Dynamic adsorption of SO2 on zeolite molecular sieves

Sulfur dioxide is one of the major pollutants resulting from fuel combustion. Numerous dry, semi-dry and wet processes have been developed for pollution control of sulfur dioxide. Solid carbonates, natural and synthetic zeolites, ion exchange resins and carbon based sorbents are the most commonly used dry sorbents for sulfur dioxide removal. In this study, measurements of the adsorption properties of sulfur dioxide on zeolites were investigated. The adsorbents used in this work are 5A, 4A and AW300 type molecular sieve zeolites. Adsorption equilibrium parameters were determined from the pulse Chromatographic response to injections of low concentrations of sulfur dioxide. The method of moments were used to evaluate the adsorption equilibrium parameters from pulse Chromatographic experiments. Data, such as adsorption equilibrium constants or reaction rate parameters are essential in the design of adsorption systems or reactors in which sulfur dioxide is removed. The experiments were conducted in a temperature range of 523-718 K. The relatively strong adsorption properties of sulfur dioxide on zeolites necessitated the use of high carrier gas flow rates and subsequently non-isobaric operation. Non-isobaric pulse Chromatography theory was found to describe accurately the adsorption trends. Adsorption equilibrium constants of SO2 were found to decrease considerably with increasing temperature. It was also found out that adsorption of SO2 on the adsorbents investigated were found to decrease in the order of AW300 > 4A > 5A. The adsorption equilibrium parameter of SO2 on 5A was found as 11.78 at 673 K, whereas it has a value of 157.11 at 523 K. The adsorption equilibrium parameter of SO2 on 4A zeolite was determined to be 8.63 at 718 K and 213.78 at 523 K

Non-isobaric adsorption analysis of SO2 on molecular sieve 13X and activated carbon by dynamic technique

Sulfur dioxide is one of the major pollutants resulting from fuel combustion. In this study non-isobaric pulse chromatography was used for the investigation of the adsorption properties of sulfur dioxide on molecular sieve 13X and activated carbon. The experimental procedure consists of introducing a pulse of sulfur dioxide on the inlet of a column packed with molecular sieve 13X and activated carbon adsorbents and measuring the concentration versus time response peak leaving the other end of the column. Adsorption equilibrium constants were calculated using the moment analysis of the chromatographic peaks. Non-isobaric pulse chromatographic technique necessitates the use of high carrier gas flow rates which avoids the tailing of the response peaks and reduces considerably the uncertainty in the measurement of the moments. The adsorption of sulfur dioxide was investigated in a temperature range of 353-453 K with the activated carbon, which is a typical temperature range of desulfurization of flue gas, and in a temperature range of 523-673 K with molecular sieve 13X. Adsorption equilibrium constants of sulfur dioxide were found to decrease considerably with increasing temperature. At 453 K, the adsorption equilibrium constant was found to be 18.78, whereas it has a value of 330.2 at 353 K with the activated carbon. At 673 K, the adsorption equilibrium constant was found to be 11.52, whereas it has a value of 167.82 at 523 K with molecular sieve 13X. Heat of adsorption of sulfur dioxide on molecular sieve 13X and the activated carbon was determined as -12.4 and -8.99 kcal mol-1, respectively.Sulfur dioxide is one of the major pollutants resulting from fuel combustion. In this study non-isobaric pulse chromatography was used for the investigation of the adsorption properties of sulfur dioxide on molecular sieve 13X and activated carbon. The experimental procedure consists of introducing a pulse of sulfur dioxide on the inlet of a column packed with molecular sieve 13X and activated carbon adsorbents and measuring the concentration versus time response peak leaving the other end of the column. Adsorption equilibrium constants were calculated using the moment analysis of the chromatographic peaks. Non-isobaric pulse chromatographic technique necessitates the use of high carrier gas flow rates which avoids the tailing of the response peaks and reduces considerably the uncertainty in the measurement of the moments. The adsorption of sulfur dioxide was investigated in a temperature range of 353-453 K with the activated carbon, which is a typical temperature range of desulfurization of flue gas, and in a temperature range of 523-673 K with molecular sieve 13X. Adsorption equilibrium constants of sulfur dioxide were found to decrease considerably with increasing temperature. At 453 K, the adsorption equilibrium constant was found to be 18.78, whereas it has a value of 330.2 at 353 K with the activated carbon. At 673 K, the adsorption equilibrium constant was found to be 11.52, whereas it has a value of 167.82 at 523 K with molecular sieve 13X. Heat of adsorption of sulfur dioxide on molecular sieve 13X and the activated carbon was determined as - 12.4 and - 8.99 kcal mol-1.This work was funded by Research Fund AFP95-112-003-19 of Zonguldak Karaelmas University. The experiments were conducted at the Industrial Support Center (ZEDEM) of Mining Engineering Department at Karaelmas University, Zonguldak, Turkey. Appendix

Investigation of the interactions and adsorption of ovalbumin with titanium dioxide and zirconia surfaces [Ovalbüminin titanyum dioksit ve zirkonya yüzeylerle etkileşimi ve adsorpsiyonunun araştirilmasi]

Knowing the interactions between the protein molecules and the biomaterial surfaces is important in a number of applications in biomedical technologies and materials engineering. The lack of knowledge on this topic due to the complexity of the protein molecular structures and their adsorption necessitates carrying out research work in order to solve the problems related with the protein-surface interactions. Protein adsorption is influenced by many parameters such as the properties of proteins, pH, concentration, ionic strength and temperature. The aim of this study is to investigate the Ovalbumin adsorption from aqueous solutions on TiO2 and ZrO2, to study the effects of solution pH, temperature and adsorbent dosage on adsorption; to investigate the adsorption kinetics, protein-metal oxide interactions, and to determine the conditions controlling the adsorption. The interactions and adsorption of Ovalbumin protein with TiO2 and ZrO2 powders in solution environment were investigated in a batch adsorption system. Adsorption experiments were carried out in pH 5, 6.4, 8 environment at 20, 25, 30 °C. The effect of adsorbent dosage was also investigated by the addition of different amounts of TiO2/ZrO2 in the range 0.5-1.0 g/L. Results have shown that the adsorbed amount of Ovalbumin increases with increasing temperature and adsorbent dosage, but decreases with increasing pH. The increase of contact surface with increasing adsorbent dosage increases protein adsorption. The zeta potential measurement results supported that the interactions between Ovalbumin with TiO2 and ZrO2 were higher at pH 5, which is close to the isoelectric point of protein. The adsorption of Ovalbumin onto TiO2 and ZrO2 at different temperatures and solution pH conditions followed first order kinetics with a better fit for both adsorbents

Comparison of the adsorption behavior of Basic Red 46 textile dye on various activated carbons obtained from Zonguldak coal [Bazik Kirmizi 46 tekstil boyasinin Zonguldak kömüründen elde edilen farkli aktif karbonlar üzerinde adsorpsiyon davranişinin karşilaştirilmasi]

The activated carbons obtained by physical and chemical activation techniques from Zonguldak-Kilimli region coal was used for the adsorption of a textile dye, Basic Red 46 from aqueous solutions. The effects of adsorbent preparation method, initial dye concentration and temperature on adsorption were investigated. The color removal performance of activated carbons prepared by physical activation (PAC), chemical activation with KOH (CAC) and the commercial activated carbon (AC) were compared. The batch adsorption experiments were carried out isothermally at 25, 30 and 35°C. The adsorption capacities at 25, 30 and 35°C were found as 62.7, 23.1, 19.6 (PAC); 201.6, 215.1, 231.5 (AC); and 277.8, 307.7, 323.6 mg g- 1 (CAC), respectively. It was found that the CAC sample having the highest micropore and surface area obtained by thermal treatment with KOH had the highest adsorption capacity. The results have shown that the adsorption of BR 46 exhibited an endothermic character on CAC and AC, and exothermic character on PAC. Kinetic data were adequately fitted by the pseudo- first order kinetic model. The study has shown that activated carbon obtained by KOH activation of coal could be effectively used for the adsorptive removal of BR 46 textile dye from wastewaters. The activated carbon obtained from Zonguldak coal with low cost, non toxic character and excellent adsorption performance has a high potential for sustainable commercial applications. © 2019 Gazi Universitesi Muhendislik-Mimarlik. All rights reserved

Propagation of acceleration waves in the viscoelastic Johnson-Segalman fluids

The propagation conditions of acceleration waves are investigated for a viscoelastic fluid using the Johnson-Segalman viscoelastic model. Explicit expressions are obtained for the wave speeds adopting the theory of singular surfaces. The simple shearing motion, uniaxial, biaxial extension and uniform dilation are considered as the initial states of deformation. The variations of the speeds with the propagation direction, stretch ratio and material parameters are presented. © 2009 Elsevier Ltd. All rights reserved