Shape Controlled Hierarchical Porous Hydrophobic/Oleophilic Metal-Organic Nanofibrous Gel Composites for Oil Adsorption

Significance Statement

The use of 3-dimensional porous oleophilic and hydrophobic materials with high adsorption capacity, low density and high oil-water selectivity are appearing to be good candidates for expelling oil contaminants from waste water from oil industries and oil spills. Organic (polyester, carbon-based and polyvinyl benzene) and inorganic hydrophobic materials such as metal oxide-metal based membranes, composites and sponges have been widely investigated for this application.

However, a number of challenges relating to reusability, gradual hydrolysis in water, multistep synthesis as well as poor oil-solvent pick up, come up. Hybrid organic-inorganic porous materials including metal-organic frameworks are helpful as high efficiency porous solids for gas separation and sensors owing to their unique structural order, and functional pores with superior chemical and thermal stabilities.

However, controlling porous metal—organic frameworks’ functionality and their moisture sensitive properties remains a problem. Developing stable hydrophobic materials through manipulating the frameworks’ chemical composition with respect to the applied organic likers in a bid to achieve strong metal—ligand bonds in moisture would be a solution to this.

In a recent paper published in Advanced Materials Kolleboyina Jayaramulu and colleagues developed an elementary procedure for synthesis of hierarchical composites which were based on metal-organic porous gels. Their main aim was to achieve the quick uptake of oils as well as high stabilities in a number of organic solvents.

Fluorinated graphene oxide was hybridized with aluminum based metal organic gel which contained aluminum cations, and benzene-tricarboxylate. The authors fabricated the aluminum based metal organic gel by mixing benzene tricarboxylic acid with aluminum nitrate. However, the gelation process depended on metal-organic liker coordination and the formation of hierarchical porous metal-organic gels via coordination perturbed self-aggregation of the metal-organic framework nanoparticles to produce the metal-organic gels.

The coordination between the aluminum ion clusters and benzene tricarboxylic yielded octahedral coordinated aluminum cations with carboxylate atoms. This was reference to the strong coordination bond relative to the aluminum cations solvation reactions. For this reason, the metal ions as well as ligands yielded the metal-organic framework like structure that aggregated to forming amorphous polymer.

The as-prepared hybrid fluorinated graphene oxide and metal-organic gel showed a 3-dimensional fibrillary micro network in which the fluorinated graphene oxide appeared to be the structure directing agent.

The authors applied scanning electron microscopy to analyze the morphological evolution of the prepared composite which appeared as a bundle of fiber networks. Through elemental mapping, they were able to conform the anticipated aluminum, carbon, fluorine and oxygen elements distribution. The morphology of the prepared composite was different from that of the metal-organic gel. Moreover, pore size distribution analysis indicated hierarchical pores in the range of 2-70 nm. This was pivotal to substantiate the concept that the self-assembly of the metal organic gel was influenced by the introduction of the fluorinated graphene oxide Here, the metal-organic framework nanoparticles were selectively chelated with oxygen functionalities of fluorinated graphene oxide which, in addition, provides pendant low surface energy C-F groups.

When the authors screened the hydrophobic-oleophilic composite for adsorption of hydrophobic organic solvents as well as oils, toluene, heptane, petroleum and others were chosen. The adsorption capacity of the composite was found to be 200-500%. The composite exhibited excellent hydrophobicity and oleophilicity (advancing water contact angle of 125° and oil contact angle of 0°) due to the hydrophobic C-F groups and high surface roughness. The larger macropores of the composite allowed faster oil uptake compared to reported metal-organic framework materials. Above all, the fibrous material exhibited superior reusability, and chemical inertness.

Shape Controlled Hierarchical Porous HydrophobicOleophilic Metal-Organic Nanofibrous Gel Composites for Oil Adsorption - advances in engineering

About The Author

Dr. Jayaramulu Kolleboyina born in Vijayawada, INDIA and carried out his masters in Banaras Hindu University (BHU) and PhD studies at Jawaharlal Nehru Centre for Scientific Research (JNCASR) Bangalore. After his PhD studies, he had an opportunity to work with Prof. Dr. CNR Rao, ICMS Bangalore and ICN2, Barcelona, Spain with Prof. Daniel Maspoch. He has been postdoctoral fellow with Prof Roland A Fischer using Alexander von Humboldt (AvH) Fellowship (2015-2016) at Ruhr-University Bochum (RUB).

Currently, he is combined senior researcher at Technical University Munich (TUM), Germany with Prof. Roland A Fischer and Regional Centre of Advanced Technologies and Materials (RCPTM) at the Palacky University Czech Republic with Prof. Radek Zbroil. His current research interests focus on the synthesis of various hierarchical porous materials, two dimensional materials (metal-organic frameworks, graphene and its derivatives) and their hybrid composites for various energy and environmental applications like water purification, gas storage/separation, capacitor, photo, electro, photoelectrochemical water splitting applications.

About The Author

Mr.Florian Geyer received his diploma degree (Dipl.-Chem.) in chemistry from Johannes Gutenberg-University Mainz in 2015, spending a semester abroad at Cornell University in 2012-2013. He is currently pursuing his PhD at the Max Planck Institute for Polymer Research. His research interests focus on the fabrication of superhydrophobic and superomniphobic surfaces and membranes for novel applications.

About The Author

Radek Zbořil (*1973) received his Ph.D. degree at the Palacky University in Olomouc, Czech Republic. After his doctoral studies, he spent some time at universities around the world in locations such as Tokyo, Delaware, and Johannesburg. Currently, he is a professor at the Department of Physical Chemistry and a General Director of the Regional Centre of Advanced Technologies and Materials at the Palacky University in Olomouc, Czech Republic.

His research interests focus on nanomaterial research including iron- and iron oxide-based nanoparticles, silver nanoparticles, carbon nanostructures, and magnetic nanoparticles, their synthesis, physicochemical characterization, and applications in catalysis, water treatment, antimicrobial treatment, medicine, and biotechnology. He is a member of the editorial board of several journals (e.g. Applied Materials Today, Scientific Reports). He is co-author of more than 400 publications, which have received over 12 800 citations. His H-index is 50.

About The Author

Prof. Doris Vollmer studied physics at the University of Bielefeld, Zürich and Utrecht. After her PhD on microemulsions she moved to Mainz and started working on phase transitions in microemulsions and their dynamics. In Dec. 2002 she joined the group of Hans-Jürgen Butt at the Max Planck Institute for Polymer Research and was appointed as a professor in the physics department of the University of Mainz in 2015. Since 2009 she is investigating the wetting behavior of droplets on surfaces, focusing on superhydrophobicity and lubricant impregnated surfaces.

About The Author

Prof. Roland A. Fischer studied chemistry at Technical University Munich (TUM) and received his Dr rer. nat. in 1989 under the guidance of Wolfgang A. Herrmann. After a postdoctoral collaboration with Herbert D. Kaesz at the University of California, Los Angeles (UCLA), he returned to TUM in 1990, where he obtained his Habilitation in 1995 and was appointed Associate Professor at Ruprecht-Karls Universität Heidelberg in 1996. He moved to Ruhr-Universität Bochum in 1997 where he took the chair of Inorganic Chemistry II. He was Dean of the Ruhr University Research School over a number of years. In 2016 he moved back to Technical University Munich and took the chair of Inorganic and Metal-Organic Chemistry.

He has been elected vice president of the Deutsche Forschungsgemeinschaft (DFG) in 2016. His research interests focus on group 13/transition mixed metal compounds and clusters, precursor chemistry for inorganic materials, chemical vapor deposition (CVD), nanoparticles, colloids and in particular the supramolecular chemistry and property tailoring of porous coordination network compounds (MOFs) and functional nano materials derived from MOFs.

Reference

Kolleboyina Jayaramulu1,2, Florian Geyer3, Martin Petr4, Radek Zboril4, Doris Vollmer3, and Roland A. Fischer2. Shape Controlled Hierarchical Porous Hydrophobic/Oleophilic Metal-Organic Nanofibrous Gel Composites for Oil Adsorption. Advanced Materials 2017, 29, 1605307.

Show Affiliations
  1. Inorganic Chemistry II, Ruhr-University Bochum, 44870, Bochum, Germany
  2. Chair of Inorganic and Metal-Organic Chemistry, Department of Chemistry and Catalysis Research Centre, Technical University of Munich, Garching, 85787, Germany
  3. Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
  4. Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Šlechtitelu˚ 27, 783 71, Olomouc, Czech Republic

 

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