Adsorption and Kinetics Modelling for Chromium (Cr⁶⁺) Uptake from Contaminated Water by Quaternized Date Palm Waste

The pervasive challenge of heavy metal pollution in water necessitates urgent interventions to mitigate chromium contamination. It poses significant threats to human health, aquatic ecosystems, and the environment. This research delves into the potential of date palm waste as a precursor of adsorbent for extraction of chromium from contaminated water, underscoring its potential in heavy metal remediation. Date palm waste, traditionally regarded as agricultural waste, underwent modification employing N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride resulting in quaternized date palm waste (QDPW) as a prospective adsorbent for chromium extraction. The characterization techniques, including FTIR, SEM/EDX, BET, XRD, TGA/DTA, and element analysis, were employed to examine the structural and surface properties of both DPW and QDPW fibers. Optimal chromium uptake was achieved at a solution pH 6.5 over two hours, with a peak removal efficiency of 88% and an adsorption capacity of 22.26 mg/g. The equilibrium isotherms studies are consistent with Langmuir, Redlich-Peterson, and Sips isotherms, presenting a coefficient of determination (R-2) of 0.989, 0.981, and 0.983, respectively. Moreover, the pseudo-second-order model was mostly aligned with the kinetics data with R-2 value of 0.999. These findings showed that the quaternized date palm waste can be considered a good option to recycle the date palm waste and reduce the environmental threats in aqueous solution.