膜吸收法分离回收废水中氨氮的研究

Removal and Recovery of Ammonia from Wastewater by Membrane Absorption Process

膜吸收法处理高浓度氨氮废水能够实现氨的回收利用。正交试验表明,废水p H值是影响氨氮去除率的主要因素。氨氮传质系数K分别与废水p H值和废水流速呈良好的线性关系,提高废水p H值和流速可以提高氨氮的去除率。废水中氨氮浓度对氨氮去除率和K值影响不大,故而膜吸收法可适用于不同浓度的氨氮废水。当硫酸吸收液浓度>0.10 mol/L时,提高硫酸浓度对氨氮的去除效果影响较小,因而可适当提高硫酸浓度;同时,为了抑制伴生膜蒸馏现象,可向废水中投加盐或提高吸收液温度,从而提高硫酸铵的回收浓度。

Membrane absorption process can recover ammonia from wastewater. Orthogonal experi- ments showed that the pH value of the wastewater was the main factor in the removal of ammonia. Ammo- nia mass transfer coefficient K showed a good linear relationship with the pH value and flow rate of wastewater, separately. Therefore, ammonia removal efficiency could be improved by increasing the pH value and the flow rate of wastewater. The ammonia concentration in wastewater showed little impact on ammonia removal or K values,which indicated that membrane absorption was suitable for a large range of wastewater ammonia concentrations. When the concentration of sulfuric acid was greater than 0.10 mol/ L, the removal of ammonia was less relevant to the increase of the sulfuric acid concentration. In order to control associated membrane distillation and to increase the recovery of ammonium sulfate, it is recom- mended to add salt to the wastewater or increase the temperature of sulfuric acid.