Abstract

This study examined the adsorption of methylene blue onto raw date fruit waste (DFW) and NaOH-modified date fruit waste (N-DFW). Experiments were done as function of contact time, initial pH (2-12), adsorbent dose (0.5-8 g/L) and initial dye concentration (20-200 mg/L). The solution pH had strong effect on the adsorption capacity of both adsorbents and the extent of the dye removal increased with increasing pH. The experimental data were fitted to different kinetic and isotherm models. The adsorption of methylene blue on both sorbents followed well the pseudo-second-order model. According to Langmuir isotherm model, the maximum monolayer adsorption capacities of DFW and N-DFW were 165.3 and 215.4 mg/g, respectively. Therefore, date fruit waste could be considered as an efficient adsorbent for the removal of MB from aqueous solutions and its adsorption properties were improved through modification with NaOH.