Cattail Preparation Of Activated Carbon, Morphological Structure And Dye Adsorption Study

Here we use wetland plant Tupha latifolia L.as the raw material to produce activated carbon by dipping the plant in phosphoric acid, which can be used for the absorption of helianthine.To determine which factors can influence the specific surface area of the activated carbon,we carried out an orthogonal experiment and we found the activation temperature has the greatest affection and the activation time,dipping ratio and dipping time comes as follows.We also found the best horizontal combination:dipping ratio—2.5:1,dipping time—9h,dipping temperature—500℃,and activation time—80 min.The structure morphology of the activated carbon was characterized and the result showed that the total pore volume is 1.786m~3/g,and the average pore diameter is 5.585nm.The micro and medium pores have strong structures and wide distribution. The surface presents an irregular structure with a lot of pores. After the activation by phosphoric acid,some functional groups containing phosphate are formed on the surface and some acid groups containing oxygen,especially—COOH have a high concentration. By electronic microscope scanning and measuring the specific surface area,we tested the influence to the absorption result by the amount of the activation carbon,initial solution concentration,pH,absorbing time and the temperature.The result showed that dipping in phosphoric acid for 12h and burning at 450℃makes the activated carbon a good capability;and the activated carbon can get rid of helianthine well at a low pH,and the reaction get balanced after 4h.The Langmuir and Freundlich isothermal adsorption equation and the secondary dynamical equation describe the absorption process well.The statistics indicate this absorption is an exothermic reaction,and temperature is not the key factor influencing the absorption result.