Enhancement of Catalytic Activity on Crude Palm Oil Hydrocracking over SiO2/Zr Assisted with Potassium Hydrogen Phthalate.

In this study, the catalytic activity of bifunctional SiO2/Zr catalysts prepared by template and chelate methods using potassium hydrogen phthalate (KHF) for crude palm oil (CPO) hydrocracking to biofuels was investigated. The parent catalyst was successfully prepared by the sol-gel method, followed by the impregnation of zirconium using ZrOCl2·8H2O as a precursor. The morphological, structural, and textural properties of the catalysts were examined using several techniques, including electron microscopy energy-dispersive X-ray with mapping, transmission electron microscopy, X-ray diffraction, particle size analyzer (PSA), N2 adsorption-desorption, Fourier transform infrared-pyridine, and total and surface acidity analysis using the gravimetric method. The results showed that the physicochemical properties of SiO2/Zr were affected by different preparation methods. The template method assisted by KHF (SiO2/Zr-KHF2 and SiO2-KHF catalysts) provides a porous structure and high catalyst acidity. The catalyst prepared by the chelate method assisted by KHF (SiO2/Zr-KHF1) exhibited excellent Zr dispersion toward the SiO2 surface. The modification remarkably enhanced the catalytic activity of the parent catalyst in the order SiO2/Zr-KHF2 > SiO2/Zr-KHF1 > SiO2/Zr > SiO2-KHF > SiO2, with sufficient CPO conversion. The modified catalysts also suppressed coke formation and resulted in a high liquid yield. The catalyst features of SiO2/Zr-KHF1 promoted high-selectivity biofuel toward biogasoline, whereas SiO2/Zr-KHF2 led to an increase in the selectivity toward biojet. Reusability studies showed that the prepared catalysts were adequately stable over three consecutive runs for CPO conversion. Overall, SiO2/Zr prepared by the template method assisted by KHF was chosen as the most prominent catalyst for CPO hydrocracking.

Enhanced Isopropyl Alcohol Conversion over Acidic Nickel Phosphate-Supported Zeolite Catalysts.

In this preliminary research, the catalytic activity of isopropyl alcohol conversion to diisopropyl ether through dehydration reaction catalyzed by zeolite-Ni and zeolite-Ni(H2PO4)2 was comparatively described. The natural zeolite was treated with 1% HF and 6 N HCl prior to modifications using the impregnation method. Isopropyl alcohol conversion was examined at a mild temperature of 150 °C for 3.5 h on the reflux system with various catalyst loadings. X-ray diffraction and Fourier transform infrared analysis confirmed the successful impregnation of nickel and nickel phosphate into the zeolite. Scanning electron microscopy analysis revealed a cubic-like structure on zeolite-Ni(H2PO4)2, whereas homogenously distributed nickel species were observed on the zeolite-Ni catalyst. Energy-dispersive X-ray spectroscopy analysis reinforced the accomplishment of zeolite modifications. The N2 physisorption isotherms showed a decline in the surface area and total pore volume of the zeolite because of the blocking of pores. The zeolite-Ni(H2PO4)2 catalyst had higher acidity than unmodified zeolite and zeolite-Ni catalysts, which inherently suggested that the presence of phosphate groups results in higher catalytic activity toward isopropyl alcohol. The highest catalytic activity was attained by 8 mEq/g metal loading zeolite-Ni(H2PO4)2 with isopropyl alcohol conversion of 81.51%, diisopropyl ether yield, and selectivity of 40.77 and 33.16%. The reusability study suggested that the zeolite-Ni(H2PO4)2 catalyst was still active and had sufficient catalytic activity stability toward isopropyl alcohol after the third cycle was reused. This nickel phosphate-based modified zeolite was adequately potential for diisopropyl ether production through isopropyl alcohol dehydration.

Hydrocracking of crude palm oil to a biofuel using zirconium nitride and zirconium phosphide-modified bentonite.

In this study, bentonite modified by zirconium nitride (ZrN) and zirconium phosphide (ZrP) catalysts was studied in the hydrocracking of crude palm oil to biofuels. The study demonstrated that bentonite was propitiously modified by ZrN and ZrP, as assessed by XRD, FTIR spectroscopy, and SEM-EDX analysis. The acidity of the bentonite catalyst was remarkably enhanced by ZrN and ZrP, and it showed an increased intensity in the Lewis acid and Brønsted acid sites, as presented by pyridine FTIR. In the hydrocracking application, the highest conversion was achieved by bentonite-ZrN at 8 mEq g-1 catalyst loading of 87.93%, whereas bentonite-ZrP at 10 mEq g-1 showed 86.04% conversion, which suggested that there was a strong positive correlation between the catalyst acidity and the conversion under a particular condition. The biofuel distribution fraction showed that both the catalysts produced a high bio-kerosene fraction, followed by bio-gasoline and oil fuel fractions. The reusability study revealed that both the catalysts had sufficient conversion stability of CPO through the hydrocracking reaction up to four consecutive runs with a low decrease in the catalyst activity. Overall, bentonite-ZrN dominantly favored the hydrocracking of CPO than bentonite-ZrP.

Hydrocracking optimization of palm oil to bio-gasoline and bio-aviation fuels using molybdenum nitride-bentonite catalyst.

In this study, molybdenum nitride-bentonite was successfully employed for the reaction of hydrocracking of palm oil to produce a bio-gasoline and bio-aviation fuel. The prepared catalyst was characterized using XRD, FT-IR, and SEM-EDX. The acidity of the catalyst was determined using the pyridine gravimetric method. The result showed that the acidity of bentonite was increased after modification using molybdenum nitride. The hydrocracking study showed that the highest conversion and product fraction of bio-gasoline and bio-aviation fuel were exhibited by molybdenum nitride-bentonite 8 mEq g-1. The catalyst was later used to optimize the hydrocracking process using RSM-CCD. The effects of the process variables such as temperature, contact time, and catalyst to feed ratio, on the response variables, such as conversion, oil, gas, and coke yield, were investigated. The analysis of variance showed that the proposed quadratic model was statistically significant with adequate precision to estimate the responses. The optimum conditions in the hydrocracking process were achieved at a temperature of 731.94 K, contact time of 0.12 h, and a catalyst to feed ratio of 0.12 w/v with a conversion of 78.33%, an oil yield of 50.32%, gas yield of 44.00% and coke yield of 5.73%. The RSM-CCD was demonstrated as a suitable method for estimating the hydrocracking process of palm oil using a MoN-bentonite catalyst due to its closeness to the optimal value of the expected yield. This study provided a potential catalyst of based on bentonite modified using molybdenum nitride for the hydrocracking of palm oil.

SnO2-Fe3O4 nanocomposites for the photodegradation of the Congo red dye.

Synthesis of SnO2-Fe3O4 nanocomposites was conducted. The purpose of this study was to obtain the SnO2-Fe3O4 nanocomposites, the effectiveness of photodegradation Congo red by SnO2-Fe3O4 nanocomposites and determine the kinetics of photodegradation. The XRD analysis showed that the SnO2-Fe3O4 nanocomposite best mass ratio was 1:1 based on the highest intensity of characteristic angle (2θ), which is 26.54° and had the smallest crystal size, which is 9.662 nm. Based on the UV-Vis DRS result, the SnO2-Fe3O4 nanocomposites bandgap value was 2.3 eV. The magnetization saturation value of SnO2-Fe3O4 nanocomposites was 64.96 emu/g. The morphology of SnO2-Fe3O4 nanocomposites showed by the TEM image, where the dark spots spread in the lighter areas. The surface of SnO2-Fe3O4 nanocomposites characterized by SEM with the result was bumpy surface and many pores. The EDS result of SnO2-Fe3O4 nanocomposites confirmed the presence of Fe, Sn, and O elements. The functional group of SnO2-Fe3O4 nanocomposites showed by FTIR data, the stretch band of Sn-O characteristics showed at wavenumber 590 cm-1, and the stretch band of Fe-O showed at wavenumber 563 cm-1. The optimum condition of nanocomposites at a contact time of 90 min and the optimum concentration of 18 mg/L showed that the percent of photodegradation was 50.76%. The photodegradation rate of SnO2-Fe3O4 was fitted to Pseudo-second-order.

Tracheostomy dislodgement: Are obese patients at increased risk?

BACKGROUND: Obesity is a risk factor for tracheostomy-related complications. We aimed to investigate whether obesity was associated with a risk of unplanned tracheostomy dislodgement or decannulation (DD). METHODS: Retrospective review of patients undergoing tracheostomy at a single institution from 2013 to 2019 was performed. The primary outcome was unplanned DD within 42 days. Obesity was assessed by body mass index (BMI) and skin-to-trachea distance (STT) measured on computed tomographic images. RESULTS: 25 (12%) episodes of unplanned DD occurred in 213 patients within 42 days. BMI ≥35 kg/m2 was associated with STT ≥80 mm (p < 0.0001). On multivariate analysis, STT ≥80 mm but not BMI was an independent predictor of unplanned DD (hazard ratio = 8.34 [95% confidence interval 2.85-24.4]). CONCLUSIONS: STT ≥80 mm was a better predictor of unplanned DD than BMI. Assessment of STT in addition to BMI may be useful to identify patients that would benefit from extended length tracheostomy tubes.