本文關鍵詞：納米鐵銅去除地下水中硝酸鹽的實驗研究　出處：《中國海洋大學》2015年碩士論文　論文類型：學位論文

  更多相關文章： 納米鐵銅 硝酸鹽去除 無機陰離子 運移沉積

【摘要】：隨著工業(yè)和農業(yè)的迅速發(fā)展,近些年硝酸鹽已成為許多國家地下水中的常見污染物,并且污染日益嚴重。作為一種新的污染控制技術,將納米零價鐵及其復合材料應用于地下水硝酸鹽污染修復,表現(xiàn)出了非常明顯的優(yōu)勢,已成為環(huán)境研究熱點方向。地下水成分復雜,共存離子對納米鐵系材料去除硝酸鹽的影響目前沒有系統(tǒng)的研究,而且比較貼近于實際地下水環(huán)境的砂柱、砂槽實驗還很少,納米顆粒在砂柱中的遷移沉積,以及對污染物的去除規(guī)律仍然不甚了解,因而非常有必要考慮地下水的實際水化學條件和水動力條件,對納米鐵系材料去除硝酸鹽開展系統(tǒng)的砂柱、砂槽實驗研究。基于上述考慮,本文采用液相還原法制備了納米級Fe/Cu金屬復合材料,采用TEM分析手段對納米材料的結構進行了表征,并且將其用于硝酸鹽污染物的去除。首先研究了初始硝酸鹽濃度對硝酸鹽去除的影響,確定了納米鐵銅的最佳投加量;在此基礎上,考察了Cl", SO42-,HCO3和PO43-四種無機陰離子在納米Fe/Cu顆粒投加不足和足量條件下對硝酸鹽的去除以及還原產物的影響。另外,研究了富里酸,溶解氧對納米Fe/Cu顆粒還原硝酸鹽過程的影響。開展了納米Fe/Cu雙金屬的砂柱注入實驗研究,分析了石英砂粒徑,納米顆粒濃度和納米顆粒體積對納米顆粒遷移影響,以及石英砂粒徑,納米顆粒濃度,納米顆粒體積和初始硝酸鹽濃度對硝酸鹽在砂柱中去除的影響。主要結論有以下幾點：(1)納米Fe/Cu足量時,硝酸鹽被徹底還原,產物只有氨氮：納米Fe/Ca不足時,硝酸鹽不能被全部還原,產物為氨氮和亞硝酸鹽。(2)當納米顆粒的投加足量時,Cl-, SO42-, HCO3和PO43-對硝酸鹽的去除均起到抑制作用,由大到小依次為：PO43SO42-HCO3-Cl-。其中P043-的作用幾乎不受P043-濃度的影響,而SO42-,HCO3和C1-三種離子濃度越大,抑制作用越強。另外,SO42-,HCO3-和C1-對氨氮的生成有促進作用,由大到小依次為：SO42-HCO3-Cl-,且濃度越大,促進作用越強。原因是,P043-通過吸附作用占據(jù)鐵表面的活性點位從而抑制硝酸鹽還原;Cl-, SO42-, HCO3-與Fe(Ⅱ), Fe(Ⅲ)和OH-形成綠銹,可以促進硝酸鹽還原成氨氮,從而增大氨氮在產物中的比例,進而降.低硝酸鹽的去除率。當納米鐵銅投加足量時,SO42和HCO3-抑制硝酸鹽和中間產物亞硝酸鹽的還原,其作用大小順序為：HCO3-SO42-,且濃度越大,作用越強,原因是,Fe(Ⅱ), Fe(Ⅲ)和OH-在SO42-或HCO3-的參與下形成了綠銹,而Cl促進了硝酸鹽的還原,可能是因為Cl-與Fe(Ⅱ)/Fe(Ⅲ)發(fā)生絡合作用,降低了鐵的氧化產物在納米顆粒上的沉積,從而提高了NO3-和NO2-與納米顆粒的接觸。(3)富里酸降低了納米鐵銅對硝酸鹽的還原速率,對其去除率沒有影響。而溶解氧降低了納米鐵銅對硝酸鹽的還原速率和去除率。(4)納米鐵銅雙金屬顆粒在砂柱中的截留分布情況隨介質粒徑,顆粒濃度和顆粒體積的不同而不同,但均在砂柱的前半部分分布較多,離出口端愈近截留量愈小。納米鐵銅顆粒對硝酸鹽的還原過程中,隨著研究因素的不同,NO3--N,NH4+-N, NO2--N以及總氮的變化趨勢相同。取樣開始,因為納米顆粒對硝酸鹽的吸附作用,使得NO3--N和總氮量為零,隨即被吸附的硝酸鹽開始發(fā)生還原反應,因為納米顆粒足量,所以產物只有氨氮,隨著反應進行,納米顆�；钚越档�,NO3--N和NO2--N出現(xiàn),同時氨氮量下降。NO3--N濃度隨時間不斷增大,NO2--N濃度先增大到最大濃度后下降,說明納米顆粒已逐漸失去對硝酸鹽的還原能力。(5)砂柱中介質粒徑影響納米鐵銅雙金屬顆粒的遷移,粒徑越大,越有利于納米顆粒的遷移,但是介質粒徑對硝酸鹽的去除效果沒有影響。納米顆粒的注入體積對納米顆粒在砂柱中的分布規(guī)律沒有影響,但是注入體積越大,截留在砂柱中納米顆粒的量越多,所以越有利于硝酸鹽的還原。納米顆粒的注入濃度越大,越有利于納米顆粒的遷移,對硝酸鹽的去除效果越佳。初始硝酸鹽濃度越大,納米顆粒維持反應活性的時間越短。
[Abstract]:With the rapid development of industry and agriculture in recent years, nitrate has become common in many countries of pollutants in groundwater, and pollution is becoming increasingly serious. As a new pollution control technology, nano zero valent iron and composite materials used in groundwater nitrate pollution remediation, showed very obvious advantages, has become a hot research environment the direction of groundwater. Complex components and coexisting ions on the effect of nano ferric nitrate removal material there is no system, and relatively close to the actual sand column groundwater environment, sand tank experiment is less, migration and deposition of nanoparticles in the sand column, and the pollutant removal law is still not fully understood, so it is necessary to consider the actual Groundwater Hydrochemical conditions and hydrodynamic conditions, the nanometer iron material on nitrate removal in sand column system, sand tank experiments. Based on the research The above considerations, this paper adopts liquid Fe/Cu nano metal composite material was prepared by reduction, by means of TEM analysis of nano materials were characterized, and used for the removal of nitrate pollutants. Firstly, the initial nitrate concentration on the nitrate removal effect, determine the best dosage of nano iron and copper add amount; on this basis, the effects of Cl, SO42-, and the effect on removal of nitrate reduction products of HCO3 and PO43- four kinds of inorganic anions and lack sufficient conditions in adding nano Fe/Cu particles. In addition, the study of fulvic acid, dissolved oxygen reduction effect of nitrate on the process of nano Fe/Cu particles. The sand column nano Fe/Cu double metal injection experiment, quartz sand particle size analysis, effects of the concentration of the nano particles and nano particle volume on migration of nanoparticles, and quartz sand particle size, particle concentration, particle Effect of volume and initial nitrate concentration on the removal of nitrate in the sand column. The main conclusions are as follows: (1) a sufficient amount of nano Fe/Cu, nitrate was completely restored, the only product of ammonia: nano Fe/Ca is insufficient, the nitrate can not be reduced completely, is the product of ammonia and nitrite (2.) when the nano particles added enough, Cl-, SO42-, HCO3 and PO43- on the removal of nitrate have played an inhibitory effect, from large to small is as follows: PO43SO42-HCO3-Cl-. the effect of P043- was not affected by the concentration of P043- and SO42-, HCO3 and C1- three kinds of ion concentration, inhibition stronger. In addition, SO42-, HCO3- and C1- to promote the production of ammonia, from large to small is as follows: SO42-HCO3-Cl-, and the higher the concentration, the stronger the effect of promoting. The reason is that the adsorption of P043- by occupying the active iron surface to point inhibition of nitrate reduction; Cl-, SO42-, HCO3-涓嶧e(鈪，

本文編號：1389801