1664 N. Virginia St, Chemical and Materials Engineering Dept, University of Nevada, Reno, Nevada, United States.
Departamento de Ingeniería Química, Universidad Autónoma de Madrid, Madrid, Spain.
Waste Manag. 2023 Aug 1;168:301-310. doi: 10.1016/j.wasman.2023.06.013. Epub 2023 Jun 16.
The work studies the recovery of nutrients (phosphorus and nitrogen) from the process water of acid-assisted hydrothermal carbonization (HTC) of cow manure. Three organic acids (formic acid, oxalic acid, and citric acid) and sulfuric acid were evaluated as additives in HTC. Using 0.3 M sulfuric acid, more than 99% of phosphorus and 15.6% of nitrogen from manure are extracted and dissolved during HTC at 170 °C with 10 min reaction time in a batch reactor. Nutrients (mainly phosphorus) were recovered through precipitation from process water by raising the ionic strength of the solution by addition of salts of magnesium and ammonia, and by raising the pH to 9.5. Subsequently, phosphorus-rich solids were recovered containing almost all (greater than 95%) of the dissolved phosphorus in the sulfuric and formic acid assisted runs. Morphology and qualitative chemical analysis of the precipitates were determined. It is shown by XRD that the precipitate formed from process water generated by HTC with oxalic acid is crystalline, although the diffraction pattern could not be matched with any expected substance.
这项工作研究了从酸辅助水热碳化（HTC）牛粪过程水中回收营养物质（磷和氮）。评估了三种有机酸（甲酸、草酸和柠檬酸）和硫酸作为 HTC 中的添加剂。使用 0.3 M 硫酸，在 170°C 下反应 10 分钟，在间歇反应器中，超过 99%的磷和 15.6%的氮从粪便中提取并溶解在 HTC 过程水中。通过添加镁盐和氨来提高溶液的离子强度，以及将 pH 值提高到 9.5，从过程水中通过沉淀回收营养物质（主要是磷）。随后，从硫酸和甲酸辅助运行的 HTC 过程水中回收了富含磷的固体，其中几乎包含了溶解在水中的所有（超过 95%）磷。对沉淀物的形貌和定性化学分析进行了测定。XRD 表明，由草酸辅助 HTC 过程水生成的沉淀物是结晶的，尽管衍射图谱与任何预期的物质都不匹配。
