Preparation of Activated Carbon from Corn Stover at Various Temperatures and Catalytic Conditions

Abstract

Biomass based feedstock has emerged as one potential candidates to pave the way forward towards bio-economy on a global scale. These bio-based resources can be deployed for the production of various sustainable products such as energy, fuels, chemicals and even biomaterials. Activated carbon, being one such important sustainable product, can also be produced from these resources both globally and even locally. Due to its high internal surface area, this has been widely used as adsorbent such as soil improvement, heavy metals, wastewater treatment, production of fine chemicals & medicines, food & beverage processing and other sectors employed this material within their processing units. Among from various available biomass resources, corn stover is the most abundant and significant commodities found in Asian countries. Therefore, in this study this agricultural feedstock as model substrates to study the characteristics of the activated carbons produced from them. Preparation of activated carbons from corn stover by chemical activation at various types of carbonization temperatures and catalyst reagents were studied. Potassium hydroxide (KOH), zinc chloride (ZnCl2) and phosphoric acid (H3PO4) were used as catalyst reagents with three different impregnation ratios (1:0, 1:1, 1:3). The chemical activation was preformed using a bed type reactors and restricted our process retention time of 1 h for all the experiments. The influence of carbonization temperatures and catalyst reagents on the structure of activated carbons were investigated. For determination of physical and chemical properties of the obtained activated carbons, elemental analysis was applied to determine the elemental composition (C, H, N, O), surface structure of activated carbons was conducted by scanning electron microscopy (SEM) and Brunauer-Emmett Teller (BET) was applied to characterized the surface area. The results revealed that ratios of catalyst agents have significant effects on the yield of activated carbons as the increasing of catalyst ratios showed a decreasing yield of activated carbons. It was found that the maximum surface areas of corn stover activated carbons were obtained at the carbonization temperature of 700 °C for both ZnCl2 and H3PO4. Meanwhile, it was found that the maximum surface area of corn stover activated carbon produced by using KOH at 800 °C shown a high surface area of 2370 m2/g. The results shown that the surface area was greatly influenced by the catalyst reagent ratios and carbonization temperatures.