Exceptional High and Reversible Ammonia Uptake by Two Dimension Few-layer BiI₃ Nanosheets

Abstract

The emission of NH3 into atmosphere is seriously harmful for human health and public safety, thus the capture and recovery of NH3 from ammonia emissions is highly desirable. In recent years, many kinds of solid adsorbents have been exploited to absorb NH3. However, these materials do not show the advantages of high uptake capacity and good recyclability at the same time. Here, nontoxic and low cost few-layer BiI3 nanosheets have been prepared from bulk BiI3 powder by a simple and efficient liquid phase exfoliation strategy using green solvents and then applied for the NH3 capture for the first time. The results show that the adsorption capacity of NH3 of BiI3 nanosheets reaches up to 22.6 mmol/g at 1.0 bar and 25 °C, which approaches the record value for NH3 adsorption. Importantly, the NH3 uptake in BiI3 nanosheets is completely reversible and no clear loss in uptake capacity is observed after 10 cycles of adsorption–desorption. Furthermore, the BiI3 nanosheets exhibit remarkable selectivity for the separation of NH3/CO2 at 70 °C with theoretical selectivity coefficient of 700, which is promising for the selective separation of NH3 and CO2 in hot tail gas of some industrial processes. Mechanism studies indicate that such superior NH3 capacity, excellent reversibility and remarkable selectivity are primarily attributed to the Bi3+-NH3 coordination interactions.

RETRACTED: Electrospun Ta-MOF/PEBA Nanohybrids and Their CH4 Adsorption Application

“…As shown in this fig., the nanoparticles are well-immobilized in the network structure, which indicates effective combining of the Ta-MOF and fibrous structures. Also, the morphology of the samples is uniform, which confirms the effective effects of the synthesis route ( Bai et al, 2021a ; Bai et al, 2021b ; Wang et al, 2021 ). EDS elemental analysis showed the distribution of related elements of Ta-MOF/PEBA nanostructures in the fibrous network.…”

High Gravimetric and Volumetric Ammonia Capacities in Robust Metal–Organic Frameworks Prepared via Double Postsynthetic Modification

“…The ammonia uptake of the postsynthetic modified frameworks at 1 bar was significant: 13.09 mmol g –1 for Ni_acrylate, 17.41 mmol g –1 for Ni_acryl_TGA, and 23.54 mmol g –1 for Ni_acrly_TMA. Remarkably, the gravimetric ammonia capacity of Ni_acryl_TMA at 1 bar and 298 K was comparable to those observed for top-performing MOFs, IL@MOF (24.12 mmol g –1 ) and Mg 2 (dobpdc) (23.90 mmol g –1 ), and superior to that of most state-of-the-art ammonia adsorbents including BiI 3 nanosheet (22.6 mmol g –1 ), CoHCC (21.9 mmol g –1 ), Ni 2 dobpdc (20.82 mmol g –1 ), CuHCF (20.2 mmol g –1 ), and Cu 2 Cl 2 BBTA (19.79 mmol g –1 ). The structures were fully retained before and after ammonia sorption, as confirmed by the PXRD patterns and IR spectra, while a slight reduction in the porosity was observed after ammonia sorption (Figures S19–S22 and Table S8).…”

Defects in a Metal–Organic Framework Fabricated by Carboxy-Functionalized Ionic Liquids for Enhancing NH3 Uptake

“…It can be seen that NH 3 adsorption is exothermic; and the defective UiO-66 shows a higher Q st value than the pristine UiO-66, and the Q st value increases with increasing degree of defects of the defective MOFs, indicating the presence of stronger intermolecular interactions with increasing degree of defects. 18 In addition, Q st is smaller than 40 kJ/mol in value, 51,52 which indicates that the NH 3 adsorption is physical in nature.…”