中孔吸附树脂对超滤膜不可逆污染的控制研究
发布时间：2018-08-18 19:38
【摘要】：吸附与超滤联用是一种有着广阔应用前景的水处理工艺,但吸附预处理中常用的活性炭等吸附剂对膜污染的控制效果并不理想,研究能够有效控制超滤膜不可逆污染的新型吸附材料对于吸附-超滤组合工艺的推广应用具有重要意义。本论文采用以制膜材料为原料制备的中孔吸附树脂(Mesoporous adsorbent resin,MAR)作为吸附剂控制超滤膜不可逆污染,并与粉末活性炭(Powdered activated carbon,PAC)进行对比,系统考察了吸附剂性质、溶液离子环境、有机物性质、膜材质和工艺形式等多个因素对吸附预处理效能的影响,并结合膜污染阻力分布、有机物迁移规律、滤饼层结构分析和有机物性质表征等手段对吸附预处理影响超滤膜污染的机理进行了探讨。以腐殖酸作为模型污染物,研究了MAR和PAC吸附预处理对不同离子条件下超滤膜不可逆污染的控制效能。结果表明,随着离子强度增加和钙离子浓度升高,有机物分子与膜之间以及有机物分子间的相互作用力增加,膜污染可逆性降低;同时有机物分子与吸附剂间相互作用力的增强促进了吸附预处理对有机物的去除,从而使吸附预处理对膜污染的控制效能有所提高。吸附预处理主要通过减少有机物在膜上的沉积来控制膜污染,中孔结构的MAR能够吸附易被膜截留的大分子组分,而PAC的微孔结构限制了其对分子量较大的有机组分的去除,其主要去除能够透过膜的小分子组分,因而,随着离子强度的增加和钙离子浓度的升高,MAR吸附预处理对膜污染的控制效能提高更为明显,在所考察的大部分离子条件下,MAR吸附预处理对不可逆污染的控制效能明显好于PAC吸附预处理。以腐殖酸、单宁酸、牛血清蛋白和海藻酸钠四种模型有机物作为天然有机物中不同组分的代表物质,系统研究了MAR和PAC吸附预处理对不同性质有机物引起的超滤膜污染的控制效能,并探讨了膜材质和工艺形式(吸附剂颗粒与膜接触和不与膜接触)对吸附预处理效能的影响。结果表明,超滤膜污染特性及吸附预处理对其影响因有机物性质不同而有显著差异,但是吸附预处理对不同材质的两种膜的影响类似。MAR吸附预处理对腐殖酸和牛血清蛋白引起的膜污染有很好的控制效果,但对单宁酸引起的膜污染控制效果较差,而且MAR颗粒是否与膜接触对膜污染控制效果无明显影响。相比而言,PAC颗粒不与膜接触时,PAC吸附预处理使腐殖酸引起的污染略有下降,但PAC颗粒与膜接触时,PAC颗粒与大分子腐殖酸形成了致密滤饼层从而加剧了膜污染;PAC吸附预处理使单宁酸和牛血清蛋白引起的污染都有明显下降,但PAC颗粒的影响方面,PAC颗粒与膜接触对单宁酸引起的膜污染的控制有一定强化作用,而对牛血清蛋白引起的膜污染的控制却有负面影响。海藻酸钠引起的膜污染主要是可逆污染,无论吸附剂颗粒是否与膜接触,MAR和PAC吸附预处理对其都无明显影响。上述分析表明,MAR吸附预处理对分子量较大的疏水性有机组分引起的膜污染控制效果很好,而PAC吸附预处理对分子量较小的疏水性有机组分引起的膜污染有较好的控制效果,但两种吸附剂对亲水性较强的组分引起的膜污染的控制效果都很差。在上述针对模型有机物研究的基础上,选取了松花江水和藻源污染水分别作为以外源有机物为主和以内源有机物为主的典型水体,进一步考察了吸附预处理对多种有机物共存的天然水超滤过程中不可逆膜污染的控制,并采用模拟生产运行工况的一体式吸附-超滤系统进行了连续流运行试验。结果表明,两种原水在有机物分子量分布、亲疏水性分布和荧光光谱等方面都有着明显差别,尽管如此,平板膜短期超滤试验表明MAR吸附预处理对两种原水引起的膜污染的控制效果都好于PAC吸附预处理。连续流运行试验表明,无论是处理松花江水还是藻源污染水,一体式MAR吸附-超滤工艺的不可逆膜污染都显著低于单独超滤;相比而言,一体式PAC吸附-超滤工艺的膜污染明显高于MAR吸附-超滤工艺,而且在处理松花江水时,PAC颗粒与江水中有机物相互作用不断粘附在膜表面,使运行后期的不可逆膜污染明显高于单独超滤工艺。
[Abstract]:The combination of adsorption and ultrafiltration is a kind of water treatment process with broad application prospects, but the effect of adsorbents such as activated carbon in adsorption pretreatment on membrane fouling control is not ideal. Mesoporous adsorbent resin (MAR) was used as adsorbent to control the irreversible fouling of ultrafiltration membrane. The properties of adsorbent, solution ionic environment, organic matter, membrane material and process were systematically investigated by comparing with powdered activated carbon (PAC). The mechanism of adsorption pretreatment on ultrafiltration membrane fouling was discussed by means of resistance distribution of membrane fouling, migration law of organic matter, structure analysis of cake layer and characterization of organic matter properties. The results showed that with the increase of ionic strength and calcium ion concentration, the interaction force between organic molecules and membranes and between organic molecules increased, and the reversibility of membrane fouling decreased. Adsorption pretreatment can control membrane fouling mainly by reducing the deposition of organic matter on the membrane. The MAR with mesoporous structure can adsorb macromolecular components which are easily intercepted by the membrane, while the microporous structure of PAC limits its ability to control membrane fouling. With the increase of ionic strength and calcium ion concentration, the control efficiency of MAR adsorption pretreatment on membrane fouling is more obvious. Under most of the ion conditions, the control efficiency of MAR adsorption pretreatment on irreversible fouling is obviously better than that of PAC adsorption pretreatment. Treatment. Using humic acid, tannic acid, bovine serum albumin and sodium alginate as representative substances of different components of natural organic matter, the control efficiency of MAR and PAC adsorption pretreatment on ultrafiltration membrane fouling caused by different organic matters was studied systematically, and the membrane materials and technological forms were discussed. The results showed that the fouling characteristics of UF membranes and the effects of adsorption pretreatment on the adsorption pretreatment efficiency were significantly different due to the different properties of organic matter, but the effects of adsorption pretreatment on the two membranes with different materials were similar. The results showed that PAC adsorption pretreatment decreased the pollution caused by humic acid slightly when PAC particles were not in contact with membrane, but PAC particles and macromolecular humus when PAC particles were in contact with membrane. The membrane fouling was aggravated by the formation of dense cake layer of acid, and the pollution caused by tannic acid and bovine serum albumin was obviously reduced by PAC adsorption pretreatment. However, the contact between PAC particles and membrane could strengthen the control of membrane fouling caused by tannic acid, while the control of membrane fouling caused by bovine serum albumin was enhanced. Negative effects. Sodium alginate-induced membrane fouling was mainly reversible, and MAR and PAC adsorption pretreatment had no significant effect on the membrane fouling regardless of whether the adsorbent particles were in contact with the membrane. Membrane fouling caused by hydrophobic organic compounds with small molecular weight has better control effect, but the two adsorbents have poor control effect on membrane fouling caused by hydrophilic components. The control of irreversible membrane fouling in the process of ultrafiltration of natural water coexisting with various organic matters by adsorption pretreatment was further investigated in a typical water body dominated by endogenous organic matters. There are obvious differences in hydrophilic and hydrophobic distribution and fluorescence spectra. However, the short-term ultrafiltration test of flat-plate membrane shows that MAR adsorption pretreatment is better than PAC adsorption pretreatment in controlling membrane fouling caused by two kinds of raw water. Compared with MAR adsorption-ultrafiltration process, the irreversible membrane fouling of the integrated PAC adsorption-ultrafiltration process was significantly higher than that of the MAR adsorption-ultrafiltration process. Separate ultrafiltration process.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU991.2
，
本文编号：2190475
[Abstract]:The combination of adsorption and ultrafiltration is a kind of water treatment process with broad application prospects, but the effect of adsorbents such as activated carbon in adsorption pretreatment on membrane fouling control is not ideal. Mesoporous adsorbent resin (MAR) was used as adsorbent to control the irreversible fouling of ultrafiltration membrane. The properties of adsorbent, solution ionic environment, organic matter, membrane material and process were systematically investigated by comparing with powdered activated carbon (PAC). The mechanism of adsorption pretreatment on ultrafiltration membrane fouling was discussed by means of resistance distribution of membrane fouling, migration law of organic matter, structure analysis of cake layer and characterization of organic matter properties. The results showed that with the increase of ionic strength and calcium ion concentration, the interaction force between organic molecules and membranes and between organic molecules increased, and the reversibility of membrane fouling decreased. Adsorption pretreatment can control membrane fouling mainly by reducing the deposition of organic matter on the membrane. The MAR with mesoporous structure can adsorb macromolecular components which are easily intercepted by the membrane, while the microporous structure of PAC limits its ability to control membrane fouling. With the increase of ionic strength and calcium ion concentration, the control efficiency of MAR adsorption pretreatment on membrane fouling is more obvious. Under most of the ion conditions, the control efficiency of MAR adsorption pretreatment on irreversible fouling is obviously better than that of PAC adsorption pretreatment. Treatment. Using humic acid, tannic acid, bovine serum albumin and sodium alginate as representative substances of different components of natural organic matter, the control efficiency of MAR and PAC adsorption pretreatment on ultrafiltration membrane fouling caused by different organic matters was studied systematically, and the membrane materials and technological forms were discussed. The results showed that the fouling characteristics of UF membranes and the effects of adsorption pretreatment on the adsorption pretreatment efficiency were significantly different due to the different properties of organic matter, but the effects of adsorption pretreatment on the two membranes with different materials were similar. The results showed that PAC adsorption pretreatment decreased the pollution caused by humic acid slightly when PAC particles were not in contact with membrane, but PAC particles and macromolecular humus when PAC particles were in contact with membrane. The membrane fouling was aggravated by the formation of dense cake layer of acid, and the pollution caused by tannic acid and bovine serum albumin was obviously reduced by PAC adsorption pretreatment. However, the contact between PAC particles and membrane could strengthen the control of membrane fouling caused by tannic acid, while the control of membrane fouling caused by bovine serum albumin was enhanced. Negative effects. Sodium alginate-induced membrane fouling was mainly reversible, and MAR and PAC adsorption pretreatment had no significant effect on the membrane fouling regardless of whether the adsorbent particles were in contact with the membrane. Membrane fouling caused by hydrophobic organic compounds with small molecular weight has better control effect, but the two adsorbents have poor control effect on membrane fouling caused by hydrophilic components. The control of irreversible membrane fouling in the process of ultrafiltration of natural water coexisting with various organic matters by adsorption pretreatment was further investigated in a typical water body dominated by endogenous organic matters. There are obvious differences in hydrophilic and hydrophobic distribution and fluorescence spectra. However, the short-term ultrafiltration test of flat-plate membrane shows that MAR adsorption pretreatment is better than PAC adsorption pretreatment in controlling membrane fouling caused by two kinds of raw water. Compared with MAR adsorption-ultrafiltration process, the irreversible membrane fouling of the integrated PAC adsorption-ultrafiltration process was significantly higher than that of the MAR adsorption-ultrafiltration process. Separate ultrafiltration process.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU991.2
，
本文编号：2190475
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