水田土壤中铜、锌的迁移活性及其控制技术初步研究

发布时间：2018-04-01 09:43

本文选题：影响因素　切入点：吸附　出处：《吉林农业大学》2015年硕士论文

【摘要】：水稻在中国粮食作物之中占有非常重要的地位,全国1/4的耕地面积为水稻耕田,水稻解决了我国大部分人的温饱问题。因此可以说,水稻生产在我国的粮食安全中的地位是举足轻重的,重金属对水田土壤的污染问题就变得尤为重要。被重金属污染的土壤,土壤性质发生改变,因此会间接的影响到农作物的品质和质量,重金属不仅仅会污染土壤,还会涉及到各个方面,例如水体环境以及大气环境等等。因此,可以说重金属污染极为严重。重金属污染会对生态环境产生极大的破坏,严重制约我国的经济,阻碍经济的可持续发展。因此,对重金属污染进行预防和治理已经成为环境保护工作的重中之重。现有的淋溶实验大部分都是在田间取土,采样回实验室后进行装柱淋溶,这种实验方法会改变土壤的结构,从而很难阐明污染物在土壤中迁移的真实情况。同时开展原状土淋溶的实验相对较少。重金属在水田土壤中控制技术成本较高,目前几乎没有实际应用,因此开展控制技术的研究势在必行。铜、锌的吸附解吸行为特征研究采用平衡振荡法。通过添加不同形式的肥料尿素和硫酸铵(含氮量相同)、改变外源重金属溶液的pH值及改变土壤有机质的含量来研究水田土壤对铜、锌吸附解吸行为的影响;淋溶实验是通过添加不同形式的肥料尿素和硫酸铵(含氮量相同)、改变淋溶液的pH值、不同的淋溶方式及土壤有机质含量来研究水田土壤对铜、锌的垂向迁移的影响,来研究土壤中铜、锌的淋溶规律。控制技术的初步研究是通过对土壤添加有机肥料和防渗剂,进而对原状土进行淋溶,从而观察对铜、锌两种重金属元素淋溶规律的影响。研究结果表明:在铜、锌的吸附动力学研究中,土壤对铜、锌两种重金属元素的吸附经历了3个阶段,即快速吸附阶段、减速吸附阶段和平衡吸附阶段。两种元素均以8 h为吸附平衡时间。在水田土壤中,供试土壤对铜、锌的吸附均是自发、吸热和熵增加的过程。所以高温对水田土壤铜、锌的吸附是有利的。施入含氮量相同但肥料形式不同的尿和硫酸铵,尿素对供试土壤中铜、锌这两种重金属元素的影响大于硫酸铵,尿素和硫酸铵能够增强供试土壤对铜、锌的吸附能力。土壤对铜、锌的吸附量与pH值呈正相关性。随pH值的降低,土壤对铜、锌的吸附量减少,pH的升高促进了土壤对铜、锌的吸附,吸附能力变强。去除有机质后的土壤对铜、锌的吸附能力减弱,吸附量均减少。有机质是影响铜、锌在土壤中吸附的主要因素。在解吸过程中,铜、锌的解吸也同样经历了快速解吸、减速解吸和平衡解吸3个阶段。温度的升高对铜、锌的解吸行为是有利的,降低温度会抑制铜、锌的解吸,降低铜、锌的迁移活性,减小重金属对土壤的危害。在土壤中施加尿素和硫酸铵(含氮量相同),尿素对铜、锌在土壤中的解吸更有利,对重金属的迁移转化具有更强的促进作用。酸性条件下,铜、锌的解吸量与pH值呈负相关性。随着溶液的pH的不断增大,铜、锌两种重金属元素的解吸量却随之减小。随着溶液中pH值的变大,降低了铜、锌的生物活性和化学活性,从而减弱了铜、锌的迁移能力,解吸量随之减少。铜、锌的解吸量与土壤有机质含量呈负相关性。土壤有机质的存在抑制铜、锌在水田土壤中的解吸。土壤有机质的含量明显影响铜、锌的解吸。在原状土淋溶试验中,土壤浸出液能抑制进铜、锌等有机污染物的淋溶,土壤浸提液使土壤对铜、锌的吸附能力增强,铜、锌淋出量减小。随淋溶液pH值降低,淋溶量显著增加,尤其是淋溶液pH值由8.9降至4.2,铜、锌的淋出量增幅分别达到19.33%和39.25%。因此pH是影响土壤中重金属活性的重要元素之一。在连续淋溶过程中,铜、锌的淋出总量大于间断淋溶的淋出总量,对铜、锌的解吸有利。间断淋溶使土壤对铜、锌的吸附能力增强。说明连续降水会加重土壤中重金属的污染。有机质含量是影响铜、锌淋溶的重要因素。有机质对铜、锌的吸附具有促进作用,抑制了铜、锌的淋出。土壤中有机质含量较高的情况下,铜、锌不易迁移,有机质含量越高,其迁移特性越差。在控制技术的初步研究中,添加有机质且添加的含量越高、对铜、锌的吸附能力越强、铜、锌的淋溶性能越小。土壤有机质含量、包括土壤颗粒组成也是影响淋溶性能的主要因素。与未添加水田专用防渗剂的土壤相对比,添加防渗剂铜、锌淋出液总量明显较小。对土壤添加专用防渗剂,从一定程度上可以改善土壤的保水能力,增强土壤保水性,改善土壤的结构,提高水温、地温,使水稻的生长环境得到很好的改善。添加水田专用的防渗剂可以减小铜锌的淋出总量。因此,在水田土壤中添加防渗剂,对土壤中重金属污染起到一定的抑制作用。
[Abstract]:Rice occupies a very important position in the China grain crops, the arable area 1/4 for paddy rice farming, solve the problem of food and clothing for most people in our country. Therefore it can be said that the status of rice production in China's food security is important, the problem of heavy metal pollution in paddy soil. It becomes very important to be the heavy metal pollution of soil, soil properties changed, it will indirectly affect the quality and quality of crops, heavy metals will not only pollute the soil, will involve various aspects such as water environment, atmospheric environment and so on. Therefore, we can say the heavy metal pollution was very serious. Heavy metal pollution will cause great damage to the ecological environment, serious restricting China's economy, hinder the sustainable development of economy. Therefore, the heavy metal pollution prevention and control has become the environmental protection work is heavy In the leaching experiment. Most of the existing in field soil sampling, back to the lab after column leaching, this method will change the structure of the soil, thus it is very difficult to clarify the real situation of migration of contaminants in the soil. At the same time to carry out the experiment of undisturbed soil leaching heavy metals is relatively small. The higher the cost of control technology in paddy soil at present, almost no practical application, so the research on the control technology. It is imperative to study the sorption and desorption characteristics of copper, zinc using the batch equilibration method. By adding urea and ammonium sulfate fertilizer (nitrogen content of different forms of the same), change the content of heavy metals and the pH value of the solution and the change of soil organic matter to research on effect of zinc copper in paddy soil, adsorption and desorption; leaching experiment by adding urea and ammonium sulfate fertilizer (nitrogen content of different forms of the same), change the pH value of leaching solution In different ways, leaching and soil organic matter content of copper in paddy soil, zinc vertical migration effect of copper in soil, leaching of zinc. Preliminary research on control technology is based on the soil with organic fertilizer and anti-seepage agent, and leaching of undisturbed soil, and observation on copper. Effect of zinc leaching of two kinds of heavy metals. The results show that: in the adsorption kinetics of copper, zinc, copper and zinc in soil, the adsorption of two heavy metals has experienced 3 stages, namely fast adsorption stage, slow adsorption stage and equilibrium adsorption stage. The two elements are 8 h for adsorption equilibrium time. In paddy soil, soils of copper, zinc adsorption was spontaneous, endothermic and entropy increase process. So the temperature of paddy soil Cu, Zn adsorption was favorable. Application of nitrogen fertilizer in different forms but the same urine and sulfuric acid Ammonium, urea on soil tested in copper, zinc effects of these two heavy metals than ammonium sulfate, urea and ammonium sulfate could enhance the soil adsorption capacity of copper, zinc. The soil of copper, there was a positive correlation between adsorption quantity and pH zinc value. With the decrease of pH value, soil adsorption of copper. The amount of zinc is reduced, the increase of pH promote the soil adsorption of copper, zinc, and strong adsorption ability. After removal of organic matter in soil of copper, zinc decreased adsorption capacity, adsorption capacity decreased. The organic matter is the main factor affecting the copper and zinc adsorption in the soil. In the process of desorption, copper the desorption, zinc also experienced 3 stages of rapid desorption, desorption and desorption equilibrium speed. With the rise of the temperature of copper, zinc desorption behavior is favorable, will reduce the temperature of the inhibition of copper, zinc desorption, copper, zinc migration activity, reduce the harm of soil heavy metal and sulfur in urea. In the soil Ammonium acid (containing the same amount of nitrogen, urea) on copper, more favorable desorption of zinc in soil, the transformation has stronger effect on the migration of heavy metals. Under acidic conditions, copper, zinc and the desorption of pH was negatively correlated. With the increasing of the solution, pH two desorption of copper, zinc one of the heavy metal elements decreases. With the solution pH value becomes large, reduce the biological activity and chemical activity of copper, zinc, thereby weakening the migration ability of copper, zinc, desorption decreases. The desorption of copper, zinc and the content of soil organic matter was negatively correlated. There was inhibition of Cu in soil organic matter, desorption of zinc in paddy soil. The content of soil organic matter significantly affect copper, zinc desorption. In the undisturbed soil leaching test, soil extract can inhibit the copper leaching, zinc and other organic pollutants, soil extracts of the soil of copper, zinc and copper enhanced adsorption capacity the leaching of zinc. The amount of decrease. With the decrease of pH value of leaching solution, leaching amount increased significantly, especially in the leaching solution pH value decreased from 8.9 to 4.2, copper, zinc leaching quantity growth reached 19.33% and 39.25%. so pH is one of the important elements in the soil heavy metal activity. In the continuous leaching process, copper, total zinc leaching over the discontinuous leaching leaching amount of copper, zinc desorption favorable. The soil discontinuous leaching of copper, zinc adsorption ability. It shows that continuous rainfall will increase the pollution of heavy metals in soil. Organic matter content is an important factor affecting the copper, zinc leaching. The organic matter of copper, zinc can promote the adsorption effect of inhibition of copper, zinc leaching. The higher content of soil organic matter in the case of copper, zinc is not easy to transfer, the high organic matter content, the migration characteristics worse. In the preliminary research on the control technology, adding the content of organic matter and add more of copper, zinc absorption With stronger ability of copper, zinc leaching, performance is small. The content of soil organic matter, the main factors include the composition of soil particles also affect the leaching performance. Compared with paddy field without adding special anti-seepage agent soil, adding copper zinc leaching agent seepage, fluid volume was significantly smaller. The soil added special anti-seepage agent. From a certain extent, can improve the water retention capacity of soil, enhance soil water, improve soil structure, increase temperature, ground temperature, the environment for the growth of rice is improved. Adding anti-seepage agents can reduce the special paddy field of copper and zinc leaching from the total amount. Therefore, adding anti-seepage agent in paddy field and to a certain inhibitory effect on the heavy metal pollution in soil.

【学位授予单位】：吉林农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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