Robust Nacrelike Graphene Oxide–Calcium Carbonate Hybrid Mesh with Underwater Superoleophobic Property for Highly Efficient Oil/Water Separation

Abstract

Inspired by the mastoid structure of the lotus leaf and the robust layered structure of the nacre, a novel nacrelike graphene oxide−calcium carbonate (GO−CaCO 3 ) hybrid mesh with superhydrophilic and underwater superoleophobic property was prepared for the first time, via a facile, economical, and environmentally friendly layer-by-layer (LBL) self-assembly method using commercially available stainless steel mesh (SSM) as a ready-made mask. Interestingly, GO nanosheets played a threefold role, regulating the growth of CaCO 3 nanocrystals between the GO interlamination for constructing a "brick-and-mortar" structure, improving the interface stability via coordination assembly onto SSM, and creating strong hydration derived from rich oxygencontaining functional groups. The surface hydrophilicity and hierarchically micro/nanoscale structure of GO−CaCO 3 artificial pearls imbed on the SSM, contributing to outstanding superhydrophilicity and underwater superoleophobicity. The biomimetic hybrid mesh exhibited a strong mechanical property with a Young's modulus of 25.4 ± 2.6 GPa. The optimized hybrid mesh showed a high separation efficiency of more than 99% toward a series of oil/water mixtures with high flux. The low oil-adhesion force, high fatigueresistance, chemical stability (acid/alkali/salt resistance), and excellent recycling performance enlighten the great prospects of GObased nacrelike material for application in oily wastewater treatment.

Nacre‐Inspired Biomineralized Mesh toward Scalable and Robust Oil–Water Separation with High Efficiency

“…The smaller chance of oil drops contacting solid surface (i.e., rough NBM) underwater from smaller f leads to a greater . Previously, biomineralized calcite coatings were synthesized mainly through gas diffusion and layer‐by‐layer self‐assembly, [ 23,32–34 ] but they have the disadvantages of slow speed, confined space, and inaccurate control. To quickly prepare the NBM at room temperature, we used ACC‐mediated biomineralization method, which can realize scalable fabrication for practical applications (Figure 1d).…”

“…[ 23–26 ] Interestingly, nacre with hierarchical structure of 5% organic matrix and 95% inorganic aragonite component shows the excellent mechanical robustness, playing very good protective properties for the internal soft body. [ 27–30 ] By mimicking its micro‐nanostructures and chemical components of natural nacre, a series of superhydrophilic and underwater superoleophobic materials can be obtained including montmorillonite/hydroxyethyl cellulose materials, [ 31 ] graphene oxide‐calcite hybrid meshes, [ 32 ] mineral‐coated polypropylene membranes, [ 33 ] and calcite‐coated filter meshes. [ 23,34 ] However, most of these materials have several problems, such as poor mechanical properties and inappropriate scalable production.…”

Dual-functional superwettable nano-structured membrane: From ultra-effective separation of oil-water emulsion to seawater desalination

“…From the materials perspective, superwettable materials with specific affinities for oil or water have drawn tremendous attention and believed to be a powerful solution to oil spill or oil contamination [6][7][8][9][10]. Recently, metallic meshes [11,12], fabrics [13], sponges [14][15][16] or polymeric membranes [17,18] with hydrophilic/oleophobic or hydrophobic/oleophilic properties have been developed to separate oil/water mixture. Most of these advanced materials exploited the synergistic effect of morphology and surface chemistry to tune the wetting behavior towards water or oil [19].…”

Surface Engineering of Ceramic Nanomaterials for Separation of Oil/Water Mixtures

“…Graphene exhibits interesting properties such as very-high electron mobility (250,000 cm 2 V·s −1 at room temperature), high Young's modulus (1 TPa) and thermal conductivity of 5,000 W m −1 K −1 (Singh et al, 2011 ; Randviir et al, 2014 ). Graphene has been utilized to produce materials for oil/water separation (Alammar et al, 2020 ; Dai et al, 2020 ; Tang et al, 2020 ). It has strong tendency toward absorption of oils, and this property was employed to create a superhydrophobic foam by dip coating a PU sponge in suspensions of graphene and cellulose nanowhiskers.…”