Resource Research On Heated Ammonia Nitrogen Wastewater With The Zeolite Treatment

Ammonia-nitrogen has become the main indexes of water pollution in recent years, whose effects have exceeded chemical oxygen delivery (COD) in surface water. The major source of ammonia-nitrogen is from industrial ammonia-nitrogen wastewater, which had a significant characterization of elevate temperature. But the conventional ammonia-nitrogen treatment technology chose the process of being down to room temperature before discharge, lacking of energy saving technology of waste heat recovery.At first, this paper studied the treatment effect of simulation high ammonia nitrogen wastewater by using four different adsorbents such as natural zeolite, synthetic zeolite, activated carbon and fly ash. The results showed that the effect on the adsorption of ammonia-nitrogen by natural zeolite enhanced when the temperature of ammonia-nitrogen nitrogen wastewater from room temperature to80℃, comparing with activated carbon, fly ash and other adsorbent. And then, the optimum operating conditions has been confirmed by discussing the influences of various factors on the adsorption process. The natural zeolite was modified through three different process of microwave heating in the solution, water bath heating, and room temperature stirring. The most appropriate modification technique has been selected in order to improve the ammonia nitrogen adsorption maximum amount of zeolite which was the method of NaCl+microwave heating technology, whereby the adsorption quantity of zeolite increased more than50%. The quantity change of zeolite was related to the change of ions on the zeolite framework and the improvement of the internal hole were obtained by SEM and XRD characterization of modified zeolite, which were the main changes of the modified zeolite and the natural zeolite. And laboratory zeolite adsorption device has been designed based on the study about the regeneration of zeolite, it could be used to process the continuous treatment of the heated ammonia nitrogen wastewater and regeneration of zeolite. The reclamation of liquid and solid wastes and thermal energy has been discussed.The paper discussed the adsorption mechanism of natural zeolite and modified zeolite from the side of thermodynamics and kinetics. And research showed that isothermal adsorption model of zeolite more accorded with the Freundlich experience model which was based on multilayer adsorption, and ion exchange of NH4+was not completely process; Through the calculation of thermodynamics parameters, the overall process of zeolite adsorption of ammonia-nitrogen was a spontaneous endothermic process of entropy, and the rise of temperature was conducive to the adsorption of zeolite. Zeolite dynamic process conformed to the quasi secondary dynamics model which was based on the exchange of electron, and it was a complicated heterogeneous mass diffusion process; Indepth analysis of the control steps on the zeolite adsorption showed that granule diffusion played a leading role in the fast adsorption stage, and liquid film diffusion was more and more obvious.