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This study aims to eliminate hexavalent chromium Cr(VI) ions from water using pomegranate peel (PGP) powder. Dynamic measurements are carried out to examine the influence of the operating factors on the adsorption efficiency and kinetics. The analyzed PGP is found to be amorphous with relatively high stability, contains hydroxyl and carboxyl functional groups, a pH of zero charge of 3.9, and a specific surface-area of 40.38 m2/g. Adsorption tests indicate that PGP exhibits excellent removal effectiveness for Cr(VI) reaching 50.32 mg/g while the adsorption process obeys the Freundlich model. The thermodynamic study favors the exothermic physical adsorption process. The influence of operating parameters like the flow rate (1 to 3 mL/min), bed height (25 to 75 mm), concentration (10 to 30 mg/L), and temperature (298 to 318 K) on the adsorption process are investigated in column mode. To assess the performance characteristics of the column adsorption data, a non-linear regression has been used to fit and analyze four different kinetic and theoretical models, namely, Bohart-Adams, Thomas model, Clark, and Dose response. The obtained experimental results were found to obey the Dose Response model with a coefficient of regression R2 greater than 0.977. This study proved the excellent efficiency in the treatment of chemical industry effluents by using cost-effect abundant biowaste sorbent. This research demonstrated great efficacy in the treatment of chemical industrial effluents by using an abundant, cost-effective biowaste sorbent, thereby achieving the UN SDGs (UN Sustainable Development Goals) primary objective.

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a b s t r a c tThe purpose of this work was to remove methylene blue (MB) from water using natural eggshell membrane (ESM) in fixed-bed column. The ESM was treated and characterized by Fourier transform infrared spectra (FTIR), scanning electron microscope (SEM) and X-ray diffraction (XRD). A series of experiments were carried out to investigate the effects of bed height on breakthrough curve, flow rate, MB concentration, solution pH (2-10), the ionic strength and temperature on the adsorption behavior. The experimental results show that the adsorption capacity increases with the increase in the bed depth and MB concentration. However, it decreases with increasing the flow rate and temperature. The ESM adsorption capacity of MB is more pronounced in basic medium. The addition of NaCl salt ions decreases the fixation of MB on ESM. Five kinetic models, Bohart-Adams, Wolborska, Thomas, Yoon-Nelson and bed depth service time (BDST) models were applied to experimental data in order to predict the breakthrough curves using non-linear regression and to determine the characteristic parameters of the column useful for process design. The results showed that Thomas and Yoon-Nelson models were found suitable for the normal description of breakthrough curve at the experimental condition, while Adams-Bohart and Wolborska models were only for an initial part of dynamic behavior of the ESM column. Desorption of MB from ESM bed was performed with distilled water as the desorbing agent, and reuse study was investigated.