MICROBUBBLES IMPROVE REMOVAL OF OIL-IN-WATER EMULSIONS STABILIZED BY HUMIC ACIDS

A b s t r a c t: This study examined the stability of fine oil-in-water (O/W) emulsions containing natural organic matter (500 mg·L–1 soybean oil and 25 mg·L–1 humic acid), named O/W-HA emulsions, formed by high-speed mixing. The calculated stability values from a 300-min stability test indicated that O/W-HA emulsions were more stable than O/W emulsions. Size distribution and Sauter mean diameter (D₃₂) of oil droplets were calculated to evaluate the use of microbubbles (MB) in treating fine O/W-HA emulsions at different airflow rates, pH levels, and sodium chloride concentrations. At a practical pressure (0.45 MPa), the designed column flotation system, featuring an F.BT-50 nozzle, produced a variety of gas bubbles to enhance separation. The application of MB in treating O/W-HA emulsion droplets (<15 μm, mean: 4.91 μm) and/or the addition of NaCl (30 mg·L–1) after 30 min of treatment increased the removal efficiency (from 60% to 82%) at pH 4.0. The results are meaningful for scale-up at treatment plants that produce oily wastewater because they indicate a high potential for the reduction and reuse of oil-floated products to improve treatment efficiency.

Keywords: Emulsions; Flotation; Humic acid; Microbubbles; Oil-in-water; Wastewater treatment

Thông tin Tạp chí Khoa học đăng tải:

Desalination and Water Treatment (1944-3994, E-ISSN: 1944-3986) // SCIE, Q3

Received 2 April 2022; Accepted 11 August 2022

Thông tin chi tiết xin vui lòng liên hệ email: lv_tuan@huetronics.vn hoặc levantuan@hueuni.edu.vn