Quantification of a Mixture of Insoluble Submicrometer Particles and Dissolved Solids in Water using Membrane Filtration and Aerosolization Method

Abstract

Microfiltration (MF) and ultrafiltration (UF) membrane filtration and separation of insoluble particles and dissolved solid in water, aerosolization, and subsequent sizing and counting of airborne particles were used to determine the number concentration of insoluble particles (#/ml) and mass concentration of dissolved solids (ppm) in water. By using a variety of solutions and their mixtures, we determined the penetration of insoluble particles and dissolved solids via the MF and UF membranes, as well as established a relationship between particle quantity in water and air. Both sub-500 nm insoluble particles and most dissolved solids passed through the MF membrane, while only dissolved solids passed through the UF membrane, enabling separation of waterborne insoluble particles and dissolved solids. Accordingly, we estimated the submicrometer particle number concentration and dissolved species mass concentrations via the proposed technique with 15% and 16% accuracy, respectively. Further, we examined the effects of mixing insoluble particles and dissolved solids with aerosolized particles by using a mixture of silica particles (insoluble particles) and artificial seawater (25,000 ppm) containing various dissolved ions. Afterward, we applied the proposed technique to quantify insoluble particles and dissolved solids in seawater. Concentrations of insoluble particles in MF membrane-filtrated seawater sampled from the cities of Pohang, Taean and Yeosu in Korea were 1.16 x 10(12), 5.45 x 10(11), and 4.82 x 10(11) #/ml, respectively; mass concentrations of dissolved solids were 24362, 23358, and 24640 ppm, respectively, concurring closely with values measured by the Total Dissolved Solids (TDS) meter. Our quantification technique will be useful in monitoring both insoluble submicrometer particles and dissolved solids to examine water quality and primary marine aerosol formation in seawater more effectively.