TY - JOUR
T1 - Enhancing flotation separation of the aged microplastics via oxidation processes based on theoretical calculations and experiments
AU - Wang, Jianchao
AU - Shao, Yuchao
AU - Su, Jiming
AU - Shi, Yanli
AU - Wang, Zhiyi
AU - Chen, Xu
AU - Jiang, Hongru
AU - Zhang, Lingyue
AU - Wang, Chongqing
N1 - This work was supported by the National Natural Science Foundation of China (52300071) and the Young Elite Scientist Sponsorship Program by BAST (BYESS2023097).
Publisher Copyright:
© 2025 Elsevier B.V.
PY - 2025/10/15
Y1 - 2025/10/15
N2 - Flotation has been regarded as a promising method for mitigating microplastics (MPs) pollution, while the aging of MPs would pose great challenges. Herein, we aimed to elucidate the aging of MPs induced by typical ferrate [Fe(VI)] and persulfate (PS) oxidation processes and its negative effects on flotation, and ascertained the enhanced flotation of aged MPs via hydrophobicity recovery with dodecyl trimethyl ammonium chloride (DTAC) and sodium oleate (SOL). The floatability of polycarbonate (PC) and poly(acrylonitrile-butadiene-styrene) (ABS) MPs decreased to 0 % with reduced kinetic constants after oxidation aging. This was mainly due to hydrophilization of MPs with the decreased water contact angle (9.1–18.7°), and both olefin and benzene moieties of ABS-MPs as reactive sites were oxidized by forming carboxyl groups. DTAC showed greater enhanced flotation for aged MPs than SOL, with removal rate reaching up to 100 % in some cases. It was ascertained that the adsorption sites of aged ABS-MPs with DTAC included aging-formed carboxyl groups and nitrile bonds with adsorption energy of −29.87 and − 41.05 kcal·mol−1, respectively; the interactions forces were dominated by electrostatic attraction, with low contributions from van der Waals and H-bonds forces. This study provides novel information on how to alleviate the negative effects of aging on eliminating MPs pollution via flotation.
AB - Flotation has been regarded as a promising method for mitigating microplastics (MPs) pollution, while the aging of MPs would pose great challenges. Herein, we aimed to elucidate the aging of MPs induced by typical ferrate [Fe(VI)] and persulfate (PS) oxidation processes and its negative effects on flotation, and ascertained the enhanced flotation of aged MPs via hydrophobicity recovery with dodecyl trimethyl ammonium chloride (DTAC) and sodium oleate (SOL). The floatability of polycarbonate (PC) and poly(acrylonitrile-butadiene-styrene) (ABS) MPs decreased to 0 % with reduced kinetic constants after oxidation aging. This was mainly due to hydrophilization of MPs with the decreased water contact angle (9.1–18.7°), and both olefin and benzene moieties of ABS-MPs as reactive sites were oxidized by forming carboxyl groups. DTAC showed greater enhanced flotation for aged MPs than SOL, with removal rate reaching up to 100 % in some cases. It was ascertained that the adsorption sites of aged ABS-MPs with DTAC included aging-formed carboxyl groups and nitrile bonds with adsorption energy of −29.87 and − 41.05 kcal·mol−1, respectively; the interactions forces were dominated by electrostatic attraction, with low contributions from van der Waals and H-bonds forces. This study provides novel information on how to alleviate the negative effects of aging on eliminating MPs pollution via flotation.
KW - Flotation separation
KW - Microplastics
KW - Surface aging
KW - Theoretical calculations
UR - http://www.scopus.com/inward/record.url?scp=105015106945&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2025.167656
DO - 10.1016/j.cej.2025.167656
M3 - Journal article
AN - SCOPUS:105015106945
SN - 1385-8947
VL - 522
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 167656
ER -