Microwave heating can produce good effects in the preparation and modification of activated carbon (S2. Microwave modification, many backwater hole is opened, the distributed capacitance change obviously, promoting the improvement of the adsorption. The microwave power and irradiation time are key determinants of modified activated carbon adsorption performance. On the mechanism of microwave carbonization and activation, it is generally believed that
Plant waste is mostly made of plant fiber raw materials, in the plant body under the action of capillary, modified solution absorbed by material whole fully, between fiber is filled with the subtle space, make the dry material volume expansion after soaking wet, and reaction. Because of the water in the raw material, modified solution constitute a polar molecule, with a strong absorption of microwave dielectric properties,Therefore, polar molecules collide and rub violently with microwave frequency, generating a large amount of heat, which makes water and modified solution volatilize rapidly, and generate steam pressure, which explodes out from the inside of the raw material to the outside. This sharp action makes the fiber space of the raw material expand and produce sharp drying.In this way, the raw material has a more obvious pore structure and a larger internal specific surface area than before microwave irradiation. Compared with the traditional heating method, the mechanism of microwave in the preparation process of activated carbon is completely different.It shows its unique advantages: high efficiency, energy saving, uniformity, selectivity, low pollution, high thermal efficiency, low energy consumption, simple process and equipment and small footprint, conducive to automation, low carbon loss, and recovery of useful substances.https://www.chinactivecarbon.com/
Many theoretical problems in this new field, especially the microwave heating mechanism, need to be further studied, and the mathematical model of the heating process needs to be establishedUsing small activated carbon fixed bed adsorption gas phase dioxin test bench, a typical activated carbon adsorption dioxin factors affecting the experimental study, discusses the types of dioxin adsorption activated carbon and activated carbon fixed bed adsorption gas phase characteristics of dioxins, and discusses the adsorption temperature and adsorption time of activated carbon adsorption of dioxins.The results showed that the specific surface area and micropore volume of activated carbon had weak correlation with the adsorption efficiency of dioxins.
The mesopore volume of activated carbon is an important factor to determine the adsorption capacity of dioxins. The surface area of the pore size between 2 nm and 20nm plays a key role in the adsorption of dioxins.The higher the adsorption temperature, the lower the adsorption efficiency of activated carbon.The longer the adsorption time, the lower the adsorption efficiency of activated carbon.There is no selective adsorption of gaseous dioxins in activated carbon fixed bed.coconut shell activated carbon pellets