M.S. Shaikh

Measurement and prediction of physical properties of aqueous sodium salt of L-phenylalanine

Physical properties such as density, refractive index and viscosity of aqueous sodium salt of l-phenylalanine (Na-Phe) were investigated in this work. These properties were measured over a temperature range of 298.15-343.15 K, and at atmospheric pressure. The mass fractions ( w ) of Na-Phe were 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40 respectively. The analysis of the experimental data shows that the values of density, refractive index and viscosity decrease with an increase in temperature at any constant concentration of Na-Phe. However, these values increase with the rise of concentration isothermally. The density values were used for estimation of thermal expansion coefficient. The thermal expansion coefficient increases slightly with the increase in temperature and concentration. Density and refractive index data were correlated using modified Graber equation, while, viscosity data were correlated using modified Vogel-Tamman-Fulcher (VTF) equation. In all the cases, a quantitative analysis of the influence of temperature and concentration was carried out.

Physical properties of aqueous solutions of potassium carbonate+glycine as a solvent for carbon dioxide removal

The physical properties such as densities, viscosities, and refractive indices of aqueous solutions of potassium carbonate (PC) blended with glycine (Gly) as solvent blends for CO2 capture were measured. The properties were measured at ten different temperatures from (298.15 to 343.15) K. The mass fractions (w1 + w2) % of the (PC + Gly) blends were (0.05 + 0.01, 0.10 + 0.02, 0.15 + 0.03, 0.20 + 0.04, 0.25 + 0.05, 0.30 + 0.06, 0.35 + 0.07, and 0.40 + 0.08), respectively. The analysis of experimental results shows that, the densities, viscosities, and refractive indices of the aqueous (PC + Gly) blend increase with increasing the concentration of the potassium carbonate and glycine, and decrease with decreasing the temperature. The experimental data of density, viscosity and refractive index were correlated by a least-squares method as a function of temperature. The predicted data were estimated from coefficients of correlation equations for all measured properties, and reported with standard deviation (SD). The experimental data are in consistent with the predicted data.

Study of CO2 Solubility in Aqueous Blend of Potassium Carbonate Promoted with Glycine

CO2 solubility in aqueous potassium carbonate promoted with amino acid (glycine) was measured at temperatures (303.15, 313.15, and 333.15) K over the partial pressure range from 200 to 1000 kPa. The solubility of CO2 is reported as the loading capacity of the CO2 in the solvent, defined as (moles of CO2 per mole of solvent). It was found that the loading capacity of the CO2 increases by increasing the partial pressure of the CO2, whereas, it reduces with increase in temperature. CO2 loading capacity in aqueous potassium carbonate (PC) promoted with glycine (GLY) was also compared with different solvents, which shows that the new solvent blend is considerably better than various solvents.

Aqueous Amino Acid Salts and Their Blends as Efficient Absorbents for CO 2 Capture

The increase in global population and industrialization has led to an increase in global energy consumption exponentially. Over 85% of global energy is supplied by burning fossil fuel, which releases large volume of CO2 emissions in the atmosphere. Increasing of CO2 emissions is the major cause for the catastrophic climate change, which has led to increased demand for efficient and effective CO2 capture. CO2 absorption by chemical solvents is the most widely used technique commercially nowadays. Alkanolamine solvents such as monoethanolamine (MEA) and methyldiethanolamine (MDEA) are the most commonly used absorbents for CO2 removal from various gas streams. However, it is well known that these solvents suffer from variety of drawbacks such as limited CO2 loading capacity, equipment corrosion, toxic nature and highly volatile. Moreover, these absorbents are easily degradable, require high regeneration energy, and cause flooding problems in the operation. Therefore, better and efficient solvents should be searched for the removal of CO2 from exhaust gas streams. Aqueous amino acid salts and their blends are the promising solvents for CO2 capture as compared to alkanolamine. In this chapter, amino acid salts and their blends are introduced and their performance analysis as potential solvents for commercial possibilities are discussed. Based on the analysis, these absorbents show superior performance as an alternative to the conventional alkanolamines for CO2 capture. These solvents are environmental friendly with higher CO2 loading capacity, faster reaction kinetics and require less regeneration energy compares to the commercial amines. Besides, these solvents are non-volatile, less corrosive and oxidative stable. Moreover, aqueous amino acid salts are more effective by blending with additives such as piperazine.