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高铁酸钾氧化法对焦化废水中煤颗粒的氧化沉降性能研究

Study onoxidation flocculation property of coal particles in coking wastewater by potassium ferrate oxidation process

  • 摘要: 焦化废水中的污染物主要由浓度高、粒径小、密度较小、带少量负电荷的碳颗粒物和浓度高、组成复杂、有毒、难降解的有机化合物组成,现有的各种处理工艺很难有效去除这些物质,达到国家一级标准。基于焦化废水无机物和有机物复合污染的特征,利用高铁酸盐的强氧化性和其反应产物铁盐的絮凝性,协同处理含高浓度悬浮态煤颗粒物和溶解态有机化合物的焦化废水,以期为进一步研发焦化废水氧化处理技术提供重要理论依据。选取表面Zeta电位指标来反映煤颗粒物的沉降性能,通过测定不同条件下的煤颗粒表面的Zeta电位,研究高铁酸钾对煤颗粒的氧化絮凝和沉降效果,考察pH、Fe(Ⅵ)投加量、溶液中无机阳离子浓度及价态对高铁酸钾氧化煤颗粒的影响,并考察高铁酸钾对实际焦化废水中化学需氧量和悬浮物的协同处理效果。结果表明,煤颗粒表面带负电,溶液pH越低,煤颗粒沉降性能越好。高铁酸钾的投加对降低煤颗粒表面Zeta电位绝对值有一些效果,并且当溶液偏中性时,效果最明显。无机阳离子可在煤颗粒物表面产生压缩双电层,从而降低颗粒表面的Zeta电位绝对值,提高颗粒物的沉降效果。实际焦化废水水样中的铬化学需氧量、悬浮物的去除率随Fe(Ⅵ)投加量的增加呈现上升趋势。当Fe(Ⅵ)投加量为2 mmol/L时,实际焦化废水中SS去除率已达到65.44%。可见,高铁酸盐氧化法对实际焦化废水中颗粒物的氧化絮凝效果良好。

     

    Abstract: The pollutants from coking wastewater are mainly coal particles with high concentration,small size,lighter weight and taking a small amount of negative charge,and toxic and refractory organic compounds with high concentration and complex composition. Various existing wastewater treatment processes are difficult to effectively remove these contaminants to meet the national standard. Based on the characteristics of combined pollution of inorganic and organic compounds,The dual role of strong oxidation and coagulation of ferrate(VI) salts is developed to degrade the high concentrations of suspended coking coal particles and dissolved organic matter from coking wastewater,so as to provide an important theoretical basis for the further development of coking wastewater treatment technology. The surface zeta potential was selected to reflect the sedimentation performance of coal particles. By measuring the zeta potential under different conditions,the effect of potassium ferrate oxidation on the flocculation and sedimentation of coal particles was studied. The influence of pH,Fe(VI) dosage and inorganic salts on the oxidation process were investigated,and the purification effect of ferrate(Ⅵ) process on the oxidation flocculation of actual coking wastewater was evaluated. The results show that the surface of coal particles was negatively charged,and the lower the pH value of the solution,the closer the Zeta potential on the surface of coal particles approached zero and the better the settlement of coal particles. The addition of ferrate(Ⅵ) has some effect on reducing the absolute value of Zeta potential on the surface of coal particles,and the effect is most obvious when the solution is neutral. Inorganic cations can compress the double electric layers on the surface of coal particles,thus reducing the absolute Zeta potential and improving the settlement of coal particles. The removal rates of COD Cr and SS in actual coking wastewater samples increased with the increase of Fe(Ⅵ)) dosage. When Fe(Ⅵ)) dosage is 2 mmol/L,the actual removal rate of SS in coking wastewater has reached 65.44%,indicating that the flocculation effect of high ferrate process on particulate matter in coking wastewater is good.

     

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