Microwave Radiation Preparation Of Activated Carbon Technology Research Of Agricultural And Forestry Wastes

In this paper, a new technology on preparation for activated carbon from agricultural and forestry waste material (cocoa nut husk, bamboo knot, cotton stem, tobacco stem) by microwave irradiation was investigated based on the review of the technology of microwave heating and preparation for activated carbon. The processing optimum conditions and the effect rule of factors to the adsorption capability and yield of activated carbon were obtained. The microstructure of activated carbon and the reaction mechanism were discussed.I,The new technology on preparation for activated carbon from cocoa nut husk and bamboo knot with physical activation method (water vapour activation) by microwave irradiaton was researched.1,The effect rule of factors to the adsorption capability and yield in preparation for activated carbon of extracting gold from cocoa nut husk with water vapour activation by microwave irradiation was carried out by conditional experiment. The processing conditions were obtained: Microwave power is 700W, activation time is 5min and flow rate of water vapor is 4.8mL/min. The yield of activated carbon of extracting gold is 54.6%. Iodine value is 1,040.6mg/g. Iodine value exceeds the state level (GB/T12496. 8-1999). Activation time by microwave irradiation is 1/60 as fast as that of the conventional process. Yield by microwave irradiation is twice as much as that of the conventional process.2,The processing optimum conditions on preparation for activated carbon of extracting gold from cocoa nut husk charcoal with water vapour activation by microwave irradiation were obtained by orthogonal test: Microwave power is 700W, activation time is 3min and flow rate of water vapour is 4.8mL/min. The iodine value of activated carbon is 1,031mg/g. Decolorizing capacity for methylene blue is 100mL/g and yield is 60.8%. Iodine value exceeds the state level (GB/T12496. 8-1999). Activation time by microwave irradiation is 1/100 as fast as that of the conventional process. Yield by microwave irradiation is twice as much as that of the conventional process.3, The processing optimum conditions on preparation for activated carbon frombamboo knot with water vapor activation by microwave irradiation were obtained by orthogonal test: Microwave power is 700W, activation time is 7min and flow rate of water vapor is 3.1mL/min. The yield of activated carbon is 52.3%. Iodine value is 1,012.2 mg/g and decolorizing capacity for methylene blue is 165mL/g. The adsorption capability of activated carbon exceeds the state level. Activation time by microwave irradiation is 1/45 as fast as that of the conventional process. Yield by microwave irradiation is twice as much as that of the conventional process.II , The new technology on preparation for activated carbon from bamboo knot(ZnCl2 activation and H3PO4 activation), cotton stem(ZnCl2 activation), tobacco stem(NH4Cl activation) with chemical activation method by microwave irradiaton was researched.1, The processing optimum conditions on preparation for activated carbon from bamboo knot with chemical activation method (ZnCl2 activation and H3PO4 activation) by microwave irradiation were obtained by orthogonal test. The processing optimum conditions of ZnCl2 activation method were: Microwave power is 350W, activation time is 5min and concentration of ZnCl2 solution is 40%. The iodine value of activated carbon is 1,088.4mg/g. Decolorizing capacity for methylene blue is 220mL/g and yield is 39.2%. Iodine value exceeds the state level (GB/T12496. 8-1999). Decolorizing capacity for methylene blue is 1.83 times as much as the state level (GB/T 12496.10 -1999). Activation time by microwave irradiation is 1/36 as fast as that of the conventional process. The processing optimum conditions of H3PO4 activation method were: Microwave power is 560W, activation time is 9min and concentration of H3PO4 solution is 40%. The iodine value of activated carbon is 889.0mg/g. Decolorizing capacity for methylene blue is 178 mL/g and yield is 31.0%. The decolorizing capacity for methylene blue is 1.48 times...