【摘要】：吸附與超濾聯(lián)用是一種有著廣闊應用前景的水處理工藝,但吸附預處理中常用的活性炭等吸附劑對膜污染的控制效果并不理想,研究能夠有效控制超濾膜不可逆污染的新型吸附材料對于吸附-超濾組合工藝的推廣應用具有重要意義。本論文采用以制膜材料為原料制備的中孔吸附樹脂(Mesoporous adsorbent resin,MAR)作為吸附劑控制超濾膜不可逆污染,并與粉末活性炭(Powdered activated carbon,PAC)進行對比,系統(tǒng)考察了吸附劑性質(zhì)、溶液離子環(huán)境、有機物性質(zhì)、膜材質(zhì)和工藝形式等多個因素對吸附預處理效能的影響,并結(jié)合膜污染阻力分布、有機物遷移規(guī)律、濾餅層結(jié)構(gòu)分析和有機物性質(zhì)表征等手段對吸附預處理影響超濾膜污染的機理進行了探討。以腐殖酸作為模型污染物,研究了MAR和PAC吸附預處理對不同離子條件下超濾膜不可逆污染的控制效能。結(jié)果表明,隨著離子強度增加和鈣離子濃度升高,有機物分子與膜之間以及有機物分子間的相互作用力增加,膜污染可逆性降低;同時有機物分子與吸附劑間相互作用力的增強促進了吸附預處理對有機物的去除,從而使吸附預處理對膜污染的控制效能有所提高。吸附預處理主要通過減少有機物在膜上的沉積來控制膜污染,中孔結(jié)構(gòu)的MAR能夠吸附易被膜截留的大分子組分,而PAC的微孔結(jié)構(gòu)限制了其對分子量較大的有機組分的去除,其主要去除能夠透過膜的小分子組分,因而,隨著離子強度的增加和鈣離子濃度的升高,MAR吸附預處理對膜污染的控制效能提高更為明顯,在所考察的大部分離子條件下,MAR吸附預處理對不可逆污染的控制效能明顯好于PAC吸附預處理。以腐殖酸、單寧酸、牛血清蛋白和海藻酸鈉四種模型有機物作為天然有機物中不同組分的代表物質(zhì),系統(tǒng)研究了MAR和PAC吸附預處理對不同性質(zhì)有機物引起的超濾膜污染的控制效能,并探討了膜材質(zhì)和工藝形式(吸附劑顆粒與膜接觸和不與膜接觸)對吸附預處理效能的影響。結(jié)果表明,超濾膜污染特性及吸附預處理對其影響因有機物性質(zhì)不同而有顯著差異,但是吸附預處理對不同材質(zhì)的兩種膜的影響類似。MAR吸附預處理對腐殖酸和牛血清蛋白引起的膜污染有很好的控制效果,但對單寧酸引起的膜污染控制效果較差,而且MAR顆粒是否與膜接觸對膜污染控制效果無明顯影響。相比而言,PAC顆粒不與膜接觸時,PAC吸附預處理使腐殖酸引起的污染略有下降,但PAC顆粒與膜接觸時,PAC顆粒與大分子腐殖酸形成了致密濾餅層從而加劇了膜污染;PAC吸附預處理使單寧酸和牛血清蛋白引起的污染都有明顯下降,但PAC顆粒的影響方面,PAC顆粒與膜接觸對單寧酸引起的膜污染的控制有一定強化作用,而對牛血清蛋白引起的膜污染的控制卻有負面影響。海藻酸鈉引起的膜污染主要是可逆污染,無論吸附劑顆粒是否與膜接觸,MAR和PAC吸附預處理對其都無明顯影響。上述分析表明,MAR吸附預處理對分子量較大的疏水性有機組分引起的膜污染控制效果很好,而PAC吸附預處理對分子量較小的疏水性有機組分引起的膜污染有較好的控制效果,但兩種吸附劑對親水性較強的組分引起的膜污染的控制效果都很差。在上述針對模型有機物研究的基礎(chǔ)上,選取了松花江水和藻源污染水分別作為以外源有機物為主和以內(nèi)源有機物為主的典型水體,進一步考察了吸附預處理對多種有機物共存的天然水超濾過程中不可逆膜污染的控制,并采用模擬生產(chǎn)運行工況的一體式吸附-超濾系統(tǒng)進行了連續(xù)流運行試驗。結(jié)果表明,兩種原水在有機物分子量分布、親疏水性分布和熒光光譜等方面都有著明顯差別,盡管如此,平板膜短期超濾試驗表明MAR吸附預處理對兩種原水引起的膜污染的控制效果都好于PAC吸附預處理。連續(xù)流運行試驗表明,無論是處理松花江水還是藻源污染水,一體式MAR吸附-超濾工藝的不可逆膜污染都顯著低于單獨超濾;相比而言,一體式PAC吸附-超濾工藝的膜污染明顯高于MAR吸附-超濾工藝,而且在處理松花江水時,PAC顆粒與江水中有機物相互作用不斷粘附在膜表面,使運行后期的不可逆膜污染明顯高于單獨超濾工藝。
[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.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：TU991.2
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本文編號：2190475