Sorption of Methyl Orange and Methylene Blue Dyes with Activated Carbon from Potato Peel Waste

The uptake of textile dyes from water using activated carbon has become a key topic because of its fast sorption capacity, easy handling, and high removal efficiency. Biomass-based activated carbon is a good adsorbent because of its easy accessibility and renewability. In this study, the adsorption capacity of activated carbon from potato peel waste was investigated. The potato peels were carbonized at 550 °C and activated with three different acids, namely hydrochloric acid (HCl), nitric acid (HNO3), and sulfuric acid (H2SO4). The prepared adsorbents were analyzed for their adsorption capacity to remove methylene blue (MB) and methyl orange (MO) from water. Although chemical activation by various acids has already been explored by other researchers, there are few studies in which potato peel waste has been converted to carbon and used for the uptake of MO dye. The adsorbents were characterized using XRD, FTIR, and SEM. Effects of pH, time, temperature, and dye concentration were investigated. The data from the isotherms indicated that the uptake of MB takes place on heterogeneous surfaces and MO on homogeneous surfaces. The thermodynamic parameters for both dyes showed that both the ΔS° and ΔH° values were negative, indicating that the sorption process of MB and MO on all adsorbents was exothermic and that the randomness increased during the removal process. ΔG° values indicated that physisorption was important during the sorption process. This work shows a great possibility of activated carbon from potato peels for the uptake of dyes.