Tyrosine-Immobilized Montmorillonite: An Efficient Adsorbent for Removal of Pb²⁺ and Cu²⁺ from Aqueous Solution

Abstract

Herein, a new effective material, tyrosine-functionalized montmorillonite (Tyr-Mt), was prepared and used in the adsorption of Pb 2+ and Cu 2+ ions. Tyr-Mt is synthesized by modifying sodium montmorillonite (Na-Mt) with L-tyrosine. The X-ray diffraction, ζ-potential, Fourier transform infrared spectroscopy, Brunauer−Emmett−Teller, and thermal analysis results showed that the modifier was successfully inserted into the interlayer of montmorillonite. In single-ion systems, various parameters were thoroughly evaluated, such as the amount of the modifier, pH value, the initial concentration of M 2+ , and contact time, affecting the adsorption processes in sodium montmorillonite (Na-Mt) and Tyr-Mt composites. The adsorption experiments of Pb 2+ and Cu 2+ showed that the adsorption effect of Tyr-Mt was better than that of Na-Mt. The balanced adsorption of Pb 2+ by Tyr-Mt was 106.21 (higher than that by Na-Mt, 89.08 mg/ g) and of Cu 2+ was 28.31 mg/g (higher than that by Na-Mt, 23.93 mg/g). The adsorption model conforms to the Langmuir model, indicating that the active sites on the adsorbent surface are the same. The kinetics conforms to the pseudo-second-order kinetics, and the adsorption process is a spontaneous endothermic process. In the binary co-adsorption system, the adsorption capacity for heavy metal ions was lower than that in a single adsorption system. Tyr-Mt is used in the adsorption of heavy ions due to its high efficiency and low cost. This study will provide a simple and convenient method for the application of other modified clays to achieve high adsorption capacity for toxic cations in soil and aqueous solutions.

Strontium and Cesium Adsorption on Exopolysaccharide-Modified Clay Minerals

“…The interlayer reaction of Sr/Cs with EPS-MMT was consistent with the results of adsorption isotherms described with Langmuir and Freundlich models. A similar phenomenon was reported by Chu et al on tyrosine adsorption on MMT.…”

“…Notably, after adsorbing Sr, the characteristic peak became sharper and more obvious with an increasing loading, suggesting a more ordered feature of the composite . This confirmed the interlayer reaction of Sr with EPS . Conversely, the characteristic peak began to weaken after adsorbing Cs, almost disappearing after absorbing 1000 mg/L Cs, demonstrating a disordered feature formation or the collapsing of interlayers. ,, On the one hand, there should be the presence of substances with an amorphous structure and/or the formation of a disordered pillared structure, which was confirmed by SEM characterization (discussed below, Figure a,f), and was consistent with the basal spacing.…”

L-Histidine immobilized montmorillonite for As(III) adsorption and statistical verification of data by PDF, AICcorrected and AADR models

“…Recently, Tyrosine immobilized montmorillonite was employed as an adsorbent for removal of inorganic metal ions, Pb 2+ and Cu 2+ and results proved an excellent performance of adsorbent for metal ion decontamination. (Chu et al 2019). Similarly, L-Cysteine modified montmorillonite alginate nanocomposite was used as an adsorbent for the removal of Ni 2+ , Pb 2+ and Cu 2+ and satisfactory results were reported (Mittal et al 2016).…”

Multilayer Graphene Oxide Supported ZIF-8 for Efficient Removal of Copper Ions

“…In particular, the elimination of Cu 2+ adsorption process can provide additional technical and economic benefits. Therefore, it is necessary to study the application of novel adsorbents to consolidate their industrial application [11][12][13]. In this direction, it has been reported that two-dimensional (2D) nanomaterials show potential as promising adsorbents for heavy metal removal [14][15][16].…”