The growing population is increasing the demand for clean, potable water, making effective wastewater treatment essential. Water pollution, particularly from industrial discharges and agricultural runoff, introduces heavy metals such as arsenic, lead, and cadmium, which are harmful in large amounts [1,2]. This project aims to develop innovative, cost-effective and sustainable organic-inorganic composite materials for the selective removal of toxic heavy metals—specifically arsenic (As V), thallium (Tl I), selenium (Se IV), and antimony (Sb V)—from contaminated water. Emphasis is placed on assessing the adsorption performance of different microporous materials, including both natural and synthetic zeolites (clinoptilolite, 13X, ferrierite, beta, and L-type zeolites), alongside the metal-organic framework ZIF-8. Under same laboratory conditions (pH, stirring time, temperature, adsorbent material concentration, and metal concentration), all tested materials exhibited adsorption capabilities, as confirmed by thermal analysis and X-Ray Diffraction (XRD). Adsorption capacity was evaluated using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), while thermal analysis (TG, DTA) and X-ray Powder Diffraction (XRD) provided structural insights into the interaction between the adsorbents and the targeted metal ions. Among the tested materials, calcined Beta-25 (Zeolyst - CP814E) and calcined Ferrierite (Zeolyst - CP914C) demonstrated superior efficiency in removing all four metals [3]. ZIF-8, characterized by its exceptionally high surface area (1300–1800 m²/g), was also evaluated. It showed notable adsorption capacities of ~65% for arsenic and ~25% for selenium, though its performance was comparatively lower for thallium and antimony. Post-adsorption structural refinements of metal-loaded zeolites revealed significant variations in lattice parameters and extraframework composition, confirming the immobilization of contaminants within the microporous networks. The presence and distribution of metal species were further corroborated by distinct thermal phenomena observed in DTA curves, attributed to differences in the type and concentration of extraframework species residing within the zeolite channels. Future work will involve in-depth optimization of key operational parameters—such as pH, temperature, solid-to-liquid ratio, and initial metal concentration—as well as the evaluation of these materials under real fluid conditions to assess competitive adsorption and long-term stability. [1] Shah, M. P. Chemistry in the Environment Series No. 5 Biological Treatment of Industrial Wastewater Edited. 2022. [2] Jian, M.; Liu, B.; Zhang, G.; Liu, R.; & Zhang, X. Colloids Surf. A Physicochem. Eng. Asp., 2015 465, 67–76. [3] Pasti, L.; Sarti, E.; Cavazzini, A.; Marchetti, N.; Dondi, F.; & Martucci, A. J SEP SCI 2013, 36(9–10), 1604–1611.
STRUCTURAL INSIGHTS INTO THE ADSORPTION OF HEAVY METALS (As, Tl, Se, and Sb) BY MICROPOROUS ADSORBENTS: A STUDY OF ZEOLITES AND METAL-ORGANIC FRAMEWORKS
Luca Adami
;Maura Mancinelli;Giacomo Ferretti;Annalisa Martucci
2025
Abstract
The growing population is increasing the demand for clean, potable water, making effective wastewater treatment essential. Water pollution, particularly from industrial discharges and agricultural runoff, introduces heavy metals such as arsenic, lead, and cadmium, which are harmful in large amounts [1,2]. This project aims to develop innovative, cost-effective and sustainable organic-inorganic composite materials for the selective removal of toxic heavy metals—specifically arsenic (As V), thallium (Tl I), selenium (Se IV), and antimony (Sb V)—from contaminated water. Emphasis is placed on assessing the adsorption performance of different microporous materials, including both natural and synthetic zeolites (clinoptilolite, 13X, ferrierite, beta, and L-type zeolites), alongside the metal-organic framework ZIF-8. Under same laboratory conditions (pH, stirring time, temperature, adsorbent material concentration, and metal concentration), all tested materials exhibited adsorption capabilities, as confirmed by thermal analysis and X-Ray Diffraction (XRD). Adsorption capacity was evaluated using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), while thermal analysis (TG, DTA) and X-ray Powder Diffraction (XRD) provided structural insights into the interaction between the adsorbents and the targeted metal ions. Among the tested materials, calcined Beta-25 (Zeolyst - CP814E) and calcined Ferrierite (Zeolyst - CP914C) demonstrated superior efficiency in removing all four metals [3]. ZIF-8, characterized by its exceptionally high surface area (1300–1800 m²/g), was also evaluated. It showed notable adsorption capacities of ~65% for arsenic and ~25% for selenium, though its performance was comparatively lower for thallium and antimony. Post-adsorption structural refinements of metal-loaded zeolites revealed significant variations in lattice parameters and extraframework composition, confirming the immobilization of contaminants within the microporous networks. The presence and distribution of metal species were further corroborated by distinct thermal phenomena observed in DTA curves, attributed to differences in the type and concentration of extraframework species residing within the zeolite channels. Future work will involve in-depth optimization of key operational parameters—such as pH, temperature, solid-to-liquid ratio, and initial metal concentration—as well as the evaluation of these materials under real fluid conditions to assess competitive adsorption and long-term stability. [1] Shah, M. P. Chemistry in the Environment Series No. 5 Biological Treatment of Industrial Wastewater Edited. 2022. [2] Jian, M.; Liu, B.; Zhang, G.; Liu, R.; & Zhang, X. Colloids Surf. A Physicochem. Eng. Asp., 2015 465, 67–76. [3] Pasti, L.; Sarti, E.; Cavazzini, A.; Marchetti, N.; Dondi, F.; & Martucci, A. J SEP SCI 2013, 36(9–10), 1604–1611.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
