Journal of Chemical Technology and Biotechnology
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Evaluation of Ba‐promoted Mo carbide catalyst for Fischer–Tropsch synthesis Abstract Background Traditional FT catalysts such as Co and Fe still suffer from carbon‐induced deactivation even with alkali promotion. The objective of this study was to examine the effect of Ba addition to carbon‐tolerant Mo carbide since it has Pt‐like characteristics and is cheaper than noble metals as an FT catalyst .Results The presence of Ba increased the Mo carbide production rate and reduced the activation energy for its formation. The promoted catalyst exhibited higher specific basic site strength and CO2 uptake for strong basic site than that of the undoped catalyst. Both catalysts exhibited optimal reaction rate at a H2 mole fraction of 0.75 while CO consumption rate, total olefin‐to‐paraffin ratio, methane suppression as well as C5 + selectivity were improved with Ba addition. The non‐standard Anderson–Schulz–Flory (ASF ) product distribution observed for the Ba‐doped catalyst may be due to the appearance of an additional polymerization site on the catalyst surface located in the BaMoO4 phase. Chain growth factor was enhanced by up to 93% from 0.43 to 0.83 with the Ba‐doped catalyst .Conclusions Ba promoter increased chain growth probability by about 93%. The deviation of product distribution from standard ASF plots with 2 chain growth factors for the 3wt%Ba‐10%MoC1 ‐x /Al2 O3 catalyst was probably due to the presence of different active sites for chain initiation. The result is unprecedented and represents excellent opportunity for industrial exploitation of a new and relatively cheap carbon‐resistant catalyst.© 2012 Society of Chemical Industry
Journal of Chemical Technology and Biotechnology - Tập 88 Số 7 - Trang 1358-1363 - 2013
Efficient synthesis of 4‐phenacylideneflavenes using recyclable gelified <scp>B</scp>rønsted acidic ionic liquid under solvent‐free and column chromatography‐free conditions: a green method and mechanistic insight Abstract BACKGROUND Synthetic routes involving recyclable catalysts, solvent‐free conditions and chromatography‐free purification are becoming more popular as favorable substitutes for conventional ones. We report here the exciting possibility of producing selective functionalization of 4‐phenacylideneflavenes using an efficient gelified Brønsted acidic ionic liquid (BAIL) as a recyclable catalyst from available and cheap starting materials. RESULTS This one‐pot cascade approach allowed the synthesis of various 4‐phenacylideneflavenes in good yields with operational simplicity and easy workup. Moreover, the condensation of salicylaldehyde and acetophenone on a gram scale gave the desired product in 78% yield using our optimized conditions. In addition, the reaction mechanism in which two crucial intermediates were identified using high‐resolution electrospray ionization mass spectrometry was also proposed in the present work. CONCLUSION This method represents the first example of using BAIL gel recyclable catalyst in a straight and clean synthesis of various 4‐phenacylideneflavenes from cheap and available starting materials, namely acetophenones and salicylaldehyde. © 2021 Society of Chemical Industry (SCI).
Journal of Chemical Technology and Biotechnology - Tập 97 Số 3 - Trang 653-661 - 2022
Degradation of C.I. Acid Orange 7 by heterogeneous Fenton oxidation in combination with ultrasonic irradiation Abstract BACKGROUND: A mesoporous alumina supported nanosized Fe2 O3 was prepared through an original synthesis procedure and used as a heterogeneous catalyst for the Fenton process degradation of the model azo dye C.I. Acid Orange 7 enhanced by ultrasound irradiation (US/Fe2 O3 ‐Al2 O3 ‐meso/H2 O2 system). The effect of various operating conditions was investigated, namely hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading.RESULTS: The results indicated that the degradation of C.I. Acid Orange 7 followed a pseudo‐first‐order kinetic model. There exists an optimal hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading for decolorization. The aggregate size of the spent catalyst was reduced after dispersion in water by ultrasonic irradiation. A very low level of iron leaching was observed ranging from < 0.1 to 0.23 mg L−1 . The intermediate products of C.I. Acid Orange 7 degradation were identified using gas chromatography–mass spectrometry (GC‐MS).CONCLUSION: The optimal conditions for efficient C.I. Acid Orange 7 degradation were pH close to 3, hydrogen peroxide concentration 4 mmol L−1 , catalyst loading 0.3 g L−1 , and ultrasonic power 80 W. Copyright © 2011 Society of Chemical Industry
Journal of Chemical Technology and Biotechnology - Tập 86 Số 7 - Trang 970-977 - 2011
Đánh giá công nghệ tách bốc hơi nước cho quá trình hồi phục sản phẩm sinh ra từ quá trình lên men sinh khối Tóm tắt Mặc dù có một số công nghệ tách bốc hơi có khả năng về mặt kỹ thuật trong việc loại bỏ các sản phẩm dễ bay hơi từ nước lên men, chưng cất vẫn là công nghệ chiếm ưu thế. Điều này đặc biệt đúng đối với việc thu hồi nhiên liệu sinh học như ethanol. Trong bài báo này, tình trạng của công nghệ tách màng nổi lên, được gọi là công nghệ bốc hơi nước cho ứng dụng này, đã được xem xét. Nhiều vấn đề và ưu tiên nghiên cứu có thể ảnh hưởng đến khả năng cạnh tranh của công nghệ bốc hơi nước để thu hồi nhiên liệu sinh học từ các hệ thống lên men được xác định và thảo luận. Chúng bao gồm: tăng cường hiệu suất sử dụng năng lượng; giảm chi phí vốn cho các hệ thống bốc hơi nước; các thử nghiệm dài hạn với nước lên men thực tế; tối ưu hóa tích hợp công nghệ bốc hơi nước với thiết bị lên men; sự cộng hưởng khi thực hiện cả việc thu hồi rượu và khử nước dung môi bằng công nghệ bốc hơi nước với công nghệ ngưng tụ phân đoạn đông lạnh; và phân tích kinh tế cập nhật của công nghệ bốc hơi nước ở các quy mô sản xuất nhiên liệu sinh học khác nhau. Công nghệ bốc hơi nước hiện đang khả dụng để thu hồi nhiên liệu sinh học trong một số tình huống, nhưng việc ứng dụng rộng rãi hơn sẽ chỉ có thể khi có tiến bộ trong những vấn đề này. Được xuất bản vào năm 2005 cho SCI bởi John Wiley & Sons, Ltd.
Journal of Chemical Technology and Biotechnology - Tập 80 Số 6 - Trang 603-629 - 2005
#công nghệ tách bốc hơi nước #lên men sinh khối #thu hồi nhiên liệu sinh học #hiệu suất năng lượng #hệ thống lên men #công nghệ màng #đông lạnh phản ứng phân đoạn
Enhanced ethanol production from enzymatically treated steam‐exploded rice straw using extractive fermentation Abstract Alcohol fermentation of an enzymatic hydrolyzate of exploded rice straw was studied experimentally. Rice straw was treated under variable conditions, such as steam pressure and steaming time. The exploded rice straw was separated into water‐soluble material, methanol‐soluble lignin, Klason lignin, and a mixture of cellulose and a low molecular weight substance. The effects of steam explosion on the characteristics of the exploded rice straw were clarified from the point of view of the amounts of extractive components. Steam explosion was found to be effective for the delignification of rice straw and for increasing its susceptibility to enzyme hydrolysis and alcohol fermentation. The polysaccharides (cellulose and hemicellulose) in the rice straw treated at a steam pressure of 3.5 MPa with a steaming time of 2 min were hydrolyzed almost completely into monosaccharides, (ie glucose and xylose) by a mixture of Trichoderma viride cellulase (Meicelase) and Aspergillus aculeatus cellulase (Acucelase). The enzymatic hydrolyzate of exploded rice straw was converted into ethanol efficiently by Pichia stipitis and the ethanol yield from sugar was about 86%(w/w) of the theoretical value. The ethanol concentration in a membrane bioreactor coupled with a pervaporation system reached 50 gdm−3 and was about five times higher than that in the culture broth. The energy efficiency (ratio of combustion energy of ethanol produced to energy for steam explosion) reached a maximum value at a pressure of 3.5 MPa for 2 min. © 2001 Society of Chemical Industry
Journal of Chemical Technology and Biotechnology - Tập 76 Số 8 - Trang 879-884 - 2001
Improved chitin production by pretreatment of shrimp shells Abstract Pretreatment of shrimp shells was investigated in order to lower the costs and to improve the sustainability of chitin production. Physical pretreatment comprising drying, grinding and sieving is attractive for the recovery of 50% of shrimp protein as a dry powder. Pretreatment of shells by shearing in acidified water results in the removal of up to 60% of the protein and a reduction of their mineral content without a decrease in the chitin yield. Both pretreatment procedures will lead to cleaner technology for chitin production, to a considerably lower need for chemicals, to useful protein by‐products, and to less‐contaminated industrial effluent. Copyright © 2004 Society of Chemical Industry
Journal of Chemical Technology and Biotechnology - Tập 79 Số 4 - Trang 421-425 - 2004
Undesired components in the transformation of biomass pyrolysis oil into hydrocarbons on an HZSM‐5 zeolite catalyst Abstract The results of the catalytic transformation on HZSM‐5 zeolite of mixtures of components of biomass pyrolysis oil in the 673–723 K temperature range are evidence of the need for previously separating certain components (aldehydes, oxyphenols and furfural) that undergo severe thermal degradation by forming carbonaceous deposits at the reactor inlet ducts and on the catalyst itself. The deactivation of the catalyst is a consequence of the deposition of two different types of coke: one of catalytic origin (similar to that generated in the transformation of methanol and bioethanol) and the other of thermal origin, which is produced by the aforementioned degradation. The remaining oxygenate components react to each other with synergistic effect, which means that their reactivity is higher than that of the pure components. The results show that the aqueous fraction of biomass pyrolysis oil may be transformed into hydrocarbons on acid catalysts similarly to the more familiar transformation of methanol and bioethanol. Copyright © 2005 Society of Chemical Industry
Journal of Chemical Technology and Biotechnology - Tập 80 Số 11 - Trang 1244-1251 - 2005
Investigation of soluble microbial products in anaerobic wastewater treatment effluents Abstract BACKGROUND: Anaerobic treatment of distillery wastewater, purified terephthalic acid (PTA) wastewater and synthetic glucose wastewater was conducted and the soluble microbial products (SMPs) in the anaerobic effluent were investigated.RESULTS: Gas chromatography‐mass spectrometry (GC‐MS) analysis showed that apart from the degradation residuals, the long chain alkanes, esters and acids totally accounted for the majority of the low molecular weight (MW) SMPs in the effluents. The sum of protein and polysaccharide SMPs in the effluent increased from 50 to 323 mg L−1 when organic loading rate (OLR) was increased from 2.5 to 10.5 kg m−3 d−1 ; when influent COD changed from 5000 to 10 000 mg L−1 , the sum increased from 54 to 98 mg L−1 at about the same OLR of 5 kg m−3 d−1 .CONCLUSION: The results showed that SMPs made up an important proportion of organic compounds in the anaerobic effluents; the main low MW SMPs were long chain alkanes, esters and acids. The protein and polysaccharide SMPs increased with the increasing OLR, while higher influent concentrations led to higher concentrations of SMPs at the same OLR. From the variation of protein and polysaccharide SMPs along the height of the anaerobic reactors, it could be inferred that the methanogens might have contributed more in SMP consumption. Copyright © 2010 Society of Chemical Industry
Journal of Chemical Technology and Biotechnology - Tập 85 Số 12 - Trang 1597-1603 - 2010
Using dynamic tests to study the continuous mixing of xanthan gum solutions Abstract BACKGROUND: The current understanding and implementation of continuous mixing of non‐Newtonian fluids is insufficient to ensure good mixing in many cases. In this study, the dynamic response of the continuous mixing of xanthan gum solution, which is a pseudoplastic fluid with yield stress, was quantified using a dynamic model that incorporated non‐ideal flows within the mixing vessel. The model allowed for two parallel flow paths through the tank: (1) a channeling zone and (2) a mixing zone.RESULTS: Dynamic tests were made using the frequency‐modulated random binary input of a brine solution with the feed to determine the magnitude of non‐ideal flows. The extent of flow bypassing the mixing zone and the effective mixed volume were determined from dynamic tests and used as mixing quality criteria. We explored the effect of impeller speed, impeller type, feed flow rate through the mixing tank, fluid rheology, and feed and exit location on the degree of channeling and the fraction of fully mixed volume. Tests show that when the surface of the cavern created by impeller approaches the tank wall, the bottom of the tank, and the surface of the fluid within the mixing vessel, the percentage of non‐ideal flow approached zero.CONCLUSION: This study identifies important criteria for continuous mixing vessels that will improve mixing efficiency. By applying these findings, a reduction in the extent of non‐ideal flow can be achieved, which will improve the quality and control of the continuous mixing processes such as continuous high‐viscosity reactor, continuous fermenter, and continuous solid–liquid mixing. Copyright © 2008 Society of Chemical Industry
Journal of Chemical Technology and Biotechnology - Tập 83 Số 4 - Trang 559-568 - 2008
Highly efficient bioconversion of methane to methanol using a novel type I <i>Methylomonas</i> sp. <scp>DH</scp>‐1 newly isolated from brewery waste sludge Abstract Background Methane is the major component of natural and shale gas. Methane can be converted into methanol via a bioprocess using methanotrophs, and methanol is a valuable chemical feedstock for the production of value‐added chemicals. This work demonstrates highly effective bioconversion of methane to methanol using a newly isolated novel methanotroph, Methylomonas sp. DH ‐1. Results A novel methanotroph strain was isolated from activated sludge from a brewery plant and characterized using phylogenetic analysis, electron microscopy and chemotaxonomic analysis. This aerobic, Gram‐negative, non‐motile rod‐shaped type I methanotroph was designated as Methylomonas sp. DH ‐1. The growth condition of Methylomonas sp. DH ‐1 and batch methane‐to‐methanol bioconversion conditions such as methane concentration, pH , biocatalyst loading, concentration of formate and MDH inhibitor were analyzed and optimized. Methanol was produced from methane with a 1.340 g L−1 titer, a 0.332 g L−1 h−1 volumetric conversion rate and a 0.0752 g g−1 cell h−1 specific methanol conversion rate. Conclusion It was demonstrated that isolation and application of a new methanotroph strain is a practical way of improving bioconversion efficiency in the conversion of methane to methanol. Moreover, one promising feature of Methylomonas sp. DH ‐1 for methanol production was its extremely high tolerance to methanol up to 7%(v/v), which is advantageous for high‐titer methanol production. © 2016 Society of Chemical Industry
Journal of Chemical Technology and Biotechnology - Tập 92 Số 2 - Trang 311-318 - 2017
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