Unlocking the rice straw agro-waste potential as activated carbon: Pyrolysis and characterization

Abstract

Rice growing is widely practiced in the northern Indian region known as the Indo-Gangetic Plain. A significant amount of rice straw is burned in the field due to the absence of a waste management system. To boost its economic value, Rice straw  is converted into activated charcoal, which can subsequently be used for wastewater treatment, metal extraction, air purification, and other applications. The purpose of this work was to produce porous activated carbon particles from RS waste using a chemical activation procedure that included 40% orthophosphoric acid. The process of synthesizing porous carbon particles involves three steps: (i) carbonization; (ii) chemical impregnation; and (iii) activation treatment. Variations were made to the activation temperature, residence time, and activating agent concentration to attain the best possible approach for the activation treatment. Activated carbon  was characterized using different techniques, such as XRD, FTIR, FESEM and EDX. Experimental results showed that this approach is effective at producing porous carbon particles. ACs synthesized were carbonaceous and amorphous in form, as determined by X-ray diffraction studies. FTIR revealed the presence of functional groups that are good for adsorption, such as hydroxyl, carbonyl, amines, aromatic, and others. Scanning electron micrographs showed that activated carbon has a compact and porous structure. When comparing the activated carbon to the original rice straw, EDX demonstrates the increased carbon content. The optimal conditions determined are 700°C, a ratio of 1:3, and a duration of 90 minutes. The results of the investigation show that the agricultural wastes used in the evaluation may serve as low-cost sources of material for the production of local ACs, thereby addressing the issue of disposing of agricultural wastes.