Home About us Contact
|
Home About us Contact | ||
|
|
||
Adsorption Rate (adsorption + rate)
Selected AbstractsEffect of bacteria-mineral water produced from bio-reacted fowl dung on seed germination of wheat (Triticum aestivum) and rice (Oryza sativa L.)ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2008Wenyuan He Abstract Positive effects of Bacteria-mineral water (BMW) produced from bio-reacted manure on plant growth and crop seed germination has been observed in agriculture practices. The experiment was conducted to examine the effects of BMW produced from bio-reacted fowl dung on seed germination of rice (Oryza sativa L.) and wheat (Triticum aestivum). Seeds were soaked in BMW at concentrations of 100, 10, 1, 0.5, 0.25, 0.125, 0.025, and 0% (control) and then incubated at 25°C ± 1°C in a seed germinator for 7 days. All BMW treatments not only enhanced germination energy and final germination percentage of wheat and rice seeds, but also significantly improved (P < 0.05) seed vigor index (VI). Compared to control, treatment with 0.25% BMW had significant effects (P < 0.05) on final germination percentage and increased significantly seed germination percentage (7.34%) and germination energy (8.67%) of wheat seeds. There were strong correlations between germination energy and final germination percentage (P < 0.05), germination index (P < 0.05), VI (P < 0.05), water absorption rate (P < 0.01), and storage reserve transform rate (P < 0.01). While for rice seeds, 0.25% and 0.125% BMW treatments significantly improved (P < 0.05) final germination percentage by 8% separately, and germination energy enhanced 8.66% and 9.33% respectively. There were strong correlations between germination energy (and final germination percentage) and other parameters except for water adsorption rate and storage reserve loss rate. BMW consistently showed positive effects on crop seed germination. 0.25% BMW treatment may be the best concentration to stimulate wheat (Triticum aestivum) seeds germination, while 0.125,0.25% BMW would be the most suitable concentration range for rice (Oryza sativa L.) seeds. © 2008 American Institute of Chemical Engineers Environ Prog, 2008 [source] Optimization of activated carbon-based decontamination of fish oil by response surface methodologyEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7 2007Åge Oterhals Abstract The effect of activated carbon (AC) adsorption on the reduction of persistent organic pollutants (POP) in fish oil was studied based on response surface methodology at a 5-g/kg AC inclusion level. Pretreatment of the oil by alkali refining and bleaching increased the POP levels. The tested process variables (contact time and temperature) affected the AC adsorption rate and significant first- and second-order response models could be established. Polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/F) showed a very rapid adsorption behavior and the concentration and toxic equivalent (TEQ) level could be reduced by 99%. Adsorption of dioxin-like polychlorinated biphenyls (DL-PCB) was less effective and depended on ortho substitution, i.e. non- ortho PCB were adsorbed more effectively than mono- ortho PCB with a maximum of 87 and 21% reduction, respectively, corresponding to a DL-PCB-TEQ reduction of 73%. A common optimum for both PCDD/F and DL-PCB adsorption could not be identified. AC treatment had no effect on the level of polybrominated diphenyl ether flame retardants. The differences in adsorption patterns may be explained based on molecular conformation. No change in oil quality could be observed based on oxidation parameters. Compliance with present PCDD/F and DL-PCB legislation levels in fish oil can be achieved based on AC adsorption. [source] Effect of ,-amylases on dough properties during Turkish hearth bread productionINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2003smail S. Do Summary The effect of ,-amylases from cereal and fungal sources on dough rheological properties was studied. Increasing the enzyme addition level to 160 SKB units (c. 1.1%, fwb) decreased dough stability and increased mixing tolerance indexes. Gas production rates with cereal ,-amylase were higher than that with fungal ,-amylases, indicating more activity during fermentation. A higher adsorption rate occurred with cereal ,-amylase. Dough stability is very important for Turkish hearth bread production, as it is for other hearth breads. Spread ratio tests on fermented doughs showed significant changes in dough rheological properties as a function of ,-amylases. The spread test is a reliable tool for observing rheological changes during fermentation. As a guide, the dough spread ratio should not be more than 2 for desirable bread. [source] Adsorption of Hg2+ on a novel chelating fiber prepared by preirradiation grafting and aminationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2009Ying Yang Abstract A novel chelating fiber was prepared by the irradiation-induced grafting copolymerization of glycidyl methacrylate on polypropylene fiber and consequent amination with diethylenetriamine. The effects of the reaction conditions, such as reaction time, temperature, and monomer concentration, on the degree of grafting were investigated. The optimal conditions for grafting were found to be 3 h, 100°C, and a 50% (v/v) glycidyl methacrylate concentration in tetrahydrofuran solution. This fiber showed good adsorption performance at different concentrations of Hg2+, in particular for trace Hg2+. Under the adsorption conditions of pH = 4, initial concentration = 1000 mg/L, and time = 20 h, the adsorption capacity of the chelating fiber for Hg2+ reached 785.28 mg/g. It completely adsorbed the Hg2+ ions in solution within a short contact time, showing a very high adsorption rate for Hg2+. Furthermore, the chelating fiber also had a high selectivity for mercury, whereas Cu2+ coexisted in different concentrations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Novel hydrogel composite for the removal of water-soluble cationic dyeJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2006Li-Ming Zhang Abstract A novel hydrogel composite was prepared by incorporating Laponite RDS clay into poly(acrylic acid- co - N -vinyl-2-pyrrolodone) hydrogel during in - situ polymerization, and investigated with respect to its adsorption kinetics and isotherm toward Crystal Violet, a widely used cationic dye. It was found that the adsorption kinetics of Crystal Violet onto the hydrogel composite was consistent with the pseudo-second-order model. Compared with pure hydrogel, the hydrogel composite is characterized by greater amounts being adsorbed at equilibrium, and a higher rate constant and initial adsorption rate. By analyzing the experimental data using the Langmuir isotherm equation, an enhanced adsorption capacity was found for the hydrogel composite. Such material is expected to be a good adsorbent for water pollutants such as cationic dyes and treatment of these organic contaminants from wastewater. Copyright © 2006 Society of Chemical Industry [source] Kinetic behaviour of the adsorption and photocatalytic degradation of salicylic acid in aqueous TiO2 microsphere suspensionJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2004XZ Li Abstract A new photocatalyst, named TiO2 microspheres, prepared by a sol-spraying-calcination method, can freely suspend with air bubbling in its aqueous suspension and easily settle down from a water phase under gravity. The experimental results demonstrated that TiO2 microspheres had better adsorption capacity than conventional TiO2 powders, due to large surface area, large pore volume, and also a porous structure. The photocatalytic activity of TiO2 microspheres in aqueous suspension was evaluated using salicylic acid (SA) as a model substrate. It was found that the Langmuir,Hinshelwood model in its integral form described the kinetics of SA photocatalytic degradation in the TiO2 microsphere suspensions better than its simplified form as a first-order reaction model, since the significant substrate adsorption on the catalysts was not negligible. The kinetics of SA photocatalytic degradation with different initial concentrations and pH was further investigated. The experiments demonstrated that the change of pH could significantly affect the adsorption of SA in the TiO2 microsphere suspensions. The effects of substrate adsorption rate and photoreaction rate on the overall performance of photocatalytic degradation is also discussed on the basis of experimental data. Copyright © 2004 Society of Chemical Industry [source] Modeling of the catalytic removal of CO and NO in dry combustion gasesAICHE JOURNAL, Issue 3 2010C. Treviño Abstract Catalytic removal of pollutants in dry combustion gases in a planar stagnation-point flow over a platinum foil is studied using both numerical and analytical tools. The governing equations have been numerically integrated with the Newton technique, and the response curve has been obtained as functions of temperature and the mixture concentrations. Using the appropriate stoichiometry, the additional oxygen needed to reduce the NO and to achieve complete oxidation of CO has been obtained. The asymptotic analysis leads to an algebraic equation for the surface coverage of empty sites as a function of two nondimensional parameters: the mass transfer number, relating the residence time to the chemical time (sort of Damköhler number), and a parameter, which relates the desorption rate to the adsorption rate of carbon monoxide and depends strongly on temperature. Critical conditions of ignition (light-off) and extinction are identified and closed form solutions are obtained for these phenomena. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Adsorption Kinetics and Thermodynamics of Acid Dyes on a Carboxymethylated Chitosan-Conjugated Magnetic Nano-AdsorbentMACROMOLECULAR BIOSCIENCE, Issue 3 2005Yang-Chuang Chang Abstract Summary: The monodisperse chitosan-conjugated Fe3O4 nanoparticles with a mean diameter of 13.5 nm were fabricated by the carboxymethylation of chitosan and its covalent binding onto Fe3O4 nanoparticles via carbodiimide activation. The carboxymethylated chitosan (CMCH)-conjugated Fe3O4 nanoparticles with about 4.92 wt.-% of CMCH had an isoelectric point of 5.95 and were shown to be quite efficient as anionic magnetic nano-adsorbent for the removal of acid dyes. Both the adsorption capacities of crocein orange G (AO12) and acid green 25 (AG25), as the model compounds, decreased with increasing pH, and the decreasing effect was more significant for AO12. On the contrary, the increase in the ionic strength decreased the adsorption capacity of AG25 but did not affect, obviously, the adsorption capacity of AO12. By the addition of NaCl and NaOH, both AO12 and AG25 could desorb and their different desorption behavior could be attributed to the combined effect of pH and ionic strength. From the adsorption kinetics and thermodynamics studies, it was found that both the adsorption processes of AO12 and AG25 obeyed the pseudo-second-order kinetic model, Langmuir isotherm, and might be surface reaction-controlled. Furthermore, the time required to reach the equilibrium for each one was significantly shorter than those using the micro-sized adsorbents due to the large available surface area. Also, based on the weight of chitosan, the maximum adsorption capacities were 1,883 and 1,471 mg,·,g,1 for AO12 and AG25, respectively, much higher than the reported data. Thus, the anionic magnetic nano-adsorbent could not only be magnetically manipulated but also possessed the advantages of fast adsorption rate and high adsorption capacity. This could be useful in the fields of separation and magnetic carriers. Acid dyes adsorption onto the CMCH-conjugated Fe3O4 nanoparticles. [source] Development of Cellulose-DNA ImmunoadsorbentARTIFICIAL ORGANS, Issue 2 2002Deling Kong Abstract: The aim of this study was to prepare a DNA immunoadsorbent for the specific, extracorporeal removal of anti-DNA antibodies from the blood of patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Two kinds of cellulose beads were applied as a carrier. Calf thymus DNA was covalently coupled to the carrier using the epichlorohydrin method. Efforts were focused on optimization of conditions for activation and coupling, trying to couple as much DNA as possible to a certain amount of carrier. It was found that the activation level increased with the increase of NaOH concentration and the amount of epichlorohydrin used. The mole of epichlorohydrin must be in excess of that of NaOH because excess NaOH could react further with the epoxy groups in the beads resulting in a decrease of activation level. High activation level could be obtained in a medium of 3.0 M NaOH. The DNA coupling was found to be mainly temperature and pH dependent. Using 0.1 M Tris-HCl buffer, pH 8 at a temperature of 50,90°C, more than 3 mg of DNA could be coupled to 1 ml of wet beads. Prolonging the coupling reaction under 50°C to 72 h resulted in the same coupling capacity as that obtained under 90°C. To evaluate the adsorption ability for anti-DNA of this immunoadsorbent, batch and circulation tests were applied using SLE patient plasma. The immunoadsorbents showed excellent adsorption capacity, especially the cellulose with smaller size (200,300 ,m). The incubation of 20 ml of patient's plasma with 1 ml of adsorbent resulted in an 80% decline in the anti-DNA antibody level. In the circulation tests, 30 ml of plasma was circulated through a column containing 3 ml of adsorbent. The maximum decline in anti-DNA level, 80%, was obtained after 60 min. Such high adsorption capacity and high adsorption rate suggest this immunoadsorbent may be used for treatment. For comparison, 1,4-butanediol diglycidyl ether activation method and other DNA sources were tested with the same protocol. [source] Engineering LacI for Self-Assembly of Inorganic Nanoparticles on DNA Scaffold through the Understanding of LacI Binding to Solid SurfacesADVANCED FUNCTIONAL MATERIALS, Issue 8 2009Haibin Chen Abstract The potential of utilizing the DNA binding protein lac repressor (LacI) to organize inorganic nanoparticles (NPs) is explored in this study. A peptide cognitive of both SiO2 and TiO2 simultaneously (STB1, -CHKKPSKSC-) is genetically engineered into the C-terminus of LacI to give LacI-STB1, and the inserted STB1 peptides in the context of LacI-STB1 molecules are shown to actively interact with both SiO2 and TiO2. Wild-type LacI is found to interact with the two surfaces at its flexible N-terminal DNA binding domain, and LacI-STB1 exhibits much stronger binding affinity to both surfaces by harnessing a second binding region (STB1 peptide) fused at its C-terminus. The quantitative analysis of binding kinetics reveals that, compared to wild-type LacI with one binding region (N-terminus), two remote binding regions (N-terminus and C-terminus) in LacI-STB1 do not lead to faster adsorption rates to the two surfaces, but remarkably slow down the desorption rates. Finally, using LacI-STB1 as a linker, the successful assembly of a sandwich nanostructure of DNA/LacI-STB1/TiO2 NPs is demonstrated using surface plasmon resonance (SPR) measurements and TEM. The demonstrated LacI-STB1-mediated assembly of TiO2 NPs on DNA scaffold may provide a generic platform for controlled spatial arrangement of various nanoparticles of engineering interest. [source] Influence of the matrix porosity on the synthesis and adsorption behavior of dithiocarbamate styrenic resins toward zinc(II) and cadmium(II) ionsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Priscila A. da Costa Abstract The dependence of the adsorption behavior toward Zn2+ and Cd2+ on the synthesis conditions of dithiocarbamate styrenic resins was investigated. We synthesized styrene,divinylbenzene copolymers with different kinds of porous structures by varying the divinylbenzene (DVB)-to-styrene ratio and the dilution degree of the monomers with n -heptane. The porous structure of these materials was characterized. The introduction of the dithiocarbamate moiety on the copolymers followed a synthetic pathway based on the nitration reaction, reduction of the nitro group to the amino one, and finally, the addition of the amino group to CS2. All of the synthesis steps were monitored by Fourier transform infrared spectroscopy. Only the addition reaction to CS2 was greatly influenced by the copolymer porosity. The effect of the dilution degree on the reaction extension was more pronounced than the effect of the DVB content. The more porous materials with higher dithiocarbamate contents adsorbed a higher amount of ions in a faster way, with Zn2+ being preferable over Cd2+ ions. The difference between the Zn2+ and Cd2+ adsorption rates was enhanced with the copolymer porosity, and also enhanced was the difference between the amounts of ions adsorbed by the copolymer; this suggested that the selectivity toward these ions could be controlled by the copolymer porous structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Protein recovery from enzyme-assisted aqueous extraction of soybeanBIOTECHNOLOGY PROGRESS, Issue 2 2010Kerry A. Campbell Abstract Enzyme-assisted aqueous oil extraction from soybean is a "green" alternative to hexane extraction that must realize potential revenues from a value-added protein co-product. Three technologies were investigated to recover protein from the skim fraction of an aqueous extraction process. Ultrafiltration achieved overall protein yields between 60% and 64%, with solids protein content of 70%, and was effective in reducing stachyose content, with fluxes between 4 and 10 L/m2 hr. Protein content was limited because of high retention of lipids and the loss of polypeptides below 13.6 kDa. Isoelectric precipitation was effective in recovering the minimally hydrolyzed proteins of skim, with a protein content of 70%, again limited by lipid content. However, protein recovery was only 30% because of the greater solubility of the hydrolyzed proteins. Recovery by the alternative of protein capture on dextran-grafted agarose quaternary-amine expanded bed adsorption resins decreased with decreasing polypeptide molecular weight. Proteins with molecular mass greater than 30 kDa exhibited slow adsorption rates. Expanded bed adsorption was most effective for recovery of proteins with molecular weight between 30 and 12 kDa. Overall, adsorption protein yields were between 14% and 17%. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Rapid and Effective Adsorption of Lead Ions on Fine Poly(phenylenediamine) MicroparticlesCHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2006Mei-Rong Huang Prof. Abstract Fine microparticles of poly(p -phenylenediamine) (PpPD) and poly(m -phenylenediamine) (PmPD) were directly synthesized by a facile oxidative precipitation polymerization and their strong ability to adsorb lead ions from aqueous solution was examined. It was found that the degree of adsorption of the lead ions depends on the pH, concentration, and temperature of the lead ion solution, as well as the contact time and microparticle dose. The adsorption data fit the Langmuir isotherm and the process obeyed pseudo-second-order kinetics. According to the Langmuir equation, the maximum adsorption capacities of lead ions onto PpPD and PmPD microparticles at 30,°C are 253.2 and 242.7 mg,g,1, respectively. The highest adsorptivity of lead ions is up to 99.8,%. The adsorption is very rapid with a loading half-time of only 2 min as well as initial adsorption rates of 95.24 and 83.06 mg,g,1 min,1 on PpPD and PmPD particles, respectively. A series of batch experiment results showed that the PpPD microparticles possess an even stronger capability to adsorb lead ions than the PmPD microparticles, but the PmPD microparticles, with a more-quinoid-like structure, show a stronger dependence of lead-ion adsorption on the pH and temperature of the lead-ion solution. A possible adsorption mechanism through complexation between Pb2+ ions and N groups on the macromolecular chains has been proposed. The powerful lead-ion adsorption on the microparticles makes them promising adsorbents for wastewater cleanup. [source] | ||||||||||||||||