流密度为0.65 mA/cm²的条件下反应2 h，Fe²⁺再生率可达60.1%，电流效率为92.1%。将酸处理后的富铁污泥溶液在上述条件下还原3 h，Fe²⁺再生率达68.8%，电流效率近100%。电化学法是富铁污泥中Fe³⁺再利用的可行方法。

关键词: 富铁污泥, 电化学还原, 制浆造纸, Fenton氧化

CLC Number: 

• X793

• X703