Study On The Treatment Of Nitrogen-contained Wastewater Using Hollow Fiber Renewal Liquid Membrane

Nitrogen-contained wastewater is the main pollutant in water, which isserious harmful to humans and aquatic organisms. The absorption, chemicaloxidation and liquid extraction are still in use; however, these traditionalmethods suffer from the disadvantages, such as high cost, complex operationand secondary pollution. So, industries have been looking for a kind of highefficient treatment method which may overcome the shortcomings of thetraditional processing method.Hollow fiber renewal liquid membrane (HFRLM) have the traits of highselectivity, high specific surface area, high mass transfer rate etc, which is apromising method in the wasterwater treatment. HFRLM not only acceleratesthe mass transfer rate, but also has a long-term stability. The effects ofoperating condition, system property and organic composition on the masstransfer performance of HFRLM are main factors. The coefficient of masstransfer in tube is expressed using Lévêque correlation. However, the casewhere mass transfer was dominated by lumen flow, is not suitable for Lévêquecorrelation. So it is necessary to study the mass transfer performance and mass model.Di(2-ethylhexly)phosphoric acid was chosen as extractant and keroseneas diluent through liquid extraction experiments. The effects of some factorson extaction equilibria were studied. Results showed that, alkaline conditionswas conducive to the extraction of aniline and ammonia. The distributioncoefficient increased with the increase of the concentration of D2EHPA andthe pH of wastewater. There was no significant effect on amonia extractionhowever, the temperature had significant effect on aniline extraction. It wasexothermic reaction, and the enthalpy change was-6.54kJ·mol-1. When thesaponification rate of D2EHPA was20%the higher extraction efficency wasgained.In this paper, the HFRLM deal with nitrogen-contained wastewater wereinvestigated. The results showed that, the flux of mass transfer increased withincreasing flow velocity of wasterwater. The flux of mass transfer had a firstincrease, then tended to gently with the increase of carrier concentration andstipping concentration; The flux of mass transfer increased with the increasingconcentration of wasterwater. However, the coefficient of mass transfer had adescending trend; The HFRLM was used to deal with nitrogen-containedwasterwater, and the effluent was lower than discharge standard of waterpollutants.The effect of organic droplet on the mass transfer of HFRLM wasinvestigated. The mass model was development for HFRLM combined with Lévêque correlation and surface renewal theory, the modeled results agreedwell with experiment results.