Mechanistic insights into the remediation of bromide ions from desalinated water using roasted date pits

Abstract

Bromide ions (Br−) are associated with toxic by-products that might be produced during the disinfection of drinking water. The removal of Br− from water using roasted date pits (RODPs) and activated carbon was investigated. The percentage removal capacity of Br− was studied under various experimental conditions including solution pH, adsorbent mass and particle size, and initial Br− concentration. Surface characterisation was investigated using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). SEMs images showed the presence of fine particles (debris) on the surface of the adsorbent solids. The raw date pits (RDPs) surface images showed a marked difference in pore sizes upon roasting, whilst FTIR spectra showed a slight shifting in –O–H, Cdouble bondO, and –C–O stretching in addition to –O–H bending for the RODPs. In addition to the Freundlich and Langmuir isotherm models, the experimental data were fitted to different adsorption kinetic models. It was found that the adsorption of Br− onto RODPs followed pseudo-second order mechanism. Removal rates of around 54% were obtained at lower pH.