不同分子量及离子度的CPAM对污泥脱水性能的影响研究  

Effect of different molecular weight and ionic strength of CPAM on sludge dewaterability

作　　者：郑育毅[1,2] 江娟[1,2] 孙启元[1,2] 刘常青[3] 

机构地区：[1]福建师范大学环境科学与工程学院,福州350007 [2]福建师范大学环境科学研究所,福州350007 [3]福建师范大学地理科学学院,福州350007

出　　处：《环境科学学报》2016年第8期2947-2954,共8页Acta Scientiae Circumstantiae

基　　金：福建省科技重大专项专题(No.2014YZ0002-1;2015YZ0001-1);福建省自然科学基金(No.2015J01187);国家自然科学基金青年基金(No.51509037)~~

摘　　要：阳离子聚丙烯酰胺(CPAM)以其良好的絮凝效果被广泛用于改善市政污泥的脱水性能.然而,由于CPAM的分子量和离子度存在多样性,其促进市政污泥脱水的机理尚不明确.本研究通过测定CPAM调理后的污泥比阻、污泥上清液浊度、Zeta电位、胞外聚合物,对12组不同分子量和离子度的CPAM促进污泥脱水的机理进行研究.结果表明:CPAM能显著提高胶体絮凝能力,进而改善污泥的脱水性能;在CPAM的离子度或者分子量较低(离子度40%或分子量6×106)时,其絮凝机理主要表现为吸附架桥;随着离子度和分子量增加到50%和8×106时,CPAM的电中和作用显著增强,并与吸附架桥作用协同促进污泥的絮凝脱水;CPAM离子度的增加更能减少胞外聚合物中核酸含量,这有利于降低污泥亲水性能,从而促进其脱水.Cationic polyacrylamide（CPAM） has been widely used to improve the dewatering of municipal sludge with its superior flocculation effect.However,because of the diversity of the molecular weight and ionic degree for CPAM,its dewatering mechanism remains unclear.In this study,the dewatering mechanism was discussed through a series of experimental design on CPAMs with 12 combinations with 4 molecular weights and 3 ionic degrees.The studied indicators included the supernatant turbidity,the specific resistance of sludge,the Zeta potential,and extracellular polymer.The results showed that absorption and bridge may be the dominant dewatering mechanism for CPAM with low molecular weight（6×106） or ionic degree（40%）.For CPAM high molecular weight and ionic degree,on the other hand,the synergistic effect between adsorption-bridging and electrical neutralization may be the dominant process.The decrease in nucleic acid content in extracellular polymer with the increasing ionic degree may weaken the hydrophilicity of sludge.

关 键 词：阳离子聚丙烯酰胺 脱水性能 絮凝机理 分子量 离子度 

分 类 号：X703[环境科学与工程—环境工程]