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Eupatorium adenophorum was utilized as raw materials for the preparation of activated carbon via microwave assisted steam activation. Influences of the three vital process parameters – activation temperature, activation duration and steam flow rate – have been assessed on the adsorption capacity and yield of Eupatorium adenophorum activated carbon (EAAC). The process parameters were optimized utilizing the Design Expert software and were identified to be an activation duration of 45 min, an activation temperature of 950 °C and a steam flow rate of 0.7 ml/min, with the resultant iodine number and yield being 1,010 mg/g and 20.13% respectively. The validity of process model to optimize the process parameters was verified using the analysis of variance (ANOVA). The key parameters that characterize quality of the porous carbon such as the BET surface area, total pore volume and average pore diameter were estimated to be 1,142 m2/g, 0.84 ml/g and 3.3 nm respectively, for the sample corresponding to the optimized process conditions. Additionally the pore structure is characterized using Scanning Electron Microscope (SEM). The present work strongly supports utilization of Eupatorium adenophorum as a potential precursor through microwave heating.

Spent coal-based activated carbon from the silicon industry has been used as raw material for the regeneration of activated carbon, with carbon dioxide as the regenerating agent. The regeneration process was optimised using response surface methodology and the optimum regeneration conditions were: regeneration temperature 985 °C; regeneration time 120 min; and carbon dioxide flow rate of 600 ml/min. The iodine number and yield of the activated carbon obtained under the optimum regeneration conditions were 1071 mg/g and 67%, with a Brunauer-Emmet-Teller surface area of 1270 m2/g and pore volume of 0.91 cm3/g. The regenerated carbon was tested for the removal of Methylene Blue dyes. The maximum adsorption capacity was found to be 395 mg/g and the equilibrium data fitted to the Langmuir isotherm model. The kinetic data indicated that the best fit corresponds to the pseudo-second-order kinetic model. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, activated carbons with high surface area from carbonized tobacco stems with K2CO3 activation by microwave radiation were investigated. Effects of microwave radiation time and K2CO3/C ratio on the yield and adsorption capacities of activated carbons were evaluated. Experimental results indicated that the optimum conditions were as follow: microwave power 700W; microwave radiation time 30min; K2CO3/C ratio 1.5:1. Iodine number, amount of methylene blue adsorption and the yield of activated carbon prepared under optimum conditions were 1834mg/g, 517.5mg/g and 16.65%, respectively. Surface area, micropore volume and pore size distribution (PSD) of the carbons were determined by the BET, H-K and DFT methods. Results showed that activated carbons had a micropore content about 59.98% and a small number of mesopores and macropores; BET specific surface area and total pore volume were 2557m2/g and 1.647cm3/g, respectively. [Copyright &y& Elsevier]

Crofton weed was converted into a high-quality activated carbon (CWAC) via microwave-induced CO2 physical activation. The operational variables including activation temperature, activation duration and CO2 flow rate on the adsorption capability and activated carbon yield were identified. Additionally the surface characteristics of CWAC were characterized by nitrogen adsorption isotherms, FTIR and SEM. The operating variables were optimized utilizing the response surface methodology and were identified to be an activation temperature of 980 °C, an activation duration of 90 min and a CO2 flow rate of 300 ml/min with a iodine adsorption capacity of 972 mg/g and yield of 18.03%. The key parameters that characterize quality of the porous carbon such as the BET surface area, total pore volume and average pore diameter were estimated to be 1036m²/g, 0.71 ml/g and 2.75 nm, respectively. The findings strongly support the feasibility of microwave heating for preparation of high surface area porous carbon from Crofton weed via CO2 activation. [ABSTRACT FROM AUTHOR]