Premium
The removal efficiency and mechanism of microplastic enhancement by positive modification dissolved air flotation
Author(s) -
Wang Yonglei,
Li Ya'nan,
Tian Liping,
Ju Ling,
Liu Yulei
Publication year - 2021
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.1002/wer.1352
Subject(s) - dissolved air flotation , microplastics , chemistry , attraction , adhesion , adsorption , chemical engineering , biofouling , electrostatic interaction , hydrophobic effect , surface charge , biophysics , chromatography , environmental chemistry , environmental engineering , membrane , environmental science , organic chemistry , wastewater , chemical physics , biochemistry , biology , linguistics , philosophy , engineering
Microplastics (MPs) are widely distributed in freshwater and have the following characteristics: small size, strong hydrophobicity, difficult degradation, and easy adsorption of toxic substances. These characteristics pose a potential threat to the environment and human health. In this paper, three common MPs in freshwater were removed by conventional dissolved air flotation (DAF) and positive modification DAF (Posi‐DAF). The results showed that the optimal removal efficiency of MPs by conventional DAF was 32%–38% at 0.4–0.5 MPa. This indicated that the adhesion between microbubbles (MBs) and MPs was not ideal when the hydrophilic/hydrophobic interaction was the dominant mechanism. However, the removal efficiency of MPs was increased by 13.6%–33.7% compared with that of conventional DAF after two surface modifiers were used on MBs. This result indicated that in addition to the hydrophilic/hydrophobic interaction, both charge attraction and sweeping had positive effects. Practitioner points The removal efficiency and mechanism of MPs by posi‐DAF were investigated. The characteristics, particle number, and adhesion of microplastics were measured. Conventional DAF was dominated by hydrophilic/hydrophobic interactions. CTAB Posi‐DAF was dominated by charge attraction. PDADMAC Posi‐DAF was dominated by charge attraction and sweeping.