Mechanistic study of Hg(II) interaction with three different α-aminophosphonate adsorbents: Insights from batch experiments and theoretical calculations

Safaa R Fouda; Ibrahim E El-Sayed; Nour F Attia; Marwa M Abdeen; Abdel Aleem H Abdel Aleem; Ibrahim F Nassar; Hamed I Mira; Ebrahim A Gawad; Abul Kalam; Ahmed A Al-Ghamdi; Ahmed A Galhoum

doi:10.1016/j.chemosphere.2022.135253

Mechanistic study of Hg(II) interaction with three different α-aminophosphonate adsorbents: Insights from batch experiments and theoretical calculations

Chemosphere. 2022 Oct:304:135253. doi: 10.1016/j.chemosphere.2022.135253. Epub 2022 Jun 10.

Authors

Affiliations

¹ Chemical Engineering Department, Higher Institute of Engineering and Technology, El-Bagor City, Menofia, Egypt.
² Chemistry Department, Faculty of Science, Menoufia University, Shebin El-Kom, Egypt. Electronic address: ibrahimtantawy@yahoo.co.uk.
³ Gas Analysis and Fire Safety Laboratory, Chemistry Division, National Institute of Standards, 136, Giza, 12211, Egypt. Electronic address: nour.fathi@nis.sci.eg.
⁴ Chemistry Department, Faculty of Science, Menoufia University, Shebin El-Kom, Egypt.
⁵ Faculty of Specific Education, Ain Shams University, Abassia, Cairo, Egypt.
⁶ Nuclear Materials Authority, P.O. Box 530, El-Maadi, Cairo, Egypt.
⁷ Research Center for Advanced Materials Science (RCAMS), King Khalid University, P.O. Box 9004, Abha, 61413, Saudi Arabia; Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004, Abha, 61413, Saudi Arabia.
⁸ Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
⁹ Nuclear Materials Authority, P.O. Box 530, El-Maadi, Cairo, Egypt. Electronic address: galhoum_nma@yahoo.com.

PMID: 35697101
DOI: 10.1016/j.chemosphere.2022.135253

Abstract

Herein, efficient and potential chelating α-aminophosphonate based sorbents (AP-) derived from three different amine origins (aniline/anthranilic acid/O-phenylenediamine) to form AP-H, carboxylated and aminated enhanced aminophosphonate as AP-H, AP-COOH, and AP-NH₂ were synthesized via a facile method. The structure of the synthesized sorbents was elucidated using different techniques; elemental analysis (CHNP/O), FT-IR, NMR (¹H-, ¹³C and ³¹P NMR), TGA and BET. The fabricated sorbents were exploited for Hg(II) removal from aqueous solution via sorption properties. Isotherm fitted by Langmuir equation: the maximum sorption capacities at optimum pH 5.5, and T:25 ± 1 °C, were found to be 1.33, 1.23, and 1.15 mmol Hg g^-1 for AP-COOH, AP-NH₂, AP-H, respectively, which is roughly correlated with the active sites density and the hard/soft characteristics of adsorbents' reactive groups. Metal-ligand binding affinities are qualitatively rationalized in terms of hard and soft acids and bases (HSAB) theory. The interaction of Hg(II) (soft) has a stronger affinity to AP-COOH can be considered a softer base compared with reference material (AP-H) over than AP-NH₂ (hard). This sequence result showed opposite trends consistent with their reciprocal properties according to the steric effect modulates and the specific surface area. Thermodynamics analysis for absolute values of ΔH°, ΔS° and ΔG° afford the selectivity towards Hg(II) sorption with the following order: AP-COOH > AP-NH₂ >AP-H. Elution and regeneration was carried out by HCl solution and recycled for a minimum of five cycles, the sorption and desorption efficiencies are greater than 91%. Such sorbents exhibit good durability, stability and promising potential for Hg(II) removal. Finally, a new modelling technique for quantitative non-linear description and comparison of equivalent geographical positions in 3D space of extended relationships. Exothermic and spontaneous behavior were observed using a proposed Floatotherm that included the Van't Hoff parameters model.

Keywords: Complexation mechanism; Hg(II) ions; Selective sorption; XPS; α-aminophosphonate.

MeSH terms

Adsorption
Hydrogen-Ion Concentration
Kinetics
Mercury*
Spectroscopy, Fourier Transform Infrared
Thermodynamics
Water Purification* / methods

Substances

Mercury