Removal of methylene blue dye using activated carbon prepared from biowaste precursor

The objective of this work is to study the adsorption capacity of activated carbon prepared from the peels of a fruit named Citrus limetta which is abundantly available and is usually thrown as a waste material. Surface characterization of the adsorbent prepared was done using scanning electron microscopy and Fourier-transform infrared spectroscopy. Removal of methylene blue (MB) dye from aqueous solution using a bioadsorbent has been investigated through batch adsorption studies on various parameters such as pH (1-9), adsorbent dosage (0.05-0.25g/50 mL), contact time and initial dye concentration (100-500 mg/L). The experimental data were also fitted to standard kinetic models (pseudofirst-order, pseudo-second-order and Elovich). Kinetics of the adsorption was best described by the pseudo-second-order model. Adsorption data were fitted to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms. Among these, the data were best fitted to Langmuir isotherm. A Weber-Morris plot indicated that diffusion was not the only mechanism responsible for the adsorption. The adsorption capacity of C. limetta peel carbon (CLPC) was determined to know the effectiveness of an adsorbent in removing MB dye. Results showed that CLPC is suitable for the adsorption of MB and could be used as a low cost-effective adsorbent in the treatment of wastewater.