A Research Of Modified Activated Carbon For Cationic Dye Methylene Blue Adsorption Performance

Due to printing and dyeing wastewater with the characteristics of high chromaticity,high water and high toxicity,so the issue of printing and dyeing wastewater treatment has become a research focus of environmental protection at home and abroad.This experiment adopts the cationic dye methylene blue simulated printing and dyeing wastewater,discuss different acid modified activated carbon adsorption capacity of methylene blue.This experiment mainly explores effects of the modified on commercial granular activated carbon modified by three kinds of acid including nitric acid,hydrogen peroxide and sulfuric acid.Using single factor experiment and orthogonal experiment respectively to get the best preparation conditions of various acid modified activated carbon.The best conditions for preparation of modified activated carbon and original activated carbon were characterized.At the same time,discussing the adsorption isotherm and adsorption kinetics experiment.Through the research we know the best conditions of using nitric acid modified granular activated carbon: modification temperature is 90?,nitric acid concentration is 1 mol/L,solidliquid ratio is 1/5 and the modification time is 2h.The best conditions of using hydrogen peroxide modified granular activated carbon: modification temperature is 60?,nitric acid concentration is 1 mol/L,solid-liquid ratio is 3/20 and the modification time is 4h.The best conditions of using sulfuric acid modified granular activated carbon: modification temperature is 30?,nitric acid concentration is 0.02 mol/L,solid-liquid ratio is 1/10 and the modification time is 0.75 h.Based on the characterization of the best conditions for preparation of modified activated carbon and original activated carbon,three acids oxidation of the activated carbon surface structure,have increased the number of surface acidic functional groups.But,the specific surface area of original activated carbon significantly increased by nitric acid modified,hydrogen peroxide modified only slightly increment of the specific surface area of original activated carbon,and sulfuric acid modified decreased the specific surface area of original activated carbon.Under the experimental condition,the equilibrium adsorption quantity of all kinds of activated carbon adsorb methylene blue: 22.44 mg/g(the original activated carbon),28.33 mg/g(nitric acid modified activated carbon),25.12 mg/g(hydrogen peroxide modified activated carbon),23.84 mg/g(sulfuric acid modified activated carbon).The maximum adsorption quantity of all kinds of activated carbon adsorb methylene blue: 25.57 mg/g(the original activated carbon),34.93 mg/g(nitric acid modified activated carbon),30.16 mg/g(hydrogen peroxide modified activated carbon),28.00 mg/g(sulfuric acid modified activated carbon).The experimental results show that the nitric acid modified live on activated carbon adsorb methylene blue best.Adsorption isotherm and adsorption kinetics research indicate that the Langmuir adsorption isotherm model and the secondary dynamic equation can better describe the activated carbon adsorption process.