Enhanced mono-aromatics production by the CH4-assisted pyrolysis of microalgae using Zn-based HZSM-5 catalysts.

This study presents the catalytic pyrolysis of microalgae, Chlorella vulgaris (C. vulgaris), using pure CH4 and H2-rich gas evolved from CH4 decomposition on three different HZSM-5 catalysts loaded with Zn, Ga, and Pt, aimed specifically at producing high-value mono-aromatics such as benzene, toluene, ethylbenzene, and xylene (BTEX). In comparison with that for the typical inert N2 environment, a pure CH4 environment increased the bio-oil yield from 32.4 wt% to 37.4 wt% probably due to hydrogen and methyl radical insertion in the bio-oil components. Furthermore, the addition of bimetals further increased bio-oil yield. For example, ZnPtHZ led to a bio-oil yield of 47.7 wt% in pure CH4. ZnGaHZ resulted in the maximum BTEX yield (6.68 wt%), which could be explained by CH4 activation, co-aromatization, and hydrodeoxygenation. The BTEX yield could be further increased to 7.62 wt% when pyrolysis was conducted in H2-rich gas evolved from CH4 decomposition over ZnGaHZ, as rates of aromatization and hydrodeoxygenation were relatively high under this condition. This study experimentally validated that the combination of ZnGaHZ and CH4 decomposition synergistically increases BTEX production using C. vulgaris.

Hydrogen-rich gas production via steam gasification of food waste over basic oxides (MgO/CaO/SrO) promoted-Ni/Al2O3 catalysts.

Food waste, a renewable resource, was converted to H2-rich gas via a catalytic steam gasification process. The effects of basic oxides (MgO, CaO, and SrO) with 10 wt% Ni/Al2O3 on the gasification properties of food waste were investigated using a U-shaped gasifier. All catalysts prepared by the precipitation method were analyzed by X-ray diffraction, H2-temperature-programmed reduction, NH3-temperature-programmed desorption, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The Ni/Al2O3 catalyst was reduced incompletely, and low nickel concentrations were detected on the surface of the alumina. The basic oxides minimized the number of acid sites and suppressed the formation of nickel-aluminate (NiAlxOy) phase in catalyst. In addition, the basic oxides shifted nickel-aluminate reduction reaction to lower temperatures. It resulted in enhancing nickel concentration on the catalyst surface and increasing gas yield and hydrogen selectivity. The low gas yield of the Ni/Al2O3 catalyst was attributed to the low nickel concentration on the surface. The maximum gas yield (66.0 wt%) and hydrogen selectivity (63.8 vol%) of the 10 wt% SrO- 10 wt% Ni/Al2O3 catalyst correlated with the highly dispersed nickel on the surface and low acidity. Furthermore, coke deposition during steam gasification varied with the surface acidity of the catalysts and less coke was formed on 10 wt% SrO- 10 wt% Ni/Al2O3 due to efficient tar cracking. This study showed that the steam gasification efficiency of the Ni/Al2O3 catalyst could be improved significantly by the addition of SrO.

Influence of sawdust addition on the toxic effects of cadmium and copper oxide nanoparticles on Vigna radiata seeds.

Studies in the literature concern the toxicity of nanoparticles either in a Petri dish or in agar media-based tests. Therefore, for environmental relevance, individual and binary mixtures of metal oxide nanoparticles (M-NPs) cadmium oxide (CdO-NP) and copper oxide (CuO-NP) were tested in this study for their effect on Vigna radiata in soil with and without the addition of sawdust. Seed germination was 67% in 100 mg CuO-NP in soil without sawdust. Seeds failed to germinate in 100 mg CdO +100 mg CuO-NPs in soil without the addition of sawdust and germination was 83% at the same concentration in soil with sawdust. In sawdust added to soil, when compared with control (soil without M-NPs), the maximum reduction in shoot (82%) and root (80%) length and wet (61%) and dry (54%) weight of plant was recorded in CdO-NP treated soil. Similarly, compared with control (soil without sawdust and M-NPs), the percent reduction in shoot (61%) and root (70%) length and wet (44%) and dry (48%) weight was highest in CdO-NP treated soil not supplemented with sawdust. In a binary mixture test (CdO-NP + CuO-NP), the addition of sawdust promoted the above plant growth parameters compared with individual CdO-NP and CuO-NP tests. Cadmium (511 mg kg-1 for individual and 303 mg kg-1 for binary mixture tests) and Cu (953 mg kg-1 for individual and 2954 mg kg-1 for binary mixture tests) accumulation was higher in plants grown in soil without sawdust. The beneficial effect of sawdust addition was observed in seed germination, plant growth, and metal accumulation. With or without sawdust, the binary mixture of CdO and CuO was antagonistic. These results indicate that sawdust can prevent M-NP-induced toxicity and reduce metal accumulation in plant tissues.

Acid-treated waste red mud as an efficient catalyst for catalytic fast copyrolysis of lignin and polyproylene and ozone-catalytic conversion of toluene.

In this study, red mud (RM), a highly alkaline waste generated from alumina production industries, was used as a catalytic material for both fast copyrolysis of organosolv lignin (OL) and polypropylene (PP) and toluene removal under ozone at room temperature. The RM was pretreated with HCl to investigate the effect of alkalinity. In the catalytic fast copyrolysis of the OL and PP, the acid-treated RM (HRM) produced more aromatics, phenolics, and light olefins (C3 to C5) but less oxygenates and heavy olefins (C6 to C46) than the RM. The difference in pyrolytic performance between the RM and HRM was likely attributed to the concentrated Fe2O3 species in the HRM catalyst. In addition, more efficient toluene removal was observed over MnOx/HRM than over MnOx/RM owing to the large Brunauer-Emmett-Teller surface area, high amounts of Al and Fe, and optimal Mn3+/Mn4+ ratio. This study demonstrates that the RM, an industrial waste, can be reused as an effective catalytic material for not only biofuel production but also pollutant removal.

Direct conversion of NO and SO2 in flue gas into fertilizer using ammonia and ozone.

This study focused on the simultaneous removal of NO and SO2 from an industrial flue gas stream. To evaluate the removal efficiency of NO and SO2 using O3 and NH3, the consumption of two reactants (O3 and NH3) in line with the conversion of NO and SO2 was quantified experimentally. In addition, NO and SO2 were converted to valuable fertilizers, NH4NO3 and (NH4)2SO4. To identify a principle strategy to enhance the generation of fertilizer, Fourier transform infrared spectroscopy was used to examine the reaction mechanisms for the formation of NH4NO3 and (NH4)2SO4. Acceleration of SO2 oxidation could be achieved effectively by adding NO to a gas mixture of SO2, NH3, and O3. The formation of HNO3 might be enhanced by the simultaneous feeding of NO and SO2. Particle generation was also 10 times higher for NH3/(NO + SO2) than for NH3/NO and for NH3/SO2, which is a prominent feature of this study. Moreover, the introduction of steam had a positive influence on particle generation. This method offers dual applications for NO and SO2 removal from a flue gas stream and direct fertilizer generation.

Production of an upgraded lignin-derived bio-oil using the clay catalysts of bentonite and olivine and the spent FCC in a bench-scale fixed bed pyrolyzer.

Lignocellulosic biomass is an abundant renewable energy source that can be converted into various liquid fuels via thermochemical processes such as pyrolysis. Pyrolysis is a thermal decomposition method, in which solid biomass are thermally depolymerized to liquid fuel called bio-oil or pyrolysis oil. However, the low quality of pyrolysis oil caused by its high oxygen content necessitates further catalytic upgrading to increase the content of oxygen-free compounds, such as aromatic hydrocarbons. Among the three different types of lignocellulosic biomass components (hemicellulose, lignin, and cellulose), lignin is the most difficult fraction to be pyrolyzed because of its highly recalcitrant structure for depolymerization, forming a char as a main product. The catalytic conversion of lignin-derived pyrolyzates is also more difficult than that of furans and levoglucosan which are the main pyrolysis products of hemicellulose and cellulose. Hence, the main purpose of this study was to develop a bench-scale catalytic pyrolysis process using a tandem catalyst (both in-situ and ex-situ catalysis mode) for an efficient pyrolysis and subsequent upgrading of lignin components. While HZSM-5 was employed as an ex-situ catalyst for its excellent aromatization efficiency, the potential of the low-cost additives of bentonite, olivine, and spent FCC as in-situ catalysts in the Kraft lignin pyrolysis at 500 °C was investigated. The effects of these in-situ catalysts on the product selectivity were studied; bentonite resulted in higher selectivity to aromatic hydrocarbons compared to olivine and spent FCC. The reusability of HZSM-5 (with and without regeneration) was examined in the pyrolysis of lignin mixed with the in-situ catalysts of bentonite, olivine, and spent FCC. In the case of using bentonite and spent FCC as in-situ catalysts, there were no obvious changes in the activity of HZSM-5 after regeneration, whereas using olivine as in-situ catalyst resulted in a remarkable decrease in the activity of HZSM-5 after regeneration.

Long-Term Efficacy of Mirabegron Add-On Therapy to Antimuscarinic Agents in Patients With Spinal Cord Injury.

OBJECTIVE: To evaluate the long-term efficacy of mirabegron add-on therapy in patients with spinal cord injury (SCI) based on an urodynamic study. METHODS: This retrospective study involved a chart audit of individuals with SCI who underwent two consecutive urodynamic studies between April 1, 2015 and April 1, 2018. After adding 50 mg of mirabegron once a day to the pre-existing antimuscarinic therapy for a period of, at least 6 months, the following variables were analyzed: change in cystometric capacity, change in bladder compliance, change in maximal detrusor pressure, change in reflex volume, and presence of significant leakage during filling cystometry. RESULTS: A total of 31 participants with a mean age of 41±15 years were included in the analysis. A significant increase in cystometric capacity (mean, 362 to 424 mL; p=0.03), reflex volume (mean, 251 to 329 mL; p=0.02), and bladder compliance (median, 12 to 18 mL/cmH2O; p=0.04) was observed. The presence of leakage during filling cystometry was significantly reduced (29% to 10%; p=0.03). Likewise, a non-significant decrease in the change in maximal detrusor pressure was observed (mean, 31 to 27 cmH2O; p=0.39). CONCLUSION: Adding mirabegron to conventional antimuscarinics further improved urodynamic parameters in patients with chronic SCI, and sustained efficacy was observed in long-term use.

The effect of two different hand exercises on grip strength, forearm circumference, and vascular maturation in patients who underwent arteriovenous fistula surgery.

OBJECTIVE: To compare the effect of two different hand exercises on hand strength and vascular maturation in patients who underwent arteriovenous fistula surgery. METHODS: We recruited 18 patients who had chronic kidney disease and had undergone arteriovenous fistula surgery for hemodialysis. After the surgery, 10 subjects performed hand-squeezing exercise with GD Grip, and other 8 subjects used Soft Ball. The subjects continued the exercises for 4 weeks. The hand grip strength, pinch strength (tip, palmar and lateral pinch), and forearm circumference of the subjects were assessed before and after the hand-squeezing exercise. The cephalic vein size, blood flow velocity and volume were also measured by ultrasonography in the operated limb. RESULTS: All of the 3 types of pinch strengths, grip strength, and forearm circumference were significantly increased in the group using GD Grip. Cephalic vein size and blood flow volume were also significantly increased. However, blood flow velocity showed no difference after the exercise. The group using Soft Ball showed a significant increase in the tip and lateral pinch strength and forearm circumference. The cephalic vein size and blood flow volume were also significantly increased. On comparing the effect of the two different hand exercises, hand-squeezing exercise with GD Grip had a significantly better effect on the tip and palmar pinch strength than hand-squeezing exercise with Soft Ball. The effect on cephalic vein size was not significantly different between the two groups. CONCLUSION: The results showed that hand squeezing exercise with GD Grip was more effective in increasing the tip and palmar pinch strength compared to hand squeezing exercise with soft ball.