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Tartaric acid is a dicarboxylic acid naturally present in grapes, and has many application areas with its salts. It can be produced synthetically, manufactured as a by-product in wine industry, or can be recovered by electrodialysis and solvent extraction methods. Since, ion exchange is one of the oldest processing techniques for the recovery and purification of valuable materials, it can be applied to obtain this valuable organic acid. In this study it is aimed to investigate the effects of resin basicity, initial concentration, and initial pH of the solution on ion exchange equilibrium. The model tartaric acid solutions were prepared for the equilibrium analysis with two different anion exchange resins in a batch type system. A shaker bath at 28 oC with 300-rpm agitation rate was used. The weakly basic resin Lewatit MP62, and strongly basic resin Lewatit M511, which are in polystyrene structure, was obtained from the producer Bayer AG. In the analysis, Shimadzu PDA Detector at 210 nm with Waters Atlantis dC18 column was used. 20 mM NaH2PO4 at pH = 2.7 was introduced to the HPLC as the mobile phase at 0.5 ml/min flow rate. In the investigation of the resin basicity, MP62 presented better performance than M511. The equilibrium experiments were performed at three different initial acid concentrations (0.01, 0.02, and 0.10 M) for both resin, and in the pH ranges pH &lt / pKa1, pKa1 &lt / pH &lt / pKa2, and pKa2 &lt / pH for weakly basic resin, and in the pH ranges pH &lt / pKa1, pKa1 &lt / pH &lt / pKa2 for strongly basic resin at each concentration. Results show that the pH of the solution is a more important parameter than the initial concentration that affects the ion exchange equilibrium. Also, Langmuir and Freundlich isotherms were plotted, and it was shown that they were in good agreement with the experimental data especially for the systems that are at low total ion concentrations.

Caffeine is a commercially important member of a group of purine alkaloids found in coffee, tea and cacao particularly. It is an important ingredient in beverages and most important chemical element of stimulating pharmaceuticals. Caffeine is either manufactured by total synthesis or as a by-product from the decaffeinated coffee manufacturing. To investigate the equilibrium relationship of caffeine in ion exchange systems, which are widely used for recovery and purification processes, was the aim of this study. The effects of initial caffeine concentration and pH of the solution on equilibrium were also investigated. Stock solutions of caffeine were prepared for screening of available adsorbents and cation exchange resins. A batch type operation was carried out in a shaker bath at 40 oC with 200 rpm agitation rate. After preliminary experiments, only Lewatit S100, which is a strongly acidic cation exchange resin with s-dvb copolymer matrix, was studied. For the analysis of samples, HPLC equipment with Shimadzu PDA Detector at 254 nm and Nucleosil 100 C18 column was used. As mobile phase, a mixture of 8% acetonitrile, 8% 2-Propanol, and 1% acetic acid was introduced at 1.5 mL/min flow rate. Results showed that, the caffeine uptake capacity of cation exchange resin was poor. A set of experiments were performed at three initial concentrations (0.005 M, 0.0075 M, and 0.01 M) and four different pH regions (acidic, slightly acidic, neutral, and basic). It was found that, at extreme pH conditions, the caffeine loading capacity of the resin was slightly increased. A significant effect of initial caffeine concentration, however, couldn&rsquo / t be observed. Due to the poor performance of gel type cation exchange resin and large molecular structure of caffeine molecule, Lewatit&rsquo / s SPC 112 macroporous resin was studied briefly for caffeine uptake performance. It was observed that SPC 112 has also poor but better loading capacity than S100 cation exchange resin.

Ion exchange of heavy metals with zeolites is important in terms of different application areas. Industrial wastewater treatment and antibacterial applications are two essential areas that have taken great attention. While silver, zinc and copper are well known for their toxicity, they are also used as antibacterial agents in zeolites. The objective of this study is to investigate the single and multicomponent ion exchange behavior of zeolite 4A for silver, zinc, copper and sodium ions. For this purpose Ag+-Na+, Zn2+-Na+, Cu2+-Na+ binary systems and Ag+-Zn2+-Na+, Ag+-Cu2+-Na+, Cu2+-Zn2+-Na+ ternary systems were investigated in batch systems at 25&deg / C and 0.1 N. Binary ion exchange isotherms indicate that zeolite 4A has high selectivity for silver, zinc and copper with respect to sodium. All exchange isotherms lie above the diagonal over the whole range. Using the equilibrium data, the thermodynamic analysis of the binary systems were carried out. The thermodynamic equilibrium constants and the standard free energies of exchange were calculated as 340.9 and -14.5 kJ/mol for silver-sodium system, 40.5 and -4.6 kJ/mol for zinc-sodium system, and 161.2 and -6.3 kJ/mol for copper-sodium system, respectively. From these values, selectivity sequence of zeolite 4A was determined as Ag+ &gt / Cu2+ &gt / Zn2+. This selectivity sequence was also verified by the results of ternary ion exchange experiments. The experimental data were compared with the Langmuir and Freundlich isotherms. While Freundlich model gives a better correlation for Ag+-Na+ and Zn2+-Na+ exchange, Langmuir model represents a better fit to the experimental data of Cu2+-Na+ exchange.

Heavy metal ions, such as cadmium and lead, should be removed from wastewaters to prevent bioaccumulation. Among many other separation processes, one of the alternatives is ion exchange involving a low cost packing material, clinoptilolite. Clinoptilolite is a natural zeolite and contains exchangeable cations such as Na+, K+, Mg2+, and Ca2+ in its structure. Aim of this study is to determine binary and multicomponent ion exchange behaviors of sodium enriched form of G&ouml / rdes clinoptilolite for lead and cadmium ions. For this purpose, Pb+2 &ndash / Na+, Cd+2 &ndash / Na+ binary and Pb+2 &ndash / Cd+2 &ndash / Na+ ternary systems were investigated in column operations for concentrations between 0.005 to 0.02 N and flow rates between 5 to 20 mL/min at 25 &amp / #730 / C. For determination of optimum particle size, 5/6, 8/10, 14/18, 20/30, 35/60, and 70/140 ASTM E-11 standard mesh ranges were tested and the optimum particle size, under the experimental conditions was found as 35/60. Furthermore, although the clinoptilolite has a theoretical ion exchange capacity of 2.14 meq/g based on its aluminum content, under experimental conditions maximum exchange level was determined as 1.08 meq/g. For binary and ternary experiments, it is observed that the clinoptilolite has affinity for both Pb2+ and Cd2+ ions. However, clinoptilolite has greater affinity to Pb2+ than Cd2+ ion. Therefore, selectivity sequence was determined as Pb2+&gt / Cd2+&gt / Na+. Additionally, for column studies, flow rates less than 10 mL/min and influent concentrations up to 0.01 N, sodium enriched form of G&ouml / rdes clinoptilolite holds great potential to remove Pb2+ and Cd2+ ions from wastewaters.

Wastewaters resulted from anthropogenic influence can encompass a wide range of potential contaminants and concentrations. There are numerous procedures that can be used to clear out wastewaters depending on the type and extent of contamination, however / disposal of pollutants from wastewaters in industrial scale is a difficult and costly problem. In this study, the use of ion exchange theory utilizing natural Turkish clinoptilolite zeolite from G&ouml / rdes-Manisa as ion exchange resins in down-flow column mode is investigated. The clinoptilolite with particle size range of 0.25-0.50 mm is used in the removal of lead Pb2+ and ammonium NH4+ ions from aqueous solutions. The aim of the study is to set up the conditions under which clinoptilolite may be used in an economical and efficient approach in the removal process. Experiments were divided into two sets: binary studies, and ternary studies, and the effects of conditioning clinoptilolite with NaCl solution, flow rate, and initial concentration of the solutions on the removal behavior were investigated. In binary studies, results showed that increasing the loading volumetric flow rate resulted in decreasing the breakthrough capacity and the column efficiency, while the total capacity remained constant. The maximum total capacity was determined as 1.16 meq/g of zeolite for NH4+, and 1.1 meq/g of zeolite for Pb2+ and these values were close to each other and to the sodium content of Na-form of pretreated clinoptilolite (1.16 meq/g of zeolite). In addition, by decreasing the initial contaminant concentration, an increase in breakthrough capacity and column efficiency was observed. In ternary studies, the results showed that the removal of Pb2+ and NH4+ ions are dependent on the flow rate, in which at moderately low flow rate, a higher ion exchange capacity is yielded. That was explained as at higher flow rates, the retention time was insufficient for the ion exchange process to take place completely between clinoptilolite and lead and ammonium ions. Thus, a competition between Pb2+ and NH4+ ions for the exchange sites on clinoptilolite was observed and this competition was in favor of lead ions. Consequently, it was observed that the clinoptilolite zeolite has affinity for both Pb2+ and NH4+ ions. However, the affinity of clinoptilolite for lead ions is higher than that for ammonium ions. Therefore, the cations selectivity for clinoptilolite according to their affinity is determined as the following sequence: NH4+ &gt / Pb2+ &gt / Na+.

The esterification of lactic acid with ethanol over Lewatit S 100, strong cation ion exchange resin catalyst, was studied in counter current vapor-liquid contactor type differential reactor by feeding ethanol and lactic acid solution as vapor and liquid phases, respectively. The ethanol vapor phase was diluted by dry air and the water removal was achieved by the mass transfer of water from liquid to vapor phase. Effect of ethanol to lactic acid feed molar ratio and vapor flow rate on fractional conversion and water removal efficiency were tested at 40-70&deg / C of column temperature range. It was observed that Lewatit S 100 was adequate catalyst for esterification of lactic acid with ethanol. Increase in ethanol to lactic acid feed molar ratio enhanced both lactic acid conversion and water removal by upper product stream. However, lactic acid conversion was suppressed by the increase of inlet vapor flow rate because of the decrease in ethanol concentration in gas phase which affected both esterification reaction rate and mass transfer rate. The reaction temperature is the other important parameter that affects the mass transfer of ethanol from vapor to liquid phase. Although reaction rate and equilibrium conversion values were promoted by temperature, the lower solubility of ethanol in liquid phase limited the fractional conversion while promoted the water mass transfer from liquid to vapor phase. The optimized vapor phase velocity and temperature can yield higher conversions than the equilibrium conversion at the same temperature and initial composition. Therefore, low pressure organic acids such as lactic acid can be successfully esterified by using counter current V-L contactor type reactors and by using integrated reaction and separation units.

In this study binary and ternary ion exchange on Zeolite NaA using silver and cadmium ions were investigated. Ion exchange were conducted at constant temperature (25oC) and normality (0.1N) in a batch system for both binary and ternary experiments. Zeolite weights were varied between 0.1 and 1 g for binary experiments. Thermodynamic analysis of binary ion exchange between Cd2+-Na+ and Ag+-Na+ were examined and thermodynamic equilibrium constant and Gibbs free energy were calculated. Thermodynamic equilibrium constants were found as respectively 28.2 and 300.4 for Cd2+-Na+ and Ag+-Na+ binary system. Standart free energy of Cd2+-Na+ and Ag+-Na+ binary exchange were calculated as -4.1 kJ/mol and -14.1 kJ/mol respectively. In literature Ay (2008) calculated the Gibbs free energy for Ag+-Na+ binary system as -14.4 kJ/mol and Biskup and Subotic (2010) and Gal et al. (1970) calculated the Gibbs free energy for Cd2+-Na+ binary system as -3.7 kJ/mol and -4.4 kJ/mol respectively. It is concluded Zeolite 4A has higher affinity to silver than cadmium and selectivity sequence was found as / Ag+&gt / Cd2+&gt / Na+. Langmuir and Freundlich isotherms were drawn to describe experimental data. As compared the R2 of isotherms, it is clearly seen that Freundlich isotherm provides better fit for Cd2+-Na+ binary ion exchange and Ag+-Na+ binary ion exchange. The ternary ion exchange isotherms were plotted using equivalent fraction of three ions (Ag+,Na+,Cd2+) which participated in ion exchange experiments to determine selectivity of zeolite 4A for cadmium and silver. Selectivity sequence was determined as Ag+ &gt / Cd2+ &gt / Na+ for ternary ion exchange.

The synthesis of ion-exchange resin which can be used in various separation and chemical purposes, such as diffusion dialysis, electro dialysis, electrolysis and fuel cells has of considerable interest. For all these applications, the interactions of the ionic groups and the resulted morphologies are critical for establishing the unique properties. Considerable researches have been continued to understand the microstructure of these materials. The aim of this study is to synthesize polypropylene (PP) based ion exchange resins and to investigate their ion-exchange properties. In the first part of this study polypropylene was functionalized by grafting maleic anhydride onto the polypropylene and the product was characterized by ATR. The effect of maleic anhydride introduced to the grafting medium and the effect of the radical initiator on the maleic anhydride content of the MA-g-PP samples were investigated. In the second part, neutralization of the MA-g-PP samples with Na+, K+, Mg2+ and Ca2+ ions and peroxide cross-linking of neutralized MA-g-PP samples were performed. Characterization of the neutralized MA-g-PP samples were performed by ATR and SEM-EDX. In the last part of the study, ion exchange properties of MA-g-PP resins towards Cu2+, Co2+, Cd2+, Pb2+ and Fe3+ ions at different pHs were investigated by batch equilibrium method. Rate of metal uptake, concentration effect on the metal uptake and regeneration of the MA-g-PP samples were also examined.

Thesis (Ph.D.)--Ohio University, November, 2009. / Release of full electronic text on OhioLINK has been delayed until December 1, 2014. Title from PDF t.p. Includes bibliographical references.