Water, Decontamination, Ecosystem and Health Laboratory, International Institute for Water and Environmental Engineering (2iE), Ouagadougou, Burkina Faso.
Laboratory on Engineering for Sustainable Sanitation, Faculty of Engineering, Hokkaido University, Sapporo, Japan.
Environ Technol. 2013 Sep-Oct;34(17-20):2809-15. doi: 10.1080/09593330.2013.790069.
Human excreta, especially urine is rich in nitrogen that can be utilized for agricultural purposes, while the slow-release fertilizer allows effective utilization of nutrients in agricultural production. The direct formation of slow-release fertilizer--methylene urea--from urine was being proposed in this study. The experiments were tried to prove formation of methylene urea from human urine, and to investigate the effect of pH and salt concentration on the reaction rate. The synthetic urine and real urine were used for the urea source of the reaction. As a result, the precipitates were prepared from synthetic urine, while the small molecule fractions generated then they grew into precipitate. The nuclear magnetic resonance, infrared spectroscopy, element analyses showed the precipitates in synthetic urine were the same compound found in the urea solution, which was methylene urea. The reaction rate was high at low pH value. The reaction rate in the buffer solution was lower than the synthetic urine at the same pH, because some salts may work as a catalyst. The urea concentration reduction rate in real urine showed the same trend with synthetic urine at the same pH, while the precipitation was quite similar to methylene urea.
人类排泄物，特别是尿液富含氮，可用于农业目的，而缓释肥料可有效利用农业生产中的养分。本研究提出了从尿液中直接生成缓释肥料——亚甲基脲。该实验旨在证明从人尿中形成亚甲基脲，并研究 pH 值和盐浓度对反应速率的影响。合成尿液和实际尿液被用作反应的尿素来源。结果表明，从合成尿液中制备出沉淀物，然后从小分子部分生成沉淀。核磁共振、红外光谱、元素分析表明，合成尿液中的沉淀物与尿素溶液中的相同化合物，即亚甲基脲相同。在低 pH 值下，反应速率较高。在相同 pH 值下，缓冲溶液中的反应速率低于合成尿液，因为一些盐可能起到催化剂的作用。在相同 pH 值下，实际尿液中的尿素浓度降低率与合成尿液呈现出相同的趋势，而沉淀与亚甲基脲非常相似。
