摘要
以城市污水二级出水为过滤介质,考察了PVA、PVP、PMMA等与PVDF的二元及三元共混超滤膜的过滤污染行为.结果表明,共混优化了PVDF超滤膜的结构参数,添加剂PVP、PVA可有效改善膜的亲水化程度,提高膜渗透通量.超滤膜的亲水性和结构特性对膜抗污染性能影响较大;堵孔阻力是二级出水过滤膜污染不可逆的主要原因.亲水性较强的超滤膜,二级出水过滤初期易因浓差极化而导致滤饼层污染,造成一定的通量衰减,但易清洗恢复,不可逆污染指数(rir)为0,抗污染性能好.致密的超滤膜表面有利于防止二级出水中的中低分子量污染物进入膜内部,而断面通透大孔和疏松海绵层结构的超滤膜,能减少二级出水中的污染物在膜中沉积形成堵孔阻力.膜表面多孔,内部大孔发育不充分,易形成堵孔污染,通量衰减大且不易清洗恢复,膜污染不可逆.
The fouling behavior of UF membranes by secondary effluent of municipal wastewater was investigated using both original PVDF membranes and PVA,PVP and PMMA modified PVDF membranes.The results showed that the structure parameters of UF membranes were optimized by blending;PVP and PVA could effectively improve the hydrophilicity and permeate flux of the membranes.The hydrophilicity and structure properties of UF membrane had stronger effect on the anti-fouling properties.Pore plugging resistance was the main reason for the unrecoverable fouling.For UF membranes with stronger hydrophilicity,there was some flux reduction in the initial filtration,which was attributed to the formation of concentration polarization layer.However,this layer can be easily removed and the irreversible fouling index（rir） was 0,thus guaranteeing the membrane a better anti-fouling property.The dense membrane surface could prevent low-molecular-weight pollutants from entering the internal pores of the membrane.For UF membrane with fully developed macropores in the cross-section and loose spongy layer structure,pollutants deposition to membrane internal pores,which would cause membrane pore plugging,could be effectively inhibited.In contrast,for membranes with porous surface and not fully developed macropores in the cross-section,pore plugging was more prone to occur.As a result,flux declined seriously and was difficult to be recovered by physical cleaning,which gave rise to the irreversible fouling.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2013年第5期1822-1827,共6页
Environmental Science
基金
国家自然科学基金项目(51008243
51178378
51278408)
陕西省科技统筹创新工程计划项目(2012KTCL03-06)
陕西省榆林市科技项目(2011)
西安市碑林区科技项目(GX1105)
关键词
城市污水
超滤
膜结构
膜性质
膜污染
urban sewage
ultrafiltration
membrane structure
membrane properties
membrane fouling
