Concentration of apricot juice using complex membrane technology

In this study, pressed apricot (Prunus armeniaca L.) juice was concentrated using complex membrane technology with different module combinations: UF-RO-OD, UF-RO-MD, UF-NF-OD and UF-NF-MD. In case of the best combination a cross-flow polyethylene ultrafiltration membrane (UF) was applied for clarification, after which preconcentration was done using reverse osmosis (RO) with a polyamide membrane, and the final concentration was completed by osmotic distillation (OD) using a polypropylene module. The UF-RO-OD procedure resulted in a final concentrate with a 65-70 °Brix dry solid content and an excellent quality juice with high polyphenol content and high antioxidant capacity.Nanofiltration (NF) and membrane distillation (MD) were not proper economic solutions.The influence of certain operation parameters was examined experimentally. Temperatures of UF and RO were: 25, 30, and 35 °C, and of OD 25 °C. Recycle flow rates were: UF: 1, 1.5, and 2 m3 h−1; RO: 200, 400, and 600 l h−1; OD: 20, 30 and 40 l h−1. The flow rates in the module were expressed by the Reynolds number, as well. Based on preliminary experiments, the transmembrane pressures of UF and RO filtration were 4 bar and 50 bar, respectively. Each experimental run was performed three times. The following optimal operation parameters provided the lowest total cost: UF: 35 °C, 2 m3 h−1, 4 bar; RO: 35 °C, 600 l h−1, 50 bar; OD: 20, 30 and 40 l h−1; temperature 25 °C.In addition, experiments were performed for apricot juice concentration by evaporation, which technique is widely applied in the industry using vacuum and low temperature.For description the UF filtration, a dynamic model and regression by SPSS 14.0 statistics software were applied

Lipidna peroksidacija i aktivnost antioksidativnih enzima u eritrocitima radnika profesionalno izloženih aluminiju

Current research indicates that lipid peroxidation could have a role in aluminium toxicity. The aim of this study was to asses lipid peroxidation and antioxidative enzyme activity in erythrocytes of workers occupationally exposed to aluminium. We investigated a group of 59 workers (Al group) exposed to aluminium fumes (contamination factor F=8.07 to 13.47, national maximal allowed concentration value is 2 mg m-3). The control group (C group) consisted of 75 subjects employed in lime production who had not been occupationally exposed to aluminium or any known toxic substance. Erythrocyte aluminium concentrations were significantly higher in the exposed group than controls [Al group (8.41±3.66) µg L-1, C group (5.60±0.86) µg L-1, p<0.001]. In the Al group, erythrocyte malondialdehyde concentration was also significantly higher [Al group (189.59±81.27) µmol L-1, C group (105.21±49.62) µmol L-1, p<0.001] and antioxidative enzyme activity reduced for glucoso-6-phosphatedehydrogenase [Al group (5.05±1.70) IU g-1 Hb, C group (12.53±4.12) IU g-1 Hb, p<0.001], glutathione reductase [Al group (1.41±0.56) IU g-1 Hb, C group (1.89±0.57) IU g-1 Hb, p<0.001], glutathione peroxidase [Al group (12.37±5.76) IU g-1 Hb, C group (15.54±4.85) IU g-1 Hb, p<0.001], catalase [Al group (116.76±26.60) IU g-1 Hb, C group (158.81±71.85) IU g-1 Hb, p<0.001] and superoxide dismutase [Al group (1175.8±149.9) IU mg-1 Hb, C group (1377.9±207.5) IU mg-1 Hb, p<0.001].Rezultati suvremenih istraživanja pokazuju da lipidna peroksidacija može imati važnu ulogu u toksičnosti aluminija. Cilj istraživanja bio je da se ispita lipidna peroksidacija i aktivnost antioksidativnih enzima u eritrocitima kod radnika profesionalno izloženih aluminiju. Ispitivanjem je obuhvaćena skupina od 59 radnika (Al skupina) profesionalno izloženih aluminiju (faktor onečišćenja F=8,07 do 13,47, nacionalna maksimalno dopuštena koncentracija je 2 mg m-3). Kontrolna skupina sastojala se od 75 osoba zaposlenih u proizvodnji vapna koje nikada nisu bile profesionalno izložene aluminiju ni drugim toksičnim tvarima. U skupini izloženoj aluminiju utvrđene su statistički signifikantno više koncentracije aluminija u eritrocitima nego u kontrolnoj skupini [Al skupina (8,41±3,66) µg L-1, kontrolna skupina (5,60±0,86) µg L-1, p<0,001]. U Al skupini utvrđene su statistički značajno više koncentracije malondialdehida u eritrocitima [Al skupina (189,59±81,27) µmol L-1, kontrolna skupina (105,21±49,62) µmol L-1, p<0,001]. Također, u Al skupini utvrđene su i statistički značajno niže aktivnosti antioksidativnih enzima u eritrocitima: glukozo- 6-fosfatdehidrogenaza [Al skupina (5,05±1,70) IU g-1 Hb, kontrolna skupina (12,53±4,12) IU g-1 Hb, p<0,001], glutationreduktaza [Al skupina (1,41±0,56) IU g-1 Hb, kontrolna skupina (1,89±0,57) IU g-1 Hb, p<0,001], glutationperoksidaza [Al skupina (12,37±5,76) IU g-1 Hb, kontrolna skupina (15,54±4,85) IU g-1 Hb, p<0,001], katalaza [Al skupina (116,76±26,60) IU g-1 Hb, kontrolna skupina (158,81±71,85) IU g-1 Hb, p<0,001] i superoksiddizmutaza [Al skupina (1175,8±149,9) IU mg-1 Hb, kontrolna skupina (1377,9±207,5) IU mg-1 Hb, p<0,001]

Trace elements in hemodialysis patients: a systematic review and meta-analysis

<p>Abstract</p> <p>Background</p> <p>Hemodialysis patients are at risk for deficiency of essential trace elements and excess of toxic trace elements, both of which can affect health. We conducted a systematic review to summarize existing literature on trace element status in hemodialysis patients.</p> <p>Methods</p> <p>All studies which reported relevant data for chronic hemodialysis patients and a healthy control population were eligible, regardless of language or publication status. We included studies which measured at least one of the following elements in whole blood, serum, or plasma: antimony, arsenic, boron, cadmium, chromium, cobalt, copper, fluorine, iodine, lead, manganese, mercury, molybdenum, nickel, selenium, tellurium, thallium, vanadium, and zinc. We calculated differences between hemodialysis patients and controls using the differences in mean trace element level, divided by the pooled standard deviation.</p> <p>Results</p> <p>We identified 128 eligible studies. Available data suggested that levels of cadmium, chromium, copper, lead, and vanadium were higher and that levels of selenium, zinc and manganese were lower in hemodialysis patients, compared with controls. Pooled standard mean differences exceeded 0.8 standard deviation units (a large difference) higher than controls for cadmium, chromium, vanadium, and lower than controls for selenium, zinc, and manganese. No studies reported data on antimony, iodine, tellurium, and thallium concentrations.</p> <p>Conclusion</p> <p>Average blood levels of biologically important trace elements were substantially different in hemodialysis patients, compared with healthy controls. Since both deficiency and excess of trace elements are potentially harmful yet amenable to therapy, the hypothesis that trace element status influences the risk of adverse clinical outcomes is worthy of investigation.</p

Morphological, anatomical and palynological properties of some Turkish Veronica L. species (Scrphulariaceae)

In this study, pollen and seed morphology, leaf and stem anatomy of four Veronica L. species (Scrophulariaceae) one of which is endemic (V. multifida) belonging to four Sections [V. persica (Sect. Pocilla), V. beccabunga (Sect. Beccabunga), V. officinalis and V. multifida (Sect. Veronica)] grown in Turkey have been studied on light and scanning electron microscopy. Different and similar features of these species were described. © 2007 Asian Network for Scientific Information

Production of activated carbon materials from kenaf biomass to be used as catalyst support in aqueous-phase reforming process

In the present study, low value-added woody biomass, kenaf (Hibiscus cannabinus L.), was utilized for production of activated carbons (ACs) that can be used as catalyst support for deposition of metal particles such as Pt to produce highly active catalysts for gasification of biomass hydrolysates by aqueous-phase reforming (APR) process. H3PO4 was used as activating agent for production of AC materials. ACs produced from kenaf and non-hydrolyzed fraction of kenaf after dissolution in subcritical water were compared with the commercial one. The activated carbon material from kenaf had highest BET surface area and total pore volume among the materials tested including commercial AC. The catalyst prepared by Pt deposition on this material (kenaf AC-Pt) had also highest BET surface area and total pore volume. This catalyst exhibited very high activity and selectivity for hydrogen production (0.015 mol H2/g catalyst) in APR of biomass hydrolysate. © 2016 Elsevier B.V. All rights reserved

Evaluation of various carbon materials supported Pt catalyts for aqueous-phase reforming of lignocellulosic biomass hydrolysate

Currently, under huge pressure from energy demands and environmental problems, much attention is being paid to produce fuel and chemicals from lignocellulosic biomass. In this matter, development of active and also recyclable catalysts are essential. In the present study, various types of carbon supported Pt reforming catalysts were prepared for use in gasification of wheat straw biomass hydrolysate by aqueous-phase reforming. The supports tested were various carbon materials having different surface and structures that were activated carbon (AC), single- and multi-walled carbon nanotubes (SWCNT and MWCNT), superdarco carbon (SDC) and graphene oxide (GO). The catalysts prepared using these supports were evaluated based on gasification yield, carbon amount consumed in the process, sugar alcohols formation and breaking down of organic compounds in the hydrolysate. Compared to other carbon-based supports tested, Pt on activated carbon showed best performance for gasification of biomass hydrolysate. This catalyst was also active on carbon consumption, sugar alcohols production and breaking down soluble organic compounds in the hydrolysate. The second active catalyst, Pt on single-walled carbon nanotube, showed significantly higher activity compared to multi-walled carbon nanotube since large polysaccharides molecules were not able to enter into narrow graphene sheets in multi-walled carbon nanotube to react with Pt deposited inside graphene layers. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Does reduced or non-reduced biomass feed produce more gas in aqueous-phase reforming process?

There has been increasing interest in the production of gaseous and liquid biofuels from biomass. Biomass feed type and its content to be used in the conversion process are very important parameters to produce high yield biofuel. In this study, reduced and non-reduced forms of biomass-derived compound (glucose) and actual biomass hydrolysate feeds were evaluated to produce hydrogen-rich gas mixture by aqueous-phase reforming (APR) in presence of supported Ru catalyst. Various hydrogenation conditions were tested for effective conversion. The results showed that reduced solutions always produced significantly higher gas yield with high hydrogen selectivity. Although biomass hydrolysate was composed of variety of complex compounds, it exhibited significantly better performance compared to glucose, simple biomass model compound. © 2014 Elsevier Ltd. All rights reserved

Biofuel production by liquefaction of kenaf (Hibiscus cannabinus L.) biomass

PubMedID: 24262837In this study, kenaf biomass, its dried hydrolysate residue (solid residue left after removing water from hydrolysate) and non-hydrolyzed kenaf residue (solid residue left after hydrolysis process) were liquefied at various temperatures. Hydrolysis of biomass was performed in subcritical water condition. The oil. +. gas yield of biomass materials increased as the temperature increased from 250 to 300. °C. Increasing temperature to 350. °C resulted in decreases in oil. +. gas contents for all biomass feeds studied. On the other hand, preasphaltene. +. asphaltene (PA. +. A) and char yields significantly decreased with increasing the process temperature. The use of carbon or activated carbon supported Ru catalyst in the process significantly decreased char and PA. +. A formations. Oils produced from liquefaction of kenaf, dried kenaf hydrolysate and non-hydrolyzed kenaf residue consist of fuel related components such as aromatic hydrocarbons, benzene and benzene derivative compounds, indane and trans/cis-decalin. © 2013 Elsevier Ltd

Co-processing of Turkish high-sulfur coals and their blends with a petroleum asphalt. part 1: In the absence of a catalyst

In this study, two Turkish coals, namely, Cayirhan (CC) and Kangal (KC), characterized by high levels of ash and sulfur, were co-liquefied with petroleum asphalt (Asp) at 400, 425, and 450 °C. The liquefaction/prolysis of coals and petroleum asphalt under nitrogen and hydrogen atmospheres was also performed at 400 °C. The distribution of the main product fractions (total conversion, oil, preasphaltene + asphaltene, and gas) obtained from liquefaction/pyrolysis and co-liquefaction and the detailed chemical composition analyses of liquid products using gas chromatography-mass spectrometry (GC-MS) are given. The effect of liquefaction/pyrolysis conditions on the product quality was assessed. These coals showed quite different responses to similar liquefaction conditions because of the structural differences in the main carbon framework and also the differences in mineral matter composition. In all co-liquefaction reactions, the oil yields decreased significantly (10-18%) at 450 °C compared to those at 400 °C, possibly because of some retrogressive reactions. The amount of open-chain paraffins (alkanes + alkenes + alkynes) in the oils obtained from co-liquefactions was observed higher under the hydrogen atmosphere than under the nitrogen atmosphere. The reverse was true for the contents of alkylbenzenes. The amount of open-chain paraffins in oils increased, while alkylbenzenes and phenols decreased when the asphalt ratio was increased in the blend. In all co-liquefaction reactions, the open-chain paraffins decreased, while the amounts of naphthalene, alkylnaphthalenes, and other condensed arenes increased at 450 °C liquefaction results compared to 400 °C liquefaction results. © 2012 American Chemical Society