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WOS: 000247150200011, PubMed ID: 17696016, The present study was carried out in a batch system using a lichen (Pseudevernia furfuracea (L.) Zopf) for the sorption of nickel(II) and copper(II) ions from water. Particularly, the effect of pH, contact time and temperature were considered. Pseudevernia furfuracea exhibited nickel(II) and copper(II) uptake of 49.87.and 60.83 mg/g at an initial pH of 4 and 5-6 at 35 degrees C respectively. Both the Freundlich and Langmuir adsorption models were suitable for describing the biosorption of nickel(II) and copper(II) by the biosorbent. Biosorption showed pseudo first order rate kinetics for nickel and copper ions. Using the equilibrium constant values obtained at 25 and 35 T, the thermodynamics properties of the biosorption (Delta G degrees, Delta H degrees and Delta S degrees) were determined. The biosorption of nickel(II) and copper(II) onto Pseudevermajurfuracea was found to be endothermic.

WOS: 000087277000010, The separation from fermentation medium of extracellular serine alkaline protease (SAP) enzyme produced by Bacillus licheniformis was investigated using a crossflow ultrafiltration system. SAP was separated from the high molecular weight neutral protease (NP) and amylase (AMY) enzymes and from the low molecular weight organic acids and amino acids in a crossflow ultrafiltration system with 30000 Da and 10000 Da MWCO polysulfone membranes, respectively. The effects of transmembrane pressure (TMP), recirculation velocity (v), and initial enzyme concentration (CE) on the permeate flux, on the activities of SAP, NP and AMY enzymes, and on the recovery of SAP were investigated. High permeate flux was obtained at high recirculation velocity and TMP, but at low initial enzyme concentration. SAP enzyme recovery and activity measured in the system also showed alterations with hydrodynamic conditions. The best operation conditions for the separation of SAP from NP and AMY were TMP = 20 kPa, v = 0.50 ms(-1) and C-E = 0.2 gdm(-3). The separation of SAP from the organic and amino acids was best performed at TMP = 100 kPa, v = 0.33 ms(-1) and C-E = 0.40 gdm(-3). (C) 2000 Society of Chemical Industry.

WOS: 000412916700001, beta-Cyclodextrin (beta-CD)-based nanosponges (NSs) were synthesized by reacting beta-CD with hexamethylenediisocyanate (HMDI) as the cross-linking agent. The effects of the reaction parameters, such as the beta-CD/HMDI molar ratio, reaction temperature, and type of cross-linker, on the NS synthesis were systematically examined. The removal of p-nitrophenol (p-NP) from water by NSs was determined through adsorption experiments. The adsorption efficiency of the NSs synthesized at different temperatures did not change significantly, but the adsorption efficiency of the NSs was influenced by the HDMI concentration and cross-linker type. The characteristic Fourier transform infrared (FTIR) bands showed that p-NP was adsorbed parallel to the surface of the NSs. The Langmuir model had the highest correlation coefficient for the adsorption of p-NP onto the NSs. The maximum adsorption capacity (Q degrees) and adsorption energy (b) for p-NP were estimated to be 1.0 mg g(-1) and 1.837 Lmg (-1), respectively. The NSs synthesized under the optimum conditions were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and laser diffraction particle size (LDPS) analysis. The combination of the results from SEM, TEM, and LDPS analysis indicated that the synthesized NSs had a porous, sponge-like, and rigid structure. The results of XRD and TGA also revealed the formation of beta-CD-NSs., Cumhuriyet University Scientific Research Projects (CUBAP) [M-541], This study was financially supported by Cumhuriyet University Scientific Research Projects (CUBAP) under project number M-541.

WOS: 000245734400009, The aim of this paper is to demonstrate the effects of hydrodynamic conditions on the permeate flux, cake resistance and sieving coefficient in a crossflow ultrafiltration process separating biomolecules of different molecular weights. A binary mixture of L-phenylalanine (L-phe) and lipase was ultrafiltered through a hydrophobic polyether sulphone (PES) membrane with 10 kDa molecular weight cut-off. The changes in permeate flux, cake layer resistance and observed sieving coefficient with different transmembrane pressures (TMP) and crossflow velocities were evaluated. The effect of TMP was examined at two different velocities (0.114 m s(-1) and 0.176 in s(-1)) and the effect of velocity was examined at two different TMP (20 kPa and 115 kPa) for the experimental system designed. In the initial stage of the crossflow filtration, it was determined that the TMP was more effective than the velocity. The cake layer resistance increased with increasing TMP and it decreased with increasing velocity for the high TMP value of 115 kPa. A maximum of the observed sieving coefficient was achieved with increasing velocity. An increase in TMP at low inlet velocity (0.114 in s(-1)) affected the observed sieving coefficient positively.

WOS: 000244295800013, The influence of electrostatic interactions on membrane fouling during the separation of bovine serum albumin (BSA) from solution was studied in a cross-flow ultratiltration system. Experiments were carried out at different pH values between 3.78 and 7.46; and for different ionic strengths between 0.001 M and 0.1 M. The changes in permeate flux, cake layer resistance, zeta potentials of BSA and polyether sulfone (PES) membranes, and electrostatic interaction energies, were evaluated. At all of the ionic conditions studied, PES membranes are negatively charged. However, BSA molecules are either negatively or positively charged depending on the ionic environment. Whereas the cake layer resistance decreased with increasing pH and ionic strength, the permeate fluxes increased. The calculated electrostatic energy was a minimum at the isoelectric point (IEP) of BSA. However, at this point, the cake resistances corresponding to fouling at each ionic strength, were not minimized. Below the IEP of BSA, the electrostatic forces were attractive, while above the IEP, repulsive electrostatic forces were dominant.

WOS: 000242060800078, Thermal characterization of maleic anhydride-styrene-allyl propionate (MA-St-AP) terpolymer and its ester derivatives named as n-alkyl maleate and shown as nPr MA-St-AP, nBu MA-St-AP, nPn MA-St-AP, and nBz MA-St-AP was carried out. The thermal characterization was performed using thermal analysis techniques such as TGA, DTA, DSC, and TMA. Different results were observed between the original terpolymer and its ester derivatives. Thermal stabilities of the terpolymer and its ester derivatives were compared by using various measurements plotted as TGA, DTA, DSC, and TMA curves. The increase in the alcohols' carbon numbers added to the original terpolymer results in ester derivatives with different thermal stability behavior. (c) 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 600-604,2007

WOS: 000234870800017, The optimum AI(III) activation conditions for white bentonite (Ordu, Turkey), used as a bleaching agent for cottonseed oil, were investigated. AICl(3) -clay suspension was hydrolyzed in situ using NaOH to investigate possible pillars. Five controllable factors that mainly affect the activation process were specified as initial AlCl3 concentration (F1), OH-/Al3+ molar ratio (F2), NaOH volumetric flow-rate (F3), cation-exchange temperature (F4) and thermal treatment temperature (F5). Each factor was examined at four levels by using a robust (Taguchi) design to determine optimum activation conditions. The response variable of each experimental run was taken as bleaching efficiency, which is defined in terms of absorbance at 420 nm. The effect of desired levels of factors to the system response was compared using the signal-to-noise (S/N) ratio. An importance factor (IF) was suggested in order to compare the affectability of each factor to the response variable by using the integrated area under the S/N ratio curves. The most important factor affecting bleaching efficiency was F5, followed in sequence by F2 > F1 > F4 > F3. The availability of Al-O species after activation in the clay crystal structure was determined by FTIR analysis. The optimum levels of each factor for Al3+ activation of clay were F1 5 meq g(-1) clay, F2 2.0, F3 1200 m Lh(-1), F4 25 degrees C and F5 700 degrees C. (c) 2005 Society of Chemical Industry.