脱墨污泥中重金属的电动学去除研究
发布时间：2019-06-08 08:18
【摘要】：废纸资源的利用越来越受到人们的高度重视,由于脱墨污泥中内含有重金属元素造成了生态安全隐患。本论文利用电动学方法强化去除脱墨污泥中的重金属。分别尝试对比了柠檬酸、磷酸、倒极NTA络合、可渗透反应墙催化、倒极、阳极靠近、倒极+电渗析等不同体系实时检测实验参数和最终去除效果,在此基础上提出了倒极+电渗析循环的综合处理技术,结果表明这是一种能耗小,污染少,成本低,持续有效去除多种重金属离子的理想电动学方法。在柠檬酸CITRIC体系中Zn的去除率71%。并且发现最难去除的区域不是最直接靠近阴极区域的4区,而是在污泥中间区域的偏阴极部分,并且发现部分金属如铅络合后络合基团离子带负电朝阳极方向迁移富集。在磷酸POSPHATE体系中发现磷酸与Cd形成的盐类物质溶解度低,去除效果较差。虽然磷酸可以在反应启动时可以给整个污泥环境提供酸性更强的重金属活化破解释放效果,但并非所有的重金属在所有区域都会得到降低去除,部分区域的污泥仍然会在处理后产生局部富集。NTA络合体系中Pb最难去除(17%),Zn去除效果最高(82%)。对比后发现Pb的去除率瓶颈在靠近阴极区域污泥的可提取态上,这说明控制阴极的pH对于NTA络合实验尤为重要,而其他大多重金属去除瓶颈在3区污泥。可渗透反应墙催化体系PEB实验中将Cd富集超原污泥4%,Cr去除78%。发现还原铁粉可以使得整个实验过程中pH变化更为温和,电导率变化范围变小,使得整个污泥室pH环境易于可控、较为理想的状态。倒极体系RERESAL实验中只能将Cd去除26%,而Zn的去除率达到了所有实验最高水平86%,这说明灵活多变的电迁移方向、不同区域倒极pH变化可以提高Zn、Mn、Pb、Cr等易迁移络合元素的去除率。阳极靠近APPROACHING实验可将大多金属去除率保持在50%以上的较高水品,同时更大面积的降低了污泥pH,提高污泥破解效果。但是也带来了阳极腐蚀的成本问题,另外由于背离阳极靠近方向的污泥在阳极靠近后并没有采取隔离措施,所以导致其区域重金属去除率较低。综合六次实验后提出的倒极+电渗析RECCYCLE实验既可以很好地平衡污泥室内的pH环境,并且增加电导率,提高例如置换阴极液的提取重金属效率,重金属去除率也达到了较为满意的水平。展望未来,电渗析循环浓缩处理提取液是一种节省成本、便于场地修复的可行技术,但是其重金属浓缩效果和半透膜污染防堵的细节还需进一步控制和挖掘。
[Abstract]:The utilization of waste paper resources has been paid more and more attention, and the hidden danger of ecological security is caused by the heavy metal elements in deinking sludge. In this paper, electrokinetic method was used to strengthen the removal of heavy metals from deinked sludge. The experimental parameters and final removal efficiency of citric acid, phosphate, inverted NTA complexation, permeable reaction wall catalysis, inverted electrode, anode proximity, inverted electrode electrodialysis and other different systems were compared. On this basis, the comprehensive treatment technology of inverted electrode electrodialysis cycle is put forward. The results show that it is an ideal electrokinetic method for the removal of many kinds of heavy metal ions continuously and effectively, which has the advantages of low energy consumption, less pollution, low cost and continuous and effective removal. The removal rate of Zn in citric acid CITRIC system is 71%. It is found that the most difficult region is not the four regions which are closest to the cathode region most directly, but the partial cathode part in the middle region of the sludge, and it is found that some metals, such as lead complex group ion bands, migrate and enrich negatively in the direction of the anode. In the phosphate POSPHATE system, it is found that the solubility of the salt formed by phosphate and Cd is low and the removal effect is poor. Although phosphate can provide more acidic activation and release of heavy metals to the whole sludge environment at the start of the reaction, not all heavy metals will be reduced and removed in all areas. The sludge in some areas will still be locally enriched after treatment. Pb is the most difficult to remove in NTA complex system (17%), Zn removal efficiency is the highest (82%). After comparison, it is found that the bottleneck of Pb removal rate is in the extractable state of sludge near the cathode area, which indicates that the control of cathode pH is particularly important for NTA complexation experiment, while most of the other heavy metal removal bottlenecks are in area 3 sludge. In the PEB experiment of permeable reaction wall catalytic system, Cd was enriched in 4% of the raw sludge and 78% of the Cr was removed. It is found that reducing iron powder can make the change of pH more mild and the range of conductivity smaller in the whole experiment process, which makes the pH environment of the whole sludge chamber easy to control and ideal. In the reverse electrode system RERESAL experiment, only 26% of Cd can be removed, and the removal rate of Zn reaches the highest level of 86% in all experiments, which indicates that the flexible electromigration direction and the change of reverse pole pH in different regions can improve Zn,Mn,Pb,. The removal rate of easily migrated complex elements such as Cr. The anode near APPROACHING experiment can keep the removal rate of most metals above 50% of the higher water products, and at the same time, the sludge pH, can be reduced in a larger area to improve the sludge cracking effect. However, it also brings the cost of anode corrosion. In addition, the sludge which deviates from the direction of anode proximity does not take isolation measures after the anode approaches, so the removal rate of heavy metals in the area is low. The inverted electrodialysis RECCYCLE experiment proposed after six experiments can not only balance the pH environment in the sludge chamber, but also increase the conductivity and improve the efficiency of heavy metal extraction, for example, replacing the cathode solution. The removal rate of heavy metals has also reached a satisfactory level. Looking forward to the future, electrodialysis cycle concentration treatment of extract is a feasible technology to save cost and facilitate site repair, but its heavy metal concentration effect and the details of semi-permeable membrane fouling and blocking prevention need to be further controlled and excavated.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
本文编号：2495141
[Abstract]:The utilization of waste paper resources has been paid more and more attention, and the hidden danger of ecological security is caused by the heavy metal elements in deinking sludge. In this paper, electrokinetic method was used to strengthen the removal of heavy metals from deinked sludge. The experimental parameters and final removal efficiency of citric acid, phosphate, inverted NTA complexation, permeable reaction wall catalysis, inverted electrode, anode proximity, inverted electrode electrodialysis and other different systems were compared. On this basis, the comprehensive treatment technology of inverted electrode electrodialysis cycle is put forward. The results show that it is an ideal electrokinetic method for the removal of many kinds of heavy metal ions continuously and effectively, which has the advantages of low energy consumption, less pollution, low cost and continuous and effective removal. The removal rate of Zn in citric acid CITRIC system is 71%. It is found that the most difficult region is not the four regions which are closest to the cathode region most directly, but the partial cathode part in the middle region of the sludge, and it is found that some metals, such as lead complex group ion bands, migrate and enrich negatively in the direction of the anode. In the phosphate POSPHATE system, it is found that the solubility of the salt formed by phosphate and Cd is low and the removal effect is poor. Although phosphate can provide more acidic activation and release of heavy metals to the whole sludge environment at the start of the reaction, not all heavy metals will be reduced and removed in all areas. The sludge in some areas will still be locally enriched after treatment. Pb is the most difficult to remove in NTA complex system (17%), Zn removal efficiency is the highest (82%). After comparison, it is found that the bottleneck of Pb removal rate is in the extractable state of sludge near the cathode area, which indicates that the control of cathode pH is particularly important for NTA complexation experiment, while most of the other heavy metal removal bottlenecks are in area 3 sludge. In the PEB experiment of permeable reaction wall catalytic system, Cd was enriched in 4% of the raw sludge and 78% of the Cr was removed. It is found that reducing iron powder can make the change of pH more mild and the range of conductivity smaller in the whole experiment process, which makes the pH environment of the whole sludge chamber easy to control and ideal. In the reverse electrode system RERESAL experiment, only 26% of Cd can be removed, and the removal rate of Zn reaches the highest level of 86% in all experiments, which indicates that the flexible electromigration direction and the change of reverse pole pH in different regions can improve Zn,Mn,Pb,. The removal rate of easily migrated complex elements such as Cr. The anode near APPROACHING experiment can keep the removal rate of most metals above 50% of the higher water products, and at the same time, the sludge pH, can be reduced in a larger area to improve the sludge cracking effect. However, it also brings the cost of anode corrosion. In addition, the sludge which deviates from the direction of anode proximity does not take isolation measures after the anode approaches, so the removal rate of heavy metals in the area is low. The inverted electrodialysis RECCYCLE experiment proposed after six experiments can not only balance the pH environment in the sludge chamber, but also increase the conductivity and improve the efficiency of heavy metal extraction, for example, replacing the cathode solution. The removal rate of heavy metals has also reached a satisfactory level. Looking forward to the future, electrodialysis cycle concentration treatment of extract is a feasible technology to save cost and facilitate site repair, but its heavy metal concentration effect and the details of semi-permeable membrane fouling and blocking prevention need to be further controlled and excavated.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
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