發(fā)布時間：2018-05-24 17:46

  本文選題：納米零價鐵 + 土壤膠體　； 參考：《山東農(nóng)業(yè)大學(xué)》2015年碩士論文

【摘要】：納米零價鐵(Nanoscale Zero-Valent Iron,簡稱NZVI)是至少兩維尺度在1-100 nm的零價態(tài)鐵顆粒狀物質(zhì)。由于NZVI具備高效的還原性能,其作為土壤及地下水污染物的新型處理劑,已得到廣泛應(yīng)用。但是,過量的NZVI進入到土壤環(huán)境中,其存在或轉(zhuǎn)化的狀態(tài)、遷移規(guī)律及其與土壤膠體協(xié)同遷移的機制還不清楚;另外,NZVI是否會對種子萌發(fā)、植物生長產(chǎn)生影響及其影響程度等問題存在爭議。本試驗基于上述問題,分別探究了NZVI在土壤中的遷移、吸附、形態(tài)轉(zhuǎn)化及其對花生種子萌發(fā)及幼苗生長的影響,為今后研究NZVI在土壤環(huán)境中的遷移轉(zhuǎn)化規(guī)律以及評價其對植物生長發(fā)育的影響提供初步的技術(shù)支撐和理論依據(jù)。主要結(jié)果如下:1、通過液相還原法制備了NZVI,利用透射電子顯微鏡(TEM)、X射線衍射儀(XRD)等手段對其進行了測試和表征,證實該鐵粒粒徑約在20-80nm范圍之內(nèi),價態(tài)為零價,符合NZVI的有關(guān)試驗要求。2、采用土柱淋溶試驗探究了NZVI在石英砂、砂土及硅藻土三種淋溶介質(zhì)中的遷移規(guī)律,同時還研究了不同分散劑及土壤膠體對NZVI在土柱中遷移規(guī)律的影響。結(jié)果表明,在相同的淋溶介質(zhì)條件下,與添加十六烷基三甲基溴化銨(CTAB)和十二烷基硫酸鈉(SDS)分散劑的處理相比,添加聚乙烯吡咯烷酮(PVP)分散劑的處理,其土柱中淋溶出了相對濃度較高的NZVI;另外,三種淋溶介質(zhì)相比,硅藻土對NZVI的吸附量最大,淋出的NZVI相對較少,石英砂柱淋出的NZVI相對較多;在相同分散劑和淋溶介質(zhì)的條件下,土壤膠體與NZVI協(xié)同向下遷移的速度和濃度均高于不加土壤膠體的試驗處理。3、在吸附試驗中,探究了三種土壤(棕壤、潮土、砂姜黑土)對NZVI的等溫吸附曲線及吸附動力學(xué)曲線。其中,Langmuir模型能夠很好的模擬等溫吸附試驗,砂姜黑土對NZVI的吸附量最大;砂姜黑土、棕壤和潮土對NZVI的吸附平衡時間分別為8小時、24小時和24小時,符合一級吸附動力學(xué)模型,為今后探究NZVI在土壤中的吸附解吸機制提供了初步的理論支撐。4、采用恒溫培養(yǎng)法,結(jié)合X射線衍射儀(XRD)、X射線光電子能譜儀(XPS)及透射電子顯微鏡(TEM)等儀器研究了NZVI在棕壤、潮土、砂姜黑土等三種不同土壤中的形態(tài)、價態(tài)及形貌轉(zhuǎn)化規(guī)律。其中,在三種土壤中,隨著培養(yǎng)時間的增加,NZVI的粒徑均增大,此外在砂姜黑土中NZVI的形貌發(fā)生變化,由規(guī)則的球形轉(zhuǎn)化為不規(guī)則的團聚形態(tài)。潮土中NZVI的氧化速率最快,24小時之后NZVI完全轉(zhuǎn)化為三價鐵態(tài),在砂姜黑土中轉(zhuǎn)化最慢。5、通過種子萌發(fā)及砂培試驗,探明了NZVI在低濃度(10-160μmol/L)下對花生種子及幼苗生長起到促進作用,在高濃度(320μmol/L)時對種子萌發(fā)及幼苗生長出現(xiàn)抑制作用。
[Abstract]:Nanoscale Zero-Valent Iron-nanoscale (NZVI) is a zero-valence iron granular substance with at least two dimensional scales of 1-100 nm. Because of its high efficiency, NZVI has been widely used as a new treatment agent for soil and groundwater pollutants. However, the presence or transformation of excessive NZVI in soil environment, the migration law and the mechanism of co-migration with soil colloids are not clear. The influence of plant growth and its influence degree are controversial. Based on the above questions, the effects of NZVI on seed germination and seedling growth of peanut were studied. It provides a preliminary technical support and theoretical basis for studying the law of NZVI migration and transformation in soil environment and evaluating the effect of NZVI on plant growth and development in the future. The main results are as follows: 1. NZVI was prepared by liquid-phase reduction method and characterized by means of transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that the iron particle size is about within the range of 20-80nm and the valence state is zero. According to the test requirements of NZVI, the migration of NZVI in quartz sand, sand and diatomite was studied by means of soil column leaching test, and the effects of different dispersants and soil colloids on the migration of NZVI in soil column were also studied. The results showed that under the same leaching medium, the polyvinylpyrrolidone (PVP) dispersant was treated with polyvinylpyrrolidone (PVP) as compared with the treatment with cetyltrimethylammonium bromide (CTAB) and dodecyl sodium sulfate (SDS) dispersants. In addition, compared with the three kinds of leaching media, diatomite has the largest adsorption amount of NZVI, less NZVI leaching and more NZVI leaching from quartz sand column. Under the condition of the same dispersant and leaching medium, the velocity and concentration of soil colloid and NZVI migration down in cooperation were higher than that in the treatment without soil colloid. In the adsorption experiment, three kinds of soil (brown soil, aquic soil) were studied. NZVI isotherm adsorption curve and adsorption kinetics curve. The Langmuir model can simulate the isothermal adsorption test very well, and the adsorption capacity of NZVI on the black soil is the largest, and the equilibrium time of adsorption of NZVI on the black soil, brown soil and aquic soil is 8 hours to 24 hours and 24 hours respectively, which is in accordance with the first-order adsorption kinetic model. In order to explore the mechanism of adsorption and desorption of NZVI in soil, the mechanism of adsorption and desorption of NZVI in soil was studied by means of isothermal culture method, X-ray diffractometer, X-ray photoelectron spectrometer (XPS) and transmission electron microscope (TEM). Morphology, Valence and Morphology Transformation of three different soils in Shajiang Black soil. In the three soils, the particle size of NZVI increased with the increase of culture time, in addition, the morphology of NZVI changed from regular spherical to irregular agglomeration in shajiang black soil. The oxidation rate of NZVI in aquic soil was the fastest after 24 hours, NZVI was completely transformed into trivalent iron state, and the transformation was the slowest in shajiang black soil. Through seed germination and sand culture experiments, it was proved that NZVI promoted peanut seed and seedling growth at low concentration of 10-160 渭 mol / L. At a high concentration of 320 渭 mol / L, it inhibited seed germination and seedling growth.
【學(xué)位授予單位】：山東農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S565.2;S153

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相關(guān)期刊論文 前1條

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本文編號：1929979