發(fā)布時間：2018-08-31 18:36

【摘要】：磷是導致水體富營養(yǎng)化的限制因素,本研究選取斜發(fā)沸石、熱液型海泡石、高嶺土等3種典型硅酸鹽礦物作為研究對象,采用響應面優(yōu)化方法得到氧化鑭改性三種硅酸鹽礦物的最佳工藝條件。研究硅酸鹽礦物物化特征變化與除磷性能之間的關系,分析硅酸鹽礦物材料與氧化鑭之間的促進及影響機制,揭示氧化鑭改性硅酸鹽礦物的作用機理及吸附磷酸根的機理。首先,以氧化鑭作為改性劑,采用改進的水解沉淀法對硅酸鹽礦物進行改性,改性工藝均可使用Quadratic模型進行模擬,pH值與焙燒溫度間的交互作用最明顯。斜發(fā)沸石、熱液型海泡石及高嶺土最佳改性pH值條件均為pH=8,改性溶液濃度分別為0.3%、0.4%、0.3%,焙燒溫度為300℃C、200℃C、300℃C,此條件下最優(yōu)改性礦物對5mg/L磷酸根的去除率分別為99.04%、99.62%、99.49%。氧化鑭改性硅酸鹽礦物在應用溶液pH=3-11的范圍內(nèi),吸附磷酸根能力不受影響。改進的水解沉淀法制備的氧化鑭改性斜發(fā)沸石的最大吸附容量可達到15.06mg/g,遠高于普通的氯化鑭改性工藝制備的改性斜發(fā)沸石的吸附容量(1.75mg/g)及文獻中報道的鑭改性礦物材料。其次,通過研究改性過程中硅酸鹽礦物成分變化、晶體結(jié)構(gòu)、分子基團及原子結(jié)合能的變化發(fā)現(xiàn)：斜發(fā)沸石、熱液型海泡石改性機理主要包括陽離子交換作用和靜電吸附作用,高嶺土的改性機理以靜電吸附作用為主。改性礦物表面的鑭與硅酸鹽礦物表面及溶液中的-OH基團結(jié)合,形成鑭氫氧化物,焙燒作用下轉(zhuǎn)化為鑭氧化物。硅酸鹽礦物吸附磷酸根的機制研究發(fā)現(xiàn)：改性斜發(fā)沸石對磷酸根的吸附主要是La-O化學鍵所引起的路易斯酸堿反應以及表面配合作用；改性熱液型海泡石和改性高嶺土對磷酸根的吸附以La-O化學鍵所引起的路易斯酸堿反應為主。最后,進行了三種改性硅酸鹽礦物對實際市政污水的應用試驗,發(fā)現(xiàn)它們對高碑店污水處理廠初沉池出水總磷的去除率可達到80%以上,出水總磷濃度低于1.00mg/L,達到城鎮(zhèn)污水處理廠一級B出水標準。同時氧化鑭改性硅酸鹽礦物不會釋放La元素進入水體,影響水質(zhì)安全。優(yōu)化得到的改進水解沉淀法工藝,是一項制備富營養(yǎng)化水體中磷污染物吸附材料的綠色、高效的應用技術(shù),可推動硅酸鹽礦物吸附材料的研發(fā)和應用。
[Abstract]:Phosphorus is the limiting factor of eutrophication in water body. Three typical silicate minerals, such as clinoptilolite, hydrothermal sepiolite and kaolin, are selected as the research objects. The optimum process conditions of three silicate minerals modified by lanthanum oxide were obtained by using the response surface optimization method. The relationship between physical and chemical characteristics of silicate minerals and phosphorus removal properties was studied. The promotion and influence mechanism between silicate mineral materials and lanthanum oxide were analyzed. The mechanism of lanthanum oxide modified silicate minerals and the mechanism of phosphate adsorption were revealed. Firstly, using lanthanum oxide as modifier, the modified hydrolysis precipitation method is used to modify silicate minerals. The Quadratic model can be used to simulate the interaction between pH value and calcination temperature. The optimum conditions of modified pH value of clinoptilolite, hydrothermal sepiolite and kaolin are as follows: the concentration of pH=8, modified solution is 0.30.40, the calcination temperature is 300 鈩，

本文編號：2215824