硅酸鹽復(fù)合基微濾膜的制備及其用于水處理除污染的研究
發(fā)布時間：2018-08-25 20:26
【摘要】：面對日益嚴(yán)重的水環(huán)境污染,常規(guī)的飲用水處理工藝某些時候已難以滿足要求。以膜過濾技術(shù)和高級氧化技術(shù)為代表的新型飲用水處理技術(shù)開始受到人們的關(guān)注。膜過濾技術(shù)和高級氧化技術(shù)均因成本過高而難以大規(guī)模應(yīng)用。其中,膜過濾技術(shù)中的膜成本和高級氧化技術(shù)中的催化劑成本是制約技術(shù)發(fā)展的關(guān)鍵。因此需要開發(fā)出廉價而高效的膜和催化劑。本文以廉價的硅酸鹽水泥和石英微粉為原料,在室溫環(huán)境下制備出一種低成本、平板型硅酸鹽復(fù)合基微濾膜�？疾炝酥颇み^程中各工藝參數(shù)對膜的影響,進而優(yōu)選出制膜的最佳工藝條件。通過掃描電鏡分析、孔徑分析、能量色散X射線光譜分析等手段,研究了硅酸鹽復(fù)合基微濾膜的膜孔形成機制,并對膜的結(jié)構(gòu)、組成和應(yīng)用性能等進行了深入的表征和分析。本文還將制備的硅酸鹽復(fù)合基微濾膜作為一種新型催化劑來催化臭氧降解水中有機污染物�？疾炝顺粞�-膜聯(lián)用工藝去除水中對氯硝基苯(p-CNB,p-chloronitrobenzene)的效能和機理。通過對膜制備過程中成型壓力、顆粒粒徑、水與硅酸鹽水泥比例(w/c)、造孔劑和熟化方式等的考察,確定了制膜的各工藝參數(shù)為:成型壓力6 MPa,石英粒徑40.6-50.0μm,硅酸鹽水泥粒徑14.6μm,w/c 0.4,20℃、95%相對濕度的空氣中熟化12天。依此條件制備的硅酸鹽復(fù)合基微濾膜可以實現(xiàn)2.3μm的平均孔徑,34%的孔隙率,13 m3?m-2?h-1?bar-1的純水通量和4 MPa的抗彎強度。該條件下膜的孔徑只呈現(xiàn)出雙峰分布的特點。通過降低制膜所用石英與硅酸鹽水泥的比例(q/c)至2.0,成功將膜的孔徑分布由雙峰分布改善為單峰分布。并依據(jù)該過程中膜孔的變化情況,分析出膜內(nèi)微米級通透孔的形成機制。硅酸鹽復(fù)合基微濾膜內(nèi)的通透孔按成因大體可概括為三類。第一類是孔徑7-8μm的膜孔,主要通過膜內(nèi)石英顆粒的堆積作用而形成;第二類膜孔的孔徑大體分布在1-3μm,是膜內(nèi)占最大比例的膜孔,這類孔主要來源于硅酸鹽水泥顆粒的堆積作用。第三類膜孔的尺寸大多在1μm以下,其孔的形成主要來源于膜內(nèi)大量生長的針狀鈣礬石對大孔徑膜孔的切割作用。通過將膜內(nèi)q/c的值控制在2.0,不僅優(yōu)化了膜的孔徑分布,還使膜的抗彎強度提升到5-6 MPa,此時膜的平均孔徑僅為1μm,膜孔隙率和純水通量的結(jié)果也能滿足要求。以篩選出的制膜條件制備硅酸鹽復(fù)合基微濾膜,并對膜的結(jié)構(gòu)和性能進行了深入的研究。對膜的結(jié)構(gòu)表征發(fā)現(xiàn),膜內(nèi)的硅酸鹽水泥在發(fā)生水化反應(yīng)后,主要的水化產(chǎn)物為水合硅酸鈣聚合物,在膜內(nèi)呈膠凝狀分布。其他產(chǎn)物還包括平板狀的氫氧化鈣,針狀或薄片狀的鈣礬石等。硅酸鹽復(fù)合基微濾膜的膜孔包含微米級孔和介孔兩部分,其中微米級膜孔的孔體積在膜內(nèi)占絕對優(yōu)勢。膜內(nèi)微米級膜孔的平均孔徑為1μm,介孔的平均孔徑為13.5 nm。對膜性能的研究發(fā)現(xiàn),硅酸鹽復(fù)合基微濾膜具有與傳統(tǒng)陶瓷膜相近的氣液通量,對5×107個/L濃度的小球藻和10 NTU濁度的無機顆粒均可實現(xiàn)80%以上的去除。其中對小球藻的去除更有優(yōu)勢。但在膜污染方面,膜的藻類污染卻比無機污染更難被清除。進一步的性能表征發(fā)現(xiàn),硅酸鹽復(fù)合基微濾膜可以承受500℃的熱處理和0.01mol/L的堿腐蝕,在水環(huán)境中使用可保證水質(zhì)的安全和膜的穩(wěn)定。將制備的硅酸鹽復(fù)合基微濾膜用于催化臭氧降解水中的有機污染物p-CNB。結(jié)果發(fā)現(xiàn),在連續(xù)流實驗中,臭氧-膜聯(lián)用工藝可以有效去除水中p-CNB。與單獨臭氧氧化工藝相比,在聯(lián)用工藝中超過1.5 mg/L的溶解態(tài)臭氧被分解,致使p-CNB的去除率提高了50個百分點,而膜本身對p-CNB的吸附去除卻可以忽略不計。電子順磁共振波譜(EPR)實驗和叔丁醇影響實驗證明,臭氧-膜聯(lián)用工藝對單獨臭氧氧化過程的強化源于體系內(nèi)羥基自由基的產(chǎn)生,膜孔表面存在的堿性水化產(chǎn)物和金屬氧化物可能是促進羥基自由基生成和提升p-CNB去除率的關(guān)鍵因素。臭氧-膜聯(lián)用工藝可以在多種水質(zhì)條件下保證p-CNB的有效降解,且降解產(chǎn)物的毒性均小于p-CNB,這說明本文制備的硅酸鹽復(fù)合基微濾膜除了具備截留能力外,還是一種廉價、高效的臭氧催化劑。此臭氧-膜聯(lián)用工藝可作為一種應(yīng)對水體突發(fā)有機污染的廉價應(yīng)急處理技術(shù)。
[Abstract]:In the face of increasingly serious water environmental pollution, the conventional drinking water treatment process is sometimes difficult to meet the requirements. New drinking water treatment technologies, such as membrane filtration technology and advanced oxidation technology, have attracted people's attention. Membrane cost in filtration technology and catalyst cost in advanced oxidation technology are the keys to restrict the development of technology.So it is necessary to develop cheap and efficient membranes and catalysts.In this paper,a low cost,flat silicate composite microfiltration membrane was prepared by using cheap silicate cement and quartz powder as raw materials at room temperature. The effect of technological parameters on the membrane was studied and the optimum technological conditions were optimized. The pore formation mechanism of silicate composite microfiltration membrane was studied by means of scanning electron microscopy, pore size analysis and energy dispersive X-ray spectroscopy. In this paper, the silicate composite microfiltration membrane was used as a new catalyst to catalyze ozone degradation of organic pollutants in water. The removal efficiency and mechanism of p-chloronitrobenzene (p-CNB, p-chloronitrobenzene) in water by ozone-membrane process were investigated. The sludge ratio (w/c), pore-forming agent and curing method were investigated. The technological parameters were determined as follows: molding pressure 6 MPa, quartz particle size 40.6-50.0 micron, silicate cement particle size 14.6 micron, w/c 0.4, 20 C, 95% relative humidity curing in air for 12 days. The porosities of the membranes under this condition show only a bimodal distribution. By reducing the ratio of quartz to Portland cement (q/c) to 2.0, the pore size distribution of the membranes is successfully improved from bimodal distribution to unimodal distribution. The formation mechanism of the micropore in the membrane is analyzed. The pore in the silicate composite microfiltration membrane can be divided into three types according to its origin. The first type is the pore with a pore diameter of 7-8 micron, which is mainly formed by the accumulation of quartz particles in the membrane; the second type is the membrane with a pore diameter of 1-3 micron, which is the largest proportion in the membrane. The pore size of the third kind of pore is mostly less than 1 micron. The formation of the pore is mainly due to the cutting effect of acicular ettringite on the large pore size of the membrane. The average pore size of the membrane is only 1 micron when the strength is increased to 5-6 MPa. The results of membrane porosity and pure water flux can also meet the requirements. The main hydration product is calcium silicate hydrate polymer, which is gelled in the membrane. Other products include flat calcium hydroxide, acicular or flaky ettringite and so on. The average pore size of the microporous membrane was 1 micron, and the average pore size of the mesoporous membrane was 13.5 nm. It was found that the silicate-based microfiltration membrane had similar gas-liquid flux to the traditional ceramic membrane, and could remove more than 80% of the Chlorella and 10 NTU turbidity inorganic particles with the concentration of 5 *107/L. However, the algae contamination is more difficult to remove than the inorganic contamination in membrane fouling. Further characterization shows that the silicate composite microfiltration membrane can withstand 500 C heat treatment and 0.01 mol/L alkali corrosion. The use of silicate composite microfiltration membrane in water environment can ensure the safety of water quality and membrane stability. The results showed that the combined process of ozone and membrane could effectively remove p-CNB in water. Compared with the single ozonation process, the dissolved ozone over 1.5 mg/L was decomposed in the combined process, resulting in an increase of 50 percentage points in the removal rate of p-CNB, while the membrane itself could effectively remove p-CNB. Electron paramagnetic resonance spectroscopy (EPR) and tert-butanol effect experiments show that the enhancement of Ozonation by ozone-membrane process is due to the generation of hydroxyl radicals in the system, and the existence of alkaline hydration products and metal oxides on the pore surface of the membrane may promote the formation of hydroxyl radicals. Ozone-membrane process can ensure the effective degradation of p-CNB under various water quality conditions, and the toxicity of the degradation products is less than that of p-CNB. This indicates that the silicate composite microfiltration membrane prepared in this paper is a cheap and efficient ozone catalyst besides its interception ability. Art can be used as a cheap emergency treatment technology to deal with sudden organic pollution of water bodies.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TU991.2
本文編號：2204007
[Abstract]:In the face of increasingly serious water environmental pollution, the conventional drinking water treatment process is sometimes difficult to meet the requirements. New drinking water treatment technologies, such as membrane filtration technology and advanced oxidation technology, have attracted people's attention. Membrane cost in filtration technology and catalyst cost in advanced oxidation technology are the keys to restrict the development of technology.So it is necessary to develop cheap and efficient membranes and catalysts.In this paper,a low cost,flat silicate composite microfiltration membrane was prepared by using cheap silicate cement and quartz powder as raw materials at room temperature. The effect of technological parameters on the membrane was studied and the optimum technological conditions were optimized. The pore formation mechanism of silicate composite microfiltration membrane was studied by means of scanning electron microscopy, pore size analysis and energy dispersive X-ray spectroscopy. In this paper, the silicate composite microfiltration membrane was used as a new catalyst to catalyze ozone degradation of organic pollutants in water. The removal efficiency and mechanism of p-chloronitrobenzene (p-CNB, p-chloronitrobenzene) in water by ozone-membrane process were investigated. The sludge ratio (w/c), pore-forming agent and curing method were investigated. The technological parameters were determined as follows: molding pressure 6 MPa, quartz particle size 40.6-50.0 micron, silicate cement particle size 14.6 micron, w/c 0.4, 20 C, 95% relative humidity curing in air for 12 days. The porosities of the membranes under this condition show only a bimodal distribution. By reducing the ratio of quartz to Portland cement (q/c) to 2.0, the pore size distribution of the membranes is successfully improved from bimodal distribution to unimodal distribution. The formation mechanism of the micropore in the membrane is analyzed. The pore in the silicate composite microfiltration membrane can be divided into three types according to its origin. The first type is the pore with a pore diameter of 7-8 micron, which is mainly formed by the accumulation of quartz particles in the membrane; the second type is the membrane with a pore diameter of 1-3 micron, which is the largest proportion in the membrane. The pore size of the third kind of pore is mostly less than 1 micron. The formation of the pore is mainly due to the cutting effect of acicular ettringite on the large pore size of the membrane. The average pore size of the membrane is only 1 micron when the strength is increased to 5-6 MPa. The results of membrane porosity and pure water flux can also meet the requirements. The main hydration product is calcium silicate hydrate polymer, which is gelled in the membrane. Other products include flat calcium hydroxide, acicular or flaky ettringite and so on. The average pore size of the microporous membrane was 1 micron, and the average pore size of the mesoporous membrane was 13.5 nm. It was found that the silicate-based microfiltration membrane had similar gas-liquid flux to the traditional ceramic membrane, and could remove more than 80% of the Chlorella and 10 NTU turbidity inorganic particles with the concentration of 5 *107/L. However, the algae contamination is more difficult to remove than the inorganic contamination in membrane fouling. Further characterization shows that the silicate composite microfiltration membrane can withstand 500 C heat treatment and 0.01 mol/L alkali corrosion. The use of silicate composite microfiltration membrane in water environment can ensure the safety of water quality and membrane stability. The results showed that the combined process of ozone and membrane could effectively remove p-CNB in water. Compared with the single ozonation process, the dissolved ozone over 1.5 mg/L was decomposed in the combined process, resulting in an increase of 50 percentage points in the removal rate of p-CNB, while the membrane itself could effectively remove p-CNB. Electron paramagnetic resonance spectroscopy (EPR) and tert-butanol effect experiments show that the enhancement of Ozonation by ozone-membrane process is due to the generation of hydroxyl radicals in the system, and the existence of alkaline hydration products and metal oxides on the pore surface of the membrane may promote the formation of hydroxyl radicals. Ozone-membrane process can ensure the effective degradation of p-CNB under various water quality conditions, and the toxicity of the degradation products is less than that of p-CNB. This indicates that the silicate composite microfiltration membrane prepared in this paper is a cheap and efficient ozone catalyst besides its interception ability. Art can be used as a cheap emergency treatment technology to deal with sudden organic pollution of water bodies.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TU991.2
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 崔素萍;郭紅霞;王辰;王子明;;納米無定形C-S-H凝膠顆粒及其結(jié)構(gòu)表征[J];硅酸鹽通報;2012年03期
相關(guān)博士學(xué)位論文 前1條
1 王永紅;新型陶瓷分離膜制備科學(xué)基礎(chǔ)和性能研究[D];中國科學(xué)技術(shù)大學(xué);2006年
相關(guān)碩士學(xué)位論文 前1條
1 張芳;多孔氧化鋁陶瓷支撐體及其微濾膜的制備與表征[D];中北大學(xué);2005年
，本文編號：2204007
本文鏈接：http://sikaile.net/jingjilunwen/jianzhujingjilunwen/2204007.html
最近更新
教材專著
