Micro-mesoporous carbon from cotton waste activated by FeCl3/ZnCl2: Preparation, optimization, characterization and adsorption of methylene blue and eriochrome black T

FeCl3/ZnCl2 was used as activating agent in order to prepare cotton waste-based activated carbon. The optimal conditions for activated carbon determined by orthogonal experiments were as follows: activation temperature of 400 C, mass ratio of 1:1 (FeCl3/ZnCl2), and activation time of 1 h. Thermogravimetric analysis was conducted to investigate the weight loss process. N-2 adsorption/desorption isotherms, XRD, SEM, and FTIR were provided to analyze the crystal structure, pore development, morphological structure, and surface chemistry, respectively. The possible pore development was ascribed to the formation of molten ZnCl2 and Fe species, which then act as templates inside the carbon to form pore structures. This process was also related to dehydration of ZnCl2 and FeCl3 on cotton waste. Carbon activated by FeCl3/ZnCl2 exhibited higher BET surface area (1342 m(2) g(-1)) than carbon activated using FeCl3 (504 m(2) g(-1)). The adsorption performance of activated carbon was estimated using methylene blue and eriochrome black T.