UiO-66-(COOH)2 Decorated Collagen Fiber Membranes for High-Efficiency Separation of Cationic Surfactant-Stabilized Oil/Water Emulsions: Toward Sustainable and Robust Wastewater Treatment

TL;DR

A new membrane made of collagen fibers and a metal-organic framework efficiently separates oil-water emulsions, offering a sustainable solution for wastewater treatment.

Contribution

A novel composite membrane combining collagen fibers and UiO-66-(COOH)2 for high-efficiency separation of cationic surfactant-stabilized emulsions.

Findings

The CFM-UiO-66-(COOH)2 membrane achieved over 99.85% separation efficiency for cationic oil-in-water emulsions.

The membrane showed permeation fluxes between 178.9 and 225.9 L·m−2·h−1 with robust antifouling and durability properties.

Stable performance was maintained over six separation cycles with good acid/alkali resistance and biocompatibility.

Abstract

Membrane separation is a promising technology for emulsified wastewater treatment. However, conventional membrane often suffer from limitations such as low mechanical strength, the inherent “trade-off” effect between flux and separation efficiency, and poor antifouling properties. To address these challenges, we report a novel composite membrane (CFM-UiO-66-(COOH)2) fabricated by in situ growth of functionalized UiO-66-(COOH)2 on a mechanically robust collagen fiber membrane (CFM) substrate. The resulting composite leverages the inherent properties of the CFM, along with the controlled generation of charge-neutralization demulsification sites and size-sieving filtration layers from the UiO-66-(COOH)2. This CFM-UiO-66-(COOH)2 exhibited superwetting behavior and achieved efficient separation of cationic surfactant-stabilized oil-in-water micro- and nano-emulsions. Specifically, the CFM-UiO-66-(COOH)2 achieved separation efficiencies exceeding 99.85% for various cationic O/W emulsions, with permeation fluxes ranging from 178.9 to 225.9 L·m−2·h−1. The membrane also demonstrated robust antifouling properties, excellent acid/alkali resistance, high abrasion durability, and good biocompatibility. Importantly, stable performance was maintained over six consecutive separation cycles. These characteristics, combined with the electrostatic interactions between carboxyl groups on the UiO-66-(COOH)2 and cationic contaminants, suggest that CFM-UiO-66-(COOH)2 holds significant potential for practical and sustainable wastewater treatment applications.

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