Bingwen Yan

Production of algae-based biodiesel using the continuous catalytic Mcgyan® process

This study demonstrates the production of algal biodiesel from Dunaliella tertiolecta, Nannochloropsis oculata, wild freshwater microalgae, and macroalgae lipids using a highly efficient continuous catalytic process. The heterogeneous catalytic process uses supercritical methanol and porous titania microspheres in a fixed bed reactor to catalyze the simultaneous transesterification and esterification of triacylglycerides and free fatty acids, respectively, to fatty acid methyl esters (biodiesel). Triacylglycerides and free fatty acids were converted to alkyl esters with up to 85% efficiency as measured by 300 MHz (1)H NMR spectroscopy. The lipid composition of the different algae was studied gravimetrically and by gas chromatography. The analysis showed that even though total lipids comprised upwards of 19% of algal dry weight the saponifiable lipids, and resulting biodiesel, comprised only 1% of dry weight. Thus highlighting the need to determine the triacylglyceride and free fatty acid content when considering microalgae for biodiesel production.

Elevated-temperature ultrahigh-pressure liquid chromatography using very small polybutadiene-coated nonporous zirconia particles

Capillary columns packed with small diameter particles typically lead to low permeability and long separation times in high-performance liquid chromatography. Ultrahigh pressures (>10,000 p.s.i.; 1 p.s.i. is identical with 6,894.76 Pa) can be used to overcome the limitations that small particles impose. Ultrahigh-pressure liquid chromatography (UHPLC) has demonstrated great potential for high-speed and high-efficiency separations. Decreasing the viscosity of the mobile phase by elevating the temperature could additionally reduce the pressure drop and facilitate the use of longer columns or smaller particles to achieve even higher total plate numbers. For this reason, we investigated the use of elevated temperatures in UHPLC. Water-resistant, flexible heater tape covered with insulation was used to provide the desired heat to the column. Polybutadiene-coated 1 microm nonporous zirconia particles were used because of their chemical stability at elevated temperature. A column efficiency as high as 420,000 plates m(-1) was obtained. The effects of temperature and pressure on the separation of parabens were investigated. Separation of five herbicides was completed in 60 s using 26,000 p.s.i. and 90 degrees C.

Synthesis of micron diameter polybutadiene-encapsulated non-porous zirconia particles for ultrahigh pressure liquid chromatography

In this study, 1-microm diameter polybutadiene-encapsulated non-porous zirconia particles were synthesized, slurry packed into 50-microm I.D. fused-silica capillary columns, and evaluated using ultrahigh pressure liquid chromatography. The dependencies of column efficiency and solute retention factor on pressure were investigated. Efficiencies as high as 280000 plates per meter were obtained for the separation of anti-inflammatory drugs at a pressure of 1351 MPa. Comparing the reversed-phase behavior of the polybutadiene-encapsulated non-porous zirconia with octadecylsilane bonded non-porous silica, greater selectivity was found using the zirconia-based material for the applications reported in this study. The encapsulated non-porous zirconia particles demonstrated excellent thermal stability in the separation of polycyclic aromatic hydrocarbons at a temperature of 100 degrees C and a pressure of 1351 MPa.