Abstract
In this work, date palm trunk (DPT) fibre was investigated for the eviction of copper ions (Cu2+) from aqueous solution. The surface chemistry of the DPT adsorbent was characterized through Fourier transform infrared spectroscopy and X-ray powder diffraction. The specific surface area and the average crystalline size of the DPT fibre adsorbent were measured as 2.104m(2)g(-1) and 320nm, respectively. Equilibrium adsorption was achieved at 150min and results reflected significantly higher adsorption of Cu2+ onto DPT fibre at pH 5 (6mgg(-1), 12%) than at pH 2-4 (1-4mgg(-1), 1-7%). The adsorption data revealed maximum removal (25.4mgg(-1)) at the adsorbent dose of 5g L-1. Significantly, removal (34mgg(-1)) was observed with particles 75m and Cu2+ removal was significantly higher (6-23mgg(-1)) with increasing Cu2+ concentration from 20 to 100mg L-1. Adsorption kinetics data were modelled using pseudo-first-order and pseudo-second-order kinetics. The behaviour and the nature of Cu2+ adsorption were analysed by employing the Langmuir, Freundlich, Harkins-Jura (H-J) and Dubinin-Radushkevich (D-R) isotherm models. The results reflect that the adsorption isotherm model fitted the experimental data in the following order: Langmuir (R-2, 0.9933) > H-J (R-2, 0.9869) > Freundlich (R-2, 0.9768) > D-R (R-2, 0.8827) with monolayer Cu2+ adsorption. The experimental data were best explained by a Langmuir isotherm model and pseudo-second-order kinetics with R-2 = 0.9933 and 0.9905, respectively, and q(max) of 25.25mgg(-1) with chemisorption (E=14.59 kJ mol(-1)). The homogeneity of the adsorbent surface functional groups makes DPT suited for sequestering toxic Cu2+ from wastewater. Suitable physical, chemical and physicochemical surface modifications can further improve the adsorption capabilities of DPT adsorbents.