吸收液对中空纤维膜接触器回收尿液中氨氮的影响

采用中空纤维膜接触器(Hollow Fiber Membrane Contactor,HFMC)回收尿液中的氨氮,系统研究了吸收液类型(H3PO4、H2SO4和HNO3)对氨回收效能、水蒸气的跨膜通量和所获液体肥料的影响.结果 表明,使用H2SO4作为吸收液时氨氮回收效能最优,其次是H3PO4和HNO3.当采用H2SO...

Effect of stripping solution on the recovery of ammonium nitrogen from human urine by hollow fiber membrane contactor

A hollow fiber membrane contactor (HFMC) was used to recover ammonium nitrogen from human urine. The effect of stripping solution on the ammonia recovery efficiency, water vapor transmembrane flux and the obtained liquid fertilizer quality were investigated. The results showed that the best performance of ammonia capture was obtained when using H₂SO₄ as the stripping solution, followed by H₃PO₄ and HNO₃. The ammonia recovery efficiency, transmembrane flux and mass transfer coefficient were 84.49%±0.01%, 22.92 g·m^-2·h^-1 and 2.37×10^-6 m·s^-1, respectively, when using H₂SO₄ as the stripping solution. The reverse mass transfer from the stripping solution side to the feed solution side was observed due to the volatility of HNO₃ with reduced transmembrane driving force of ammonia transfer. In addition, NH₄NO₃ aerosol could be generated by HNO₃ and NH₃ reactions in the membrane pores, increasing the mass transfer resistance and decreasing the ammonium nitrogen capture efficiency. The water activity difference and water vapor transmembrane flux were calculated for different acids as stripping solutions. The results showed that the water activity difference and transmembrane flux gradually increased as ammonia was continuously captured by the stripping solutions with the water fluxes of H₃PO₄, H₂SO₄ and HNO₃ of 7.44×10^-2 kg·m^-2·h^-1, 9.06×10^-2 kg·m^-2·h^-1 and 2.00×10^-2 kg·m^-2·h^-1, respectively at the end of experiments. Liquid single N fertilizer was directly obtained using HNO₃ or H₂SO₄ as stripping solutions, while liquid N-P fertilizer was obtained using H₃PO₄ as the stripping solution with the proportions of (NH₄)₂HPO₄ and NH₄H₂PO₄ were 88.33% and 11.67%, respectively.