两段式高级氧化工艺处理含镍废水研究

发布时间：2018-04-04 03:55

本文选题：电镀废水　切入点：络合态镍　出处：《哈尔滨工业大学》2017年硕士论文

【摘要】：含络合镍的电镀废水一般采用先破络后混凝沉淀的处理方式,而破络是该类废水处理的关键。目前,工程中常用的破络方法为芬顿法,该方法虽然操作简单,但也存在水力停留时间长、处理费用高、产泥量大的问题,且出水难以稳定达标。目前,基于臭氧的高级氧化工艺越来越受重视。课题组在前期研究中发现,采用臭氧催化联用工艺“O_3/H_2O_2+Fe~(2+)”处理含次亚磷酸盐的电镀废水具有良好效果,同时具有水力时间短、处理成本低、产泥量小等优势。次亚磷酸盐与络合镍的去除原理接近,因此臭氧催化联用工艺具有有效处理含络合镍废水的潜力。本研究考察了芬顿和臭氧催化联用工艺处理含络合镍废水的特性,确定了合适的络合镍废水处理工艺,在此基础上,对该工艺进行系统优化,并以实际废水为处理对象,进行中试研究。通过小试试验,对比了芬顿和臭氧催化联用工艺对络合镍废水的处理效果。实验结果表明,针对络合镍含量为50 mg/L的Ni-EDTA模拟废水,在最佳投加量下进行单级芬顿反应,出水镍的含量最低达0.7 mg/L;臭氧催化联用工艺出水镍浓度能够达到0.1 mg/L的排放标准,但同时存在臭氧投加成本过高的问题。通过两种工艺的对比发现,在高浓度模拟废水下,芬顿工艺与臭氧催化联用工艺相比,具有反应速率快的优势;而臭氧催化联用工艺适用于低浓度络合镍废水。因此,针对络合镍含量较高的废水,宜采用“芬顿+臭氧催化联用”两段式组合,且两种工艺之间的浓度为15 mg/L左右为宜。针对模拟废水对“芬顿+臭氧催化联用”组合进行优化可知,芬顿段出水只需达到15 mg/L以下,后续工艺可将水中镍浓度处理至0.1 mg/L以下。因此,对两段式高级氧化组合进行优化试验。结果表明:减少芬顿段的试剂投加量,可以将芬顿段出水镍浓度维持在15 mg/L左右;芬顿出水不进行加碱沉淀有利于与后续工艺的结合;芬顿工艺出水中残留的过氧化氢可以保证后续臭氧工艺的高效运行,同时可将臭氧催化联用工艺中过氧化氢的投加过程进行简化;经过工艺对比,O_3和Fe~(2+)同时投加对处理效果具有一定的提升作用。因此,针对含络合镍废水,适宜采用的工艺为“芬顿+O_3/Fe~(2+)”两段式高级氧化工艺,并对该工艺进行参数优化。基于上述研究成果,考察了“芬顿+O_3/Fe~(2+)”两段式高级氧化工艺对实际废水的处理效果。实验结果表明,针对络合镍含量为2~20mg/L的实际废水时,该工艺经过参数优化,体现了稳定高效的处理效果,出水镍能稳定达到0.1 mg/L的电镀废水排放标准,且能同步高效去除Cu、COD和TP,去除率分别可达到93%、76%和99%。与传统两段芬顿工艺相比,该工艺处理成本节省30~50%,可以实现含镍废水高效经济处理的目的。
[Abstract]:The electroplating wastewater containing complexed nickel is usually treated by first breaking the complexing and then coagulating and precipitating, and breaking the complexing is the key to the treatment of this kind of wastewater.At present, Fenton method is commonly used in engineering. Although the method is simple, it also has the problems of long HRT, high treatment cost and large sludge production, and it is difficult to reach the standard of effluent stability.At present, more and more attention has been paid to the advanced oxidation process based on ozone.In the previous study, it was found that the treatment of electroplating wastewater containing hypophosphite by ozone catalytic combined process "O_3/H_2O_2 Fe~(2" had a good effect, and had the advantages of short hydraulic time, low treatment cost and low sludge production.The removal principle of hypophosphite and complexed nickel is similar, so the combined ozone catalytic process has the potential to effectively treat wastewater containing complexed nickel.In this study, the characteristics of Fenton combined with ozone catalytic process for treating nickel complex wastewater were investigated, and the suitable treatment process of nickel complex wastewater was determined. On the basis of this, the process was systematically optimized, and the actual wastewater was treated as the object.Pilot study was carried out.The effect of Fenton combined with ozone catalysis on the treatment of nickel complex wastewater was compared.The experimental results show that for the simulated wastewater of Ni-EDTA containing 50 mg/L complex nickel, single stage Fenton reaction is carried out under the optimum dosage, the lowest nickel content in effluent is 0.7 mg / L, and the effluent nickel concentration of ozone catalytic combined process can reach the discharge standard of 0. 1 mg/L.But at the same time there is the problem of excessive cost of ozone addition.By comparing the two processes, it is found that the Fenton process has the advantage of faster reaction rate compared with the ozone catalytic combined process under the high concentration simulated wastewater, while the ozone catalytic combined process is suitable for the low concentration complex nickel wastewater.Therefore, for the wastewater with high nickel complexing content, a two-stage combination of "Fenton ozone catalytic combination" and the concentration of about 15 mg/L between the two processes should be adopted.According to the optimization of "Fenton ozone catalytic combination" combination of simulated wastewater, the effluent of Fenton section only needs to be less than 15 mg/L, and the nickel concentration in water can be treated to less than 0.1 mg/L by the subsequent process.Therefore, the two-stage advanced oxidation combination was optimized.The results show that the nickel concentration in Fenton section can be maintained at about 15 mg/L by reducing the dosage of reagents in Fenton section, and that no alkali precipitation in Fenton effluent is beneficial to the combination with subsequent processes.The hydrogen peroxide residue in the effluent of the Fenton process can guarantee the efficient operation of the subsequent ozone process and simplify the addition process of hydrogen peroxide in the combined ozone catalytic process.The addition of O _ 3 and Fe~(2 at the same time can improve the treatment effect.Therefore, for the wastewater containing complexed nickel, the suitable process is "Fenton O_3/Fe~(2" two-stage advanced oxidation process, and the parameters of the process are optimized.Based on the above research results, the effect of "Fenton O_3/Fe~(2" two-stage advanced oxidation process on actual wastewater treatment was investigated.The experimental results show that when the nickel complexing content is 2~20mg/L, the process is optimized by parameters, and the effluent nickel can reach the discharge standard of 0. 1 mg/L electroplating wastewater.And the removal rate of COD and TPcould reach 9376% and 99% respectively.Compared with the traditional two-stage Fenton process, the cost of this process can be reduced by 30% and 50%, and the purpose of high efficiency and economic treatment of nickel wastewater can be realized.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X781.1

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