Concentration–composition-isotherm for the ammonia absorption process of zirconium phosphate

Yamaguchi, Masakuni; Miyaoka, Hiroki; Kojima, Yoshitsugu

doi:10.1039/d0ra03817b

Cited by 8 publications

(21 citation statements)

References 7 publications

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“…It has been reported that the interlayer distance of Zr(HPO 4 ) 2 ·H 2 O is similar to that of Zr(NH 4 PO 4 )(HPO 4 )·H 2 O 14 as shown in Table S1 . When ammonia is absorbed above 1.0 mol(NH 3 )/mol[Zr(HPO 4 ) 2 ·H 2 O], the interlayer distance changes, which probably caused a change in the ammonia absorption rate.…”

Section: Resultsmentioning

confidence: 54%

“… (a) TG curves of Zr(NH 4 PO 4 ) 2 ·H 2 O (black line), 14 HTS473K (red line), and HTS673K (blue line) and (b,c) mass spectra at m / z 18 and 17 of desorption gas from Zr(NH 4 PO 4 ) 2 ·H 2 O (black line), 14 HTS473K (red line), and HTS673K (blue line) in a flowing Ar gas (300 cm 3 /min) with a heating rate of 5 K/min. …”

Section: Resultsmentioning

confidence: 99%

“…), respectively. 14 0.5 g of each sample was added to the solution, and the NH 3 concentration and pH were continuously measured at regular time intervals. Here, ammonia has two kinds of forms which are NH 3 and NH 4 + in ammonia water.…”

Section: Methodsmentioning

confidence: 99%

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Regeneration Process of Ammonia-Absorbed Zirconium Phosphate to Zirconium Phosphate

2022

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Zirconium phosphate [Zr(HPO 4 ) 2 ·H 2 O] absorbs 2 mol(NH 3 )/mol[Zr(HPO 4 ) 2 ·H 2 O] with a low equilibrium plateau ammonia concentration of around 1 ppm in water. In this study, in order to investigate the regeneration process of ammonia-absorbed zirconium phosphate [Zr(NH 4 PO 4 ) 2 ·H 2 O], Zr(NH 4 PO 4 ) 2 ·H 2 O was heat-treated above 353 K under an inert gas. Then, the structures of the heat-treated samples were evaluated using powder X-ray diffraction and thermogravimetry–mass spectrometry measurements. Zr(NH 4 PO 4 ) 2 ·H 2 O started to desorb ammonia and the crystal water at 353 K. Then, Zr(NH 4 PO 4 ) 2 ·H 2 O was changed to the anhydrous monoammoniate [Zr(NH 4 PO 4 )(HPO 4 )] at 473 K and formed anhydrous zirconium phosphate [Zr(HPO 4 ) 2 ] at 673 K. The anhydrous zirconium phosphate and the anhydrous monoammoniate reabsorbed ammonia in ammonia water. Those initial absorption rates were small compared with Zr(HPO 4 ) 2 ·H 2 O. The slow kinetics of the anhydrous zirconium phosphate corresponded to the small interlayer distances. The ammonia concentration composition isotherms indicated that the anhydrous zirconium phosphate and anhydrous monoammoniate have a low ammonia equilibrium plateau concentration of around 1 ppm in ammonia water. Zr(NH 4 PO 4 ) 2 ·H 2 O is formed from Zr(NH 4 PO 4 )(HPO 4 ) by the reabsorption of ammonia and water after 1–10 cycles. We found that zirconium phosphate is an ammonia remover which can be used repeatedly at 473 K.

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Section: Resultsmentioning

confidence: 54%

Section: Resultsmentioning

confidence: 99%

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Regeneration Process of Ammonia-Absorbed Zirconium Phosphate to Zirconium Phosphate

2022

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“…The ammonia absorption process of zirconium phosphate has been studied using the concentration-composition-isotherm X-ray diffraction and thermogravimetry-mass spectrometry. It was clarified that the equilibrium plateau concentration appeared due to two-phase coexistence [ 59 ].…”

Section: Applications To Complexes and Compoundsmentioning

confidence: 99%

On-Line Thermally Induced Evolved Gas Analysis: An Update—Part 1: EGA-MS

et al. 2022

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Advances in on-line thermally induced evolved gas analysis (OLTI-EGA) have been systematically reported by our group to update their applications in several different fields and to provide useful starting references. The importance of an accurate interpretation of the thermally-induced reaction mechanism which involves the formation of gaseous species is necessary to obtain the characterization of the evolved products. In this review, applications of Evolved Gas Analysis (EGA) performed by on-line coupling heating devices to mass spectrometry (EGA-MS), are reported. Reported references clearly demonstrate that the characterization of the nature of volatile products released by a substance subjected to a controlled temperature program allows us to prove a supposed reaction or composition, either under isothermal or under heating conditions. Selected 2019, 2020, and 2021 references are collected and briefly described in this review.

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“…In our previous study, we have reported that α-zirconium phosphate (ZrP) , has a large ammonia absorption capacity compared with other proton-based materials such as zeolite, activated carbon (AC), and montmorillonite in the solid state in water . In recent years, Prussian blue (PB) type has been attracting attention as an ammonia adsorption material because of a large amount of ammonia adsorption. , Figure shows a comparison of the ammonia sorption of ZrP, Prussian blue analogues (PBAs), and conventional adsorbents in the low concentration of ammonia (under 10 ppm). ,, …”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and Spectroscopic Analyses of Zirconium Phosphate-Absorbed Ammonia

2021

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Zirconium phosphate is insoluble in water and has a large ammonia storage capacity with a low ammonia plateau concentration in water. In this study, the thermodynamics of ammonia on zirconium phosphate (ZrP) and the local structure such as the interaction between ammonia and ZrP have been investigated using the temperature dependence of ammonia concentration composition isotherm (CCI) measurements, 31 P magic angle spinning nuclear magnetic resonance ( 31 P MAS NMR), and Fourier transform infrared (FT-IR) spectroscopy. The standard enthalpy changes ΔH 0 of ZrP-absorbed ammonia (1 mol(NH 3 ) mol −1 (ZrP):ZrP-NH 3 and 2 mol(NH 3 ) mol −1 (ZrP):ZrP-2NH 3 ) were calculated to be ≤ −111 and −64 kJ mol −1 (NH 3 ), respectively. 31 P MAS NMR and FT-IR indicated that the local structures of ZrP-NH 3 and ZrP-2NH 3 were different. It was suggested that nitrogen in ammonia reacts with hydrogen in the phosphate group to form a N−H covalent bond in NH 4 + having hydrogen bonds, although the number of hydrogen bonds in ZrP-NH 3 was smaller than that in ZrP-2NH 3 .

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Concentration–composition-isotherm for the ammonia absorption process of zirconium phosphate

Abstract: Ammonia absorption process of zirconium phosphate has been studied by concentration–composition-isotherm, X-ray diffraction and thermogravimetry-mass spectrometry. The equilibrium plateau concentration appeared due to two phase coexistence.

Cited by 8 publications

References 7 publications

Regeneration Process of Ammonia-Absorbed Zirconium Phosphate to Zirconium Phosphate

Regeneration Process of Ammonia-Absorbed Zirconium Phosphate to Zirconium Phosphate

On-Line Thermally Induced Evolved Gas Analysis: An Update—Part 1: EGA-MS

Thermodynamic and Spectroscopic Analyses of Zirconium Phosphate-Absorbed Ammonia

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