【摘要】：地下水是自然水文循環(huán)的重要組成部分,也是人類的一種重要飲用水源。近年來,隨著工農(nóng)業(yè)生產(chǎn)的迅速發(fā)展,大量含氮化肥的使用、生活污水和工業(yè)廢水的不達標排放以及固體廢棄物的淋濾下滲等導致地下水遭受到了嚴重的硝酸鹽污染。長期飲用高含量硝酸鹽氮的地下水將對人體健康產(chǎn)生嚴重的危害。因此,必須對其進行處理,以保證供水安全。與傳統(tǒng)的物理化學以及生物處理技術(shù)相比,硝酸鹽電化學具有效率高、投資成本低、操作簡便、環(huán)境友好等優(yōu)勢。然而,目前電化學技術(shù)存在能耗高、電流效率低以及極板易鈍化的問題,難以滿足大規(guī)模的實際應用。因此,優(yōu)化和改良傳統(tǒng)的電化學體系,提高其性能是十分必要的。在硝酸鹽電化學處理過程中,硝酸鹽的還原速率主要受陰極材料的硝酸鹽催化還原特性、陽極材料的氨氮氧化特性、電極板間距、電流密度、電解質(zhì)性質(zhì)等的影響。本研究主要研究了陰極材料、Na Cl濃度、電流密度和極板間距對硝酸鹽還原的影響,并得出了最優(yōu)的電化學還原硝酸鹽條件:以Ti/Ir O2-Pt為陽極,Cu-Zn為陰極,極板間距為20 mm,電流密度為20 m A/cm2時,投加0.5 g/L Na Cl,1.5 g/L Na2SO4。在此條件下,硝酸鹽的去除率達到72.1%,氨氮基本被氧化,出水中未檢測到亞硝酸鹽的存在。在本研究中,利用兩種方法強化硝酸鹽電化學去除效果:增強陰極的還原和抑制陽極的氧化。采用Ti/Ir O2-Pt陽極,Cu-Zn陰極,分別投加甲醇和水楊酸強化硝酸鹽去除效果。電解甲醇,產(chǎn)生氫氣,促進陰極還原。投加水楊酸,吸收羥基自由基,抑制陽極氧化。實驗結(jié)果表明,投加0.0067 g/L的甲醇(100 mg/L COD),硝酸鹽氮在180 min內(nèi),由50 mg/L降低到3.2 mg/L,硝酸鹽的還原效率提高了16.5%;投加0.0316 g/L的水楊酸(20 mg/L COD),硝酸鹽的還原速率提高了14.4%。盡管在反應過程中,投加了甲醇,以及產(chǎn)生了亞硝酸鹽和氨氮等副產(chǎn)物,但最終被完全去除。綜上,本研究能夠提高地下水硝酸鹽的去除效果,是一種高效的去除硝酸鹽污染的方法。
[Abstract]:Groundwater is an important part of natural hydrological cycle and also an important drinking water source for human beings. In recent years, with the rapid development of industrial and agricultural production, the use of a large number of nitrogen-containing fertilizers, the discharge of domestic sewage and industrial wastewater, as well as the leaching and infiltration of solid wastes, the groundwater has been seriously polluted by nitrate. Drinking groundwater with high nitrate nitrogen for a long time will cause serious harm to human health. Therefore, it must be treated to ensure the safety of water supply. Compared with the traditional physical chemistry and biological treatment technology, nitrate electrochemistry has the advantages of high efficiency, low investment cost, simple operation and environmental friendliness. However, the current electrochemical technology has many problems, such as high energy consumption, low current efficiency and easy passivation of the electrode plate, so it is difficult to meet the practical application on a large scale. Therefore, it is necessary to optimize and improve the traditional electrochemical system and improve its performance. In the process of nitrate electrochemical treatment, the reduction rate of nitrate is mainly affected by the catalytic reduction characteristics of the cathode material, the characteristics of ammonia-nitrogen oxidation of the anode material, the electrode plate spacing, the current density and the electrolyte properties. The effects of Na Cl concentration, current density and plate spacing on nitrate reduction were studied in this paper. The optimal electrochemical reduction conditions of nitrate were obtained as follows: Ti/Ir O2-Pt as anode and Cu-Zn as cathode. When the plate spacing is 20 mm, and the current density is 20 m A/cm2, 0.5 g / L Na Cl,1.5 g / L Na2SO4. is added. Under these conditions, the removal rate of nitrate reached 72.1%, the ammonia nitrogen was basically oxidized, and no nitrite was detected in the effluent. In this study, two methods were used to enhance the electrochemical removal of nitrate: to enhance the reduction of the cathode and to inhibit the oxidation of the anode. The removal efficiency of nitrate was enhanced by adding methanol and salicylic acid into the Cu-Zn cathode of Ti/Ir O2-Pt anode. Electrolysis of methanol produces hydrogen and accelerates cathodic reduction. Add salicylic acid to absorb hydroxyl radical and inhibit anodic oxidation. The results showed that the reduction efficiency of 0.0067 g / L methanol (100 mg/L COD), nitrate nitrogen decreased from 50 mg/L to 3.2 mg/L, nitrate in 180 min) and 0.0316 g / L of salicylic acid (20 mg/L COD), nitrate) increased the reduction rate. Although methanol was added and nitrite and ammonia nitrogen were produced during the reaction, they were completely removed. In conclusion, this study can improve the removal effect of nitrate in groundwater, and it is an efficient method to remove nitrate pollution.
【學位授予單位】：中國地質(zhì)大學(北京)
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X523

【參考文獻】

相關(guān)期刊論文 前9條

1 邵留;徐祖信;尹海龍;;污染水體脫氮工藝中外加碳源的研究進展[J];工業(yè)水處理;2007年12期

2 陳干;羅繼紅;;合肥市濱湖新區(qū)硝酸鹽污染研究[J];河北農(nóng)業(yè)科學;2009年03期

3 童桂華;彭昌盛;賈永剛;曹陽;;離子交換樹脂去除水中硝酸鹽的研究[J];工業(yè)用水與廢水;2008年04期

4 張燕,陳英旭,陳光浩;化學反硝化去除硝酸鹽的試驗研究[J];環(huán)境科學;2003年04期

5 李鐵龍;劉海水;金朝暉;康海燕;劉振英;王薇;;納米鐵去除水中硝酸鹽氮的批試驗[J];吉林大學學報(工學版);2006年02期

6 關(guān)亮炯;我國水污染現(xiàn)狀及治理對策[J];科技情報開發(fā)與經(jīng)濟;2004年06期

7 董克虞;畜禽糞便對環(huán)境的污染及資源化途徑[J];農(nóng)業(yè)環(huán)境保護;1998年06期

8 楊惠芬，黃流生，謝斌，張秀珍，王金風，羅雁非;食品中亞硝酸鹽允許限量的研究[J];衛(wèi)生研究;1995年03期

9 曹國民;盛梅;費宇雷;孟科偉;史偉偉;俞益峰;;離子交換法連續(xù)流處理受硝酸鹽污染的地下水[J];凈水技術(shù);2011年05期

，

本文編號：2257654