Cailong Zhou

Separating surfactant-stabilized dual-type oil/water emulsions remains challenging due to the intrinsic limitations of traditional single-wettability filters. Herein, a heterogeneous composite particle-based bed was constructed by blending pristine hydrophilic MOF UiO-66-NH2 with oleyl phosphate-modified hydrophobic MOF UiO-66-NH2–OP. The mixed bed combines droplet capture with interfacial destabilization: tortuous interparticle channels promote hydrodynamic deformation, while adjacent domains of contrasting wettability are proposed to induce asymmetric interfacial stresses and Marangoni-driven film disruption. Subsequent droplet coalescence and interception enable separation of both emulsion types. Filtration tests proved the composite bed outperformed single-wettability counterparts for dual-type emulsions, achieving over 90% rejection and a peak permeance of 5861.3 L·m–2·h–1·bar–1. This work establishes an emulsion separation strategy via MOF wettability modulation and particle-bed construction, shedding light on the design of high-performance, tunable separation materials.

Crystalline one-dimensional covalent organic frameworks were synthesized at room temperature using n -butanol as the solvent.

The escalating discharge of oily wastewater presents a considerable threat to both ecological systems and human health, making the development of efficient treatment technologies an ongoing challenge. This study constructed binary composite membranes that effectively integrate polymeric and metallic substrates by integrating a polyvinylidene fluoride (PVDF) membrane with an acid‐etched copper mesh (CM). The binary composite membranes were subsequently modified with a polydopamine/polyethylenimine (PDA/PEI) complex to produce superhydrophilic and underwater superoleophobic PVDF/mesh binary composite membranes (PP@PVDF/triethyl phosphate (TEP) _n ‐roughened CM (RCM)). By varying the mass ratio of PVDF to the solvent TEP, the phase separation kinetics were systematically regulated, resulting in five distinct membranes with tailored pore sizes and porosity levels. Among these, PP@PVDF/TEP ₃₀ ‐RCM exhibited outstanding separation performance for various immiscible oil–water mixtures, achieving separation efficiencies exceeding 99.60% and reaching a maximum of 99.97%. When applied to the separation of surfactant‐stabilized oil‐in‐water emulsions under gravity‐driven conditions, PP@PVDF/TEP ₃₀ ‐RCM demonstrated high permeation fluxes, all above 1010 L·m ⁻² ·h ⁻¹ , coupled with separation efficiencies exceeding 99.10%. Furthermore, PP@PVDF/TEP ₃₀ ‐RCM maintained high separation efficiency over 15 repeated cycles. The PVDF/mesh binary composite membranes developed in this work combine high separation efficiency with robust durability, making them promising candidates for the sustainable separation of challenging oil/water emulsions.