Mesoporous activated carbon from waste tyre rubber for dye removal from effluents

The disposal of waste tyre represents a serious concern in environmental management. Owing to the high carbon content of waste tyre rubber, it is feasible to convert waste tyres to a value-added product, i.e. activated carbon, for environmental applications. This study focuses on the effect of different activation conditions (e.g. temperature, holding time and acid treatment) on the porosity of activated carbons produced from tyre rubber. Experimental studies showed that nitric acid treatment to tyre chars is able to remove certain mineral contents such as Ca, K and Na, which affect the reactivity of gas-solid reactions in the subsequent physical activation process (CO₂ as activating agent). Those acid-treated carbons developed high surface areas (over 1000 m²/g) that were comparable to commercial products. They also posses high mesopore volume up to 0.855 cc/g which has been shown favourable to the adsorption of larger-sized dye molecules. The Redlich-Peterson equilibrium isotherm model yielded the best-fit to experimental data for all three dyes using the non-linear error functions.