xDLVO理論解析天然有機(jī)物存在下納米顆粒膜污染行為
發(fā)布時(shí)間：2018-10-15 14:09
【摘要】：近年來,納米技術(shù)已廣泛用于許多工業(yè)產(chǎn)品中,導(dǎo)致工程納米顆粒在水環(huán)境中的濃度升高。在納米顆粒中,二氧化鈦(TiO_2)納米顆粒被制造用作許多和工業(yè)產(chǎn)品中的顏料,防曬劑,光催化劑和半導(dǎo)體,對(duì)微生物,植物和動(dòng)物有毒性作用,并且可能對(duì)生態(tài)系統(tǒng)造成損害。因此,納米顆粒如何被廢水處理系統(tǒng)去除并如何影響其性能已經(jīng)受到學(xué)者們廣泛的關(guān)注。超濾被認(rèn)為是廢水處理中去除納米顆粒的有效方法。然而,由于膜污染會(huì)導(dǎo)致膜處理技術(shù)維護(hù)和操作成本的增加,膜污染仍然是限制超濾技術(shù)的廣泛應(yīng)用的桎梏因素。目前關(guān)于從膜分離技術(shù)中去除納米顆粒的研究很少。當(dāng)納米顆粒排入水中時(shí),環(huán)境因素例如天然有機(jī)物質(zhì)和水中的溶液條件將影響納米顆粒的行為。以前的研究只集中在單個(gè)納米顆粒的膜污染,還未對(duì)在天然有機(jī)物存在下納米顆粒膜污染的機(jī)理的進(jìn)行定量分析。本研究利用 extended Derjaguin-Laudau-Verwey-Overbeek(xDLVO)理論對(duì)腐殖酸與納米TiO_2混合物膜污染過程中的界面作用力進(jìn)行定量解析,評(píng)價(jià)不同界面作用能(范德華力作用能、雙電層力作用能以及極性力作用能)對(duì)膜污染的貢獻(xiàn)程度,探究腐植酸濃度及溶液條件影響HA-TiO_2混合物膜污染的主控機(jī)制。在對(duì)界面作用力進(jìn)行定量解析的基礎(chǔ)上,分別對(duì)不同污染條件下HA-TiO_2混合物膜污染趨勢(shì)與界面作用能進(jìn)行線性擬合,從而更為全面、系統(tǒng)的對(duì)xDLVO理論描述HA-TiO_2混合物膜污染行為的適用性作出評(píng)價(jià)。研究結(jié)果表明,極性力作用能對(duì)總界面作用能的貢獻(xiàn)最大,污染條件的影響主要是通過改變極性力作用能來實(shí)現(xiàn)。腐植酸濃度對(duì)于HA-TiO_2混合物的表面特性及界面作用能的大小具有顯著影響,腐植酸濃度的升高使HA-TiO_2混合物疏水性增加,從而減小膜與HA-TiO_2混合物間及污染物之間的作用能,導(dǎo)致更嚴(yán)重的膜污染。對(duì)于HA-TiO_2混合物,pH值的升高或離子強(qiáng)度的降低會(huì)減弱界面作用力的吸引性或增強(qiáng)界面作用力的排斥性,從而減緩HA-TiO_2混合物的膜污染。不同溶液條件下HA-TiO_2混合物膜污染趨勢(shì)與界面作用能具有良好的線性相關(guān)性,故xDLVO理論可以較好地預(yù)測(cè)HA-TiO_2混合物的膜污染。
[Abstract]:In recent years, nanotechnology has been widely used in many industrial products, resulting in the concentration of engineering nanoparticles in the water environment increased. Among nanoparticles, titanium dioxide (TiO_2) nanoparticles are manufactured as pigments, sunscreens, photocatalysts and semiconductors in many and industrial products, toxic to microorganisms, plants and animals, and may damage ecosystems. Therefore, how nanoparticles are removed by wastewater treatment system and how to affect their performance have been widely concerned by scholars. Ultrafiltration is considered to be an effective method to remove nanoparticles in wastewater treatment. However, because membrane fouling will lead to the increase of maintenance and operation cost of membrane treatment technology, membrane fouling is still the shackle factor that limits the wide application of ultrafiltration technology. At present, there is little research on the removal of nanoparticles from membrane separation technology. When nanoparticles are discharged into water, environmental factors such as natural organic matter and solution conditions in water will affect the behavior of nanoparticles. Previous studies focused on membrane fouling of a single nanoparticle, but not on the mechanism of membrane fouling in the presence of natural organic matter. In this study, extended Derjaguin-Laudau-Verwey-Overbeek (xDLVO) theory was used to quantitatively analyze the interfacial forces in the process of membrane fouling of the mixture of humic acid and nanometer TiO_2, and to evaluate the different interaction energies (van der Waals force). The contribution of double layer force energy and polar force energy to membrane fouling was investigated. The main control mechanism of HA-TiO_2 mixture membrane fouling influenced by humic acid concentration and solution conditions was explored. On the basis of quantitative analysis of interfacial forces, the membrane fouling trend of HA-TiO_2 mixture under different pollution conditions and the interaction energy of the interface were fitted linearly respectively, so that it was more comprehensive. The applicability of xDLVO theory to describe membrane fouling behavior of HA-TiO_2 mixtures is systematically evaluated. The results show that the interaction energy of polar force has the greatest contribution to the total interaction energy of the interface, and the influence of pollution conditions is mainly realized by changing the action energy of polar force. The concentration of humic acid has a significant effect on the surface characteristics and interfacial interaction energy of HA-TiO_2 mixture. The increase of humic acid concentration increases the hydrophobicity of HA-TiO_2 mixture, thus reducing the interaction energy between the membrane and HA-TiO_2 mixture and between pollutants. Leading to more serious membrane fouling. For HA-TiO_2 mixtures, the increase of pH value or the decrease of ionic strength will reduce the attraction of interfacial forces or the repellency of interfacial forces, thus reducing the membrane fouling of HA-TiO_2 mixtures. There is a good linear correlation between membrane fouling trend and interfacial interaction of HA-TiO_2 mixtures under different solution conditions, so xDLVO theory can better predict membrane fouling of HA-TiO_2 mixtures.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X703
本文編號(hào)：2272787
[Abstract]:In recent years, nanotechnology has been widely used in many industrial products, resulting in the concentration of engineering nanoparticles in the water environment increased. Among nanoparticles, titanium dioxide (TiO_2) nanoparticles are manufactured as pigments, sunscreens, photocatalysts and semiconductors in many and industrial products, toxic to microorganisms, plants and animals, and may damage ecosystems. Therefore, how nanoparticles are removed by wastewater treatment system and how to affect their performance have been widely concerned by scholars. Ultrafiltration is considered to be an effective method to remove nanoparticles in wastewater treatment. However, because membrane fouling will lead to the increase of maintenance and operation cost of membrane treatment technology, membrane fouling is still the shackle factor that limits the wide application of ultrafiltration technology. At present, there is little research on the removal of nanoparticles from membrane separation technology. When nanoparticles are discharged into water, environmental factors such as natural organic matter and solution conditions in water will affect the behavior of nanoparticles. Previous studies focused on membrane fouling of a single nanoparticle, but not on the mechanism of membrane fouling in the presence of natural organic matter. In this study, extended Derjaguin-Laudau-Verwey-Overbeek (xDLVO) theory was used to quantitatively analyze the interfacial forces in the process of membrane fouling of the mixture of humic acid and nanometer TiO_2, and to evaluate the different interaction energies (van der Waals force). The contribution of double layer force energy and polar force energy to membrane fouling was investigated. The main control mechanism of HA-TiO_2 mixture membrane fouling influenced by humic acid concentration and solution conditions was explored. On the basis of quantitative analysis of interfacial forces, the membrane fouling trend of HA-TiO_2 mixture under different pollution conditions and the interaction energy of the interface were fitted linearly respectively, so that it was more comprehensive. The applicability of xDLVO theory to describe membrane fouling behavior of HA-TiO_2 mixtures is systematically evaluated. The results show that the interaction energy of polar force has the greatest contribution to the total interaction energy of the interface, and the influence of pollution conditions is mainly realized by changing the action energy of polar force. The concentration of humic acid has a significant effect on the surface characteristics and interfacial interaction energy of HA-TiO_2 mixture. The increase of humic acid concentration increases the hydrophobicity of HA-TiO_2 mixture, thus reducing the interaction energy between the membrane and HA-TiO_2 mixture and between pollutants. Leading to more serious membrane fouling. For HA-TiO_2 mixtures, the increase of pH value or the decrease of ionic strength will reduce the attraction of interfacial forces or the repellency of interfacial forces, thus reducing the membrane fouling of HA-TiO_2 mixtures. There is a good linear correlation between membrane fouling trend and interfacial interaction of HA-TiO_2 mixtures under different solution conditions, so xDLVO theory can better predict membrane fouling of HA-TiO_2 mixtures.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X703
【相似文獻(xiàn)】
相關(guān)碩士學(xué)位論文 前2條
1 田琳;xDLVO理論解析天然有機(jī)物存在下納米顆粒膜污染行為[D];山東大學(xué);2017年
2 陳德坤;xDLVO理論解析混凝預(yù)處理對(duì)葡聚糖超濾膜污染的影響機(jī)理[D];山東大學(xué);2017年
，本文編號(hào)：2272787
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