| Double membrane process is widely used in advanced treatment of coking wastewater,70% high quality effluent was obtained,and at the same time,a reverse osmosis water of 30% was formed.The organic matter in ROC is 2-3 times higher than that of the system.It is usually difficult to biodegradable dissolved organic matter.Without proper treatment,it will cause great harm to the environment.Compared with the adsorption method,the biological method and advanced oxidation method are more affected by water quality.The treatment effect is not ideal.Traditional adsorbents such as activated carbon have the disadvantages of high cost,difficult regeneration and no reasonable fate of pollutants.so that the adsorption method has not been widely used.In this paper,we try to find a new adsorbent to remove organic pollutants in reverse osmosis concentrated water,to ensure the use of lower costs and improve the adsorption efficiency,adsorption technology to promote the application of more widely in practice.In the literature review and theoretical analysis basis,this paper choose coal powder,fine coke powder,coarse coke powder fine coal as three alternative adsorbent.Firstly,the effects of three kinds of adsorbents on the removal of organic pollutants in ROC were compared by using the static adsorption test at the level of three.Secondly,the adsorption effect,adsorption model and adsorption properties of the selected adsorbents were analyzed.,to provide theoretical guidance for the industrial application of the adsorbent.The main research contents are as follows:Water quality analysis of ROC.The effluent was light yellow with higher ionic content,and the chloride ion concentration was 3347 mg/L,while the COD and UV254 were about 219 mg/L and 4.36.Physical and chemical properties of the adsorbent were analyzed.The particle size composition,surface morphology,surface oxygen functional groups,surface area,pore volume,pore size distribution of coal powder,fine coke powder,coarse coke powder were obtained by laser particle size analyzer,SEM,FTIR and BET.The results showed that-0.074 mm particles were in powder,fine coke powder,coarse coke powder accounted for 82.69%,69.68%,62.85%.The pore structure of fine coke powder is more abundant than that of pulverized coal.The specific surface area of pulverized coal,fine coke powder and coarse coke powder BET 5.027 m2/g,24.813 m2/g and 20.508 m2/g.Study on the selection and adsorption properties of adsorbent.Through the three stage static adsorption test,it is found that the removal rate of COD reach 76.26%,74.06% and 65.75%,respectively,for the fine coke powder,coarse coke powder and pulverized coal in ROC.The static adsorption test system was established,and the removal efficiency of COD and UV254 in the reverse osmosis concentrated water was obtained by adding the amount of fine coke powder,adsorption time and pH value of the solution.The results show that when the test conditions are as follows: the amount of fine coke powder is 120 g/L,the adsorption time is min,the solution pH is about 7.56,The removal rate of COD and UV254 in the ROC reach 77.72% and 86.22%,the COD value of wastewater was 48.8 mg/L after adsorption.The effect of solution pH value on pore structure and surface functional groups of fine coke powder.Compared with the original fine coke powder,it was found that the absorption peaks,functional groups and pore structure of the fine coke did not change obviously after the treatment of weak acid and strong alkali.Based on this,the functional equation is obtained by response interview,and the prediction model is validated.The results show that the model can well reflect the removal rate of COD and UV254.Study on Adsorption Properties of adsorbent.The surface functional groups and surface micro morphology of fine coke powder before and after adsorption were compared.The kinetics and thermodynamic characteristics of fine coke powder adsorption on reverse osmosis concentrated water were investigated.It was found that the adsorption process of coke quenching powder in reverse osmosis concentrated water was in good accordance with the pseudo-second-order equation and Langmuir equation of isothermal adsorption. |
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