Sorption of Hg(II) and Zn(II) ions using lignocellulosic sorbent (date pits)

Abstract

This work focuses on the study of Hg(II) and Zn(II) sorption using pristine date pits. The effect of pH is evaluated before considering the influence of both temperature and contact time on sorption efficiency. Sorption isotherms are also determined and modelled using conventional models such as Langmuir, Freundlich, and Dubinin‐Radushkevich (D‐R) equations. The best fit was obtained with the Langmuir equation and maximum sorption capacities reached 38.5 and 52.6 mg · g−1, for Hg(II) and Zn(II), respectively. An analysis of the temperature effect by the Gibbs equation showed that the sorption is exothermic and spontaneous. The mean free energy of sorption (obtained from D‐R equation) confirms that metal binding occurs through a chemical ion‐exchange mechanism. The kinetic profiles can be accurately fitted with the pseudo‐second order rate equation. Complementary analyses (using FTIR spectrometry and SEM‐EDX analysis) confirm that ion‐exchange is the main binding mechanism, though a contribution of surface complexation cannot be neglected.

Removal of nitrobenzene from aqueous solution by adsorption onto carbonized sugarcane bagasse

“…The reaction rate can be modeled using the resistance to intraparticle diffusion if the sorption is not limited by the reaction between the sorbate and the active sites. A kinetic model was developed by Weber and Morris Rezgui et al. (2017) and defined as follows where K d is the adsorption constant of W-M (mg·g −1 ·min −1/2 ), and C is constant.…”

“…Kinetics is a critical parameter in the design of the sorption process and in evaluating the suitability of a sorbent because it controls the size of the sorption units (Rezgui et al, 2017). Removal rate (%) Figure 5.…”

“…Thus, the experimental data did not agree well with the intraparticle diffusion kinetic model. Kinetic profiles can be used not only to determine the equilibrium time (as a function of experimental conditions) but also to identify the controlling (limiting) mechanisms and steps (Rezgui et al, 2017). Among the four kinetic models, the pseudo-second-order equation generates the best fit to the experimental data of the three investigated adsorption systems at initial NB concentrations of 50, 200, and 400 mg/L for the entire adsorption period.…”

Adsorption mechanism modeling using lead (Pb) sorption data on modified rice bran-insoluble fiber as universal approach to assess other metals toxicity

“…Dubinin-Radushkevich (D-R) isotherm D-R isotherm is widely used to determine the nature of sorption. [23] D-R model equation is given as:…”

Utilization of date pits derived Bio-adsorbent for heavy metals in wastewater treatment: Review

“…The majority of metal adsorption at pH less than 3 sh ows a lower percentage of metal removal, whereas increasing pH decreases H + ion concentration, resulting in more sorption sites becoming available [60,61].…”