Separation of ethanol from solutions with different concentrations in a BIOTRON bioreactor integrated with the direct contact membrane distillation system has been investigated. The experiments were carried out using immersed, capillary polypropylene membranes. The permeability of the membrane at the feed inlet temperatures of 308, 318 and 333K was determined. The permeate and ethanol flux was strongly affected by the vapour pressure which increased with the feed temperature and it was also associated with ethanol concentration in the feed. It was found that the membrane distillation can be successfully applied for the separation of volatile components such as ethanol.
The diluted ethanol solutions and fermentation broth (Saccharomyces cerevisiae) were separated by membrane distillation (MD). Hydrophobic macroporous (pore size 0.2 μm) capillary polypropylene membranes, Accurel PP V8/2 HF and Accurel PP S6/2, were used for these studies. The MD process can be successfully applied to remove the volatile components from the fermentation broth. Besides ethanol, propionic and acetic acids were moved from the broth to the distillate. Therefore, the course of the fermentation carried out in a membrane distillation bioreactor considerably accelerate its rate and increase the efficiency by a selective removal of fermentation products. It was found that the broth subjected to the separation did not affect the hydrophobic properties of the polypropylene membrane assembled in the MD modules.
This study proposes a method for the production of ethanol from wheat straw lignocellulose where the raw material is chemically processed before hydrolysis and fermentation. The usefulness of wheat straw delignification was evaluated with the use of a 4:1 mixture of 95% ethanol and 65% HNO3 (V). Chemically processed lignocellulose was subjected to enzymatic hydrolysis to produce reducing sugars, which were converted to ethanol in the process of alcoholic fermentation. Chemical processing damages the molecular structure of wheat straw, thus improving ethanol yield. The removal of lignin from straw improves fermentation by eliminating lignin’s negative influence on the growth and viability of yeast cells. Straw pretreatment facilitates enzymatic hydrolysis by increasing the content of reducing sugars and ethanol per g in comparison with untreated wheat straw.
Consecutive hydroconversion of acetic acid (AA) to ethanol was compared over monometallic and novel bimetallic (containing In as guest metal) catalysts on alumina and silica supports (inter alia highly ordered SBA-15) of different porosity and pore structure. The transformation was studied in a fixed bed, flow-through reactor in the temperature range of 220–380°C using hydrogen flow at 21 bar total pressure. AA hydroconversion activity of Cu and Pt catalysts and the yield of selectively produced alcohol were increased drastically by applying SBA-15 as highly ordered, mesoporous silica support instead of alumina. The most active nickel catalysts do not allow the selective addition of hydrogen to carbon-oxygen bonds independently of supports producing mainly CH4; however, indium doping can completely eliminate the hydrodecarbonylation activity as found in earlier studies. The textural properties of studied silica supports of various textures such as SBA-15, CAB-O-SIL, and Grace Sylobead have a profound impact on the catalytic performance of Ni and Ni2In particles.
In recent years there have been remarkable developments in the prevention of diseases, especially with regards to the role of free radicals and antioxidants. Ethanol-induced oxidative stress appears to be one mechanism by which ethanol causes liver injury. The protective effect of aqueous plant extract of Aframomum melegueta on ethanol-induced toxicity was investigated in male Wistar rats. The rats were treated with 45 % ethanol (4.8 g/kg b.w.t.) for 16 days to induce alcoholic diseases in the liver. The activities of alanine aminotransferase, aspartate aminotransferase and triglyceride were monitored and the histological changes in liver examined in order to evaluate the protective effects of the plant extract. Hepatic malondialdehyde and reduced glutathione, as well as superoxide dismutase and glutathione-S-transferase activities were determined for the antioxidant status. Chronic ethanol administration resulted in a statistically significant elevation of serum alanine aminotransferases and triglyceride levels, as well as a decrease in reduced glutathione and superoxide dismutase which was dramatically attenuated by the co-administration of the plant extract. Histological changes were related to these indices. Co-administration of the plant extract suppressed the elevation of lipid peroxidation, restored the reduced glutathion, and enhanced the superoxide dismutase activity. These results highlight the ability of Aframomum melegueta to ameliorate oxidative damage in the liver and the observed effects are associated with its antioxidant activities.
Nowadays, embalming has become more popular as it is often performed due to sanitary, hygienic, or psychological reasons. In special circumstances, like transporting a corpse from abroad, embalming is an administrative requirement. Embalming is performed using chemical substances that inhibit enzymes, bacteriological activity, and therefore cease decomposition processes. The study shows the toxicological analyses of sampled materials collected during post mortem examinations performed on six corpses subjected to the embalming process. It also presents the concentration of used preservatives in the tissues and body fluids. Analysis performed using gas chromatography with a flame ionization detector (GC-FID) revealed that in five cases, the deceased were intoxicated with ethanol during the time of death, and liquid chromatography-mass spectrometry (LC-MS) excluded the presence of psychoactive substances in all six cases. The results showed that in cases of toxicological analyses of embalmed corpses, it is crucial to secure isolated body fluids, such as cerebrospinal fluid, vitreous humor, and a wide range of reference material.
PL
Balsamacja zwłok staje się coraz bardziej popularna ze względów sanitarnych, higienicznych lub psychologicznych. W szczególnych okolicznościach, jak transport zwłok z zagranicy, balsamowanie jest wymogiem administracyjnym. Balsamacja odbywa się za pomocą substancji chemicznych, które hamują aktywność enzymatyczną i bakteriologiczną, wstrzymując tym samym procesy rozkładu. Prezentowana praca przedstawia analizy toksykologiczne materiałów po-branych podczas sekcji sześciu zwłok poddanych procesom balsamowania oraz wyniki pomiarów stężenia użytych konserwantów w tkankach i płynach ustrojowych badanych zwłok. Analiza przeprowadzona za pomocą chromatografii gazowej z detektorem płomieniowo-jonizacyjnym (gas chromatography with a flame ionization detector – GC-FID) udowodniła obecność etanolu w pięciu przypadkach. Chromatografia cieczowa połączona ze spektrometrią mas (liquid chromatography-mass spectrometry – LC-MS) wykluczyła obecność substancji psychoaktywnych we wszystkich sześciu przypadkach. Wyniki wykazały, że w przypadku analiz toksykologicznych zabalsamowanych zwłok kluczowe znaczenie ma zabezpieczenie izolowanych płynów ustrojowych, takich jak płyn mózgowo-rdzeniowy, płyn gałki ocznej, oraz wielu materiałów referencyjnych.
Growth kinetics of vitamin C crystals during the batch mass crystallization process in L(+)-ascorbic acid - methanol - ethanol - water system was determined. The linear growth rate values were estimated on the basis of the product crystal size distributions. The kinetic model of the continuous process in a MSMPR crystallizer was adopted for the batch mode description according to Nyvlt's conception, taking the sizedependent growth (SDG) rate effects into consideration. The kinetic parameter values were determined with a Rojkowski hyperbolic SDG model. A good compatibility between the experimental product crystal population density distributions and the SDG model predictions was observed. The interpretation of the kinetic data was presented and discussed.
In this paper, we have shown modification of high-silicon zeolite ZSM-5 by zirconium, and the results of ethanol conversion on this catalyst. Effect of process parameters on the selectivity of ethanol dehydration products was analyzed. In addition, a mechanism of aromatic hydrocarbons formation including reactions of dehydrogenation, dehydrocyclization and alkylation of intermediates was discussed. It was found that with increasing temperature a selectivity decreased for reactions of isomerization and increased selectivity for aromatic products and products of cracking reactions. The data also confirms that hexene-1 is an intermediate in the conversion process of ethanol and the catalyst system with 1% Zr-ZSM-5 has a bi-functionality. Catalytic properties of the system in the conversion of hydrocarbons are determined by the presence on their surface of both Broensted and Lewis acid sites.
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