Facile Synthesis and Characterization of Novel Analcime@Calcium Aluminate@Polyethylene Glycol 400 Nanocomposite for Efficient Removal of Zn(II) Ions from Aqueous Media

Excessive Zn(II) ions in aquatic environments pose significant risks to both human health and ecological systems due to their toxic effects, bioaccumulation potential, and interference with essential biological processes. To address this issue, a novel analcime@calcium aluminate@polyethylene glycol 400 (ACP) nanocomposite was fabricated using the hydrothermal technique, alongside an analcime@calcium aluminate (AC) nanocomposite for the efficient elimination of Zn(II) ions from aqueous media. X-ray diffraction (XRD) analysis affirmed the successful formation of crystalline phases, revealing average crystallite sizes of 72.93 nm for AC and 63.60 nm for ACP. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition of the nanocomposites, showing that AC primarily contained oxygen, sodium, aluminum, silicon, and calcium, whereas ACP incorporated 19.3% carbon due to the polyethylene glycol 400. Field emission scanning electron microscopy (FE-SEM) revealed that AC exhibited hexagonal and platelet-like structures, whereas ACP displayed more dispersed and layered morphologies. High-resolution transmission electron microscopy (HR-TEM) confirmed the presence of stacked platelet-like structures in AC and more defined, separated nanosheets in ACP. The maximum adsorption capacities of AC and ACP were 149.93 and 230.95 mg/g, respectively. The adsorption pathway of Zn(II) ions onto ACP nanocomposite involved three primary interactions: electrostatic attraction facilitated by calcium aluminate, ion exchange provided by analcime, and complexation promoted by polyethylene glycol 400. Thermodynamic analysis indicated that the adsorption process was exothermic, spontaneous, and primarily chemical in nature. Kinetic modeling confirmed that adsorption followed the pseudo-second-order model, while isotherm studies demonstrated adherence to the Langmuir model, indicating monolayer adsorption on homogeneous sites.