Study On Preparation And Adsorption Performance Of Activated Carbon Derived From Walnut Pericarp

In this work, a new kind of activated carbon has been obtained from walnut pericarp by zinc chloride with high surface area ratio, good adsorption effect. We study the adsorption properties of activated carbon and modified activated carbon for methyl orange and acid magenta, p-nitrophenol, Pb2+and Cd2+. The influence of adsorption time, p H and initial concentration are investigated, and adsorption thermodynamics and kinetics are studied.Experiment using orthogonal design, with activation temperature, activation time, the activator concentration and particle size of four factors, each factors three levels, activated carbon of walnut pericarp was obtained by muffle furnace heating method, the best condition of preparation of activated carbon by the zinc chloride activation was found, by poor analysis and variance analysis to arrange the best preparation technology combination, namely zinc chloride concentration was 50%, particle size was 60 mu, activation temperature was 600 ℃, activation time was 1 h, under the condition of the preparation of activated carbon specific surface area was 1258.050 m2 / g.The adsorption effect of activated carbon prepared by walnut pericarp was better for methyl orange and acid magenta, p-nitrophenol, Pb2+ and Cd2+. The maximum number of saturated adsorption of ammonia modified activated carbon and sodium hydroxide modified activated carbon on the p-nitrophenol were as high as 204.080 and 204.080 mg/g, The maximum saturated adsorption amount of Hydrogen peroxide modified activated carbon for Pb2+ and Cd2+ were 58.498 and 58.498 mg/g, modified activated carbon adsorption effect was better. Increasing adsorption time, The removal rate and adsorption quantity of five kinds of pollutants increases, The adsorption equilibrium time of activated carbon for methyl orange, acid magenta and p-nitrophenol were 6 h, and for Pb2+ and Cd2+ adsorption equilibrium time were 5 h.Increasing initial concentration of five kinds of pollutants, the results show the activated carbon for the adsorption quantity increases, removal rate reduced. Solution p H on the adsorption effect was bigger. The best of adsorption p H of activated carbon based walnut pericarp for methyl orange and acid magenta and p-nitrophenol was 6, 6 and 3, respectively, the adsorption amount and the removal rate increases with the decrease of the p H, the best adsorption p H for Pb2+ and Cd2+ was 4 and 4, respectively, the adsorption amount and removal rate increases with the increase of p H.Adsorption isotherm of fitting show unmodified activated carbon based walnut pericarp for p-nitrophenol adsorption conforms to the Langmuir model, sodium hydroxide and ammonia modified activated carbon was accord with the Freundlich model. After alkali modification of activated carbon on the p-nitrophenol adsorption and removal rate has increased, which can be concluded that alkali modification of activated carbon on the nitro phenol adsorption effect is better. Freundlich model can better describe the adsorption isotherm of activated carbon for Pb2+and Cd2+. Langmuir model can better describe the oxidation of activated carbon adsorption isotherm of Pb2+. And Freundlich model can better describe the activated carbon oxidation and activated charcoal adsorption isotherm of Cd2+. Adsorption of methyl orange belongs to monolayer adsorption behavior. Five kinds of pollutants adsorption dynamics behavior consistent with secondary dynamics equation.