Gorokhovsky Alexander, Burmistrov Igor, Kuznetsov Denis, Gusev Alexander, Khaidarov Bekzod, Kiselev Nikolay, Boychenko Elena, Kolesnikov Evgeny, Prokopovich Ksenia, Konyukhov Yuri, Kravchenko Maksim
Department of Functional Nanosystems and High Temperature Materials, National University of Science and Technology (MISIS), 119049 Moscow, Russia.
Moscow Power Engineering Institute, National Research University, 111250 Moscow, Russia.
Molecules. 2023 Jul 17;28(14):5466. doi: 10.3390/molecules28145466.
The xerogels based on the aqueous solutions of urea in potassium silicate liquid glass (PSLG) were produced by CO bubbling and investigated. The structure and chemical composition of the obtained materials were analyzed. Using the SEM, XRD, IR-FT, DSC, and low energy local EDS analysis, it was recognized that the dried gels (xerogels) contained three forms of urea: oval crystals of regular shape appeared onto the surface of xerogel particles; fibrous crystals were located in the silicate matrix; and molecules/ions were incorporated into the silicate matrix. It was shown that an increase in [(NH)CO] in the gel-forming system promoted increased contents in crystalline forms of urea as well as the diameter of the fiber-shaped urea crystals. A rate of the urea release in water from the granulated xerogels containing 5.8, 12.6, and 17.9 wt.% of urea was determined by the photometric method. It was determined that the obtained urea-containing xerogels were characterized with a slow release of urea, which continued up to 120 days, and could be used as controlled release fertilizers containing useful nutrients (N, K).
通过鼓入二氧化碳制备并研究了基于尿素在硅酸钾水玻璃（PSLG）水溶液中的干凝胶。对所得材料的结构和化学成分进行了分析。利用扫描电子显微镜（SEM）、X射线衍射（XRD）、傅里叶变换红外光谱（IR-FT）、差示扫描量热法（DSC）和低能局部能谱分析（EDS），发现干燥后的凝胶（干凝胶）含有三种形式的尿素：规则形状的椭圆形晶体出现在干凝胶颗粒表面；纤维状晶体位于硅酸盐基质中；分子/离子则融入硅酸盐基质中。结果表明，凝胶形成体系中[(NH)CO]含量的增加促进了尿素结晶形式含量的增加以及纤维状尿素晶体直径的增大。采用光度法测定了含尿素5.8%、12.6%和17.9%（质量分数）的颗粒状干凝胶在水中的尿素释放速率。结果表明，所制备的含尿素干凝胶具有尿素缓释特性，缓释持续时间长达120天，可作为含有有益养分（氮、钾）的控释肥料。
