Experimental Performance Evaluation of a Filter Coated with Castor Oil for Particulate Matter Absorption (PM2.5 and PM10)

Particulate matter naturally comes from volcanoes, dust storms, forest fires, living vegetation, and sea spray and carries bacteria and viruses. More than 90% of urban population in megacities is exposed to particulate matter. This study evaluates laboratory performance of oil-coated filters for particulate matter removal and to investigate if such air filters can trap bacteria-carrying particles from entering human body. To measure the filter’s efficiency, a cubical laboratory pilot with a polyester fabric bed was constructed, and the filters were placed exposed to a polluted air flow (85 l/min). After spraying different concentrations of oil (castor seed with a viscosity of 6546 mPa.s) on the filter bed, contaminated airflow tests were performed using cigarette smoke. Airborne cigarette smoke particles before and after the filters were measured for PM 10 and PM 2.5 , by a HAZ-DUST device. The highest efficiencies in removing PM 2.5 and PM 10 are 82% and 89.1%, respectively, when a polyester filter with 10 mg of sprayed oil is used. Also, pressure drops across the filters obtained during the experiments vary from 0.3 to 0.6 cm H 2 O. To evaluate the anti-bacterial properties of the oil, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested for Escherichia coli , Pseudomonas aeruginosa , Bacillus subtilis , and Staphylococcus aureus by microdilution method. MICs for Escherichia coli and Staphylococcus aureus were 50% of the oil concentration and for Bacillus subtilis and Pseudomonas aeruginosa were 100% for all bacteria. In general, natural oil–coated filters seem to be efficient and probably more economical than most studies in the field of particulate matter removal by filters. Low-pressure drop across them suggests them as a good candidate for popular large-scale usage as breathing masks.