Graft-modified amphiphilic dendron/polyimide regular through-pore composite membranes for oil/water separation
Journal
Chemical Engineering Journal
Journal Volume
522
Start Page
167148
ISSN
13858947
Date Issued
2025-10-15
Author(s)
Hu, Chien-Chieh
Sung, Cai-Syuan
Wu, Chien-Hsin
Huang, Ying-Chi
Chang, Huai-Che
Lee, Kueir-Rarn
Lai, Juin-Yih
Abstract
The rapid advancement of industrial processes has resulted in the substantial discharge of oily wastewater into the environment. Such contamination significantly increases BOD and COD levels while disrupting the pH balance of aquatic systems, thereby posing a serious threat to the survival of aquatic organisms. Oily wastewater is characterized by its wide variety and large volume. To effectively address this issue, this work aims to develop ultrahigh-flux membranes with tunable properties capable of adapting to different types of wastewater. In this study, a casting solution was prepared by dissolving C18 polyurethane/malonamide dendron and polyimide (PI) in chloroform. This solution was then applied to the filter paper via drop-casting. The surface of the filter paper was subsequently treated using the breath-figure method, facilitating the formation of a regular through-pore composite membrane. The membrane surface incorporates azetidine-2,4-dione, a functional moiety presented in the C18 polyurethane/malonamide dendron, which undergoes a ring-opening reaction with primary amine-functionalized compounds. Hydrophilic branched polyethyleneimine (PEI) or hydrophobic octadecylamine can be covalently attached to the membrane surface, enabling the fabrication of membranes tailored for either oil-in-water or water-in-oil emulsion separation. This tunable surface chemistry, combined with the highly ordered through-pore structure, enables the development of versatile oil-water separation composite membranes with ultra-high permeance and excellent rejection. The degree of membrane hydrophilicity or hydrophobicity can be precisely modulated by adjusting parameters such as grafting density, molecular weight of the grafted compound, and reaction duration. The breath figure method, combined with surface grafting modification, enables the membrane developed in this study to possess a unique pore structure and tunable surface wettability. This membrane exhibits performance significantly superior to that of conventional oil–water separation membranes. Under optimized conditions, modification with branched polyethyleneimine (PEI 10000) for 6 h yielded a membrane with high hydrophilicity and underwater superoleophobicity, achieving an oil-in-water emulsion permeance of 49,518.4 LMH/bar and a rejection rate of 99.1 % (feed: Tween 80, 0.06 g; 4 mL oil in 200 mL water; downstream pressure: 10 mbar). Conversely, the original regular through-pore composite membrane demonstrated a water-in-oil emulsion permeance of 380,520.8 LMH/bar with a rejection of 96.1 %. These findings highlight the potential of integrating regular through-pore composite membrane with surface grafting modifications as a promising strategy for the development of high-performance oil-water separation membranes.
Subjects
Amphiphilic dendron
Breath-figures method
Membrane with regular through-pore active layer
Oil-water separation
Surface grafting
SDGs
Publisher
Elsevier B.V.
Type
journal article