Modification of halloysite nanotubes by hydroxyl terminated triazine‐based dendritic polymer for efficient adsorptive removal of Cd (II) from aqueous media

Abstract

In the present study, the hydroxyl terminated triazine-based dendritic polymer was synthesized and grown on the halloysite nanotubes surface (HNT-G2) to efficiently remove the Cd (II) ions from aqueous solution. The nanoadsorbent morphology and structure were determined through transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analyzer, Brunauer-Emmett-Teller isotherm, and energy dispersive X-ray spectroscopy analysis methods. The adsorption of Cd (II) has resulted a maximum of 105.26 mg g À1 at 298 K at optimal pH 6. As research revealed the adsorption kinetic followed the pseudo-second-order model, while the adsorption isotherms corresponded the Langmuir model. Accordingly, it could be inferred that the Cd (II) was a single-layer adsorption occurring on the adsorbent surface, and further, the rate-controlling step was denoted chemical adsorption. Also, the thermodynamic results showed that the adsorption process could occur spontaneously; therefore, it was considered as an endothermic reaction. Surprisingly, the adsorption and desorption efficiency after four cycles was high, while the Cd (II) adsorption mechanism affecting the adsorbent was basically via chelation through the O atoms. Hence, it can be concluded that the HNT-G2 was effective in efficiently removing of Cd (II) from the aqueous solution, having high applicability significance.

Synthesis of carboxylic graphene oxide‐carboxymethyl chitosan composite and its applications toward the remediation of U6+, Pb2+, Cr6+, and Cd2+ ions from aqueous solutions

“…The Langmuir equation is given by nonlinear Equation (3), and the linear form is given by Equation (4). [ 43,44 ] where q e (mg g −1 ) denotes the equilibrium adsorption capacity of HTMIs adsorbed on the adsorbent surface, q max denotes the maximum adsorption capacity of HTMIs adsorbed, and K L denotes the Langmuir's isotherm adsorption constants.…”

“…The Langmuir equation is given by nonlinear Equation (3), and the linear form is given by Equation ( 4). [43,44] F I G U R E 1 0 Langmuir adsorption isotherm linear curve between 1/C e and 1/q e for HTMIs…”

“…The positive values of ΔH (+Ve) indicate that the adsorption process is endothermic in nature, whereas positive values of ΔS (+Ve) indicate that the composite (COOH-GO-CMC) has an affinity for HTMIs in aqueous solutions and that the solid-solution interface is more random throughout the adsorption process. [21,43,52]…”

Removal of Cd2+ from zinc smelter wastewater using graphene oxide foam cross-linked with epichlorohydrin: comprehensive optimization, isotherms, kinetics, and real water column studies

“…Cadmium can occur in various oxidation forms, including Cd(0), Cd(I), and Cd(II). 6 This gradually accumulate in the bodies of living organisms through the food chain, and even at trace levels, it can seriously affect the vital parts of the body, negatively impacting normal human life. 7,8 The most effective solution to prevent the entry of heavy metals into the ecosystem is to use environmentally friendly methods that do not harm the environment.…”

Fe3O4@SiO2‐APTES@Isophthaloyl Dichloride/Montmorillonite Magnetic Nanoparticles for Efficient Removal of Pb2+ and Cd2+

“…In some cases, the adsorption process is reversible and the adsorbent can be recovered through the desorption process [5]. Substances such as graphene, magnetic nanoparticles, nanoclays, and composites have been employed for this purpose due to their high catalytic performance and great adsorption capacity [6][7][8].…”