本文選題：電絮凝 + 鋁形態(tài)��； 參考：《河北工業(yè)大學》2015年碩士論文

【摘要】：電絮凝與膜分離是近幾年廣泛研究和應用的水處理技術。本文旨在從鋁形態(tài)、絮體特性等進一步探討電絮凝去除污染物的機理以及與膜分離技術的聯用。本文通過電解鋁板研究了電絮凝過程中鋁形態(tài)的分布、電解過程中Al13的形成機制,并考察了pH值、電流密度、外加電壓等對鋁形態(tài)分布的影響,以及相應的絮體特性,并在此基礎上進行了電絮凝去除天然有機物,電絮凝-超濾去除飲用水中氟的研究和相應的膜污染探討。得出以下主要結論:(1)電絮凝過程中,特別是陰極表面OH-的不斷生成與金屬-溶液界面處不平衡的pH分布促進了Al3+離子的水解-聚合反應。隨著電絮凝的進行,初始階段以Ala為主要優(yōu)勢形態(tài),逐漸轉化為Alb為優(yōu)勢形態(tài),繼而Alc成為主要的鋁形態(tài)。電絮凝過程能夠原位產生Al13聚合物。(2)電絮凝過程中Al13形成的適宜pH范圍為5-7。降低電流密度和電壓有利于Al13形成。提高pH值、電流密度和極板電壓能夠加劇陽極溶出的鋁離子的水解-聚合反應,導致Ala、Alb的相對含量顯著減少,Alc的相對含量增加。(3)pH值與電流密度對多羥基聚合鋁絮體特性有重要影響。隨著電解的進行,酸性、中性條件下,pH值先升高繼而趨于穩(wěn)定;堿性條件下,pH先降低,2 min之后也變?yōu)橄壬咴仝呌诜�(wěn)定。Zeta電位都有一個短暫的上升階段,繼而都開始下降,最后趨于穩(wěn)定。增大電流密度,pH增加的更快,Zeta電位下降的更快。(4)pH值與電流密度對電絮凝去除天然有機物與濁度有重要影響。弱酸性下,電流密度在10 A/m2下,Zeta電位在10 min左右到達等電點附近,此時膠體、天然有機物的穩(wěn)定性最低,最容易失穩(wěn)聚集。粒徑在10 min左右達到穩(wěn)定,此時形成比較均勻、多孔隙、具有一定密實度的絮體團簇,絮體強度高,比表面積大,吸附能力強。(5)在連續(xù)流下EC-UF工藝除氟效果良好,在電流密度30 A/m2、水力停留時間20 min、初始pH值在6.0-7.0的最佳工藝條件下,氟的去除率達到80%以上。膜污染主要是由電解過程產生的鋁絮凝劑與氟離子形成的顆粒物質導致。
[Abstract]:Electroflocculation and membrane separation are widely studied and applied water treatment technology in recent years.The aim of this paper is to discuss the mechanism of electroflocculation removal of pollutants and its combination with membrane separation technology from the aspects of aluminum morphology and flocculation characteristics.In this paper, the distribution of aluminum forms in electroflocculation process and the formation mechanism of Al13 in electrolysis process are studied. The effects of pH value, current density, applied voltage on aluminum speciation distribution and the corresponding flocs characteristics are also investigated.On this basis, the removal of natural organic matter by electroflocculation and the removal of fluoride from drinking water by electroflocculation-ultrafiltration were studied and the corresponding membrane fouling was discussed.The main conclusions are as follows: during electroflocculation, especially the unbalance pH distribution between the formation of OH- on cathode surface and the interface between metal and solution promotes the hydrolysis polymerization of Al3 ion.With the development of electroflocculation, Ala is the main dominant form in the initial stage, and gradually transformed into Alb as the dominant form, and then Alc becomes the main aluminum form.The suitable pH range of Al13 formation during electroflocculation is 5-7.The reduction of current density and voltage is beneficial to the formation of Al13.Increasing pH value, current density and plate voltage can accelerate the hydrolysis-polymerization reaction of anodic dissolved aluminum ions.As a result, the relative content of Ala Alb decreased significantly. The increase of the relative content of Alc. The pH value and the current density had important effects on the properties of polyhydroxyl polymerized aluminum floc.With the electrolysis, pH value increased first and then stabilized under neutral condition, and pH decreased at first for 2 min under alkaline condition, and then increased at first and then stabilized. Zeta potential increased for a short period and then began to decrease.Finally, it tends to stabilize.Increasing the current density and increasing the pH value of Zeta potential decrease faster. The pH value and current density have important influence on the removal of natural organic matter and turbidity by electroflocculation.When the current density is 10 A/m2, the Zeta potential reaches the isoelectric point at about 10 min, and the colloid has the lowest stability and the most easily unstable aggregation.The particle size is stable at about 10 min, and the flocs with uniform and porous size and certain density are formed. The flocs have high strength, large specific surface area and strong adsorption ability. The EC-UF process has a good effect on fluoride removal under continuous flow.Under the optimum conditions of current density 30 A / m 2, HRT 20 min, initial pH 6.0-7.0, the removal rate of fluorine is over 80%.Membrane fouling is mainly caused by aluminum flocculant produced by electrolysis and particulate matter formed by fluorine ion.
【學位授予單位】：河北工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU991.2

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相關期刊論文 前1條

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本文編號：1769459