热水解预处理工艺条件对污泥中重金属Cu、Zn稳定性的影响

发布时间：2018-03-30 21:40

  本文选题：热水解条件　切入点：重金属　出处：《武汉理工大学》2015年硕士论文

【摘要】：随着水处理设施的进一步普及,污泥产量日益增多,而重金属作为一种污泥中主要污染物,关于其有效处理途径的研究正在受到越来越多的关注。本文以研究热水解条件对污泥中重金属的化学形态分布的影响为目的,通过单一改变热水解温度或者时间,采用改进BCR法作为重金属不同形态的浸提方法,选取Cu、Zn为重金属代表元素对其浓度及稳定性影响进行研究,寻求最佳的热水解条件;并比较最佳条件下热水解前后污泥的絮体和其中微生物细胞结构、有机物官能团、矿物结晶度变化及处理前后污泥中Cu、Zn的浸出特性变化,试验所得结论如下:(1)随着热水解温度的不断升高,污泥中Cu的浓度由原泥的162.4mg/kg上升至210℃时的193.3mg/kg;Zn的浓度由779.7 mg/kg升至210℃时的975.7mg/kg,均上升20%左右。随着热水解时间的变化,污泥中Cu的浓度升至处理90min时的218.4 mg/kg;而Zn的浓度在30min时达到最大,为975.7mg/kg。(2)当以提高污泥中Cu和Zn的稳定性为目的时,污泥的最佳热水解条件为210℃、30min,其中Cu与Zn的稳定形态所占比例分别达到了83.0%和47.4%,相较于原泥分别增加了11.9%和7.3%。比较210℃、30min热水解处理前后污泥的SEM、FTIR光谱及XRD图谱均可在微观上证明污泥在最佳条件下的热水解有利于其中重金属的稳定化。(3)210℃,30min热水解前后的污泥中Cu的浸出率均基本随着浸提液pH的增加而降低,在pH=12时最低,仅为0.3037%。Zn的浸出率变化规律与Cu相似,不同的是,Zn的浸出率的最低点出现在浸提液pH=10时,Zn的浸出率为0.4123%-0.7526%。在酸性浸提中浸提相同时间,热水解污泥中Cu和Zn的浸出率明显均低于原泥,且Zn的浸出率差异相对较大,在pH=2浸提液中浸提率较原泥减少了5.847%-6.591%。(4)210℃,30min热水解前后的污泥中Cu和Zn在酸性浸提剂中的浸出率均随着浸提时间的延长基本呈增加趋势,其中热水解污泥在酸性浸提剂中浸提15d后Cu的浸出率保持在1.752%-1.978%,较原泥中2.25%左右的浸出率有所降低;相同情况下,原泥中Zn的浸出率为11.91%-14.31%,热水解后则为6.706%-7.716%,浸出率降低明显。而在碱性浸提剂中两种污泥中Cu和Zn的浸出率随浸提时间的增加均变化不大。(5)通过线性拟合可得到热水解前后污泥中Cu、Zn在不同pH浸提液中浸提15d后的浸出率(L)与相应酸溶态占Cu、Zn总量比例(P)的线性关系式,L=aP+b。
[Abstract]:With the further popularization of water treatment facilities, sludge production is increasing day by day. As a major pollutant in sludge, the research on the effective treatment of heavy metals is getting more and more attention.In order to study the influence of hot water hydrolysis conditions on the chemical speciation distribution of heavy metals in sludge, the improved BCR method was adopted to extract different heavy metals by changing the temperature or time of hot water hydrolysis.The effects of Cu Zn as the representative elements of heavy metals on its concentration and stability were studied in order to find the best conditions of hot water hydrolysis, and to compare the flocs of sludge before and after hot water hydrolysis with the microbial cell structure and organic functional groups.The change of mineral crystallinity and leaching characteristics of Cu ~ (2 +) Zn in sludge before and after treatment. The experimental results are as follows: (1) with the increasing of hot water temperature,The concentration of Cu in sludge increased from 162.4mg/kg of raw sludge to 193.3 mg / kg Zn at 210 鈩，

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