Author(s)

R Sasai, M Torazawa, K Yano, F S Zhang & H Itoh

Abstract

In order to increase the recycling rate of industrial solid waste (ISW) for solving the depletion problem of landfilling sites, carbon-ceramics porous (CCP) adsorbent was synthesized from the mixture of inorganic and organic ISW’s. Sludge discarded from a gravel plant was used as an inorganic ISW and sawdust from wood plant was used as an organic ISW. The two ISW’s were calcined with a swelling clay (bentonite) used as a binder. After mulling and extruding these mixtures in the presence of water, CCP compacts were prepared by the two calcination techniques, i.e., a rapid heating/cooling process and a slow heating process under N2 atmosphere. CCP compacts obtained at 850°C for 6 min by the rapid heating/cooling process adsorbed more than 60 mg of methylene blue (MB) from aqueous solution for 1 g of CCP powder. However, the increase in calcination time caused a decrease in adsorption ability of MB. XRD analysis revealed that the excess heating caused the destruction of layered structure of bentonite which possessed ion-exchange characterization. This leads to the conclusion that the porous structure originated from the organic components would have less contribution to the adsorption of ME molecules. In order to increase the adsorption ability of CCP powder, the effects of addition of activator, K2C03, were investigated. As a result, activated CCP powder exhibited an increase in adsorption ability for MB molecules. Porous adsorbent, which has a practical adsorption ability, would be fabricated by a simultaneous calcination of the activated ISW’s.

Keywords