Study On Adsorption Of Cr(?)from Electroplating Wastewater By A New Strongly Basic Anion Exchange Resins

Ecosystem and human health is threatened by the pollution of chromium containing wastewater.Chromium pollution has become an urgent problem in the world.Ion exchange technology is considered to be a simple and effective method to remove heavy metals from water.Therefore,many separation processes are realized by ion exchange technology.Resin,the crucial role of ion exchange,is a kind of functional polymer,which depends on the exchange of ions by reactive groups for the purpose of adsorption,separation and purification.Nowadays,it has been widely used in the field of wastewater treatment.In this paper,the treatment of high concentration electroplating chromium containing wastewater by macroporous N-methylimidazolium base anion exchange resin was studied.The main contents are as follows:The static and dynamic adsorption performances of chromium containing wastewater in high concentration by macroporous N-methylimidazolium base anion exchange resin(PCI)were investigated.The effects of various experimental factors on the static adsorption features and the influence of different operation conditions on the kinetic adsorption in column experiment were studied systematically and deeply.The Cr(VI)reduction behavior and its influencing factors were studied.The results showed that PCI resin had a good selectivity for Cr(VI).The adsorption performance of Cr(VI)was stable in the range of pH 1-14 and it showed a high adsorption capacity in the low acidity and high concentration of chromium solution.The maximum adsorption capacity was up to 187.7 mg/g.The production of Cr(III)in the adsorption process showed that the resin was oxidized by Cr(VI).SEM,XPS and FT-IR analysis further verified this conclusion,and the oxidation mechanism can be inferred.It was found that the reduction rate of Cr(VI)was mainly related to the pH value of the effluent and the initial equilibrium concentration.Based on the above-mentioned research,a double anion column saturated ion exchange process was designed.Based on the small column experiment,column operation condition was extended to the actual column experiment on a high scale,and then was validated by our experiment.The maximum adsorption capacity of PC1 resin still remained in the range of about 60 g/L after the operation of the adsorption and regeneration for 30 times.The concentration of Cr(VI)in recovery phase was about 140 g/L,and the content of Cl-and SO42-reached the chrome plating standard.