Study On Ultrasonic Modified Resin And Its Removal Effect Of Ammonia Nitrogen In Water

As a synthetic adsorbent,ion exchange resin has high selective adsorption for ammonia nitrogen,but its adsorption capacity is limited,which restricts its application in the field of environmental protection.Therefore,it is necessary to modify the resin to improve its adsorption performance.In this paper,the preparation of ultrasonic modified resin and its removal characteristics of ammonia nitrogen were studied.The effects of ultrasonic time,ultrasonic temperature and ultrasonic power on the adsorption of ammonia nitrogen by 001×7 strong acid cation exchange resin were investigated.The results showed that the modified resin had the best removal effect on ammonia nitrogen when the ultrasonic time was 30 min,the ultrasonic temperature was 40?and the ultrasonic power was 50 W.The dynamic adsorption experiment was carried out under the condition of influent concentration of 200 mg/L,resin dosage of 10 m L and influent flow rate of 10 BV/h.The optimal saturated adsorption capacity of the modified resin was 87.96 mg/g,22.8% higher than the original resin.The original resin and the modified resin with different ultrasonic time were characterized by specific surface area,pore volume,sulfonic acid group capacity and FTIR.The mechanism of ultrasonic strengthening modified resin was analyzed.The results show that with the increase of ultrasonic time,the specific surface area and pore volume of the resin increase slightly,while the capacity of sulfonic acid group increases first and then decreases.The good specific surface area and pore volume are conducive to the transport and exchange of ions in the pore.Ultrasonic makes the resin exposed more binding sites in the deep layer,so it shows better adsorption performance.The effects of the optimal dosage of ultrasonic modified resin,reaction time,temperature,p H and initial concentration of ammonia nitrogen on the removal efficiency of ammonia nitrogen were studied by static experiment,and the adsorption thermodynamics and adsorption kinetics curve were fitted.When the dosage is 8 g/L,reaction time is 30 min,temperature is 30?,p H=6,the removal rate of ammonia nitrogen is over 92.2%.The analysis of reaction kinetics shows that the adsorption of ammonia nitrogen by the modified resin is more in line with the quasi second-order adsorption kinetics model.The results show that the adsorption process of ammonianitrogen is mainly controlled by the diffusion of liquid membrane.The results of adsorption thermodynamics show that Langmuir fitting equation can better fit the experimental data,and the correlation coefficients are greater than 0.99.The change of adsorption free energy,adsorption enthalpy and adsorption entropy of modified resin for simulated ammonia nitrogen wastewater are ?G<0,?H>0 and?S>0,indicating that the adsorption process can be spontaneous,endothermic and entropy increasing.The results of dynamic analysis showed that the effect of regeneration of adsorption saturated resin was satisfactory with 100 m L of 20% NaCl + 0.5% NaOH at 5 m L/min flow rate,and the resolution was 98.94%.After 10 times of regeneration treatment,the adsorption capacity of the resin is still strong,which shows that the modified resin has good cycling performance.The modified resin is applied to the removal of ammonia nitrogen from industrial waste water,which has better adsorption performance.The analytical solution is concentrated in multiple stages,and the concentration of ammonia nitrogen in the final concentrated analytical solution reaches 15000 mg/L,which provides feasibility support for the utilization of ammonia nitrogen resources.