TY - JOUR
T1 - Efficient removal of silver ions from wastewater via chelation with dithiooxamide-functionalized polymeric adsorbent
AU - Al-Bogami, Abdullah S.
AU - Akhdhar, Abdullah
AU - Tolan, Dina A.
AU - Ismael, Mohamed H.
AU - Elshehy, Emad A.
AU - El-Said, Waleed A.
N1 - Publisher Copyright:
© 2025 Al-Bogami et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2025/12
Y1 - 2025/12
N2 - This study investigates Ag(I) adsorption on a dithiooxamide/glutaraldehyde resin (DTG-R) using both experimental and theoretical approaches. Characterization confirmed the resin’s porous structure and sulfur/nitrogen active sites. Batch experiments revealed high Langmuir capacity (27.2 mmol/g at 25°C), with kinetics following a pseudo-second-order model (R2>0.99), indicating chemisorption. Thermodynamic analysis showed endothermic (ΔH°=121.25 kJ/mol), spontaneous adsorption (ΔG°= −12.8 to −17.3 kJ/mol), driven by entropy gains (ΔS°=449.9 J/mol.K) from Ag(I) dehydration and polymer swelling. DFT calculations demonstrated preferential Ag(I) binding to deprotonated sulfur (S–Ag: 2.50–2.60 Å, bond order: 0.76–0.86) over nitrogen, with mononuclear complexes being most stable (ΔE= −175.6 kcal/mol). The resin exhibited high selectivity, reusability of 96% efficiency over five cycles, and optimal performance at pH 5.75. NBO analysis revealed charge transfer to Ag(I) (partial charge less than +1), while binding energy trends explained the observed temperature-dependent capacity. DTG-R combined high capacity, rapid kinetics, and molecular-level affinity for Ag(I) make it better than existing adsorbents for industrial wastewater remediation. This work bridges macroscopic adsorption properties with quantum-chemical mechanisms, offering a template for rational adsorbent design.
AB - This study investigates Ag(I) adsorption on a dithiooxamide/glutaraldehyde resin (DTG-R) using both experimental and theoretical approaches. Characterization confirmed the resin’s porous structure and sulfur/nitrogen active sites. Batch experiments revealed high Langmuir capacity (27.2 mmol/g at 25°C), with kinetics following a pseudo-second-order model (R2>0.99), indicating chemisorption. Thermodynamic analysis showed endothermic (ΔH°=121.25 kJ/mol), spontaneous adsorption (ΔG°= −12.8 to −17.3 kJ/mol), driven by entropy gains (ΔS°=449.9 J/mol.K) from Ag(I) dehydration and polymer swelling. DFT calculations demonstrated preferential Ag(I) binding to deprotonated sulfur (S–Ag: 2.50–2.60 Å, bond order: 0.76–0.86) over nitrogen, with mononuclear complexes being most stable (ΔE= −175.6 kcal/mol). The resin exhibited high selectivity, reusability of 96% efficiency over five cycles, and optimal performance at pH 5.75. NBO analysis revealed charge transfer to Ag(I) (partial charge less than +1), while binding energy trends explained the observed temperature-dependent capacity. DTG-R combined high capacity, rapid kinetics, and molecular-level affinity for Ag(I) make it better than existing adsorbents for industrial wastewater remediation. This work bridges macroscopic adsorption properties with quantum-chemical mechanisms, offering a template for rational adsorbent design.
UR - https://www.scopus.com/pages/publications/105026416359
U2 - 10.1371/journal.pone.0338510
DO - 10.1371/journal.pone.0338510
M3 - Article
C2 - 41474712
AN - SCOPUS:105026416359
SN - 1932-6203
VL - 20
JO - PLoS ONE
JF - PLoS ONE
IS - 12 December
M1 - e0338510
ER -