The chemical process of producing activated carbon using walnut shells and plastic wastes

In this work, the chemical preparation of activated carbon (AC) using walnut shell (WS) and plastic wastes (primarily consisting of polyethylene, polypropylene, and polystyrene) as feedstocks and chemical activators (KOH and NaOH) was investigated in a fixed-bed reactor. Thermogravimetric analysis (TG) (TGA) was used to carbonize WS together with plastic waste. Furthermore, the Brunauer-Emmett-Teller (BET) method, FTIR, dye adsorption, iodine number, and SEM experiments were applied to characterize the obtained ACs. The results indicated that the polyolefinic waste acted as insulation and controlled the energy reaching WS particles to a certain extent. In addition, the reactive pyrolysis products of plastics such as styrene and light olefins reacted with the unstable structure of WS and intensified the secondary reactions during the carbonization process. Secondary reactions led to the creation of new structures that were clearly visible in the FTIR spectra. Also, the results indicated that the participation of plastics in secondary reactions has led to an increase in AC production. Furthermore, during the activation process, plastics have led to a significant increase in the surface area and volume of pores. The curve of WS degradation together with plastic waste showed that plastics have slowed down the WS degradation, as indicated by the slope of the degradation graph has clearly decreased.

Automated summary

In this study, the chemical preparation of activated carbon (AC) using walnut shell and plastic wastes as feedstocks and chemical activators (KOH and NaOH) was investigated. The obtained ACs were characterized using various methods. The results showed that the participation of plastics in the process led to an increase in AC production and the formation of new structures, as well as an increase in surface area and pore volume.