Search

Zeolitic octahedral metal oxide is a newly synthesized all‐inorganic zeolitic material and has been used for adsorption, separation, and catalysis. Herein, a new zeolitic octahedral metal oxide was synthesized and characterized. The porous framework was established through the assembly of [P2Mo13O50] clusters with PO4 linkers. Guest molecules occupied the framework, which could be removed through heat treatment, thereby opening the micropores. The pore characteristics were controlled by the cations within the micropore, enabling the adjustment of the interactions with alkynes and alkenes. This resulted in good separation performance of ethylene/acetylene and propylene/propyne even under high temperature and humidity conditions. The high stability of the material enabled the efficient recovery and reuse without discernible loss in the separation performance. Due to the relatively weak interaction between the adsorbed alkyne and the framework, the adsorbent facilitated the recovery of a highly pure alkyne. This feature enhances the practical applicability of the material in various industrial processes. [ABSTRACT FROM AUTHOR]

The potassium and proton mixed salt of mono-Nb substituted Keggin-type phosphomolybdate, KH3[PMo11NbO40], was isolated in a pure form by reacting Keggin-type phosphomolybdic acid (H3[PMo12O40]) and potassium hexaniobate (K8Nb6O19) in water, followed by freeze-drying. The all protonic form, H4[PMo11NbO40], was isolated via proton exchange with H-resin and subsequent freeze-drying. The most crucial factor to isolate KH3[PMo11NbO40] and H4[PMo11NbO40] in pure forms is the evaporation of water using the freeze-drying method. Using a similar procedure, the potassium salt of the di-Nb substituted compound K5[PMo10Nb2O40] was isolated. H4[PMo11NbO40] exhibited high catalytic activity for oxidizing isobutylaldehyde to methacrolein and moderate catalytic activity for the Wacker-type oxidation of allyl phenyl ether when combined with Pd(OAc)2. [ABSTRACT FROM AUTHOR]

Zeolitic octahedral metal oxides based on vanadotungstate have shown great potential in gas separation. The microporosity of these materials is highly dependent on their structure and composition, allowing for precise tuning of their separation performance. In this study, zeolitic vanadotungstate is utilized for the separation of ethylene and ethane. The choice of cation is found to significantly impact the separation performance of the material. Specifically, the material with only Cu as the cation exhibits differentiated adsorption performance for ethylene and ethane, with high theoretical selectivity. Breakthrough experiments demonstrate that the Cu‐based material is able to effectively separate ethylene and ethane even at high temperature and humidity levels. Furthermore, the material exhibits excellent stability and is able to be reused without any loss in separation performance. [ABSTRACT FROM AUTHOR]

Cellulosic bioethanol produced from wood is a candidate for alternative fuel to fossil fuels. In the cellulosic ethanol production process, pretreatment before enzymatic saccharification should be introduced for acceleration of the process. We proposed a new pretreatment technique for the cleavage of inter-cellulose hydrogen bonds by underwater discharge shock waves. In this study, we quantitatively analyzed the relationship among discharge conditions, shock wave properties, and treatment efficiency to estimate the optimal treatment conditions. The shock wave pressure was measured at several MPa, and optical microscopy results suggested wood flour fragmentation. The relationship between the discharge characteristics and the treatment effect was investigated by measuring the water retention value as an indicator of hydrogen bond cleavage and the amount of glucose as bioethanol intermediate products. The discharge energy of 0.85–1.16 J/pulse did not affect the treatment effect, while an increased discharge frequency in the range of 3.3–7.3 Hz did. The independence of treatment effect on the discharge energy was investigated to arise from the saturation in the discharge-current rising rate and shock-wave pressure. [ABSTRACT FROM AUTHOR]

Background: Serrated polyps have recently been reported in patients with ulcerative colitis (UC); however, their prevalence and detailed characteristics remain unclear. Methods: The prevalence and clinicopathological and biological characteristics of serrated polyps in patients with UC were retrospectively examined in a single tertiary inflammatory bowel disease center in Japan from 2000 to 2020. Results: Among 2035 patients with UC who underwent total colonoscopy, 252 neoplasms, including 36 serrated polyps (26 in colitis-affected segments, 10 in colitis-unaffected segments), were identified in 187 patients with UC. The proportion of serrated polyps was 1.8% (36/2035). Serrated polyps in colitis-affected segments were common with extensive colitis (88%), history of persistent active colitis (58%), and long UC duration (12.1 years). Serrated polyps in colitis-affected segments were more common in men (88%). Of the 26 serrated polyps in colitis-affected segments, 15, 6, and 5 were categorized as sessile serrated lesion-like dysplasia, traditional serrated adenoma-like dysplasia, and serrated dysplasia not otherwise specified, respectively. Sessile serrated lesion-like dysplasia was common in the proximal colon (67%) and with BRAF mutation (62%), whereas traditional serrated adenoma-like dysplasia and serrated dysplasia not otherwise specified were common in the distal colon (100% and 80%, respectively) and with KRAS mutations (100% and 75%, respectively). Conclusions: Serrated polyps comprised 14% of the neoplasias in patients with UC. Serrated polyps in colitis-affected segments were common in men with extensive and longstanding colitis, suggesting chronic inflammation in the development of serrated polyps in patients with UC. [ABSTRACT FROM AUTHOR]

River water degradation arising from wastewater effluents is a major factor contributing to the deterioration of river ecosystems; yet direct evidence of the beneficial influence of long-term sewerage development on such ecosystems is scarce at a basin scale. The present study, over 12 years, examined changes in sewerage connection rate, water quality, and invertebrate assemblages at 10 study sites in the Shigenobu River, southwestern Japan, and investigated the relationships between them. Sewerage connection rates increased in the three main municipalities in the basin during the study period (range: 8.6%–31.4%). At the lowland sites, the concentration of total inorganic nitrogen (TIN) decreased by 38.9% on average and the richness metrics of invertebrate assemblages significantly increased at several sites. Furthermore, the richness metrics negatively related with TIN concentration, implying that invertebrate diversity recovery was the result of water quality improvement. Our findings strongly suggest that sewerage system improvement is an effective measure for restoring river ecosystems. [ABSTRACT FROM AUTHOR]

Separation of CO2/C2H2 to obtain pure C2H2 presents a challenge for the chemical industry. CO2‐selective adsorbents are favored because of the convenient separation process. However, there are only a few CO2‐selective adsorbents that can effectively isolate CO2 from CO2/C2H2, and there is almost no research on CO2/C2H2 separation under harsh conditions, such as with high temperatures and humidities. Herein, a zeolitic octahedral metal oxide based on ϵ‐Keggin polyoxometalates is utilized for separations of CO2/C2H2 at high temperatures and humidities. Single gas adsorption measurements show that the material only adsorbs CO2 with almost no C2H2 taken up. Dynamic competitive adsorption experiments show that the material efficiently separates CO2/C2H2, and highly pure C2H2 is obtained directly. The robust material maintains a high separation performance at 333 K with 18.12 % water. The high stability of the material enables reuse without loss of separation performance. [ABSTRACT FROM AUTHOR]