Adsorption of Lead(II) by Silica/Cell Composites from Aqueous Solution: Kinetic, Equilibrium, and Thermodynamics Studies

Abstract

Silica/cell composites were prepared for the adsorption of lead ions, Pb(II), from aqueous solution in a batch system. The silica/cell composites possessed micropores, high surface area, and abundant functional groups. Adsorption performance was investigated by analyzing the effects of such factors as the initial pH, contact time with different initial concentration, and initial Pb(II) concentration at different temperature. The kinetic data were fitted to pseudo-second-order and intraparticle diffusion kinetic models. The results were better fitted by the pseudo-second-order kinetic model. Intraparticle diffusion increased with an increase of initial concentration and the sorption process was controlled by film diffusion. The Langmuir isotherm model was fitted to the experimental data significantly better than Freundlich and Dubinin-Radushkevich isotherm models. The maximum adsorption capacity was 97.10 mg g(-1), according to the Langmuir isotherm model. Thermodynamics parameters confirmed the spontaneous, endothermic, and entropy-gained nature within the studied temperature range (from 298 to 318 K). The composites could be effectively desorbed by the 2.0 mol L(-1) HNO3 solution and would be a potential adsorbent.

Adsorption of Organic Dyes by TiO2@Yeast‐Carbon Composite Microspheres and Their In Situ Regeneration Evaluation

“…The best fit to the pseudo-secondorder kinetics model indicates that the adsorption mechanism depends on the adsorbate and adsorbent, and the rate controlling step might be chemical sorption involving valence forces through exchange or sharing of electrons [2]. The rate constant ( 2 ) also decreased with the increase of the initial CR concentrations, owing to that the higher probability of collisions among CR molecules would decrease the sorption rate [28]. Similar kinetic results have also been reported for the CR adsorption onto bagasse fly ash [34], activated carbon from coir [44], and chitosan/montmorillonite [45].…”

“…Adsorption isotherm models are important to investigate how adsorbates interact with adsorbents [28] and are widely used to describe the adsorption progress [10]. Langmuir, Freundlich, Temkin, and Koble-Corrigan isotherm models were used to fit the equilibrium data obtained from the study of MB and CR adsorption onto TiO 2 @yeast-carbon at initial concentrations of 1.0∼5.0 mg/L and 3.0∼11.0 mg/L, respectively.…”

Ni(II) removal from wastewater by solar energy-degreased spent coffee grounds

“…Generally, adsorption isotherms provide vital information in optimizing the use of adsorbents. Langmuir and Freundlich models are commonly used to describe the adsorption isotherms and provide significant parameters for predicting adsorption capacities [28,29]. In this study, for evaluating the adsorption isotherms of various SCG treatments, the combined condition with Ni(II) concentration of 10 mg/L, contact time of 60 min, and temperature at 25˚C was adopted while the SCG dose was varied from 1 to 6 g.…”

Applicability and toxicity evaluation of an adsorbent based on jujube for the removal of toxic heavy metals

“…For these reasons, numerous researchers have been previously conducted for the treatment of lead and copper, such as chemical precipitation [11,12], ion-exchange [13,14], membrane filtration [15,16], flotation [17], and adsorption [18,19]. However, chemical precipitation is only optimal for high heavy metal ion concentration in wastewater and ion-exchange may cause secondary contamination when resins are regenerated by chemical reagents.…”