To improve the durability of oil/water separation materials, the superhydrophobic/superoleophilic epoxy/attapulgite nanocomposite coatings on the stainless steel meshes for oil/water separation were fabricated via a facile spray-coating method. The surface microstructure and wettability of the coated mesh were closely related to the attapulgite content. At the attapulgite content of 44.4 wt%, the coated mesh exhibited superhydrophobicity with the water contact angle of 160 ± 1° and superoleophilicity with the oil contact angle of 0°, which caused water to run off the mesh while allowing oil to permeate through. Various oil/water mixtures, such as hexadecane/water mixture, lubrication oil/water mixture, and paroline/water mixture, can be successfully separated by a simple filtering method using the coated mesh with the separation efficiency above 98%. This gravity-driven oil/water separation using the coated mesh was simple, time saving, and repeatable for at least 30 times. Most importantly, after being treated in various harsh conditions, including mechanical scratch, high temperature, humid atmospheres, and corrosive substance, the coated mesh still maintained highly efficiency for oil/water separation. The advantages of scalable production, high efficiency, and excellent durability for the epoxy/attapulgite coating make it to be a good candidate for oil/water separation in practical applications.

Durable superhydrophobic/superoleophilic epoxy/attapulgite nanocomposite coatings for oil/water separation

The bacterial endophytic communities of four plants growing abundantly in soils highly contaminated by hydrocarbons were analyzed through culturable and and culture-independent means Given their tolerance to the high levels of petroleum contamination at our study site, we sought evidence that Achillea millefolium, Solidago canadensis, Trifolium aureum and Dactylis glomerata support high levels of hydrocarbon degrading endophytes A total of 190 isolates were isolated from four plant species The isolates were identified by partial 16S rDNA sequence analysis, with class Actinobacteria as the dominant group in all species except Solidago canadensis, which was dominated by Gammaproteobacteria Microbacterium foliorum and Plantibacter flavus were present in all the plants, with M foliorum showing predominance in D glomerata and both endophytic bacterial species dominated T aureum More than 50% of the isolates demonstrated degradative capabilities for octanol, toluene, naphthalene, kerosene or motor oil based on sole carbon source growth screens involving the reduction of tetrazolium dye P flavus isolates from all the sampled plants showed growth on all the petroleum hydrocarbons substrates tested Mineralization of toluene and naphthalene was confirmed using gas-chromatography 16S based terminal restriction fragment length polymorphism analysis revealed significant differences between the endophytic bacterial communities showing them to be plant host specific at this site To our knowledge, this is the first account of the degradation potential of bacterial endophytes in these commonly occurring pioneer plants that were not previously known as phytoremediating plants

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Bacterial Endophytes Isolated from Plants in Natural Oil Seep Soils with Chronic Hydrocarbon Contamination.

Effect of an electric field on n-hexadecane microbial degradation in contaminated soil

Superhydrophobic filters can be applied as cost-effective separation media to overcome oil contamination issues. In this study, superhydrophobic material based on natural resources was explored as a coating material for sustainable oil/water separation membranes. Epoxy (EP) cured with cashew nut shell liquid (CNSL, a bio-based curing agent) was coated on a stainless steel mesh (E-mesh) using a simple immersion technique. Different amounts of ZnO (0–60 wt%) were added to EP/CNSL to increase coating surface roughness. The highest water contact angle (WCA) of 149.2° was measured for the E-mesh containing 60 wt% ZnO (E-ZnO-60 mesh). Modification of coated ZnO by immersion in acetic and stearic acid can create the flower-like morphology of ZnO (F-ZnO), which even further enhanced the coating hydrophobicity. The E-mesh containing 60 wt% F-ZnO (E-F-ZnO-60 mesh) showed superhydrophobicity with a WCA of 163.8°. This high hydrophobicity was obtained after chemical and mechanical durability tests, indicating excellent coating stability. The continuous oil/water separation efficiency of E-F-ZnO-60 mesh was over 97% for 75 min after the mechanical stability testing. Based on these results, this durable superhydrophobic mesh showed promising cost-effective coating applications and oil/water separation medium.

Fabrication of durable superhydrophobic epoxy/cashew nut shell liquid based coating containing flower-like zinc oxide for continuous oil/water separation

Superwetting inorganic membranes or films have recently attracted considerable interest for the separation of oils or organics from water. In this work, attapulgite (ATP)-based films consisting mostly of ATP nano-crystals and cellulose fibers from wastepaper were fabricated by a suspension casting method. The as-synthesized ATP-based films exhibited good structural flexibility and tensile ability with σκ values of up to 6.14 MPa. After modification with PDMS, the surface wettability of the ATP-based films was tailored from being amphipathic to being superhydrophobic toward water and superoleophilic toward oils. Taking advantage of the simple fabrication, high mechanical stability and low cost, such superhydrophobic and superoleophilic ATP-based films could be used for the efficient separation of oily or organic contaminants from water and show great potential in such applications as purification, separation, oil spill cleanups and so on.

Superhydrophobic attapulgite-based films for the selective separation of oils and organic solvents from water

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/43801/1/IBB64-6_519-524.pdf

Naofumi Sakaguchi

Papers

Establishment and characterization of turbine oil-degrading bacterial consortia