On the view of dielectric properties in microwave‐assisted activated carbon preparation

Abstract

Dielectric properties are important in the conversion of agro-wastes into activated carbon as they indicate the suitability of materials to be heated under microwave. However, dielectric properties of materials in microwave-assisted process are very much neglected in much of published literature. This paper aims to offer perspectives on the characteristics and dielectric properties of some agro-wastes in microwave heating. Issues involving the microwave-assisted activation strategies and the characteristics of the derived activated carbon are also discussed.

Dielectric properties in microwave‐assisted solvent extraction—Present trends and future outlook

“…This indicates that the moisture‐rich oil with shorter penetration depth would not be heated thoroughly because it is mainly centered in heating the moisture. As such, the dried materials might give a higher penetration depth than materials with high moisture content …”

Dielectric properties of potassium carbonate‐impregnated cempedak peel for microwave‐assisted activation

“…The ε ′ of CC is lower than that of CP because of low moisture content (6.75%), even though CC possesses higher carbon content (63.7%). Moisture can influence the profile of dielectric properties because water is a natural polar dielectric or prominent absorber of microwave energy with high ε ′ . CK1.75 demonstrates a higher ε ′ among the impregnated samples because of high moisture content.…”

“…The carbon content indeed plays an important role in dielectric properties because of dense graphitic structure and the presence of aromatic rings. Delocalized π‐electrons of aromatic structure can move freely, and might also create ionization to the surrounding . Yet, the ε ′ of CC is lower than that of CP.…”

Preliminary evaluation of resorcinol-formaldehyde carbon gels for water pollutants removal

“…It signifies the liberation of functional groups to form elementary carbon-rich (graphitic) structure of RC. In addition, the possible acidic functional groups in Ox-RC could not be detected probably due to strong absorption of infrared signals by rich carbon layer [9]. Figure 5 shows the removal of methylene blue (MB + ) by carbon gels.…”