Application of Microwave Energy to Treat Granular Activated Carbon Contaminated With Chlorobenzene

摘要

Granular activated carbon (GAC) is an excellent dielectric material to absorb and convert microwave (MW) energy into thermal energy. The MW heat is effective in decomposing organic substances adsorbed on the carbon. One gram of GAC loaded with chlorobenzene (CB) was subject to the MW output power varying from 400 to 800 W for 60 s, the carbon temperature rises to 325 to 470℃; 81.9% to 100% of the adsorbed CB is decomposed with the GAC dielectric loss factor between 16.2 and 24.8 F/m. Additionally, for the same dielectric material, larger surface area will absorb more MW energy. With more GAC (e.g., 2 g), the heat generated within GAC will cause sparks to occur if the MW irradiation time exceeds 80 s. The occurrence of sparks causes the GAC surface to graphitize thus destroying the surface micropore structure that leads to more smooth surface with less adsorption capacity. After five repetitive uses, dielectric loss of the recovered GAC decreases from 29.8 to 19.4 and the CB removal rate declines from 100 to 91%.