Electrophoretic Deposition of Graphene Oxide on Laser-Ablated Copper Mesh for Enhanced Oil/Water Separation

Abstract

The fabrication of bionic surfaces resembling hydrophobic plants through micro manufacturing, which creates abundant multi-level micro/nanostructures and elemental variations, has been widely employed to change the surface wettability of metallic materials. Based on the mechanisms for selective permeation of various liquids, it could achieve the function of oil/water separation. Herein, a separation copper membrane fabricated with pulsed laser ablation and modified with graphene oxide (GO) deposition showed a synergetic effect on tunable surface wettability. Micro/nanostructures were generated on the copper substrate membrane through concentric circular scanning, which was followed by hole drilling. Afterwards, charged GO nanosheets were deposited via electrophoresis. The spacing of circular lines, the diameter of the holes and the abundant high-surface-energy hydrophilic oxygen contained in deposited GO amounts could be regulated in the laser processing and deposition, resulting in oleophobicity and hydrophilicity at the same time. The highest contact angle of oil in water of the prepared mesh could reach above 165° with a hole size of 200 µm and a circular line spacing of 100 µm after the laser processing. Water flux and oil-holding capacity, which represent the separation capability of the mesh, were also evaluated. The as-prepared separation mesh also showed great stability under harsh environments.

Expedited Transition in the Wettability Response of Metal Meshes Structured by Femtosecond Laser Pulses for Oil-Water Separation

“…Moreover, femtosecond laser-induced structuring of stainless steel (Yin et al, 2017 ) and titanium (Cao et al, 2019 ) meshes have been employed to produce superhydrophilic underwater superoleophobic membranes used for separating oil-water mixtures. Generally, femtosecond laser ablation is accompanied with functionalization steps to alter or retain the laser-induced surface wettability of materials (Liu et al, 2017 ; Zhou et al, 2019 ). In most cases, surface structures generated as a result of laser ablation demonstrate superhydrophilic underwater-superoleophobic properties depending on the exposure conditions and material properties, and in order to transform them to a superhydrophobic-superoleophilic wetting state, a low surface energy coating of complex chemical reagent is applied (Liu et al, 2017 ).…”

Hydrophobicity of laser-textured soda-lime glass

“…A heat-affected zone (HAZ) develops when a substrate is subjected to laser radiation because the surface material absorbs the energy. Although the surface temperature rises when exposed to laser light, no discernible morphological change occurs [18] A crack appears for this sample and results from samples (i) to (vi) in Figure 5(b) are comparable and reliable in terms of pattern size compared to 0.3 mm patterns. The samples (vii) and (viii) display outstanding results with no sample cracks.…”

“…Figures 5(a) and 5(b) illustrate the morphologies of the glass surface, (i), (ii), and (iii) experienced laser power at 1.0W, (iv), (v), (vi) experienced laser power at 1.2W and (vii), and (viii) experienced laser power at 1.4W with scanning speeding increasing at 600, 800 and 1000 mm/min respectively for a pattern with hatch spacing 0.3 and 0.5 mm. Figure 5(a) shows how the laser treatment resulted in a homogeneous coating of micro/nanoparticles of various sizes on the initially smooth surface between the bricklayer scan lines [18]. All the fabricated samples have different finishing in terms of the size of the pattern design, this occurs because of the different parameters used.…”

Pulsed Laser Deposited Zeolite Coatings on Femtosecond Laser-Nanostructured Steel Meshes for Durable Superhydrophilic/Oleophobic Functionalities

“…Sen et al fabricated a superhydrophobic titanium filter for oil–water separation by drilling micro-holes through a titanium foil ( Ye et al, 2016 ). Zhou et al prepared copper filters from Cu sheets by drilling micro-holes with a diameter of 200 μm followed by a raster scan approach to create nanostructures on the surface ( Zhou et al, 2019 ). The sheet was further decorated with graphene oxide through the electrophoresis method to create a superhydrophilic/oleophobic surface with an underwater oil contact angle (OCA) of 165° ( Zhou et al, 2019 ).…”

“…Zhou et al prepared copper filters from Cu sheets by drilling micro-holes with a diameter of 200 μm followed by a raster scan approach to create nanostructures on the surface ( Zhou et al, 2019 ). The sheet was further decorated with graphene oxide through the electrophoresis method to create a superhydrophilic/oleophobic surface with an underwater oil contact angle (OCA) of 165° ( Zhou et al, 2019 ). Titanium oxide film was grown on titanium substrate (TiO 2 @Ti) through femtosecond laser ablation where the laser ablation process oxidized the surface of Ti substrate and formed microchannels with a rough TiO 2 layer, which created highly stable, self-cleaning, and pollutant-free oil–water filters with high separation efficiency ( Cao et al, 2019 ).…”