Treatment Of Wastewater From Methomyl Production With Resin Adsorption

In this paper, we synthesized two hypercrosslinked resins which had different chemical modifications through the Friedel-rafts reaction of macroporous St-DVB copolymers and tested their adsorption property.The results presented by static experiment showed that the adsorption property to resin containing oxygen was superior to hydroxyl resin and AB-8 resin.So resin containing oxygen was used as adsorbent in the following research. Methomyl solution was studied firstly.The effect of initial concentration,pH and temperature on adsorption property was studied.The results indicated that the adsorption equilibrium time of methomyl was about 8 hours and accorded with a first order process,;the adsorption capacity of resin containing oxygen was increased with the increasing of mass concentration of methomyl solution,and basically is linear; methomyl was easily adsorbed under lower temperature;pH was 6～7;the adsorption property of resin containing oxygen to methomyl accorded to the Freundilich adsorption isotherm and attributed to the favorable adsorption equation.The adsorption-desorption process of methomyl manufacturing wastewater was also investigated in this paper and the parameters were determined through test,such as flow rate of wastewater,pH,volume of treated wastewater;type,temperature and flow rate of regenerant.The results indicated that the optimum operation conditions were as follows:adsorption temperature was room temperature;adsorption flow rate was lml/min;batch volume treated was 5BV;the regenerant was alcohol;desorption flow rate was 0.5—1 ml/min,desorption temperature was 40℃.Under the optimum process conditions,the working adsorption capacity of the resin was 68～78mg/ml;the COD was reduced from 49000～52000mg/L to 17000—21000mg/L;the concentration of methomyl in the wastewater was reduced from 13000mg/L～15000mg/L to less than 400mg/L.The removal rate of COD and methomyl were 60%～70% and 97% respectively.Furthermore,methomyl EC in the wastewater could be recovered by distillation,with purity above 20%,which accorded the technique requirement of HG 2612-94.The recycling property of resin containing oxygen is satisfactory.This method not only eliminates the environmental pollution but also obtain distinct economic benefit.