人工湿地基质配制对废水中重金属Pb的钝化吸附效果研究

发布时间：2018-10-24 15:22

【摘要】：水是生命之源,水是生存之本。随着经济的高速发展,人口不断增加,水环境问题成了限制人类发展甚至生存的关键因素之一。近年来,我国工农矿业和交通运输业发展迅猛,但随之带来的重金属污染已经成为了国内关注的焦点话题。因此,重金属废水的处理研究对生态环境保护和国内经济发展具有重要意义。本课题以黄土、污泥、细沙、煤渣、粉煤灰及砾石为原材料,按一定的比例配制5种不同的湿地基质(基质SSFGF、FSSGF、FSSFF、FSSFG和FSFGF),置于无植被垂直流人工湿地系统中,控制水力停留时间为0.25、0.5、1、2、4、8、12、24和48 h,处理含Pb浓度分别为10、20、40、80、160 mg/L铅废水。测定处理前5种基质的理化指标以及各处理后出水中Pb浓度和基质中赋存的Pb的5个形态(可交换态、碳酸盐结合态、有机结合态、铁锰氧化态和残渣态)含量,通过方差分析、相关性等统计分析方法综合评价得出:(1)浓度分别为10、20、40、80和160 mg/L的含Pb废水经5种不同基质的湿地处理后Pb在一定程度上被去除,尤其是在最佳水力停留时间12h时5种基质的吸附钝化处理效果都较好,SSFGF基质湿地Pb的去除率为75.41-81.91%,平均值为79.01%;FSSGF基质湿地Pb的去除率为83.04-94.19%,平均值为89.07%;FSSFF基质湿地Pb的去除率为81.34-92.78%,平均值为86.27%;FSSFG基质湿地Pb的去除率为47.86-92.43%,平均值为73.75%;FSFGF基质湿地Pb的去除率为44.70-90.42%,平均值为68.40%。相较,基质为FSSGF和FSSFF的湿地对含Pb废水的去除效果更佳;(2)方差分析与多重比较表明同一水力停留时间下处理同一浓度废水后,不同基质湿地对废水中Pb的去除率之间存在着显著性差异;并且不同基质中赋存的Pb的5个形态含量之间存在着显著性差异;(3)相同水力停留时间下,不同湿地系统处理不同浓度的废水后各基质中赋存的Pb的各形态含量所占百分比之间存在着一定的差异,但是总体上重金属Pb赋存于各基质中残渣态含量所占比例最高,在30-45%;重金属Pb赋存于各基质中的可交换态和碳酸盐结合态含量所占比例之和在21-27%。(4)将水力停留时间为12h时5种湿地对废水中Pb的去除率与湿地基质的物化指标进行相关性分析表明,一定条件下去除率与基质的D10、D80、CEC、导水率、交换性Ca、交换性Al和有效性Fe显著相关,且为负相关关系,结合线性回归方程表明5种基质湿地对废水中Pb的去除率会随着基质中上述指标的增大而减小;(5)将水力停留时间为12 h时5种基质中赋存的各形态Pb含量与基质的理化指标进行的相关性分析表明,一定条件下基质中赋存的可交换态和碳酸盐结合态Pb含量与D10、D80、K80、CEC、导水率、交换性Ca、有效性Fe显著相关,且为正相关关系,与有效性Mn显著相关,且为负相关关系;残渣态Pb含量与D10、CEC和容重显著相关,且为正相关关系,与有效性Mn、总孔隙度、K80和交换性Al显著相关,且为负相关关系。
[Abstract]:Water is the source of life, water is the basis of survival. With the rapid development of economy and the increasing population, water environment has become one of the key factors restricting human development and even survival. In recent years, China's industry, agriculture, mining and transportation industry has developed rapidly, but the heavy metal pollution has become the focus of attention in China. Therefore, the treatment of heavy metal wastewater is of great significance to the protection of ecological environment and the development of domestic economy. Using loess, sludge, fine sand, cinder, fly ash and gravel as raw materials, five different wetland substrates (matrix SSFGF,FSSGF,FSSFF,FSSFG and FSFGF),) were prepared in this paper. The hydraulic retention time (HRT) is 0. 25? 0. 5? 1? 5? 1? The physicochemical indexes of the first five substrates and the concentrations of Pb in effluent and the five forms of Pb (exchangeable, carbonate bound, organic bound, iron-manganese oxidized and residual) were determined. By means of variance analysis, correlation analysis and other statistical analysis methods, it was concluded that: (1) Pb wastewater containing 10 ~ 20 ~ 4080 and 160 mg/L was treated with five different substrates to some extent Pb was removed. The removal rate of Pb in SSFGF substrates wetland was 75.41-81.91, the average value was 79.01%, the removal rate of Pb was 83.04-94.19g, and the average value was 89.07g Pb in FSSFF matrix wetland. The adsorption passivation effect of the five substrates was better when the optimal HRT was 12h, and the removal rate of Pb was 75.41-81.91g, with an average of 83.04-94.19g. The average removal rate of Pb was 47.86-92.433.The average rate was 73.75cm and the removal rate of Pb was 44.70-90.42, and the average was 68.40. Compared with the wetland with FSSGF and FSSFF, the removal efficiency of the wastewater containing Pb was better. (2) the analysis of variance and the multiple comparison showed that the wastewater of the same concentration was treated with the same HRT. There were significant differences in the removal rate of Pb among different substrates wetland, and there were significant differences among the five speciation contents of Pb in different substrates. (3) under the same HRT, There were some differences in the percentage of Pb forms in different substrates after treatment of wastewater with different concentrations in different wetland systems, but in general, the residual content of Pb was the highest in different substrates. The ratio of exchangeable and carbonate bound state content of heavy metal Pb in various substrates was 21-27%. (4) the removal rate of Pb in wastewater and the physicochemical index of wetland substrate were determined when the HRT was 12 h. Correlation analysis shows that Under certain conditions, the removal rate was significantly correlated with D10 / D80 CEC, water conductivity, exchangeable Ca, exchangeable Al, and available Fe, and was negatively correlated with each other. Combined with the linear regression equation, the removal rate of Pb in wastewater from 5 kinds of substrates wetland will decrease with the increase of the above mentioned indexes in the substrate. (5) the content of Pb in the five substrates and the matrix when the HRT is 12 h. The correlation analysis of physical and chemical indexes based on the Under certain conditions, the interchangeable and carbonate bound Pb content in the matrix was significantly correlated with the Fe, water conductivity and exchangeable Ca, availability of D10 D80 K80, and was positively correlated with the availability of Mn, and negatively correlated with the available Mn. The residual Pb content was positively correlated with D10 CEC and bulk density, and negatively correlated with the total porosity of available Mn, K80 and exchangeable Al.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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