关键词: 支撑气膜, 中空纤维, 膜接触器, 传质模型, 盐效应

Abstract: The experiments were carried out to investigate the effect of salts on the mass transfer performance and the effect of temperature on the salt-effect in the removal of ammonia from aqueous solutions by gas-membrane-based stripping-absorption process.The experimental results show that the mass transfer of ammonia is affected by the salt-effect and the viscosity of salt solutions.The stronger the salting-out effect is, the higher the membrane transfer coefficient（k_M）is; and the higher the viscosity of the feed is, the lower the liquid transfer coefficient（k_L)is.The change of the overall transfer coefficient depends on the change of kM and kL.Sodium chloride, sodium sulfate and ammonium sulfate exhibit a salting-out effect on ammonia and prompt the mass transfer.Although the viscosity of feed containing ammonium chloride becomes slightly smaller with the increase of the concentration, ammonium chloride exhibits a salting-in effect on ammonia, so the overall transfer coefficient changes little.Calcium chloride shows a significant salting-in effect on the gas-membrane-based ammonia stripping process.The temperature affects the salt-effect and the mass transfer performance dramatically.With the increase of temperature, the salt-effect of ammonium sulfate and calcium chloride becomes weaker and the overall transfer coefficient increases significantly.

Key words: supported-gas-membrane, hollow fiber, membrane contactor, mass transfer model, salt-effect