生物碳吸附去除溶液中的阿特拉津

发布时间：2018-12-18 07:04

【摘要】：如今化学药品在农业、渔业、动物保护以及其他领域的广泛应用所产生的环境问题已经引起了全世界的关注。阿特拉津（2-氯-4-乙胺基-6-异丙胺-均三嗪）是一种除草剂，因其能够有效控制阔叶类杂草的生长而被广泛应用于农业中，如咖啡、甘蔗、香蕉、大豆、玉米、小麦、高粱、菠萝等作物的生产中。阿特拉津难溶于水，但在某些特定的环境条件下具有高迁移性，所以残留在土壤中的阿特拉津易通过径流作用进入地表受纳水体；也可通过淋滤作用迁移至土壤深层，甚至污染地下水源。农业中使用的阿特拉津通过径流和沉降作用间接污染了收纳水体（地表水和地下水），含有高浓度阿特拉津的地表水或地下水会引发许多环境问题，人类健康（生长发育、癌症以及生殖器官的损害）、水生生物（雌性化）、植物生长等都会受到影响。寻找从被污染的水体和土壤中去除阿特拉津的方法已经引起了许多科研工作者的注意。生物碳作为一种可供选择的阿特拉津去除剂而被广泛使用。生物碳是一种在缺氧条件下，热解生物量而获得的多孔性材料，现已广泛用于土壤和水体污染物的去除。论文首先利用大豆杆(soybeans，SBB)、玉米杆(corn stalks，CSB)、水稻杆(ricestalks，RSB)、家禽粪便(poultry manure， PMB)、牛粪(cattle manure， CMB)、猪粪(pig manure，PgMB)作为原材料来制备生物碳，并对六种生物碳的理化性质进行研究（元素组成、表面形态结构、表面官能团、比表面积、平均孔径、总孔隙体积等）。通过批次实验来研究不同材质的生物碳在不同环境条件下（阿特拉津初始浓度、吸附剂含量、温度、pH）对阿特拉津的吸附量效果的影响。其次做了六种不同材质的生物碳对阿特拉津吸附等温线和吸附动力学的研究。最后选出对一种对阿特拉津吸附效果最好的生物碳，利用响应曲面法进行最优化研究。通过上述研究，得出以下结论：（1）六种不同材质生物碳的吸附容量都随着阿特拉津初始浓度、吸附剂含量以及温度的增加而增加。阿特拉津在酸性或碱性溶液中均有很好的去除效果。但是由于吸附和水解的双重作用，相对于酸性溶液而言，阿特拉津在碱性溶液中的去除率更高。设置不同的初始的pH值（4.5-11），随着试验的进行溶液的pH值最终都会趋于碱性（8.17-9.33）。（2）弗罗因德利希等温线（Freundlich isotherm adsorption）的吸附参数显示，六种不同类型生物碳的吸附容量比较如下：SBB RSB CMB CSB PMBPgMB。基于阿特拉津吸附容量的所有参数显示：SBB比其他五种类型生物碳能够更好的吸附阿特拉津。六种生物碳的总孔隙体积介于0.05cm3/g（PgMB和PMB）与0.19cm3/g（SBB）之间。SBB拥有更多的孔隙，且微孔占总孔隙体积的12.5%。生物碳的总孔隙体积和pH在生物碳的吸附容量方面十分重要，而且他们可能对物理吸附机制（生物碳的活化能小于42kJ/mol）在整体吸附过程中占支配地位做出贡献。（3）通过对比假一级动力学，假二级动力学，耶诺维奇（Elovich）和内部颗粒扩散模型（Intraparticle diffusion model，IPD）以及改进弗罗因德利希（Freundlich）模型的吸附动力学，得出生物碳对阿特拉津的吸附过程更符合改进的弗罗因德利希模型和颗粒内部扩散模型。 (4)利用响应曲面法最优化研究得出最适操作条件为pH6.67、SBB含量为7.75g/L、32oC，此时的吸附去除率为92.18%。此外，对于模型的统计数据在95%的可信度条件下分析发现，，独立变量对于吸附过程会产生有效影响（pH、吸附剂含量、阿特拉津初始浓度、温度的P值分别为0.005、0.000、0.000和0.000）。吸附剂含量（P=0.009）以及初始pH与初始浓度之间的相互作用（P=0.034）会对吸附过程产生方块效应。相关系数接近于1，修正的拟合值F=169.660和在统计上具有显著意义的P=0.000显示二次式模型对于数据的拟合是有意义的。生物碳（SBB）可以作为一种既经济又高效的污染物吸附剂，为今后修复被阿特拉津污染的水和生态系统提供了吸附材料和技术支持。
[Abstract]:Environmental issues arising from the widespread use of chemicals in agriculture, fisheries, animal protection and other areas have attracted worldwide attention. atrazine (2-chloro-4-ethylamine-6-isopropanamine-all three-stage) is a herbicide which is widely used in agriculture due to its ability to effectively control the growth of broad-leaf weeds, such as coffee, sugar cane, banana, soybean, corn, wheat, sorghum, and the production of the pineapple and the like. Atrazine is difficult to dissolve in water, but has high mobility under certain environmental conditions, so the Atrazine remaining in the soil is easy to enter the surface receiving water through the runoff, and can also be transferred to the deep layer of the soil through the leaching action, and even the source of the underground water can be polluted. Atrazine, used in agriculture, indirectly pollutes the storage water (surface water and ground water) through runoff and sedimentation, and surface water or ground water containing high-concentration Atrazine can cause many environmental problems, human health (development, cancer and reproductive organ damage), Aquatic organisms (feminization), plant growth, and so on are affected. The search for the removal of atrazine from contaminated water and soil has attracted the attention of many researchers. Biocarbon is widely used as an alternative atrazine remover. Biocarbon is a porous material obtained by pyrolysis of biomass under the condition of hypoxia, and has been widely used in the removal of soil and water pollutants. In this paper, the soybean rods (soybeans, SBB), corn rods (CSB), rice rods (RSB), poultry manure (PMB), cow dung (CMB) and pig manure (PgMB) were used as raw materials to prepare the biological materials. Carbon and study on the physical and chemical properties of the six biological carbons (element composition, surface morphology, surface functional group, specific surface area, average pore size, total pore volume, etc.) The effect of the biological carbon of different materials under different environmental conditions (the initial concentration of atrazine, the content of the adsorbent, the temperature and the pH) on the adsorption of atrazine was studied by batch experiments. In response, the adsorption isotherms and the adsorption kinetics of the six different kinds of biological carbon on the Atrazine adsorption isotherm and the adsorption kinetics were studied. and finally, the best biological carbon for the atrazine adsorption effect is selected, and the optimization research is carried out by using the response surface method. by the above-mentioned study, the following knot is obtained (1) The adsorption capacity of six kinds of biological carbon with different materials increases with the initial concentration of atrazine, the content of the adsorbent and the temperature. and the addition of the atrazine in the acidic or alkaline solution in addition to that effect, however, as a result of the double action of adsorption and hydrolysis, the removal of atrazine in the alkaline solution, relative to the acidic solution, The rate is higher. Different initial pH values (4.5-11) are set, and the pH of the solution will eventually tend to be basic (8.17-9) as the pH of the solution is tested. (2) The adsorption parameters of Freundlich isotherms show that the adsorption capacity of the six different types of biological carbon is as follows: SBB RSB CMB CSB PM BPgMB. All parameters based on Atrazine's adsorption capacity show that SBB is better than other five types of biocarbon The total pore volume of the six kinds of biocarbon is 0. 05cm3/ g (PgMB and PMB) and 0.19cm3/ g (S BB). The SBB has more pores and the pores account for the total pore volume. 12.5%. The total pore volume and pH of the biological carbon are important in the adsorption capacity of the biological carbon, and they may be dominant in the overall adsorption process for the physical adsorption mechanism (the activation energy of the biological carbon is less than 42kJ/ mol). (3) By comparing the pseudo-first-order dynamics, the pseudo-secondary dynamics, the Elovich and the internal particle diffusion model, the IPD, and the modified Freundlich model, The adsorption kinetics of biocarbon to atrazine is more in line with the modified Freund's model and one. (4) The optimum operating conditions are pH 6.67 and the SBB content is 7.75g/ L, 32oC. In addition, for the statistical data of the model, it was found that the independent variable had an effective effect on the adsorption process (pH, the content of the adsorbent, the initial concentration of atrazine, the P-value of the temperature was 0. 005, 0. 000, and 0. 0, respectively). 00 and 0.000). The content of the adsorbent (P = 0. 009) and the interaction between the initial pH and the initial concentration (P = 0.034) will be considered The correlation coefficient is close to 1, the corrected fitted value F = 169.660 and the P = 0.000, which is statistically significant, shows the secondary model for the number It is significant that biocarbon (SBB) can be used as an economical and efficient pollutant adsorbent for future remediation of the water and ecosystem contaminated by Atrazine.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X592

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