Chunyan Huang,Zichen Li,Yuning Pan,Zhili Li,Yuanyuan Ge
Developing efficient dual functional membranes through simple methods to remove various water pollutants remains challenging. Herein, a dual functional geopolymer/copper mesh membrane (GM/CM) was fabricated by one-step coating for oil–water separation and dye degradation. The geopolymer coating, serving as armor, improved hydrophilicity and pore structure, enabling rapid pollutant adsorption and degradation via advanced oxidation processes (AOPs) while inhibiting copper ion leaching. The GM/CM had a water flux of 4936 L m −2 h −1 bar −1 and demonstrated a separation efficiency of over 99 % for five different oil–water emulsions. Copper ions in GM/CM, with multiple valences, could efficiently catalyze reactive oxygen species production from H 2 O 2 . In batch mode, the GM/CM + H 2 O 2 system removed 98.48 % of methylene blue (MB) in water with 1 O 2 as the primary active species. Multiple anions had no significant impact on the degradation efficiency of the GM/CM + H 2 O 2 system. In filtration mode, the GM/CM + H 2 O 2 system achieved over 98 % removal of MB within a continuous 180 min period. Compared to other membranes, GM/CM had both high flux and competitive removal efficiencies. Moreover, due to the ion exchange and chelating effects of the geopolymer armor, the leaching concentration ratio of copper ions was two orders of magnitude lower than that in the unarmored catalyst CM + H 2 O 2 system, and significantly below the standard limit and the results reported in other literature. Overall, this work shows the potential application of GM/CM in water treatment and offers a new method for convenient preparation of dual functional membranes.
Thabang Mokoba,Zhikai Li,Tian C. Zhang,Shaojun Yuan
The development of superwetting materials for the separation of oily wastewater and emulsified oil/water mixtures has been accelerated to handle the ever-increasing oil spills from industrial and sanitary wastewaters that contain organic contaminates (e.g., dyes). Herein, sea urchin-like BiOBr@Co 3 O 4 nanowire clusters were fabricated on the copper mesh substrates via combination of hydrothermal synthesis and calcination of Co 3 O 4 nanowire clusters, and hydrothermal deposition of a BiOBr photocatalyst. Such a hierarchical nanostructure composite membrane acquired superhydrophilicity and underwater superoleophobic properties, and consequently presented excellent self-cleaning and anti-fouling with an underwater oil contact angle of 160.6 ± 2°. The membrane had high emulsion separation efficiency and permeation flux for both surfactant-free (≥99.98%, up to 4656.33 L·m −2 ·h −1 ) and surfactant-stabilized oil-in-water emulsions (≥98.66%, up to 887.67 L·m −2 ·h −1 ). Moreover, the deposition of BiOBr enhanced the photo-Fenton-like catalytic activity so that the membrane could degrade ≥96.0% methylene blue (50 mL, 10 ppm) within 60 min under visible light irradiation. Furthermore, the as-fabricated superwetting mesh membrane demonstrated great reusability as well as good mechanical and corrosion resistance when exposed to harsh environmental conditions. Thus, this study presents a novel high-performance superwetting material with great potential in efficient removal of insoluble and soluble organic contaminants from oily wastewater.
Significant progress has been made in the development of membranes characterized by high permeation flux, special wettability, selectivity, and stability during oily wastewater separation. However, more research is needed in multitasking membranes. Herein, we introduce a facile strategy of fabricating a superhydrophilic and underwater superoleophobic agave-angustifolia-like Cu3Mo2O9 nanoplate-coated copper mesh membrane via subsequent chemical oxidation, hydrothermal deposition, and calcination methods. The synergistic effect of the hierarchical structure and photocatalytic activity of the Cu3Mo2O9 coating endowed the as-fabricated membrane with superwettability and self-cleaning ability, resulting in high permeation flux (up to 3503.18 L·m–2·h–1 for surfactant-free emulsions and 917.20 L·m–2·h–1 for surfactant-stabilized emulsions) and low oil residues in the filtrate (COD value of 11.4 mg L–1 for surfactant-free emulsions and 86.8 mg L–1 for surfactant-stabilized emulsions) during oil-in-water emulsion separation, as well as photocatalytic dye degradation capabilities for methylene blue (92.4%) and rhodamine B (68.6%). Furthermore, the as-fabricated membrane exhibited favorable chemical stability and abrasive resistance. The strategy presented in this work provided a method to produce a durable membrane for efficient oil–water separation with photocatalytic properties and can withstand harsh environments.
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