發(fā)布時間：2018-05-30 05:50

  本文選題：除磷 + 碳酸鑭　； 參考：《浙江大學(xué)》2017年碩士論文

【摘要】：磷是水體中的主要污染物,水中過多的磷將導(dǎo)致水體富營養(yǎng)化,所以有效去除廢水中的磷是亟待解決的問題。目前吸附法除磷效果易受pH影響,難以在中性條件下達到較高的去除效率,本文通過對含鑭吸附劑的研究,擴大了除磷劑的pH適用范圍,提高了其在中性及弱堿性條件下的除磷效果,降低了除磷成本。本文首先從不同金屬離子中篩選出了除磷效果最好的鑭離子,接著研究了不同鑭化合物對磷的去除率,得到除磷效果最好為碳酸鑭,在此基礎(chǔ)上,研究了制備條件對碳酸鑭、金屬摻雜碳酸鑭以及鑭改性膨潤土除磷效果的影響,最終得到了吸附速率快、能在中性條件下高效除磷的鐵-鑭改性膨潤土(B-FeLa),本文的概括如下:首先,研究了鐵、鈣、鎂、鑭四種金屬離子對不同濃度KH2PO4的去除效果,篩選出最有效的除磷元素為鑭;接著對比了氫氧化鑭(C-La(OH)3)、氧化鑭(C-La2O3)和碳酸鑭(C-La2(CO3)3)三種鑭化合物在不同時間和pH條件下對磷的去除率。結(jié)果表明:C-La(OH)3、C-La2O3和C-La2(CO3)3的除磷實驗中,C-La2(CO3)3是除磷效率更高的鑭化合物,在pH=7.5溫度為25 ℃的條件下符合Langmuir等溫吸附曲線,飽和吸附量達到了 66.23 mg/g。其次,探究制備條件對制得的La2(CO3)3組成、結(jié)構(gòu)和除磷效率的影響,最后研究了除磷效率最高的碳酸鑭在不同條件下對磷的吸附。結(jié)果表明:除磷效率最高的仍為La2(CO3)3;最優(yōu)制備的條件是:沉淀劑為Na2CO3,沉淀pH為8,沉淀溫度為45℃,干燥溫度為35℃ 在除磷實驗中,La2(CO3)3達到平衡時間縮短至12h,飽和吸附量增加到了 112.36 mg/g。然后,采用共沉淀的方法合成了不同金屬摻雜的碳酸鑭除磷劑,以除磷效率最高的鐵-鑭除磷劑(Fe-La)為對象,繼續(xù)研究了鐵鑭摻雜比例、沉淀pH和金屬離子濃度對鐵鑭復(fù)合物組成及除磷效率的影響,確定最佳的制備條件是:總金屬離子濃度為20 mmol/L,沉淀pH = 8,n(Fe):n(La)= 0.3:1。研究結(jié)果表明,Fe-La比表面積增大,等電點升高,除磷效果受pH影響減小;飽和吸附量達到了 101.09 mg/g。最后,研究了不同方法制得的鑭改性膨潤土的除磷效果,以B-FeLa為對象系統(tǒng)地討論了 B-FeLa的除磷效果。結(jié)果表明B-FeLa除磷速率提高,平衡反應(yīng)時間縮短到了 4 h;飽和吸附量達到了 27.86mg/g,除磷效果受pH的影響小。
[Abstract]:Phosphorus is the main pollutant in water, and excessive phosphorus in water will lead to eutrophication, so it is an urgent problem to remove phosphorus from wastewater effectively. At present, the removal effect of phosphorus by adsorption method is easily affected by pH, and it is difficult to achieve a higher removal efficiency under neutral conditions. Through the study of lanthanum adsorbent, the pH range of phosphorus removal agent has been expanded in this paper. The efficiency of phosphorus removal under neutral and weak alkaline conditions was improved, and the cost of phosphorus removal was reduced. In this paper, the best phosphorus removal efficiency was obtained from different metal ions, and then the phosphorus removal efficiency of different lanthanum compounds was studied. It was found that the best phosphorus removal effect was lanthanum carbonate. On this basis, the preparation conditions of lanthanum carbonate were studied. The effect of metal doped lanthanum carbonate and lanthanum modified bentonite on the removal of phosphorus was studied. Finally, the Fe-La modified bentonite with fast adsorption rate and high efficiency phosphorus removal under neutral conditions was obtained. The summary of this paper is as follows: firstly, iron, calcium, magnesium, iron and lanthanum modified bentonite were obtained. The removal effect of lanthanum ions on KH2PO4 with different concentrations was screened out as the most effective phosphorus removal element, and the phosphorus removal efficiency of three lanthanum compounds (lanthanum hydroxide C-LaHH _ 3, lanthanum oxide C-La _ 2O _ 3) and lanthanum carbonate C-La _ 2o _ 3CO _ 3C _ 2O _ 3 were compared at different time and pH. The results show that in the experiment of phosphorus removal by C-La2(CO3)3 and the ratio of C-LaH3O _ 2O _ 3 and C-La2(CO3)3, the lanthanum compounds with higher phosphorus removal efficiency are found to be the lanthanum compounds with higher phosphorus removal efficiency. Under the condition of pH=7.5 temperature of 25 鈩，

本文編號：1954163