SAP-CS复式包膜尿素的制备及水肥调控效果研究

发布时间：2018-02-09 00:16

本文关键词： 高吸水性树脂壳聚糖尿素缓释水肥调控　出处：《仲恺农业工程学院》2015年硕士论文　论文类型：学位论文

【摘要】：肥料利用率低和水资源短缺是制约我国农业可持续发展的两大主要因素,如何提高肥料和水的利用率就成为迫切需要解决的问题。保水型缓/控释肥料是具有吸水、保水和养分缓释功能的新型肥料,可以达到水肥一体化调控效果。为进一步优化保水型缓释肥料的缓释效果,本文在研究壳聚糖(Chitosan,CS)分子量及其浓度、增塑剂和交联剂对壳聚糖膜性能影响的基础上,以5万、20万和50万3种分子量的壳聚糖为包膜材料,制备了壳聚糖(CS)包膜尿素,进而以分子量50万的壳聚糖为内包膜材料,分别以3种高吸水性树脂(Super absorbent polymer,SAP)P(AA-AM)、P(AA-AMPS)、P(AA-AM-AMPS)为外包膜材料,制备了高吸水性树脂-壳聚糖(SAP-CS)复式包膜尿素,通过肥料物理化学性质测定、水中溶出率和土柱淋溶试验,对肥料综合性能进行了研究,得出以下结论:(1)壳聚糖的成膜性与其溶液的粘度有很大关系,相对分子量和浓度越大,溶液的粘度越大。浓度为2%时,分子量为5万、20万和50万的壳聚糖膜均表现出良好的成膜性。增塑剂聚乙烯醇、交联剂戊二醛的加入都不同程度的改善了壳聚糖膜的性能,但增塑剂甘油的效果不明显。应用浓度2%(m/V)、分子量为50万的壳聚糖,聚乙烯醇用量为0.85%(m/V)、戊二醛用量为0.5%(V/V)时,壳聚糖膜的拉伸强度、断裂伸长率和溶胀度均表现出良好的性能,是壳聚糖膜制备的最佳工艺条件。此时,壳聚糖膜的拉伸强度为39.5MPa,断裂伸长率为52.3%,溶胀度为6.85%。(2)壳聚糖分子量、交联剂戊二醛、密封剂石蜡和增塑剂聚乙烯醇都能显著影响CS包膜尿素的氮素缓释性能。选用分子量为50万的壳聚糖,包膜量为3%,密封剂用量为20%,聚乙烯醇用量为0.85%,戊二醛用量为0.5%是制备CS包膜尿素的最佳工艺条件。此时,CS包膜尿素的氮素初级溶出率为68.38%,7天累积溶出率为76.40%。(3)在CS包膜尿素的基础上制备了SAP-CS复式包膜尿素。以P(AA-AM)为外膜,通过对壳聚糖包膜量、石蜡、胶黏剂和表面交联剂等因素进行优化,壳聚糖的分子量为50万,包膜量为3%,外膜P(AA-AM)包膜量为10%,水作为胶黏剂,表面交联剂用量为10%,不用石蜡做密封剂是比较适宜的制备条件。此时,SAP-CS复式包膜尿素的缓释效果较明显,在水中的初级溶出率为39.8%,7天累积溶出率为68.59%。(4)SAP-CS复式包膜尿素具有良好的水肥调控效果。水中溶出率表明,不同包膜量的SAP-CS复式包膜尿素的吸水倍率和氮素释放速率均不同程度的较SAP包膜尿素改善,且随包膜量的增加效果愈加明显。SAP-CS复式包膜尿素的初级溶出率介于38.9%-56.57%,7天累积溶出率介于75.78%-94.11%,较SAP包膜尿素,吸水倍率增加4.14%-19.21%,初级溶出率降低22.55%-25.74%,7天累积溶出率降低5.87%-16.58%。SAP-CS复式包膜尿素在土壤中的养分释放规律与在水中相似,但在土壤中的缓释效果更显著。相对于普通尿素,高吸水性树脂与尿素混施和SAP包膜尿素,SAP-CS复式包膜尿素的氮素累积淋出率分别减少7.76%-9.23%、12.87%-22.99%、13.47%-29.59%。综合比较,P(AA-AM-AMPS)制备的包膜尿素的水肥调控效果均优于P(AA-AM)、P(AA-AMPS)制备的包膜尿素。
[Abstract]:The fertilizer utilization rate is low and the shortage of water resources are the two major factors restricting the sustainable development of agriculture in China, how to improve the utilization rate of fertilizer and water becomes an urgent problem to be solved. The water holding slow / controlled release fertilizer is a new fertilizer with water absorption, water retention and slow-release function, can achieve the integration of water and fertilizer regulation effect. In order to further optimize the release effect of water retaining fertilizer, based on the study of chitosan (Chitosan, CS) molecular weight and concentration, the basic effect of plasticizer and crosslinking agent on the properties of chitosan membrane, with 50 thousand, 200 thousand and 500 thousand and 3 kinds of molecular weight chitosan as coating materials, preparation of chitosan (CS) coated urea, and with molecular weight of 500 thousand chitosan as coating materials, respectively, with 3 kinds of super absorbent resin (Super absorbent, polymer, SAP) P (AA-AM), P (AA-AMPS), P (AA-AM-AMPS) as coating material, high water absorbent preparation Chitosan resin (SAP-CS) coated urea by physical and chemical properties of fertilizer determination rate and soil column leaching test water dissolution, the comprehensive performance of the fertilizer was studied, draw the following conclusions: (1) has a lot of chitosan film and its solution viscosity, molecular weight and concentration large, the greater the viscosity of the solution. When the concentration is 2%, the molecular weight of 50 thousand, 200 thousand and 500 thousand chitosan membrane showed good film-forming properties. The plasticizer of polyvinyl alcohol, adding glutaraldehyde are different degree of improving the properties of chitosan membrane, but the effect of plasticizer glycerin the application is obvious. The concentration of 2% (m/V), the molecular weight of 500 thousand chitosan, polyvinyl alcohol (m/V) was 0.85%, the amount of glutaraldehyde was 0.5% (V/V), tensile strength, elongation and swelling degree showed a good performance, is the best preparation process of chitosan membrane . at this time, the tensile strength of chitosan membrane was 39.5MPa, elongation was 52.3%, the swelling degree of 6.85%. (2) the molecular weight of chitosan, glutaraldehyde, paraffin sealant and plasticizer of polyvinyl alcohol can significantly affect the performance of CS coated urea nitrogen release. The molecular weight of 500 thousand chitosan coating quantity 3%, the sealant dosage was 20%, the polyvinyl alcohol is 0.85%, the dosage of glutaraldehyde is 0.5% is the optimal conditions for preparation of CS coated urea. At this time, CS coated urea nitrogen primary dissolution rate was 68.38%, 7 days cumulative dissolution rate of 76.40%. (3) based on CS coated urea were prepared on SAP-CS double coated urea. The P (AA-AM) into the outer membrane based on chitosan coated, paraffin wax, crosslinking agent and surface adhesive factors were optimized, the molecular weight of chitosan was 500 thousand, coating weight is 3%, P membrane (AA-AM) coating weight is 10%, water is used as an adhesive, table The surface crosslinking agent is 10%, no paraffin sealant is suitable for preparation conditions. At this time, SAP-CS coated urea release effect is obvious, the initial dissolution rate in water is 39.8%, 7 days cumulative dissolution rate of 68.59%. (4) SAP-CS double coated urea has good effect of water and fertilizer regulation rate. That water dissolution, release rate of different coating amount of SAP-CS coated urea nitrogen and water absorbency were different degrees of improvement compared with SAP coated urea, and the effect is more obvious with.SAP-CS coated urea dissolution rate of 38.9%-56.57% in primary dielectric coated amount increasing, 7 days cumulative dissolution rate is between 75.78%-94.11%, compared with SAP coating urea, water absorption rate increased by 4.14%-19.21%, the initial dissolution rate decreased 22.55%-25.74%, 7 days cumulative dissolution rate decreased 5.87%-16.58%.SAP-CS coated urea in soil nutrient release and water in a similar, But the sustained release effect in soil is more significant. Compared with common urea, high water absorbent resin mixed with urea and SAP coated urea, SAP-CS coated urea nitrogen accumulated leaching rates were reduced by 7.76%-9.23%, 12.87%-22.99%, 13.47%-29.59%. comparison, P (AA-AM-AMPS) preparation of coated urea fertilizer was better than P (AA-AM), P (AA-AMPS) preparation of coated urea.

【学位授予单位】：仲恺农业工程学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ441.41

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