聚丙烯酰胺残留物在矿井水处理中的迁移规律

Migration rule of polyacrylamide residue in mine water treatment

  • 摘要: 聚丙烯酰胺(PAM)作为一种高效絮凝剂被广泛应用于矿井水处理过程中,PAM残留物丙烯酰胺(AM)单体存在于矿井水处理环节中,而AM已被国家癌症中心列为ⅡA类致癌物。为揭示PAM残留物AM在矿井水处理中的迁移规律,对10个矿区的矿井水处理环节进行了检测分析,并通过混凝沉淀与过滤实验研究了PAM投加量、分子量、水解度、矿井水pH值和含盐量等因素对AM质量浓度和处理效果的影响。结果表明:在调研的10个矿区的矿井水处理中,有80%的澄清(沉淀)池出水AM质量浓度>0.000 5 mg/L,在0.001 7~0.087 5 mg/L,有60%的过滤出水AM质量浓度﹥0.000 5 mg/L,在0.001 1~0.076 7 mg/L,过滤过程对AM的去除率在12.3%~99.1%,矿井水常规处理难以保证AM质量浓度满足饮用水标准,回用于饮用水需考虑PAM选型和投加量的优化,或采用反渗透等膜技术处理;在试验条件下(PAM投加量0.5~2.5 mg/L、分子量500万~1 800万、水解度5%~30%、聚合氯化铝投加量为80 mg/L),AM质量浓度在沉淀与过滤2个处理环节均随各因素水平的增加而呈现先减小后增加的趋势,过滤过程对AM的去除率在30.0%~58.3%,当PAM投加量为1.0 mg/L、分子量为1 200万、水解度为22%,原水pH值为7、电导率为2 000 μS/cm时,沉淀和过滤出水AM质量浓度最低,实验中最低值分别为0.002 6和0.001 2 mg/L。

     

    Abstract: Polyacrylamide (PAM) is widely used as a high-efficiency flocculant in the process of mine water treatment.Acrylamide (AM) monomer exists as a residue of PAM in the mine water treatment process,and AM has been listed as ⅡA carcinogen by the National Cancer Center.In order to reveal the migration rule of PAM residue AM in mine water treatment,mine water treatment units in 10 mines are tested and analyzed,and the impacts of PAM dosage,molecular weight,degree of hydrolysis,pH value and salt content of mine water on AM content and treatment effect were studied through coagulation sedimentation and filtration experiments.The results show that in the mine water treatment of 10 mining areas investigated,80% of the clarifier (sedimentation) effluent AM content is more than 0000 5 mg/L,between 0.001 7 mg/L and 0.087 5 mg/L,and 60% of the filtered effluent AM content is more than 0.000 5 mg/L,between 0.001 1 mg/L and 0.076 7 mg/L,the removal rate of AM in the filtration process is 12.3%-99.1%.It is difficult to ensure that the content of AM in the mine water can meet the drinking water standard in the conventional treatment.The optimization of PAM type selection and dosage should be considered in the reuse of drinking water,or membrane technology such as reverse osmosis should be used.Under the experimental conditions (PAM dosage:0.5-2.5 mg/L,PAM molecular weight:5 million-18 million,PAM hydrolysis degree:5%-30%,poly aluminum chloride dosage:80 mg/L),the content of AM first decreased and then increased with an increasing level of various factors in both precipitation and filtration units.The removal rate of AM is 30.0%-58.3% in filtration unit.When PAM dosage is 1.0 mg/L,molecular weight is 12 million,hydrolysis degree is 22%,pH value of raw water is 7,conductivity is 2 000 μS/cm,AM content of precipitated and filtered water is the lowest,the lowest values in the experiment are 0.002 6 and 0.001 2 mg/L respectively.

     

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