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微电解法处理棉粕蒸煮制浆过程黑液
Treatment of Black Liquor in the Cottonseed Meal Pulping Process by Micro-electrolysis Method
【作者】 杨晓林;
【导师】 张秀玲;
【作者基本信息】 河北理工大学 , 化学工艺, 2010, 硕士
【摘要】 棉浆黑液作为一种高浓度有机废水,是制浆造纸行业进行污水治理的难点。本文采用微电解法、微电解-电催化氧化及微电解絮凝法对棉浆黑液进行了处理。采用微电解方法处理棉浆黑液时,对阴极材料、铁炭比、铁炭量、反应时间、pH值、曝气量等条件进行了实验研究,考察了各因素对棉浆黑液COD去除率和色度去除率的影响。结果表明,微电解的最佳阴极材料为活性炭,最佳处理工艺参数为,铁炭比1:1,铁炭量0.4g/mL,微电解时间120min,pH=3,曝气量0.4L/min,单独使用微电解时,COD去除率达到86.5%,色度去除率达到94.3%。为了进一步提高处理效果,降低处理费用,采用了微电解-电催化氧化复合处理方法。结果表明,微电解-电催化氧化复合处理方法在不用额外添加酸的情况下也可以得到较好效果。通过正交试验得到最佳工艺参数为,铁炭量50g/L,电流密度5.0mA/cm2,反应时间40min,支持电解质用量5g/L,pH=11,此时COD去除率达到95.4%,色度去除率达到89.2%。采用NaF为酸浸助溶剂,碱浸条件为,焙烧温度800℃,碱浓度2.5mol/L,溶出时间6h,液固比100mL/g。制得的聚合铝铁和聚合硅酸钠按照SiO2含量2.0%,铝铁摩尔比4:1,二氧化硅铝铁摩尔比1:1的配比制备了粉煤灰无机絮凝剂,先将棉浆黑液絮凝,其清液保持pH值不变再进行微电解。研究得出自制粉煤灰无机絮凝剂最佳投加量为4mL/L,清液微电解后,色度去除率可达到93.7%,COD去除率达到92.6%。同条件下,使用聚合氯化铝絮凝后再进行微电解,色度去除率达到78.5%,COD去除率达到84.2%。实验表明,采用微电解-电催化氧化复合处理方法COD去除率较高,但耗电大,成本高。单独微电解时色度去除率高,但需要加酸调pH值,增加成本。采用粉煤灰无机絮凝剂絮凝微电解时,COD去除率与色度去除率都较高。
【Abstract】 Cotton pulp black liquor, a high concentration organic wastewater, is the difficulty of sewage treatment in pulp and paper industry. In this paper, micro-electrolysis method, micro-electrolysis - electro-catalytic oxidation and micro-electrolytic flocculation method have been used for the treatment of cotton pulp black liquor.When micro-electrolysis method was used for the treatment of cotton pulp black liquor, the cathode material, iron-carbon ratio, the amount of iron-carbon, reaction time, pH and aeration conditions were studied.The experiment examined the effect of cotton pulp black liquor COD removal rate and decolorization rate. The results showed that activated carbon was obtained for the best cathode material of micro-electrolysis method, and the best treatment process parameters were, iron-carbon ratio 1:1, the amount of iron-carbon 0.4g/mL, micro-electrolysis time 120min, pH = 3, aeration 0.4L/min. At this time, COD removal rate reached 86.5%, and decolorization rate was 94.3%.To further enhance the treatment efficiency, reducing processing costs, micro-electrolysis - electro-catalytic oxidation of compound treatment was adopted. Through orthogonal experiments, the optimum parameters were, iron-carbon capacity 50g/L, current density 5.0 mA/cm2, the reaction time 40min, electrolyte dosage 5g/L, pH = 11. At this time, COD removal rate reached 95.4%, and decolorization rate was 89.2%.Studies showed dosage of fly ash inorganic coagulant is 4mL/L. The decolorization rate was 93.7%, and COD removal rate reached 92.6%. At the same conditions, the PAC flocculation micro-electrolysis got the decolorization rate of 78.5%, and COD removal rate was 84.2%.Experiments showed that the use of micro-electrolysis - electro-catalytic oxidation of compound treatment had high COD removal efficiency, but power consumption and costly. Micro-electrolysis had high color removal, but needed to add acid. The COD removal and color removal rate of micro-electrolysis flocculation were all relatively high.