工业碱木质素基缓释氮肥的制备及缓释性能研究

发布时间：2018-03-17 05:01

本文选题：工业碱木质素　切入点：脲甲醛　出处：《中国科学院大学(中国科学院教育部水土保持与生态环境研究中心)》2017年硕士论文　论文类型：学位论文

【摘要】：缓释肥作为未来化学肥料的主要发展方向,将为现代农业的发展发挥重要作用。因缓释肥高效、环保和节省劳动力而备受关注。以工业木质素作为材料研制缓释肥相比其他材料具有更大优势:木质素是天然高分子有机物,制备的缓释肥对环境无污染;木质素能够延缓肥料中养分溶解,降低肥料水溶性,进一步提高肥料缓释性能;木质素能抑制脲酶活性,降低NO3-N释放,减少氨挥发,增加NH4+-N利用率;以工业木质素为原料将解决制浆造纸业所产生工业木质素资源浪费问题,提高资源利用率,此外也避免了炓液(工业木质素)对环境的污染。因此本文以工业碱木质素为主要材料制备缓释氮肥。羟甲基化可以显著提高碱木质素羟基含量,是增强木质素反应活性的有效改性方法。在对工业木质素羟甲基化改性过程中,通过红外光谱(FTIR)、碳谱(DEPT 135)和异核单量子关系(HSQC)对改性前后木质素结构分别进行表征,分析碱木质素在反应过程中结构变化,并对反应过程进行初步探索和验证。在此基础上以改性后的羟甲基化木质素构建缓释模型:通过自身缩合构建缓释模型和以羟甲基化木质素、海藻酸钙凝胶和钠基-蒙脱土共同组建缓释模型制备缓释氮肥。本文系统探讨了这两种肥料的缓释性能,得出主要结论如下:(1)木质素羟甲基化反应主要有两种反应过程,在侧链区域甲醛和对羟基肉桂酸或阿魏酸单元侧链的双键发生Prings反应形成羟甲基;在芳香区域甲醛和对羟基苯基C-3、C-5,愈创木基C-5上发生Lederer-Manasse反应形成羟甲基。而木质素其他结构单元,如紫丁香基单元,β-O-4醚键结构,苯基香豆满均未与甲醛发生羟甲基化反应。(2)通过正交试验优化羟甲基化反应,得出最佳工艺条件为反应温度80℃,反应时间3 h,pH为11,m(木质素):m(甲醛)为6:1,在此最优条件下羟甲基的质量分数为2.32%。(3)通过羟甲基化木质素自身缩合构建紧密三维网络结构,包裹、嵌入游离尿素、羟甲基脲和脲甲醛制备缓释氮肥。结果表明该肥料具有良好的缓释性能。土壤淋溶25天后,氮的释放量不超过75%。(4)以羟甲基化木质素、钠基-蒙脱土和海藻酸钙凝胶共同组建缓释模型制备缓释氮肥。该肥料具有较好的缓释性能。海藻酸钙凝胶作为尿素主要载体,其浓度高低直接决定了游离尿素“包裹”量。以2%海藻酸钠作为基质相比3%、4%的海藻酸钠对尿素有更好缓释效果。羟甲基化木质素在海藻酸钙凝胶基质中主要起到疏松结构作用,提高“包裹”游离尿素的缓释活性,改善肥料缓释性能。羟甲基化木质素占海藻酸钙凝胶的150%时,具有的缓释性能最好,其累计释放率达到19.13%,潜在释放率达到5.83%。具有片层结构的钠基-蒙脱土可以较好调节羟甲基化木质素和海藻酸钙凝胶基质二者的关系。钠基-蒙脱土构成更多的微孔隙,更加有效包裹尿素。当钠基-蒙脱土含量为羟甲基化木质素含量的1/3时,构建的三维网络结构对游离尿素的“包裹”效果最好,其肥料的缓释性能也最好。
[Abstract]:Slow release fertilizer as the main development direction of future chemical fertilizers, will play an important role in the development of modern agriculture. Due to fertilizer efficiency, environmental protection and labor saving and concern. With the industrial lignin as a material for slow release fertilizer compared to other materials have more advantages: lignin is a natural organic polymer, the sustained-release fertilizer no pollution to the environment; lignin can delay nutrient dissolved in the fertilizer, reducing fertilizer water solubility, further improve the performance of slow release fertilizer; lignin can inhibit urease activity, reduce NO3-N release, reduce ammonia volatilization, increase the utilization ratio of NH4+-N; industrial lignin as raw material to solve the pulp and paper industry from industrial lignin waste of resources the problem, improve the utilization rate of resources, in addition to avoid Liao liquid (industrial lignin) pollution to the environment. So this paper takes industrial alkali lignin as the main material for the preparation of hydroxyl release fertilizer. Methylation can significantly improve the alkali lignin content of hydroxyl, is an effective method to enhance the modified lignin reactivity. The lignin hydroxymethylation modification process, through infrared spectroscopy (FTIR), carbon spectrum (DEPT 135) and heteronuclear single quantum relation (HSQC) before and after the modification of wood prime structures were characterized by analysis of alkali lignin structure in the reaction process, and the preliminary exploration and verification of the reaction process. Based on the modified hydroxymethylation of wood after the construction in sustained-release model: through self condensation model and to construct sustained release of hydroxymethylated lignin, calcium alginate gel and sodium base montmorillonite jointly set up the model for the preparation of sustained-release slow-release nitrogen fertilizer. This paper discusses the system performance of the two kinds of slow-release fertilizer, the main conclusions are as follows: (1) there are two main types of reaction process of lignin hydroxymethylation in formaldehyde and the hydroxyl side chain region The base of cinnamic acid or ferulic acid units in the side chain double bonds Prings reaction to form hydroxymethyl formaldehyde and aromatic; in the area of hydroxylphenyl C-3, C-5, C-5 on the Lederer-Manasse reaction of guaiacyl lignin. The formation of methylol and other structural elements, such as syringyl units, beta -O-4 phenyl ether bond structure, coumaran not with formaldehyde hydroxymethylation. (2) by optimizing the reaction of hydroxymethyl orthogonal test, the optimum process conditions for the reaction temperature is 80 DEG C, the reaction time is 3 h, pH 11, m (lignin): m (formaldehyde) is 6:1, the mass fraction of hydroxymethyl under the optimum conditions for 2.32%. (3) by hydroxymethylated lignin self condensation buildclose three-dimensional network structure, embedded free package, urea, methylolurea and preparation of urea formaldehyde slow-release nitrogen fertilizer. The results showed that the fertilizer has a good sustained release performance. Soil leaching after 25 days, the release amount of nitrogen is less than 7 5%. (4) by hydroxymethylated lignin, sodium Based Montmorillonite and calcium alginate gel to form sustained-release preparation of the model release fertilizer. The fertilizer has a good sustained release effect. Calcium alginate gel as the main carrier of urea, the urea concentration directly determines the free "package". By 2% sodium alginate as compared to matrix 3%, 4% sodium alginate has better slow-release effect on urea. Hydroxymethylated lignin in calcium alginate gel matrix plays a major role in loose structure, improve the activity of sustained-release package free urea fertilizer, improve release property. Lignification of hydroxymethyl group in calcium alginate gel accounted for 150%, with the best release properties, the cumulative release rate reached 19.13%, with sodium base layer structure of 5.83%. - release potential rate of MMT could well adjust relations of hydroxymethylated lignin and calcium alginate gel matrix two sodium. Montmorillonite made up more micropores and more effective encapsulation of urea. When the content of sodium montmorillonite was 1/3 of hydroxymethylated lignin, the three-dimensional network structure constructed had the best package effect on free urea, and its slow release performance of fertilizers was also the best.

【学位授予单位】：中国科学院大学(中国科学院教育部水土保持与生态环境研究中心)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ441

【参考文献】