纳滤膜孔径对沼液超滤透过液养分富集与膜污染行为的影响  

Effects of membrane pore size on nutrient enrichment and membrane fouling behavior in nanofiltration of ultrafiltration permeate from biogas slurry concentration

作　　者：黄致祥 崔文静[4] 刘婉岑 夏若涵 曹丁戈 丁相瑞 李国学 罗文海 HUANG Zhixiang;CUI Wenjing;LIU Wancen;XIA Ruohan;CAO Dingge;DING Xiangrui;LI Guoxue;LUO Wenhai(Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation,College of Resources and Environmental Sciences,China Agricultural University,Beijing 100193,China;Organic Recycling Research Institute(Suzhou)of China Agricultural University,Suzhou 215100,China;Key Laboratory of Low-carbon Green Agriculture,Ministry of Agriculture and Rural Affairs,P.R.China,Beijing 100193,China;College of Resources and Environment,Qingdao Agricultural University,Qingdao 266109,China)

机构地区：[1]中国农业大学资源与环境学院农田土壤污染防控与修复北京市重点实验室,北京100193 [2]中国农业大学有机循环研究院(苏州),苏州215100 [3]农业农村部农业绿色低碳重点实验室,北京100193 [4]青岛农业大学资源与环境学院,青岛266109

出　　处：《农业工程学报》2023年第8期205-214,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：中国科学技术协会青年人才托举工程项目(YESS20200124);“十四五”国家重点研发计划(2022YFD1900300);中国农业大学2115人才工程资助(2017025)。

摘　　要：超滤(ultrafiltration,UF)能有效浓缩沼液,但透过液中仍含有大量养分,可进一步采用纳滤(nanofiltration,NF)等精密膜浓缩利用。NF膜的孔径会直接影响膜的截留特性和通量,从而影响浓缩性能。为了探究NF膜孔径对沼液浓缩过程养分富集效果和膜污染行为的影响,该研究以鸡粪沼液的UF透过液为研究对象,分别采用800 D、500 D、100 D的NF膜(平均膜孔径分别为2.0、1.0、0.5 nm)进行浓缩,重点分析养分截留效果和膜污染特征。结果表明:不同孔径的NF膜均能高效截留化学需氧量(chemical oxygen demand,COD)和总磷(total phosphorus,TP),截留率可达68%以上,但对总氮(total nitrogen,TN)和总钾(total potassium,TK)的截留较低,仅为19%~35%。随着膜孔径降低,NF对COD、TN、TP、TK的截留效果略有提高,但整体差异不明显。不同孔径NF膜在沼液浓缩过程均出现了明显的水通量降低。与1.0 nm的NF膜相比,0.5 nm膜较小的孔径和2.0 nm膜较大的初始通量均会导致膜表面有机—无机致密污染层的形成,从而造成水通量快速降低;而1.0 nm膜表面形成的以无机晶体为主的污染层较为疏松,通量下降较为缓慢。综合养分截留效果和水通量变化规律,确定孔径为1.0 nm的NF膜更适用于浓缩沼液的UF透过液,研究结果可为推动沼液膜浓缩的发展与工程应用提供理论与技术支撑。Ultrafiltration(UF)can effectively concentrate the biogas slurry,but a large number of nutrients are still remained to be further permeated using nanofiltration(NF)and precision membranes.The pore size of NF membranes can directly dominate the retention characteristics and flux of the membrane,thus affecting the concentration performance.In response to the lack of research on the effect of NF membrane pore size on nutrient enrichment and membrane fouling behavior in the concentration process of biogas slurry,this study aims to determine nutrient retention and the characterization of membrane fouling.The research object was taken as the chicken manure in the biogas slurry of UF,while the NF membranes were set with the membrane pore sizes of 2.0,1.0,0.5 nm for the concentration.Results showed that the retention rates of chemical oxygen demand(COD)by NF membranes of 2.0,1.0,0.5 nm were 68%,77%,and 81%,respectively.The retention rate of COD was higher,as the membrane pore size decreased.By contrast,the retention rates of total nitrogen(TN)by NF membranes of 2.0,1.0,0.5 nm were 29%,30%and 35%,respectively.The retention rate of TN was higher,as the membrane pore size decreased.The retention percentages of total phosphorus(TP)by NF membranes of 2.0,1.0,0.5 nm were 68%,71%,and 73%,respectively.The retention of TP was higher with the decrease in membrane pore size.The retention rates of total potassium(TK)by NF membranes of 2.0,1.0,0.5 nm were 19%,21%and 23%,respectively,where the retention rates of TK were higher,as the membrane pore size decreased.Once the biogas slurry was concentrated to 1/3 of the original volume,there was no difference in the running time between 2.0 and 1.0 nm membrane(1082-1204 min),but the running time of 2.0 and 1.0 nm was significantly less than that of 0.5 nm one(3200 min,P<0.05),indicating that the smaller pore size NF membrane was less efficiency in the concentration.Energy Dispersive Spectrometer(EDS)revealed that the contents of the organic element(C,O,and N)on the surface contamination la

关 键 词：纳滤 膜孔径 鸡粪沼液 膜污染 养分富集 

分 类 号：X713[环境科学与工程—环境工程]