Breakthrough Technique Research Articles

Efficient micro carbon column rapid breakthrough technique for water and wastewater treatability studies

A simple and cost-effective method for conducting adsorption breakthrough experiments in a microsize carbon column is proposed; it is much faster than the conventional methods. Relative to the existing microcolumn rapid breakthrough (MCRB) methods, this method employs simplified procedure, low cost and readily available pump, sampler, and piping and fittings to allow its practice in an ordinary environmental laboratory. The efficient MCRB method may be employed to identify the best granular activated carbon, to verify its treatment effectiveness, and to estimate its capacity utilization rate and the adsorption treatment cost. The effects of particle size and empty bed contact time on MCRB test results were determined. The validity and benefits of this MCRB method were demonstrated by the adsorption breakthrough data for phenol, red dye X3B, tannic acid, MTBE, 2,4-dichrophenol, and the organic pollutants in a biologically treated coking plant effluent. © 2007 American Institute of Chemical Engineers Environ Prog, 2007

Adsorptive removal of Methylene blue and Methyl orange from aqueous media by carboxylated diaminoethane sporopollenin: On the usability of an aminocarboxilic acid functionality-bearing solid-stationary phase in column techniques

The adsorption phenomena of Methylene blue (MB) and Methyl orange (MO) on a carboxylated diaminoethane sporopollenin (CDAE-S) solid phase were investigated in a column arrangement by using breakthrough technique. The adsorption phenomena were evaluated using some common adsorption isotherm models and Scatchard plot analysis, and obtained results were interpreted for evaluating the usability of CDAE-S for removal, recovery and preconcentration of the studied dyes both at the laboratory and industrial scales. On the basis of Scatchard plot analysis, the interaction types between the CDAE-S and the studied dyes were criticized in terms of affinity phenomena. Thus, the usability of a biomacromolecule-derived material, CDAE-S, as a cheap, environmentally-friendly and effective solid-stationary phase exhibiting both cation-exchange and anion-exchange characteristics at the same time, is discussed through the present study. Besides, from the obtained results, the protonated CDAE-S, which functionally resembles an amino acid structure, are presented as a two-in-one solid-stationary phase, and its adaptability to common processes performed under column conditions is also drawn in detail.

Interaction of nucleic acid bases and nucleosides with cobalt ions immobilized in a column system

The interactions of ligands, such as adenine, adenosine, uracil and uridine with Co(II) ions immobilized by carboxylated diaminoethyl matrix on sporopollenin were investigated as a function of temperature by the breakthrough technique. The adsorption characteristics of ligands on Co(II)-carboxylated diaminoethyl sporopollenin [Co(II)-CDAE-S] were investigated by Scatchard plot analysis under optimized conditions of flow rate and temperature. Equilibrium binding data used in Scatchard plot analysis for adenosine gave rise to a linear plot, indicating the presence of specific interaction and Langmuirean behavior. However, the adsorption of uracil on this ligand-exchange stationary phase was affected by the electrostatic or hydrophobic interaction in the whole concentration range. In the case of adenine and uridine, the adsorption performance was strongly affected by the initial ligand concentration. At high concentration, adenine and uridine were adsorbed specifically to the ligand exchanger matrix exposed on the adsorbent. At lower concentrations, the binding to the second sets of adsorbent was appeared because of nonspecific interaction such as hydrophobic and electrostatic.

Nondestructive Technique for the Characterization of the Pore Size Distribution of Soft Porous Constructs for Tissue Engineering

Polymer scaffolds tailored for tissue engineering applications possessing the desired pore structure require reproducible fabrication techniques. Nondestructive, quantitative methods for pore characterization are required to determine the pore size and its distribution. In this study, a promising alternative to traditional pore size characterization techniques is presented. We introduce a quantitative, nondestructive and inexpensive method to determine the pore size distribution of large soft porous solids based on the on the displacement of a liquid, that spreads without limits though a porous medium, by nitrogen. The capillary pressure is measured and related to the pore sizes as well as the pore size distribution of the narrowest bottlenecks of the largest interconnected pores in a porous medium. The measured pore diameters correspond to the narrowest bottleneck of the largest pores connecting the bottom with the top surface of a given porous solid. The applicability and reproducibility of the breakthrough technique is demonstrated on two polyurethane foams, manufactured using the thermally induced phase separation (TIPS) process, with almost identical overall porosity (60-70%) but very different pore morphology. By selecting different quenching temperatures to induce polymer phase separation, the pore structure could be regulated while maintaining the overall porosity. Depending on the quenching temperature, the foams exhibited either longitudinally oriented tubular macropores interconnected with micropores or independent macropores connected to adjacent pores via openings in the pore walls. The pore size and its distribution obtained by the breakthrough test were in excellent agreement to conventional characterization techniques, such as scanning electron microscopy combined with image analysis, BET technique, and mercury intrusion porosimetry. This technique is suitable for the characterization of the micro- and macropore structure of soft porous solids intended for tissue engineering applications. The method is sensitive for the smallest bottlenecks of the largest continuous pores throughout the scaffold that contributes to fluid flow.

Modeling and analysis of uranium isotope enrichment by chemical exchange

Starting with an accurate mathematical model a theoretical study for the analysis of the separation of uranium isotopes by chemical exchange has been presented. The experimental data used in this study were obtained by reverse breakthrough technique and the numerical algorithm developed for simulation in previous studies was adapted and found to be suitable for this kind of processes. The model parameters were identified from experimental data and simulations were carried out for different experimental conditions.

Ligand adsorption of adenine and adenosine on poly(vinyl chloride) bound cobalt(II)–carboxylated diaminoethyl complex

Abstract Ligand adsorption of adenine and adenosine has been studied by using cobalt(II)–poly(vinyl chloride) carboxylated diaminoethyl (PVC–CDAE) resin. Column runs were conducted to study the performance of the ligand exchanger. The adsorption of adenine and adenosine from solutions of different initial concentrations onto resin was measured using by breakthrough technique at 25 °C. The ligand concentration was chosen to be 0.0125–0.2 mmol l−1. The characteristics of the adsorption process were investigated by using Scatchard plot analysis (q/C versus q). And the adsorption behaviour of these ligands on cobalt(II)–PVC–CDAE is expressed by the Langmuir and Freundlich isotherms. The adsorption data with respect to all ligands provide an excellent fit to the Freundlich isotherm, giving correlation coefficients in the range of 0.95–0.99 for the Freundlich isotherm. On the contrary, when the Langmuir isotherm model was applied to these data, a good fit was not obtained for the high ligand concentrations.

Determination of the rate control step of chlorinated anilines in ligand exchange reactions on solid phase by using breakthrough technique

Abstract Kinetic studies of chlorinated anilines as ligands on the cobalt(II)-carboxylated diaminoethyl-sporopollenin (CDAE-sporopollenin) have been performed using continuous column runs. Adsorption rate measurements were carried out by using a UV–visible spectrophotometer, and rate control step of the reaction was determined. The adsorption of chlorinated anilines from solutions of different initial concentrations onto resin was measured as a function of time at 25 °C. The initial ligand concentrations ranged from 6.0×10 −4 to 2.5×10 −3 mol l −1 . The results concerning the influence of the external solution concentration of the ligands upon the fractional attainment of equilibrium prove that the diffusion of the ligands into the resin beads plays an important role in the mechanism of the exchange reaction, although the exchange rate is chemical in its ultimate mechanism. A very fast initial adsorption resulting in an almost instantaneous attainment of the bulk of the equilibrium adsorption was followed immediately by a very slow rate of adsorption. In the case of 4- and 2,5-dichloroaniline, in all of the concentration range, the graphs of −ln[1− U ( α )] versus t were a straight line, which suggests that fractional attainment of equilibrium adsorption under film diffusion control is observed. On the contrary, 2- and 3-chloroaniline, the graphs were not a straight line and have underwent adsorption under particle diffusion control.

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Determination of binding constants of labile ligands in metal–ligand complexes containing carboxylic groups bound polymer by using breakthrough technique

This study was conducted to confirm the possibilities of determining the binding constants of ligands in metal–ligand complexes containing carboxylic groups bound polymer by using breakthrough technique. Aniline and o -anisidine were selected as model ligands. A mini column apparatus was used to study sorption of ligands onto ligand exchange resin. The experiments were conducted in a constant temperature at 25 °C. The equilibrium sorptions of aniline and o -anisidine were measured in order to determine the part of the sorption on Co(II)-CDAE-sporopollenin resin. The sorption of aniline is seen to be higher than that sorption of o -anisidine. The characteristics of the sorption process were investigated using Scatchard plot analysis ( q / C vs. q ). In the sorption of o -anisidine, deviation from linearity in the plot of q / C versus q was observed, indicating the presence of multi-model interaction and non-Langmuirean behavior. Furthermore, in high concentration of aniline deviation from linearity in the plot of q / C versus q was appeared. Particularly for o -anisidine, divergence from the Scatchard plot was evident, consistent with the participation of secondary equilibrium effects in the adsorption process. However, Scatchard plot analysis of the equilibrium binding data for aniline onto ligand exchanger gave rise to a linear plot. The ligand binding constants of aniline and o -anisidine were determined as 0.071 and 0.156 mol mol −1 Co 2+ , respectively.

Isotope Effects of Copper in Cu(II) Ligand-Exchange Systems by Ion Exchange Chromatography.

The isotope effects of copper in ligand exchange processes were studied by means of chelating ion exchange resin system and EDTA complex/cation-exchange resin system. Two cases of different ionic interactions systems were investigated using chelating ion exchange resin system; Cu-H and Cu-Co systems. Both cases were investigated using the breakthrough technique, while the reverse breakthrough technique was applied in the case of EDTA. The chromatograms obtained from two different chelating resin systems were not ideal but they can be improved in future work. The heavier isotope 65Cu was found to be enriched in the ligand side in all cases, the resin phase in the case of chelating resin and the solution phase in the case of EDTA complex system. The separation coefficients in the two chelating systems were found to be constant and equal to 1.1×10-5. Concerning the EDTA complex system, the chromatogram obtained was ideal one and the separation coefficient was found to be 1.3×10-5.

Void damage model and service life prediction for solid high polymer

Based on the analysis of three void damage variety models, this note presents (i) a method that regards the void content as a damage variation of the grain and (ii) a geometric model for micro-unit of void damage. Equations of the void damage variety containing void content are analyzed. This work is focused on the measurement of internal damage level and the damage variety estimation is directly related to the life predication in the practical engineering applications. Nowadays, the critical service life of the solid grain/polymers is usually presumed at domestic and international level. The strength or strain reduction of 20% or the stabilizer consumption of 50% is generally regarded as a critical storage life of the solid grain/polymers, and the service life is predicted by the extrapolation method on Anhenius formula. The applications, however, show that the above method is unreliable and has significant errors. With the aid of the discontiguous automatic measuring device of real time volume deformation and void content, the master curve of void damage variety, the storage service life and the surplus life of a solid rocket grain are obtained. Since the critical storage life has been measured, and the accuracy of the service life prediction has been greatly increased. It is a novel ideal and a break-through technique.

Rapid breakthrough measurement of void volume for field-flow fractionation channels

A peak breakthrough technique is described and evaluated for measuring the void volume of field-flow fractionation (FFF) channels, particularly those used for flow FFF. This technique uses a high-molecular-mass macromolecular or particulate probe that can be displaced rapidly by flow through the FFF channel with minimal transverse diffusion. The particles that emerge first are those carried through the entire length near the channel at the apex of the parabolic flow profile. These particles generate a sharp breakthrough profile. The measured breakthrough time is two thirds of the void time, thus making it possible to calculate both the void time and the associated void volume. This method, although applicable to all FFF channels (and capable of extension to open tubes), is particularly useful for flow FFF because conventional low-molecular-mass void probes can diffuse into the permeable wall and thus distort void measurements. The theoretical basis of the breakthrough technique and an explanation for the sharpness of the breakthrough front are given. A method for compensating for deviations from perfect sharpness is developed in which the breakthrough time is identified with the time needed to reach 85–88% of the breakthrough peak maximum. Preliminary experimental results are shown using various protein probes in four different FFF channel systems.

Separation of the enantiomers of β-receptor blocking agents and other cationic drugs using a CHIRAL-AGP ® column : Binding properties and characterization of immobilized α 1-acid glycoprotein

The effect of the immobilization procedure on the conformation of α 1-acid glycoprotein (AGP) was investigated by recording the fluorescence spectra of native and immobilized AGP. A 20-nm red shift was obtained for the immobilized form of AGP compared with the emission maximum of 338 nm obtained for native AGP. This demonstrates that the tryptophan residues are exposed on the protein surface after immobilization, indicating that the immobilized form of AGP has a more unfolded structure than the native AGP. The effect of N,N-dimethyloctylamine on the enantioselectivity for some fentiazine derivatives, observed with immobilized AGP, was equal to that obtained with AGP as a chiral complexing agent in the mobile phase. This demonstrates that even though the immobilization procedure affects the conformation of the protein there still exist large similarities between native and immobilized AGP concerning chiral recognition. The adsorption isotherm of (−)-terodiline was studied by use of the breakthrough technique. The adsorption isotherm indicates that (−)-terodiline is adsorbed to one site with high affinity and at least one more site with lower affinity. It was also observed that the enantiomers of amines, acids and non-protolytic compounds compete with the cationic compound, (−)-terodiline, for binding to the same sites. The β-receptor blocking agents atenolol, metoprolol, pindolol, alprenolol, oxprenolol and propranolol were resolved on a CHIRAL-AGP ® column. The retention and enantioselectivity are highly influenced by the structure of the solute and the nature of the uncharged mobile phase additives. Separation factors of 1.2–1.8 were obtained for the β-blockers under the studied conditions.

Dynamic capacity and mass transfer for removal of Na+ by a composite hydrated antimony pentoxide-organic ion exchanger

The removal of Na+ by a composite hydrated antimony pentoxide-sulfonated phenol-formaldehyde ion exchanger (C-HAP) from 4M HCl was studied using the breakthrough technique. The dynamic removal capacity for Na+ from 4M HCl is 12.3 mg Na+/g and 9.87 mg Na+/g at 0.2 ml/min and 0.8 ml/min, respectively. Height equivalent to a theoretical plate varies almost linearly with flow rate indicating particle diffusion control.

Zone formation in ion-pair RPLC I. Effects of adsorption of organic ions on established column equilibria

Adsorption of organic ions to μBondapak Phenyl from a water-based mobile phase was studied by the breakthrough technique. The adsorption of decanesulfonate as sodium ion pair as well as of an organic cation, dimethylprotriptyline, as phosphate ion pair was best fitted to a two-site ion-pair adsorption model of the Langmuir type indicating a heterogenous solid phase surface. Introducing an organic ion into a column in equilibrium with an organic ion of opposite charge created negative zones due to increased adsorption of the second ion. The positions of the beginning and the end of the zone were dependent of the concentrations of the two organic ions in the system.

Permeation characteristics of some iron and nickel based alloys

The permeation characteristics of deuterium in several iron and nickel based alloys were measured by the gas phase breakthrough technique in the temperature range 100 to 500 °C with applied pressures ranging from 10 Pa to 100 kPa. The restriction of the gas flux imposed by surface oxides was modeled in order to evaluate the effects of surface oxide retardation of the gas flux on the effective values of the deuterium permeabilities and diffusivities in the alloys. The most permeable alloys were 430 and 431 stainless steels. The next most permeable alloy was Monel K-500, which exceeded the permeability of pure Ni by more than a factor of five at room temperature. The alloys with permeabilities less than pure Ni were, in order of decreasing permeability: the Inconels 625, 718, and 750, the Fe-Ni-Co glass-sealing alloys Kovar and Ceramvar, and the 300-series stainless steels. Deuterium trapping within the alloys appeared to influence the values of bulk diffusivities, which were not correlated with either the permeabilities or the chemical compositions of the alloys.

Removal of organic compounds by ligand sorption on polymer-anchored ferric ion

The sorption of phenol, aniline and ethylamine on polymer-bound ferric ion has been measured, both kinetically and under equilibrium, using a sulfonic polystyrene resin and an iminodiacetic chelating resin to bind the ferric ion. Of the three ligands, only phenol forms polymer-bound ferric complexes, which are easily decomposed by alkali, facilitating recovery of the ligand in the iron-free state. Aniline is oxidized by resin-Fe(III) to insoluble products, while ethylamine is found to react with resin-Fe(III), precipitating the metal ion as hydroxide. The saturation sorption capacity of the resins in ferric form and the stability constant of the sorption complexes have been evaluated from the equilibrium data for phenol. The initial kinetic data have been used to obtain an estimate of particle diffusivities for the resin-ligand systems. The ligand sorption capacity and the distribution coefficient have been determined by a breakthrough technique for comparison with the respective values obtained from batch equilibrium data. The level of pH in the range 2–7 has a marked influence on the sorption of phenol and amine, but has little effect on the removal of aniline.

Separation factors for lithium isotope exchange on the amberlite IR-120 cation exchange resin

The effect of concentration on the elementary separation factor for various lithium compounds (LiNO/sub 3/, LiCl, Li/sub 2/SO/sub 4/, CH/sub 3/COOLi, and LiOH) Was investigated using the breakthrough technique on an exchange column. Depending on the concentration and the anion, the separation factors varied from 1.019 to 0.999, Li/sup 7/ being enriched in the solution. In cases of the chloride and nitrate solutions distinct maxima at the concentration of 2N (1.019 and 1.014 resp.) were observed. Minima appeared at 3 resp. 4N with factors of 1.007 and 0.999. The solutions of sulfate, acetate, and hydroxide showed factors between 1.0021 and 1.0003 with a less pronounced concentration dependence. Addition of alcohol, glycol, or dioxane to the lithium salt solutions acted in the sense of decreasing the separation parameters. A qualitative explanation is based on ion pair formation. (auth)