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Acid Extraction (acid + extraction)
Selected AbstractsRemoval of heavy metals from municipal solid waste incineration (MSWI) fly ash by traditional and microwave acid extractionJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2010Jun Xue Abstract BACKGROUND: Municipal solid waste incinerator (MSWI) fly ash is regarded as hazardous waste because it contains various toxic metals. A previous study has shown that fly ash can be detoxified by removal of heavy metals. In this work, the extractability of heavy metals from MSWI fly ash by traditional and microwave acid extraction were compared. RESULTS: A 24 , 1 fractional factorial experimental design was adopted using acid concentration, extraction time, temperature, and liquid/solid (L/S) ratio as the experimental factors for traditional extraction, and acid concentration, extraction time, liquid/solid (L/S) ratio and microwave power as the experimental factors for microwave extraction. The traditional extraction results show that L/S played an important role in Zn, Cd extraction while L/S ratio and extractant concentration were important for Pb extraction. However, no controlling parameter was determined for Cu and Cr extraction. For the microwave extraction, it was shown that L/S was important for Pb and Zn and extractant concentration was important for Pb, Zn and Cd. The time and the power were not significant for the extractability of heavy metals. CONCLUSION: Hydrochloric acid was an effective extractant. Microwave heating promoted extraction and shortened extraction time. Microwave acid extraction treatment is a potentially feasible method for the removal of heavy metals from MSWI fly ash. Copyright © 2010 Society of Chemical Industry [source] Reactive extraction of propionic acid using tri-n-octylamine, tri-n-butyl phosphate and aliquat 336 in sunflower oil as diluentJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2009Amit Keshav Abstract BACKGROUND: Propionic acid is widely used in chemical and allied industries and can be produced by biocultivation in a clean and environmentally friendly route. Recovery of the acid from the dilute stream from the bioreactor is an economic problem. Reactive extraction is a promising method of recovering the acid but suffers from toxicity problems of the solvent employed. There is thus a need for a non-toxic solvent or a combination of less toxic extractants in a non-toxic diluent that can recover acid efficiently. RESULTS: The effect of different extractants (tri-n-butylphosphate (TBP), tri-n-octylamine (TOA) and Aliquat 336) and their mixed binary solutions in sunflower oil diluent was studied to find the best extractant-sunflower oil combination. Equilibrium complexation constant, KE, values of 4.02, 3.13 and 1.87 m3 kmol,1 were obtained for propionic acid extraction using Aliquat 336, TOA and TBP, respectively, in sunflower oil. The effect of different modifiers (1-decanol, methylisobutyl ketone, butyl acetate and dodecanol) on the extraction was also studied and it was found that modifiers enhance extraction, with 1-decanol found to be the best. CONCLUSION: The problem of toxicity in reactive extraction can be reduced by using a non-toxic diluent (sunflower oil) or a modifier in a non-toxic solvent, with the extractant. The addition of modifiers was found to improve the extraction. Copyright © 2008 Society of Chemical Industry [source] CHARACTERIZATION AND COMPARISON OF COLLAGENS EXTRACTED FROM THE DIGESTIVE TRACT AND SKIN OF A JAPANESE AMBERJACK SERIOLA QUINQUERADIATAJOURNAL OF FOOD BIOCHEMISTRY, Issue 6 2009MAKI NISHIMOTO ABSTRACT Collagen was extracted from the digestive tract and skin of a Japanese amberjack (Seriola quinqueradiata) by acid extraction and limited pepsin digestion. The amounts of collagen solubilized from the digestive tract were smaller than those from the skin. Based on the solubility in NaCl solution, electrophoretic and peptide map patterns, and amino acid composition, the main digestive tract collagen was identified as type I, having characteristics different from those of the body wall collagen in cyclostome intestine. Further, the degree of hydroxylation of prolyl and lysyl residues in the type I collagen of the digestive tract is significantly higher than that of the skin. Collagen preparations from the digestive tract have a higher ratio of type V collagen than those from the skin. Hence, the digestive tract collagen differs from that in the skin in the degree or property of intermolecular crosslinking, posttranslational modification, and molecular species composition. PRACTICAL APPLICATIONS Partial hydrolyzate of gelatin, in other word collagen peptide, has gained popularity as a food ingredient, as it has been suggested to have health benefits, such as improvement of skin and joint conditions. Recently, attention toward collagen derived from marine origin such as fish skin increased because of the outbreak of bovine spongiform encephalopathy. Large amounts of the digestive tract, stomach, intestine and adhesion tissues are generated by fishery industries and most of them are by-products of low value. Although these organs are also rich in collagen, the collagen in fish digestive tract has not been characterized. The present study demonstrates that the collagen in digestive tract differs from the skin collagen in the solubility, posttranslational modification and molecular species composition. These facts suggest that modified collagen peptides might be obtained from the digestive tract. [source] Composition and properties of biologically active pectic polysaccharides from leek (Allium porrum)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2010Maria Kratchanova Abstract BACKGROUND: Leek (Allium porrum) is very commonly used vegetable in Bulgaria and is distinctive with high content of bioactive components1. Previously2 we obtained five crude pectic polysaccharides from leek through consecutive extraction. Some of them appeared to be good stimulators of the immune system. Schols and Voragen3 investigated the composition of modified hairy regions of pectic polysaccharides isolated from leek cell walls. Samuelson et al.4 identified the polysaccharide structures encountered in hairy regions as bioactive. The aim of this work was to study the isolation, composition and biological activities of pectic polysaccharides from leek. RESULTS: Two pectic polysaccharides from leek were isolated through consecutive water and acid extraction. The water extractable pectin had higher polyuronic content, higher protein content and lower neutral sugar content. It was found that next to galacturonic acid they also contain glucuronic acid in ratio 9:1 for the water- and 3:1 for the acid-extractable polysaccharide. The main neutral sugar was galactose. The water-extractable pectic polysaccharide had higher molecular weight (106 Da) and homogeneity. It was shown that the pectic polysaccharides from leek have considerable immunostimulating activities. CONCLUSION: Leek polysaccharides have relatively high galacturonic and glucuronic acid content and are distinguished with high biological activity. Copyright © 2010 Society of Chemical Industry [source] The effect of experimental conditions on the detection of spermine in cell extracts and tissuesNMR IN BIOMEDICINE, Issue 2 2010Nicholas G. Spencer Abstract The aim of this work was to investigate the effect of experimental conditions on the visibility of polyamines. In solution the chemical shift of the three groups of peaks (at approximately 1.8, 2.1 and 3.1,ppm) were found to be pH dependent. Relaxation times in aqueous solution at pH 7.0, 298,K and 11.74,T were measured to be: putrescine (T1,=,2.49,s, T2,=,2.07,s), spermidine (T1,=,1.27,s, T2,=,1.05,s) and spermine (T1,=,1.02,s, T2,=,0.82,s). Simple spin-echo sequences could not be used to measure T2 as the spins also experience phase evolution from homonuclear coupling which imposes a modulation on the T2 decay curve. This modulation is eliminated by using CPMG sequences with an echo spacing of <500,µs. Relaxation times for spermine in solution in presence of metal ions and protein showed that metal ions had little effect on T2; however, addition of 15,mg/ml bovine serum albumin reduced T2 of spermine (0.41,s at 298,K and 0.19,s at 277,K) but was not as short as the T2 of the polyamine peak in prostatic tissue (0.03,s at 277,K). The MR visibility of polyamines in prostate cell extracts, PC-3 xenograft (intact as well as extracted) and intact human prostatic tissues were investigated. Polyamines were not detected in methanol/chloroform extracts, but were visible in perchloric acid extracts of prostate tumour cells. No polyamines were detected in the HR MAS spectra of three samples of whole PC-3 xenograft tissue studied. In summary, the chemical shift of polyamine species is pH dependent, while protein binding causes peak broadening and reduction in T2. Perchloric acid extraction improves visibility of intracellular polyamines, but whole tissue polyamines are not seen in xenografts without epithelial/ ductal structure. Copyright © 2009 John Wiley & Sons, Ltd. [source] Brief communication: Mass spectroscopic characterization of tetracycline in the skeletal remains of an ancient population from Sudanese Nubia 350,550 CEAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2010Mark L. Nelson Abstract Histological evidence of tetracycline use has been reported in an ancient X-Group population (350,550 CE) from Sudanese Nubia (Bassett et al., 1980). When bone samples were examined by fluorescent microscopy under UV light at 490 Å yellow,green fluorophore deposition bands, similar to those produced by tetracycline, were observed, suggesting significant exposure of the population to the antibiotic. These reports were met skeptically with claims that the fluorescence was the result of postmortem taphonomic infiltration of bacteria and fungi. Herein, we report the acid extraction and mass spectroscopic characterization of the antibiotic tetracycline from these samples. The bone samples were demineralized in anhydrous hydrogen fluoride which dissolved the bone-complexed tetracycline, followed by isolation by solid phase extraction on reverse-phase media. Chemical characterization by high pressure liquid chromatography mass-spectroscopic procedures showed that the retention times and mass spectra of the bone extract were identical to tetracycline when treated similarly. These results indicate that a natural product tetracycline was detectable within the sampled bone and was converted to the acid-stable form, anhydrotetracycline, with a mass + H of 427.1 amu. Our findings show that the bone sampled is labeled by the antibiotic tetracycline, and that the NAX population ingested and were exposed to tetracycline-containing materials in their dietary regime. Am J Phys Anthropol 143:151,154, 2010. © 2010 Wiley-Liss, Inc. 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