The Chemical Activation Mechanism Research On Preparation Of Activated Carbon From Solid Organic Wastes

Pyrolysis technology is one of important refuse disposal techniques in preparation of activated carbon from solid organic wastes with little secondary pollution, quite innocuity and high reusability, and it has been paid more attention from all over the world.Activated carbon has been used widely as an adsorption material in chemical industry, environment protection, food industry, pharmaceutics, catalyst carriers and electrode materials, etc. With the development of science and technology, the demand for activated carbon is increasing rapidly. In this paper, activated carbon was prepared by chemical activation, to study the activation mechanism and the factors that influence the yield of carbon. This experiment used Poplar particles as material and its particle size was20±1mg, the solution of K+in the different acid, alkali, salt environments and different alkali metal salt solution as chemical activation agent, used TGA by controlling the heating process under nitrogen atmosphere to produce the activated carbon. The activation of different chemical activator mechanism and carbon yield was discussed by analyzing the TG, DTG, DSC pyrolysis curves, to provide theoretical basis for producing activated carbon.It was found that the weight loss process shift to the lower temperature when activator added KOH, indicating that the K+in activated agent KOH had catalytic effect on wood pyrolysis. Activated carbon was generally produced at600℃; up to800℃, the activated carbon was reacted and lost, and the extent of loss is related to the amount of activator, the more active agent, the greater the loss on ignition. So in the process of preparation of activated carbon, not only to select the appropriate amount of activator, but also to control the temperature of activation strictly.Different heating rates had no obvious effect on the final yield of coke and activated carbon; After adding KOH activator, carbon yield increased by18.6%than did not add any activator, while the carbon yield and the activating agent/poplar particles weight ratio have not a linear relationship, when the KOH/poplar particles is0.15/1, the yield of activated carbon is the highest,41.8%. H3PO4can promote the catalyst of potassium, or phosphoric acid itself can serve as an activator. KOH+H3PO4pH=1solution as activator are better than KOH+H3PO4pH=4～5solution as activator; HC1have no impact on activation of KCl, mainly potassium play a role in activation.The activation effect of K+in the phosphorylation environment is very good, activation temperature was lowest, and the yeild of carbon was the highest. In Alkali metal salts, the potassium salt as the activator,the production of activated carbon is the largest,MgCl2Basically did not play the role as activater.