Rhizomucor miehei Lipase-Immobilized Sodium Alginate Membrane Preparation and Usage in a Pervaporation Biocatalytic Membrane Reactor

In this study, Rhizomucor miehei lipase-coated alginate membrane was prepared and put in a biocatalytic membrane reactor to produce ethyl lactate from ethyl alcohol and lactic acid. Effects of the amount of coated lipase, reaction temperature and initial molar ratio on lactic acid conversion were investigated to evaluate the performance of the system. In order to compare the performance of the membrane reactor, the reaction was also carried out in a classical batch reactor by using lipase-immobilized membrane as a catalyst. The highest lactic acid conversion achieved was 0.63 in the membrane reactor at 50 °C, while the lactic acid conversion was 0.37 in the batch reactor under the same operating conditions. After six reaction runs, approximately 90 % of the lipase’s catalytic activity was preserved in the membrane reactor

Removal of Acetone from Wastewater by POSS Loaded PDMS Membrane

The waste-water of the chemical processes includes hundreds of hazardous pollutants with low concentration. Although the emission of trace amounts of these chemicals is allowed by the laws, they are quite harmful to the water ecosystem and the human health. These chemicals including the acetone, toluene, phenol, and esters are defined as volatile organic compounds (VOCs). Separation of the VOCs from the large volume of industrial waste-water is required practically complicated and advanced processes. In this approach, more economically and efficient separation methods can be more favorable such as pervaporation. Pervaporation (PV) is an attractive and promising method for separation the small amount of dissolved chemicals from the waste-water. Pervaporative separation does not need any toxic solvent or external heat energy during the separation process. Therefore, it is defined as a cost effective and environmentally friendly process. In this study, acetone was selected as a VOC component and it was selectively separated from the model mixture (acetone-water) by pervaporation where the poly(hedral oligomeric silsesquioxane)(POSS) loaded poly(dimethyl siloxane) hydrophobic membrane was used. The structure of the membrane was characterized by scanning electron and polarized microscopy methods. The surface structure of the membrane was also analyzed by contact angle measurements. Effects of feed temperature and acetone-water concentration on separation performance were evaluated in terms of the total flux and acetone separation factor. Compared to the pristine PDMS membrane, 212% improvement on separation factor was achieved by 10 wt.% POSS incorporated membrane. The highest acetone separation factor was obtained as 237 when the temperature was 30 ºC and the acetone concentration was 1%