Research On The Treatment Of Copper-containing Wastewater With Different Forms Of Modified Activated Carbon Materials

With the development of industrialization process and introduction of Water Pollution Control Action Plan,some heavy industrial enterprises have failed to obtain the requirements of current wastewater discharge in the pollution of water bodies,and need to be treated with renovations to meet new standards.As a cost-effective water treatment method,adsorption method has received extensive attention.The carbonaceous adsorbent has excellent adsorption performance with a wide source of materials,high physical surface structure and active chemical surface properties.So,it has good application and research value in the treatment with industrial wastewater containing heavy metal ions by adsorption.In this paper,activated carbon powder and activated carbon fiber felt were used as adsorbents to adsorb copper-containing wastewater.The activated carbon powder and activated carbon fiber felt were firstly pretreated,then respectively modified by chemical coprecipitation and chemical impregnation to prepare iron-based magnetic activated carbon powder and chitosan-modified activated carbon fiber felt.SEM,FTIR,XRD,BET and other means were used to analyze the structure and performance of adsorbent materials.The static adsorption test was used to investigate the influence factors of pH,initial copper ion concentration,adsorption time and temperature.Isothermal adsorption line,adsorption kinetics and adsorption thermodynamics models were studied to show the adsorption behavior and process of chitosan-modified activated carbon fiber felt.Chitosan-modified activated carbon fiber felt with better adsorption was studied for electrochemical regeneration.The research results were as follows:（1）Iron-based magnetic activated carbon powder with pure phase Fe₃O₄was obtained.The optimum process conditions including pretreatment（1M HF impregnation ratio of 100 m L:1 g at 60℃）and adsorption conditions（0.5 g dosage,initial concentration of 50 mg/L,pH=5.5,temperature is 45℃）.The adsorption reached equilibrium at 14 h with equilibrium adsorption amount of 5.79 mg/g and adsorption rate was 96.27%.The effluent concentration reached the third-grade discharge standard.（2）Adsorption process of chitosan-modified activated carbon fiber felt was investigated.The best adsorption conditions were 30℃,pH=3,initial concentration of 100 mg/L with 25 mm×40 mm modified carbon felt,adsorption equilibrium was reached within 8 h.The adsorption rate was greater than 99.7%,equilibrium adsorption capacity was 8.58 mg/L.Effluent concentration was less than 0.5 mg/L,which met the first-grade standard of the comprehensive emission standard.According to the kinetic and thermodynamic analysis,this adsorption process was a self-heating process involving multiple adsorptions such as chemical and physical adsorption,multi-layer and non-uniform adsorption,which conformed to quasi-secondary kinetic model.（3）Electrochemical regeneration of chitosan-modified activated carbon fiber felt was explored.During the regeneration process,0.03 mol/L Na Cl electrolyte solution,1×10^-4mol/L EDTA regeneration aid,2 V regeneration voltage,10 mm electrode spacing,and 90 min regeneration were used to obtain the best regeneration effect.