Biomass Engineering Center, Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Key Laboratory of Plant-Soil Interactions of Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Biomass Engineering Center, Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Key Laboratory of Plant-Soil Interactions of Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
J Environ Manage. 2019 Apr 15;236:108-117. doi: 10.1016/j.jenvman.2019.01.018. Epub 2019 Feb 2.
Valorization of corn waste involves synthesis of hydrochar for use as a sorbent for ammonium nitrogen recovery from swine manure compost leachate. However, the inability to directly capture organic nitrogen and insoluble nitrogen, and the low sorption ability of hydrochar remain key issues. To overcome these issues, we used hydrothermal assisted pretreatment of compost leachate to promote the solubilization of nitrogen contained in feces, and the conversion of organic nitrogen into ammonium nitrogen in the compost leachate. The synthesis hydrochar was activated with KOH to enhance its sorption ability, and then characterized by SEM, FTIR, elemental analysis, specific surface area, pore volume and size analysis. The content of ammonium nitrogen in hydrolysis leachate at 210 °C increased by 22.3% compared with raw compost leachate. 3D-EEM analysis indicated that aromatic protein substances were rapidly hydrolyzed to gradually increase the content of ammonium nitrogen and produce considerable humic acids. The maximum adsorption capacity of ammonium nitrogen reached 140.3 mg/g at 45 °C for KOH-activated hydrochar of 260 °C. The Langmuir isotherm and pseudo second order kinetic models were good fit for the adsorption process of ammonium nitrogen at higher temperature (35 °C or 45 °C), and this reaction was mainly dominated by chemisorption. The adsorption of ammonium nitrogen was exothermic, spontaneous, and showed an increase in disorder at the solid-liquid interface. For resource recovery, the total release amount of ammonium nitrogen of five interval extractions could reach 12.2% of maximum adsorption capacity (140.3 mg/g) under alkaline (pH 8.0) condition. The nitrogen mass balance calculation revealed that 8.9% of total nitrogen in the compost leachate could be recovered.
玉米废物的增值利用包括合成水热炭，以用作从猪粪堆肥渗滤液中回收氨氮的吸附剂。然而，水热炭不能直接捕获有机氮和不溶性氮，且吸附能力低仍然是关键问题。为了解决这些问题，我们使用水热辅助预处理堆肥渗滤液，以促进粪便中含氮物质的溶解，以及将堆肥渗滤液中的有机氮转化为氨氮。使用 KOH 对合成水热炭进行活化，以增强其吸附能力，然后通过 SEM、FTIR、元素分析、比表面积、孔体积和尺寸分析对其进行表征。与原始堆肥渗滤液相比，210°C 下水解渗滤液中的氨氮含量增加了 22.3%。3D-EEM 分析表明，芳香族蛋白质物质迅速水解，逐渐增加氨氮含量，并产生相当数量的腐殖酸。在 45°C 下，260°C 的 KOH 活化水热炭对氨氮的最大吸附容量达到 140.3mg/g。Langmuir 等温线和拟二级动力学模型很好地拟合了较高温度（35°C 或 45°C）下氨氮的吸附过程，该反应主要由化学吸附主导。氨氮的吸附是放热的、自发的，并且在固液界面表现出无序度的增加。为了资源回收，在碱性（pH 8.0）条件下，五次间隔提取的氨氮总释放量可达到最大吸附容量（140.3mg/g）的 12.2%。氮质量平衡计算表明，堆肥渗滤液中总氮的 8.9%可以被回收。
