Batch Column Research Articles

Unified design of chromatographic separation processes

A unified method is developed for the designing preparative chromatographic processes of various types. The method allows, for example, generalizing the established triangle theory of counter-current simulated moving bed technique for other single and multi-column chromatographic schemes including (1) classical batch chromatography, (2) mixed-recycle steady state recycling chromatography, (3) cross-current chromatography, and (4) mixed-recycle cross-current recycling chromatography. The approach allows direct prediction of the range of feasible dimensionless operating parameters that lead to complete separation of a binary feed mixture. By using the equilibrium theory of chromatography, explicit design equations are derived for systems that follow linear or competitive Langmuir isotherm model. It is shown that under ideal conditions the boundaries of the dimensionless operating parameters are identical for all studied process concepts, except for the upper limit of a parameter that is related to the regeneration of the fluid phase in the case of Langmuir isotherm. The practical relevance of the unified design method is demonstrated with numerical simulations. It is shown that even under non-ideal conditions the counter-current SMB can be designed with good accuracy based on a single pulse injection to a batch column, especially for relatively low purity requirements.

PURIFICATION OF RUMEN MICROBIAL XYLANASE WITH IMMOBILIZED SEPHAROSE-CIBACRON BLUE F3GA IN COLUMN CHROMATOGRAPHY

Sepharose-Cibacron blue (CB) F3GA for pseudo-affinity adsorption of bioproducts was synthesized and was subjected to rumen microbial enzyme evaluation through batch binding and column chromatography of xylanase. Based on equilibrium adsorption data, the best temperature, contact time, and elution agent were 30°C, 15 min, and 0.5 M NaCl (pH 6), respectively. The results show that homogenizing method had better performance in the liberation of enzyme, so that the amount of enzyme in rumen liquor approximately doubled. In pre-concentration methods, it was shown that freeze drying and precipitation of enzyme using ammonium sulfate were the best. Microbial xylanase was purified from rumen liquor to 1.85- and 11.80-fold by ammonium sulfate fractionation and Sepharose-CB column chromatography, respectively.

English

English

Stability of Prussian Blue in Soils of a Former Manufactured Gas Plant Site

Soil contamination with iron-cyanide complexes is a common problem at former manufactured gas plant (MGP) sites. Dissolution of the cyanide, from Prussian Blue (ferric ferrocyanide), creates an environmental hazard, whereas the risk of groundwater contamination depends on the stability of dissolved iron–cyanide complexes. Lack of a standard leaching method to determine the water-soluble (plant-available) cyanide fraction generates potential limitations for implementing remediation strategies like phytoremediation. Applicability of neutral solution extraction to determine the water-soluble cyanide fraction and the stability of Prussian Blue in surface and near-surface soils of an MGP site in Cottbus, undersaturated and unsaturated water conditions, was studied in column leaching and batch extraction experiments. MGP soils used in the long-term tests varied according to the pH (5.0–7.7) and the total cyanide content (40–1718 mg kg−1). Column leaching, after four months of percolation, still yielded effluent concentrations exceeding the German drinking water limit (> 50 μg L−1) and the solubility of Prussian Blue reported in the literature (< 1 mg L−1) from both alkaline and acidic soils. Long-term (1344 h) extraction of MGP soils with distilled water was sufficient to dissolve 97% of the total cyanide from the slightly alkaline soils and up to 78% from the acidic soils. Both experiments revealed that dissolution of ferric ferrocyanide under circum-neutral pH and oxic water conditions is a function of time, where the released amount is dependent on the soil pH and total cyanide content. Unexpectedly high and continuous solubility of Prussian Blue, both in acidic and slightly alkaline MGP soils, implies the need to introduce an additional cyanide fraction (“readily soluble fraction”) to improve and specify cyanide leaching methods. Long-term extraction of cyanide-contaminated soil in neutral solution seems to be a promising approach to evaluate the potential hazard of groundwater pollution at the MGP sites.

Sorption and Retardation of &lt;sup&gt;90&lt;/sup&gt;Sr&lt;sup&gt;2+&lt;/sup&gt;in Loess Media

Non-radioactivestrontium(Sr2+) was used to investigate the migration of radioactivestrontium in loess. The sorption and retardation characteristics of strontiumin loess were studied by batch tests and column experiments. The experimentalresults showed that the equilibrium sorption data for Sr2+ was fitting well tothe Freundlich isotherm models(r2= 0.97). And the Rd obtained frombatch experiment was larger than Rd determined by column test. The resultsindicated that Rd values derived from column tests are more accurate toevaluate transport of radionuclides in contact medium.

Batch and Fixed-Bed Column Studies of Arsenic Adsorption on the Natural and Modified Clinoptilolite

The samples of natural and iron-modified clinoptilolite (GC, Na-GC, Fe1-GC, and Fe2-GC) were assessed as adsorbent for arsenate removal by batch and column studies. The influences of retention time, pH, adsorbent dosage, and initial arsenate concentration on the arsenate adsorption efficiency were investigated. The experiments demonstrated that Fe1-GC has the highest arsenate removal efficiency with the adsorption capacity of 8.4 μg g−1 at equilibrium time of 60 min. Both the Fe1-GC and Fe2-GC removed arsenate effectively over the initial pH range 4–10. Adsorption capacity of Fe1-GC was adequately described by Freundlich isotherm. According to the results of the desorption performance experiments, the Fe1-GC was used six times until arsenic removal efficiency was reduced to 19 %. The adsorption percentage of arsenic increased with the diminish of initial concentration of arsenic and increase of adsorbent dose for all types of clinoptilolite. The column study demonstrated that Fe1-GC was achieved to reduce final arsenate of about 10 μg L−1 or below for up to 300 bed volumes in a continuous flow mode. The results of this study show that Fe1-GC can be used as an alternative adsorbent for arsenate removal.

STUDI OZONISASI SENYAWA ORGANIK AIR LINDI TEMPAT PEMROSESAN AKHIR SARIMUKTI

Existing treatment leachate from Sarimukti Landfill doesn’t meet the quality standards of waste water.Preliminary treatment is necessary to break down persistent leachate compounds. Ozone can act directly orindirectly with organic material (Glaze 1986). Column batch reactor system use one liter volume. Ozone ispumped into the leachate in the form of fine bubbles. Variations include Ozone Pumping Flow, Ratio ofhigh/diameter (t/d), and pH. Kinetic Reaction of oxygen dissolution in the average leachate is zero order.Increased pumping air discharge and increased pH makes ozone transfer process better. Best value occurs at pH11, where the value of the reaction rate constant ozone 1.48. The average percentage of organic materialallowance 31% COD and 26% TOC. The decline TOC and COD have a tendency to be influenced by the pHoptimum 8-9. At alkaline pH makes carbonate (CO3) formed the greater, that make ozone compounds killquickly. FTIR results showed the intensity of hydroxyl groups increased after ozone oxidation where thesubstitution of functional groups of organic matter associated with electrophilic addition reaction of oxygenatoms. Existence Fulfic acid also increased the effect compounds and Humic Acid, Humad large has been cut byradicals.

Determination of Rosiglitazone and 5-Hydroxy Rosiglitazone in Rat Plasma Using LC–HRMS by Direct and Indirect Quantitative Analysis: A New Approach for Metabolite Quantification

With recent advances in mass spectrometry instrumentation, HRMS is of increasing interest for quantitative bioanalysis due to its high sensitivity, rapid acquisition of full scan data, and advanced software for metabolite identification. In particular, there is strong interest in use of HRMS for simultaneous quantification of parent drug and metabolites without authentic metabolite standard materials. Rosiglitazone and 5-hydroxy rosiglitazone in rat plasma were analyzed using LC-Q-TOF by both direct and indirect quantitative analysis. Direct quantitative analysis used an authentic metabolite standard (5-hydroxy rosiglitazone). Indirect quantitative analysis firstly used the parent drug (rosiglitazone) calibration curve to provide a semiquantitative measure of metabolite concentration. A correction factor was then applied to the original data to re-calculate the 5-hydroxy rosiglitazone metabolite concentration. The ratio of the calibration curve slope of rosiglitazone to that of 5-hydroxy rosiglitazone was determined to be 2.09 ± 0.28 using different batches of mobile phases and columns. The correction factor 2.09 was then used to correct for the 5-hydroxy rosiglitazone concentrations found from the semiquantitative results using the rosiglitazone calibration standard curve. The concentrations of 5-hydroxy rosiglitazone found by direct and indirect quantitative analysis were highly comparable (within ±8%). Indirect quantitative analysis provides an alternative approach for metabolite quantification for discovery PK studies.

Solid Phase Extraction of Phenol on Zeolitic Material: Batch Sorption and Column Dynamics

The solid phase extraction of phenol using hydrothermal (CZBFA) and fusion synthesized zeolitic materials (FZBFA) were carried out by batch and column mode. The chemical composition and the functional groups of synthesized zeolitic materials were investigated by XRF and FTIR. The major zeolitic phases and morphology were identified by PXRD and SEM techniques. The isotherms were estimated for the nature of sorption of phenols on sorbents. Thermodynamics parameters exhibited the endothermic nature of sorption. The phenol sequestration is highest for FZBFA as compare to bentonite, mud, and resin sorbents but lower than the activated carbon. Desorption of phenol is highest for BFA with 0.5 M NaOH.

Evaluating the performance of different multicolumn setups for chromatographic separation of proteins on hydrophobic interaction chromatography media by a numerical study

A theoretical study has been performed on the effectiveness of isolating a target component out of a multi-component protein mixture using different arrangements of chromatographic columns. Three continuous systems have been considered which were able to perform solvent gradient separations, such as: open loop simulated moving bed, countercurrent solvent gradient purification and carousel multicolumn setup. The performance of the continuous processes was examined with respect to productivity, yield and eluent consumption and compared to a single-column batch system. As a case study separation of a ternary mixture of proteins on HIC media has been selected. Two separation problems have been analyzed referring to the situation when the target component was the most strongly adsorbed as well as when it exhibited intermediate adsorption strength. A mathematical model has been used to simulate the process dynamics and to optimize operating conditions for the separation. The numerical study indicated that batch column arrangements can outperform SMB-based configurations regarding all performance indicators considered, which has been attributed to solvent mixing in the recycled streams and distortion of the gradient shape in SMB units. It has been concluded that the performance of complex multicolumn systems should be verified vs. batch column operations prior to the realization of the separation process.

Adhesion of bacteria to pyrophyllite clay in aqueous solution

The aim of this study was to investigate the adhesion of bacteria (Escherichia coli) to pyrophyllite clay using batch and flow-through column experiments. Batch results demonstrated that pyrophyllite was effective in removing bacteria (94.5±2.0%) from aqueous solution (1 mM NaCl solution; pyrophyllite dose of 1 g/ml). At solution pH 7.1, negatively-charged bacteria could be removed due to their adhesion to positively-charged surfaces of pyrophyllite (point of zero charge=9.2). Column results showed that pyrophyllite (per cent removal of 94.1±2.3% ) was far more effective in bacterial adhesion than quartz sand (53.6±5.3%) under the given experimental conditions (flow rate of 0.3 ml/min; solution of 1 mM NaCl + 0.1 mM NaHCO3). Bacterial removal in pyrophyllite columns increased from 90 to 100% with decreasing flow rate from 0.6 to 0.15 ml/min due to increasing contact time between bacteria and filter materials. In addition, bacterial removal remained relatively constant at 94–97% even though NaHCO3 concentration increased from 0.1 to 10 mM (flow rate of 0.3 ml/min). This could be related to the fact that pyrophyllite remained positively-charged even though the solution conditions changed. This study demonstrates that pyrophyllite could be used as adsorptive filter materials in the removal of bacteria.

Model reduction and optimization of a reactive dividing wall batch distillation column inspired by response surface methodology and differential evolution

Carrying out reaction and separation simultaneously in a reactive dividing wall batch distillation column batch RDWC in the case of ethyl acetate synthesis provides the possibility of separating both products and increasing the equilibrium reaction conversion. Overcoming the known azeotrope conditions, high purity for ethyl acetate and decreasing the batch time compared to simple reactive batch distillation are the advantages of this configuration. The corresponding dynamic simulation is carried out by simultaneously solving the model-associated system of differential and algebraic equations. In this study, the optimal values of the vapour and liquid split ratios are considered as the decision variables in order to maximize the amount of ethyl acetate accumulated during batch time. The optimization strategy is implemented inspired by response surface methodology in which an optimal surface is fitted to the collected data set using differential evolution (DE). The optimal surface relevant algebraic equation is then considered as the reduced form of the complex model and the optimal values are obtained using the DE method.

Arsenic Entrapment in Reactive Columns of Residual Soils

Fil: Carro Perez, Magali Evelin. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Estudios Avanzados en Ingenieria y Tecnologia. Universidad Nacional de Cordoba. Facultad de Ciencias Exactas Fisicas y Naturales. Instituto de Estudios Avanzados en Ingenieria y Tecnologia; Argentina

Application of Polythiophene–Sawdust Nano-Biocomposite for Basic Dye Removal Using a Continuous System

A novel dye adsorbent was developed by a poly (3-methyl thiophene) nano layer coated onto sawdust obtained from Narra wood. The polymer was synthesized chemically under in-situ conditions on the surface of the sawdust. Methylene blue, a typical cationic textile dye, was employed as a test probe for adsorption experiments. The experiments were conducted in both batch and fixed-bed column systems. The effects of variables such as pH, initial dye concentration, flow rate, and bed height were investigated. The Thomas dynamic model was applied to calculate the sorption capacity of adsorbents. Based on the breakthrough curves analysis, the highest column capacity of 191 mg/g was obtained. The introduced nano-biocomposite was found to be more than seven times more efficient than unmodified sawdust for methylene blue removal. The regeneration of the modified sawdust is quite possible using 0.10 M HCl in ethanol as a washing solution with high efficiency.

Organic substrates as electron donors in permeable reactive barriers for removal of heavy metals from acid mine drainage

This research was conducted to select suitable natural organic substrates as potential carbon sources for use as electron donors for biological sulphate reduction in a permeable reactive barrier (PRB). A number of organic substrates were assessed through batch and continuous column experiments under anaerobic conditions with acid mine drainage (AMD) obtained from an abandoned lignite coal mine. To keep the heavy metal concentration at a constant level, the AMD was supplemented with heavy metals whenever necessary. Under anaerobic conditions, sulphate-reducing bacteria (SRB) converted sulphate into sulphide using the organic substrates as electron donors. The sulphide that was generated precipitated heavy metals as metal sulphides. Organic substrates, which yielded the highest sulphate reduction in batch tests, were selected for continuous column experiments which lasted over 200 days. A mixture of pig-farm wastewater treatment sludge, rice husk and coconut husk chips yielded the best heavy metal (Fe, Cu, Zn and Mn) removal efficiencies of over 90%.

Bacteriophage removal by Ni/Al layered double hydroxide in batch and flow-through column experiments

The objective of this study was to investigate the removal of the bacteriophage MS2 by Ni/Al layered double hydroxide (LDH). Batch experiments were performed using a powder form of Ni/Al LDH under various conditions. Column experiments were also performed under flow-through conditions with Ni/Al LDH coated sand. Batch tests showed that the powder form of Ni/Al LDH was effective for bacteriophage removal under the given experimental conditions (LDH dose of 2.5 g L−1; initial MS2 concentration of 1.35 × 105 plaque forming unit (pfu) mL−1) with a removal capacity of 5.5 × 107 pfu g−1. The results also indicated that the effect of the solution pH on the bacteriophage removal was minimal at pH 4.3−9.4. The influence of divalent anions (SO2− 4, CO2− 3, HPO2− 4; concentrations 1−100 mM) on the removal of the bacteriophage was significant, while the effects of monovalent anions (NO− 3, Cl−) were negligible. Column experiments showed that the log removal of MS2 was 4.51 in columns containing 100% Ni/Al LDH-coated sand, while it was 0.02 in columns containing 100% quartz sand (initial MS2 concentration of approximately 7.0 × 105 pfu mL−1; flow rate of 0.5 mL min−1). These findings indicated that Ni/Al LDH-coated sand was far more effective at removing bacteriophage than sand alone. This study demonstrates that Ni/Al LDH can be used for virus removal in water treatment and filtration applications.

Energetic optimization of algal lipid production in bubble columns: Part II: Evaluation of CO2 enrichment

This study evaluated growth and lipid productivity of Nannochloropsis salina under sparging with carbon dioxide-enriched air. Carbon dioxide enrichments ranging from 0.5 to 9.5% and gas-to-culture volume ratios ranging from 0.02 to 1.0 min−1 were tested in 900 mL bubble column batch reactors. An energy-based approach is proposed to optimize CO2 enrichment. Cultures sparged with CO2-enrichments of 0.5–4% grew at nearly double the rate of those sparged with ambient air, accumulating 64% or more lipids. Based on energy efficiency, CO2-enrichment of 0.5% was found to be optimal while CO2-enrichments of 6.5% and greater were observed to cause inhibition. At this optimal CO2-enrichment of 0.5%, no significant changes were noted in the lipid content over the range of gas-to-culture volume ratios tested. These studies indicated that optimal energy recovery from N. salina can be achieved with CO2-enrichment of 0.5% sparged at a gas-to-culture volume ratio 0.18 min−1. Under this optimal condition, biomass growth rate was 0.161 g L−1 d−1, and the lipid content was 67.8%, yielding total lipid production of 0.771 g L−1 over 10 days at a net energy yield of 25 W m−3.

Consideration of emerging pollutants in groundwater-based reuse concepts

Elimination of pathogens and emerging pollutants represents a key factor in integrated water resources management in arid regions. Within the SMART Jordan Valley project it is the objective of this study to assess the occurrence and examine the elimination of selected emerging pollutants and pathogens in waste water treatment and aquifer recharge. In batch and soil column studies non-chlorinated organophosphorous compounds (tri-n-butylphosphate, triphenylphosphate) and endocrine disruptors (e.g. 17-ß-estradiol, bisphenol A) proved to be biodegradable, while the X-ray contrast agents iomeprol and iopromide were eliminated in the soil columns only, and the chlorinated trialkylphosphates showed persistency. Treating waste water in a membrane bioreactor (MBR) in combination with powdered activated carbon (PAC) resulted in considerable removal rates also for the more persistent compounds such as the antiepileptic carbamazepine. Viruses were shown to be present in most of the Jordan Valley surface water samples. MBR treatment resulted in a decrease of MS2 bacteriophages used as model viruses.

REMEDIATION OF ORGANICS-CONTAMINATED SANDY SOIL BY IN-SITU WASHING

A new method of in situ soil remediation called in situ washing by sedimentation (IWS) was introduced, by injecting a high air-pressure into a mixture of saturated water-sandy soil and hydraulically separating the soil particles based on their particle size and density. This physical separation exploits the distribution of contaminant in the soil by physically separating a selected contaminant-rich fraction. The effect of soil-water ratio and diameter geometry of the column on the effectiveness of separation by IWS was investigated. Soil-water ratio 1:2 (v/v) was found to be optimum for particle segregation produced by IWS, however, generally the diameter geometry column was not effect on the particle separation. The suitability of IWS for organics remediation was investigated by batch column experiment. The laboratory experiment was effective to produce a distinct size separation of the contaminated soil into the coarse and fine fractions, as well as the wash water, and indicating that a significant reduction in organics contaminant level (90%) may be achieved.

Application of Nano Surfactant Modified Biosorbent as an Efficient Adsorbent for Dye Removal

In the current study, sorption of methylene blue dye (MB) from aqueous solutions, using sawdust modified with sodium dodecyl sulfate (SDS/SD) has been investigated. Sorption experiments were performed using batch and fixed-bed column systems. The effects of important parameters, such as pH, initial dye concentration, flow rate, and bed depth on the sorption of MB dye have been studied. Thomas and the bed-depth service time model (BDST) were applied for analysis of sorption data and estimating of sorption capacity. In order to drive adsorption isotherms, sorption experiments were conducted in batch mode and the treatment of the obtained data were carried out using the Langmuir and Freundlich equations. Based on the breakthrough analysis obtained from continuous sorption experiments, the highest column capacity of 129.68 mg g−1 was obtained for the SDS/SD adsorbent. The results of this study indicated that surfactant-modified sawdust is much more effective for basic MB dye removal compared to untreated sawdust (SD) and the exhausted SDS/SD column can be easily regenerated using dilute HCl solution with high performance (>95%). The results of this study also indicated the successful applicability of the introduced adsorbent as a very efficient and cost effective adsorbent for the removal of cationic dye molecules from aqueous wastes.