Weaving Gallium-Sulfide Clusters with Antimony Bridges into an Open-Framework for Ni²⁺ Adsorption

Area of Science:

• Materials Science
• Environmental Chemistry
• Inorganic Chemistry

Background:

• Radioactive wastewater poses significant environmental and safety risks.
• Existing ion exchangers struggle with stability and selectivity for removing heavy metals like Ni²⁺.
• Developing advanced materials is crucial for effective radionuclide removal.

Purpose of the Study:

• To synthesize and characterize a novel open-framework gallium-antimony sulfide, GaSbS-2K.
• To evaluate the efficiency of GaSbS-2K for Ni²⁺ removal from wastewater.
• To assess the material's stability, selectivity, and applicability in continuous-flow systems.

Main Methods:

• Synthesis of K_3.6[NH₄]_0.1[CH₃NH₃]_0.3Ga₄SbS₉SH·0.9H₂O (GaSbS-2K) with a unique framework structure.
• Adsorption experiments to determine Ni²⁺ uptake kinetics, capacity, and selectivity.
• Stability tests across a wide pH range and in the presence of competing ions.
• Fabrication and testing of GaSbS-2K/PTFE composite membranes for continuous-flow applications.

Main Results:

• GaSbS-2K demonstrated rapid Ni²⁺ adsorption, reaching 97.54% removal at equilibrium.
• The material exhibited a high adsorption capacity of 90.78 ± 2.74 mg/g and maintained stability from pH 3-12.
• GaSbS-2K showed strong selectivity for Ni²⁺, even in seawater, and achieved >99% removal in continuous-flow systems.
• A GaSbS-2K/PTFE membrane completely removed Ni²⁺ with a short contact time (0.25 s).

Conclusions:

• GaSbS-2K is a highly efficient and stable adsorbent for Ni²⁺ removal from wastewater.
• Its rapid kinetics and selectivity make it suitable for continuous-flow treatment processes.
• The material's properties suggest its potential for practical applications in radioactive wastewater management.