Effects of Activation Conditions on the Properties of Sludge-Based Activated Coke

Abstract

Sewage sludge and waste biomass are unavoidable byproducts of municipal and industrial processes. Both materials have significant carbon contents. Activated coke with a developed pore structure can be obtained after its physical activation. In this study, sewage sludge and waste poplar bark were used as precursor materials to prepare activated coke by steam, carbon dioxide gas, and their mixtures. The effects of different concentrations of activation gas on the activated coke product were investigated. Through nitrogen adsorption analysis, it was found that activated coke has a higher specific surface area and better pore structure when activated in gas containing 20% steam. The activated coke prepared by carbon dioxide gas activation has higher microporosity than that prepared by steam activation. Infrared spectrum analysis shows that steam activation is beneficial to the formation of free hydroxyl functional groups. Through scanning electron microscopy analysis, the pores of activated coke prepared by steam activation appeared to extend deeper in the structure of the coke, while the pores of activated coke prepared by carbon dioxide activation appeared to have fine circular structures. The activated coke prepared by the activation of mixed gas appeared to have ablated particles on the surface due to the ablation of the pore structure. In order to prepare activated coke with excellent adsorption performance, the physical and chemical properties of activated coke under different activation conditions were studied in detail.

Replacing Potassium Hydroxide with Carbide Lime Waste in Preparing Sludge-Based Activated Carbon for Methylene Blue Removal from Aqueous Solutions

“…This peak also superimposes the stretching vibration peaks of the amine group [41]. The bands at 3000-2800 cm −1 can be assigned to saturated C−H stretching vibration [42], mainly the methyl and methylene groups. The bands in the region of 1600-1560 cm −1 can be ascribed to the stretching vibrations of C=O moieties in conjugated systems or OH bending vibrations overlapped with aromatic ring stretching and double bond vibrations [39,40].…”

Biomass and Coal Modification to Prepare Activated Coke for Desulfurization and Denitrification

“…In flue gas, SO 2 and NOx are the most harmful to human health and the environment [1,2]. Activated coke is an excellent adsorbent, and its specific surface area, pore structure abundance, and functional group types can all affect its physicochemical properties and adsorption performance [3][4][5][6]. Due to the difference in adsorption medium (gas phase and liquid phase) and adsorbate, the properties of activated coke are also different.…”