环境友好型水基共聚物—生物炭复合包膜氮肥制备及其缓释性能的研究

发布时间：2018-01-13 11:32

本文关键词：环境友好型水基共聚物—生物炭复合包膜氮肥制备及其缓释性能的研究　出处：《沈阳农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：养分缓释效果好、环境友好的膜材料是当前包膜缓控释肥料研究的重点,本研究以聚乙烯吡咯烷酮、聚乙烯醇为原料,以生物炭为填充剂,根据有机高分子共聚理论及溶液共混技术制备水基共聚物-生物炭复合包膜材料及包膜尿素。通过对水基共聚物-生物炭膜材料吸水性、透水性、铵的渗透性的测定研究其适宜改性条件;利用膜材料红外光谱特性、扫描电镜分析和埋土试验探讨了膜材料的改性及降解机理;同时通过红外光谱测定、扫描电镜分析以及土柱淋溶试验研究不同处理下包膜尿素的微观结构及其氮素释放特性,并通过田间试验对所选包膜尿素肥效进行验证。研究结果如下:(1)添加不同材料(玉米秸秆(Y)、水稻秸秆(S)、枯枝落叶(K))制成的生物炭均能降低膜材料的吸水率;并根据其渗透性、红外光谱特性、生物降解性筛选出了三个处理,即玉米基生物炭用量为3%、水基共聚物浓度为6%、生物炭粒级为60目(Y1),水稻基生物炭用量为5%、水基共聚物浓度为8%、生物炭粒级为200目(S5),枯枝落叶基生物炭用量为7%、水基共聚物浓度为8%、生物炭粒级为60目(K6)三种条件下制备的水基共聚物吸水率分别降低了27.89%、28.19%、26%,120 d降解率达到了32.44%、32.94%、33.88%,且随着埋土时间的延长降解率会进一步的增加,不会对种植土壤造成二次污染。(2)扫描电镜结果表明水基共聚物-生物炭复合膜材料能够相对均匀的混合且能够较为完整的分布于肥料颗粒表面,同时部分包膜物质渗透到尿素颗粒表面的空隙中,使得膜材料与尿素结合更为紧密,形成了水分子进入包膜尿素的一道屏障,延长其缓释性能。(3)土柱淋洗试验结果表明当水稻基生物炭用量为5%、水基共聚物浓度为8%、生物炭粒级为200目(S5)时包膜肥料的缓释效果最佳,且具有较长的缓释期,在22 d时氮素累积释放率为65.28%。(4)玉米田间肥效试验结果表明,与常规施肥相比水基共聚物-生物炭复合包膜尿素在用量减少20%的情况下仍有1.45%的增产效果。总之,以聚乙烯醇、聚乙烯吡咯烷酮及生物炭为原料制备的水基共聚物-生物炭复合包膜材料在土壤环境中有较强的降解能力,不会对种植土壤造成污染,同时制备的水基共聚物-生物炭复合包膜尿素具有良好的缓释效果及良好的增产效果,根据需求可以用来制备环境友好型膜材料及包膜尿素。
[Abstract]:The nutrient release effect is good, and the environmentally friendly membrane material is the focus of the research on coated slow release fertilizer. In this study, polyvinylpyrrolidone and polyvinyl alcohol were used as raw materials and biochar as filler. Based on the theory of organic polymer copolymerization and solution blending technology, water-based copolymers and biochar composite coating materials and coated urea were prepared. The water absorption and water permeability of water-based copolymers and biochar membrane materials were studied. The suitable modification conditions of ammonium were studied. The modification and degradation mechanism of membrane material were studied by SEM and buried soil test. At the same time, the microstructure and nitrogen release characteristics of coated urea under different treatments were studied by IR, SEM and soil column leaching test. The effect of coated urea fertilizer was verified by field experiment. The results were as follows: (1) adding different materials (corn straw and rice straw). The water absorption rate of the membrane materials was decreased by the biochar. According to its permeability, infrared spectrum and biodegradability, three treatments were selected, namely, the amount of corn-based biochar was 3, the concentration of water-based copolymers was 6, and the particle size of biochar was 60 mesh / y _ 1). The amount of rice based biochar is 5, the concentration of water-based copolymer is 8, the particle level of biochar is 200mesh, the amount of withered and deciduous biochar is 7 and the concentration of water-based copolymer is 8%. The water absorbency of the water-based copolymers was decreased by 27.89% and 28.19%, respectively. The degradation rate of the copolymers reached 32.44% in 120 days. 32.94 and 33.88, and the degradation rate will further increase with the time of soil burying. The SEM results showed that the water-based copolymers and biochar composite membrane materials could be relatively evenly mixed and distributed completely on the surface of fertilizer particles. At the same time, some of the coating material permeated into the void of urea particles, which made the membrane materials more closely bound to urea, forming a barrier for water molecules to enter into the coated urea. The results of soil column leaching test showed that the concentration of water-based copolymers was 8% when the amount of biochar used in rice was 5 and the concentration of water-based copolymers was 8%. The coated fertilizer has the best sustained release effect and has a long slow release period when the biological carbon particle size is 200 mesh / s 5. At 22 days, the cumulative release rate of nitrogen was 65.28%. Compared with conventional fertilization, the water-base copolymers and biochar coated urea still had an increase of 1.45% when the amount of urea was reduced by 20%. In a word, polyvinyl alcohol was used. The water-based copolymers and biocarbon composite coating materials prepared from polyvinylpyrrolidone and biochar have strong degradation ability in soil environment and will not pollute the planting soil. The water-base copolymers and biocarbon coated urea have good slow release effect and good yield increasing effect. It can be used to prepare environment-friendly membrane materials and coated urea according to the demand.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ441.41

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