New Efficient Adsorbent Materials for the Removal of Cd(II) from Aqueous Solutions

Abstract

The rapid increase of industrial activities leads to serious environmental pollution, especially, in aqueous systems and particularly with heavy metals. Cadmium, one of the most poisonous elements, is rapidly accumulated in the human body, therefore, the efficient removal of cadmium ions from wastewater is an urgent need. Coordination networks (CNs) and its subdivision metal-organic frameworks (MOFs), are structured porous composites which present various special properties. In this work two CNs were used as adsorbent materials for the removal of Cd(II) ions from aqueous solutions. By the reaction of CoSO4·7H2O and NiSO4·7H2O with N,N-bis(phosphonomethyl)glycine (Gly) in hydrothermal conditions two CNs—Co–Gly and Ni–Gly— were synthesized, respectively. Cadmium adsorption onto the studied CNs was conducted in batch mode, and the effect of pH, initial concentration, contact time, temperature and sorbent weight on the sorption process were investigated. Parametric Method 3 (PM3)semi-empirical analyses of the CNs’ structural properties were performed in order to predict the adsorption properties. For this reason, two octahedral models were calculated and computational predictions were compared with the experimental results. Both computational and experimental adsorption studies found that Ni–Gly presents higher affinity for cadmium ions. Moreover, the adsorbent materials can be readily regenerated and recycled without significant loss of cadmium uptake capacity.

Simultaneous sorption of heavy metals on Algerian Bentonite: mechanism study

“…Then, adsorption on bentonite surface may occur by cation exchange of Na þ present in the structure of bentonite, or by formation of bonds with active sites. In addition, metal ions could precipitate at the surface of bentonite as hydroxides Cd(OH) 2 , Fe(OH) (Visa et al 2020). Accordingly, all these data indicate that adsorption in this system can be done by several mechanisms such as: electrostatic interactions, ion exchange, and formation of bonds (Figure 8).…”

“…They represent a serious public health problem because they are toxic to living organisms even at low concentrations. These substances have the ability to accumulate throughout the food chain and in the environment because they are not biodegradable (Visa et al 2020).…”

IL-Functionalized Mg3Al-LDH as New Efficient Adsorbent for Pd Recovery from Aqueous Solutions

“…The pseudo-first order model is expressed in its linear form, according to the following equation [ 40 , 41 , 42 ]. where: q e and q t represent the amount of Pd(II) adsorbed onto 1 g of adsorbent materials at equilibrium and after the treatment time, t; k 1 represent the rate constant specific for the adsorption process of Pd ions onto studied materials.…”

Experimental Investigations of AlMg3 Components with Polyurethane and Graphene Oxide Nanosheets Composite Coatings, after Accelerated UV-Aging

“…The graphite oxide GON has been modelled and optimized using density functional theory (DFT) with the Becke, three-parameter, Lee–Yang–Parr (B3LYP) functional and, the 6-31G(d,p) basis set level of theory, using the Jaguar module of the Schrödinger package [ 68 ]. These quantum chemical methods are extensively used to study physicochemical properties and to predict the adsorption centres of the GON responsible for the interaction with the metal surface [ 69 , 70 , 71 , 72 ]. In addition to the E HOMO (energy of the highest occupied molecular orbital) and the E LUMO ( energy of the lowest unoccupied molecular orbital) values, the DFT simulations make it possible to estimate other parameters, using Koopman’s theorem [ 73 , 74 ], such as: the energy gap (ΔE = E LUMO − E HOMO ), the electron affinity (A = −E LUMO ), the ionization potential (I = −E HOMO ), the electronic hardness of the molecule (η = (I − A)/2), the global softness of the molecule (σ = 1/2η), the electronegativity of the molecule (χ = (I + A)/2), and the chemical potential of the molecule (μ = −(I + A)/2).…”