过磷酸钙对氨气的吸附解吸特性研究

禽畜粪便堆肥过程中氨气挥发既导致肥料养分下降又使周边环境出现恶臭,常用的化学磷肥过磷酸钙,由于其含有的游离酸可与氨反应,是潜在的堆肥挥发氨气回收固定的吸附剂.本研究以氨水挥发出来的氨气来模拟堆肥过程中的氨挥发,以过磷酸钙含氮量表征其对氨的吸附,分析过磷酸钙对氨气的吸附解吸特性及其pH的变化.结果表明：过磷酸钙对氨气吸附...

Adsorption and desorption of calcium superphosphate to ammonia gas

Ammonia emission in poultry manure composting not only results in nitrogen loss, but also acts as the source of odor. Calcium Superphosphate (CSP) is a typical chemical fertilizer containing free acid which could bond ammonia by chemical reaction. Therefore, CSP can be used as a potential sorbent of ammonia gas from composting, which will form compound fertilizer of phosphorus and nitrogen. This study was conducted to investigate the adsorption and desorption characteristics of CSP to ammonia gas. The aqua ammonia was selected as a source of ammonia gas. Both the nitrogen content in CSP which reflected the ammonia absorbed and pH were monitored. The nitrogen content reached about 12% of CSP (dry weight) when the adsorption was saturated. Concurrently, its pH increased largely and reached 11.5. When the CSP with ammonia saturation was stored in different ways, the nitrogen content reduced gradually due to desorption of ammonia partly, and its pH decreased correspondingly. Ultimately, the nitrogen content reduced to about 4% when the CSP was exposed in the air, and to about 6% when the CSP was put into sealed bag without complete air evacuation. The pH of CSP ranged from 6.21 to 7.54 after ammonia desorption in both aforementioned disposal ways. Water vapour evaporated from aqua ammonia was also adsorbed by CSP largely, which affected the ammonia adsorption. The CSP with ammonia saturation had too high pH to be used directly as a fertilizer of crop. Moreover, it also lost some ammonia due to high pH when stored. Therefore, the adsorption saturation should be avoided when the CSP was used as a sorbent of ammonia gas from composting. For CSP adsorbing ammonia, it was suitable to be a fertilizer that the nitrogen content kept at 4%~6% with pH near to 7.