Facile hydrothermal synthesis of calcium silicate nanostructures for removal of Hg(II) and Cd(II) ions from aqueous media

• Published in: International journal of environmental analytical chemistry Vol. 103; no. 18; pp. 6687 - 6703
• Main Authors: Al-Wasidi, Asma S., Hegazey, R.M., AlReshaidan, Salwa, Naglah, Ahmed M.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 22.12.2023; Taylor & Francis LLC
• Subjects: Adsorbents; adsorption; Aqueous solutions; Cadmium; Calcium; Calcium silicate nanostructures; Calcium silicates; Cd(II) ions; Crystallites; Crystals; Hg(II) ions; Hydrothermal treatment; Ions; Mercury; Nanostructure; Removal; Silicates; Sodium; Thermodynamic equilibrium
• ISSN: 0306-7319; 1029-0397
• DOI: 10.1080/03067319.2021.1959568

In this work, we have synthesised a mixture consisting of sodium calcium silicate and calcium silicate nanostructures in the presence and absence of the hydrothermal method. The synthesised products were identified utilising many techniques such as XRD, EDS, FT-IR, HR-TEM, and FE-SEM. The XRD demonstrated that the mean crystallite size of the product, which was synthesised in the absence of the hydrothermal method, is 72.71 nm. The average crystallite size of the products, which were synthesised using the hydrothermal method at 160℃ for 4, 8, and 16 h, are 44.85, 34.89, and 37.38 nm, respectively. HR-TEM confirmed that all the products consist of irregular and rod shapes. The product, which was synthesised after 8 h of hydrothermal treatment, was operated as an adsorbent for the efficient removal of toxic ions (Cd(II) and Hg(II)) from aqueous media. The maximum adsorption capacity of the adsorbent towards Hg(II) and Cd(II) ions are 177.94 and 199.20 mg/g, respectively. The removal process of the studied ions was fitted well with the pseudo-second-order kinetic model and Langmuir equilibrium isotherm. Thermodynamic parameters confirmed that the removal process of the studied ions was spontaneous, chemical, and endothermic.