Studies On Preparation And Application Of Activated Carbon From Disposable Linen Fabric

Activated carbon is an effective adsorbent, it is widely used since its well-developed porous structure, stable chemical properties and considerable surface functional groups with high quality. In recent years, the research on the hotspot is to synthesize activated carbon with excellent performance, using cheap waste as raw materials and by simple preparing process.The pyrolysis of hemp waste was carried out by means of the thermogravimetric analyzer in high pure N₂ atmosphere. According to the TG-DTG cyrves, the influences of different heating rates on the pyrolysis process were investigated and the pyrolysis mechanism was discussed. The results showed that the non-isothermal pyrolysis process of linen fabric waste includes three stages: dehydration, carbonization-pyrolysis and calcining decomposition. Gas chromatography and mass spectrometry was to analyze the pyrolysis liquid products, and the research showed that the composition of pyrolysis liquid products were very complicated, which were mainly made up of levoglucose and phenolic compounds. According to the pyrolysis dynamics of linen fabric waste, it was found that the pyrolysis reaction agreed with chemical reaction mechanism, the activation energy and frequency factor increased as temperature rose.In this study, activated carbon was prepared from the linen fabric waste by KOH as activator. There were two steps, carbonization and activation in the production of linen-based activated carbon. The method of factor analysis and the orthogonal design were employed to investigate the characteristics of linen-based activated carbon (LAC).The preparation factors (the ratio of alkali to carbon, activation temperature, activation time, carbonization temperature), which effect the adsorption properties of iodine and methyleneblue and the yield of LAC were discussed and the technological conditions were optimized. Results showed that it was appropriate to choose linen fabric waste as raw materials. The optimum preparation conditions were the ratio of alkali to carbon 3:1, activation temperature 700℃with activation 50min, carbonization temperature 400℃. The basic adsorption properties of sample were theiodine capacity 1070.24mg/g, the methylene blue capacity 11.6ml/0.1g and the yield of LAC 24.28%. For prepared activated carbon, a specific surface area and pore size distribution analyzer was employed to determine the N₂ adsorption-desorpion at 77K. The Langmuir equation, BET equation, t figure and BJH method were used to calculate the specific surface area, pore volume and pore size distribution. The scan electric microscope (SEM), X-ray diffraction (XRD) and FT-IR were also used to investigate the morphology, crystallite structure and chemistry structural characteristics, respectively. Adsorption of copper ion from aqueous solution onto activated carbon prepared from linen fabric waste (LAC) was investigated in a batch system. At the same time, Adsorption kinetics, thermodynamics and mechanism were discussed in this study. Adsorption studies were carried out to investigate influence of different conditions on the adsorption, such as initial pH value, adsorption time, dosage of activated carbon, temperature et.al. The experimental results of Cu(II) adsorption onto the LAC showed that the pH value of Cu(II) solution is the most important factor to effect on the Cu( II) adsorption capacity of LAC. Under the conditions of the initial pH=6 approximately, the concentration of Cu( II): 40⁹0mg/L, the dosage of LAC:2mg/L and adsorption time: 120min, the activated carbon revealed relatively strong capability of adsorbing copper ions. In addition, Langmuir and Freundlich isotherms were used to analyze the adsorption equilibrium data. The results showed that the Langmuir adsorption isotherms can agree with the adsorption behavior of Cu( II) on LAC. The adsorption data were analyzed by using pseudo-first-order and pseudo-second-order kinetic models, and the adsorption kinetics was found to follow the pseudo-second-order kinetic model. The regeneration of waste powder activated carbon is very important applications. In this paper, the acid alkali reclaiming method was discussed for the regeneration of waste activated carbon. The result showed that the percent of primary recycling can reach 70.33% by acid-alkali regeneration.