Nitrogen release characteristics of polyethylene-coated controlled-release fertilizers and their dependence on membrane pore structure  

作　　者：Xiangdong Yang Rongfeng Jiang Yangzheng Lin Yanting Li Juan Li Bingqiang Zhao 

机构地区：[1]Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agricultureflnstitute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China [2]College of Resources and Environmental Sciences, Centre for Resources, Environment and Food Security, China Agricultural University, Beijing 100193, China [3]Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, USA

出　　处：《Particuology》2018年第1期158-164,共7页颗粒学报（英文版）

基　　金：This work described above was financially supported by National Key R＆D Program of China （No. 2017YFD0200703）, and the General Program of Natural Science Foundation of China （grant number 31572204）. The authors would like to thank Hongying Cai from the Department of Chemical Engineering of Tsinghua Univer- sity for his help with SEM observations and Dongwu Chang from the Department of Thermal Energy Engineering of Tsinghua University for assistance with MP measurements.

摘　　要：In this study, controlled-release fertilizers （CRFs） with five different nitrogen release periods were pre- pared by coating large urea particles with polyethylene （PE） membranes under various experimental conditions. The preliminary and differential solubility rates, release periods, and membrane pore sizes of the obtained CRFs were measured using water immersion, scanning electron microscopy, and mercury porosimetry. For all CRF samples, the median pore diameters of the membranes were equal to 4.5-5.3 nm and pores with sizes smaller than 10 nm accounted for 86-96% of the total pore surface area. The obtained pore diameter distributions differed for the five studied types of CRF, having release periods of 1,2, 4, 6, and 8 months. Thus, for the CRFs with a 1-month release period, the maximum pore diameter reached a magnitude of 4000 nm, while this value did not exceed 30 nm for the CRFs with a release period of 8 months. Hence, we have established a relationship between the release period of CRFs and their effective maximum pore sizes.In this study, controlled-release fertilizers （CRFs） with five different nitrogen release periods were pre- pared by coating large urea particles with polyethylene （PE） membranes under various experimental conditions. The preliminary and differential solubility rates, release periods, and membrane pore sizes of the obtained CRFs were measured using water immersion, scanning electron microscopy, and mercury porosimetry. For all CRF samples, the median pore diameters of the membranes were equal to 4.5-5.3 nm and pores with sizes smaller than 10 nm accounted for 86-96% of the total pore surface area. The obtained pore diameter distributions differed for the five studied types of CRF, having release periods of 1,2, 4, 6, and 8 months. Thus, for the CRFs with a 1-month release period, the maximum pore diameter reached a magnitude of 4000 nm, while this value did not exceed 30 nm for the CRFs with a release period of 8 months. Hence, we have established a relationship between the release period of CRFs and their effective maximum pore sizes.

关 键 词：Controlled-release fertilizer Nutrient release period Membrane pore structure Mercury porosimetryPore size 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业] TQ440.5