Chemical technologiesResearches

Research on Hydrogel-coated basalt fibre with superhydrophilic and underwater superoleophobic performance for oil-water separation

With ever-increasing production and usage of petroleum products, oil spillage and chemical leakage occur frequently worldwide every year. Pollution arising from these accidents has led to severe environmental problems.

Necessary rock studies of the gabbro and andesite basalt groups for the suitability as the raw material base for the production of continuous basalt fiber (CBF). A unique technique including laboratory melting and pilot-industrial melting at the high-tech equipment.

Besides the leakages arising from industrial oily compounds and chemicals, the discharge of sewage containing waste cooking oil also causes negative impact on surrounding ecosystems.

Therefore, materials that can effectively separate oils and chemicals from water are in urgently needed. Inspired by some natural species (lotus leaf, water fly, etc), superhydrophobic and superoleophilic
sponges/aerogels/meshes modified by nanoparticles and polymers were designed to achieve such objective. These composites are also called “oil-removing” materials, which realize the absorption or filtration of various oils from water selectively and effectively. However, the problems associated with the high cost of nanoparticles, pore plugging and contamination by viscous oily compounds, have limited the practical applications of these materials.
As an alternative, great attention was focused on developing materials with superhydrophilic performance, namely “water removing” performance. One of the unique advantages of such materials is that when contacting with water, the liquid spreads quickly to form a flat film on the surface of material rather than in the state of droplet, and the oily contaminants on the material can be easily cleaned by the super-spreading water film.

Many techniques have been adopted to prepare superhydrophilic materials through a combination of surface chemistry and construction of rough structure, such as vapor deposition, etching, hydrothermal treatment, and so on. Among these methods, surface coating has more advantages over the others as the process does not take a prolonged chemical reaction time. In addition, the coating method can be applied to polymeric or assembled structures by static or dynamic absorption without changing the structures of the substrates. As a matured technique, this process does not require complicated or expensive equipment, thus providing a possibility for the scale-up production of materials.
As for the substrate materials, metallic meshes (stainless steel, copper, nickel) are mainly used as a suitable substrate for oil-water separation, the biggest problem of these substrates is the high cost and marginal resistance to the chemical corrosion. Sponge is a cheap and commercially available material with huge space for oil absorption and storage, but it brings complex post-treatment as it has to be squeezed to get oils from the pores in the material for cyclic operation.

Carbon-based aerogels have intrigued huge attention due to the low density, high porosity and large surface area, the materials usually contained carbon nanotubes or graphene that are not cheap. Therefore, a suitable substrate with an excellent cost-performance property is highly desirable.

Herein, the report shows a low-cost and facile method to fabricate superhydrophilic basalt fibre (BF) with a surface modifier originated from konjac glucomannan (KGM), aiming at developing a green and in-exhaustible composite material with remarkable sustainability.

Different techniques were employed to characterize the morphology, surface states and wetting behavior of the material. The applicability of the developed fabric for separating oil-water mixture was studied, and the mechanism behind the superoleophobicity of material was illustrated.

The results showed that the KGM was deacetylated to form a hydrogel when processed in an alkali condition, and the excellent film-forming performance of the hydrogel led to the formation of a coating layer on BF fabric. The coating endowed the developed fabric with enhanced mechanical performance and super- hydrophilicity in air condition. Interestingly, the material, subjected to a water condition, exhibited a stable superoleophobicity as confirmed by the extremely low adhesion to oil and remarkable resistance to the corrosive liquids, thus holding the promise to be a suitable candidate for separating various oil-water mixtures.

    • Deng-Liang Cai, Laboratory of Environmental Science and Technology, The Xinjiang Technical Institute of Physics and Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi, 830011, China
      Center of Material and Opto-electronic Research, University of Chinese Academy of Sciences, Beijing, 100049, China
  • Peng-Cheng Ma, Laboratory of Environmental Science and Technology, The Xinjiang Technical Institute of Physics and Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi, 830011, China
    Center of Material and Opto-electronic Research, University of Chinese Academy of Sciences, Beijing, 100049, China

Countries: China

Persons: Peng-Cheng Ma

Industries: Science

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