Researchers from the SASTRA University (India) have successfully produced biodiesel from crude Hevea brasiliensis oil (CHBO) using an enzymatic transesterification process. 

Figure: Hevea brasiliensis seeds.

The major advantage of this process over the commonly deployed chemical transesterification process is that both the energy and post-treatment requirements are reduced significantly. This is because enzymatic transesterification neither requires high reaction temperatures nor basic or acid catalysts. Instead, an enzyme (here: lipase) active at temperatures slightly above ambient temperature, immobilized on a support material (here: silica aerogel), catalyzes the transesterfication reaction.

The researchers obtained fatty acid methyl ester (FAME) yields comparable to those reported for chemical transesterification (>90 %) at 30 °C when using lipase immobilized on silica aerogels. Furthermore, it was found that the enzymes largely retained their activity even after ten cycles. A characterization of the fuel synthesized from the rubber seeds showed that the fuel properties were compatible with ASTM Biodiesel (D 6751a) and European Biodiesel Standards (EN 14214).

Hence, the authors concluded that the enzymatic transesterfication of CHBO offers a more environmental compatible and economical approach to biodiesel synthesis when compared to the state of the art chemical transesterfication processes.

More details: A.Arumugam, D.Thulasidharan & Gautham B.Jegadeesan; Process optimization of biodiesel production from Hevea brasiliensis oil using lipase immobilized on spherical silica aerogel, Renewable Energy Volume 116, Part A, February 2018, Pages 755-761 https://doi.org/10.1016/j.renene.2017.10.021

A team of researchers from the Fuzhou University (China) has accomplished to synthesized self-supporting carbon nitride (CN) aerogels through an aqueous sol-gel process followed by freeze drying (see Figure).

a) Fabrication strategy of CN aerogel. b) Images of colloidal solutions of CN nanoparticles, CN hydrogel and CN aerogel.

The resulting aerogels, which were manufactured without the need for strong acids or cross-linking agents, exhibit electrical conductivity and high specific surface areas. In theory, these reported material characteristics are ideal preconditions for the utilization of the novel aerogels as photocatalysts.

To demonstrate the aerogels’ photocatalytic activity, the authors measured hydrogen evolution rates of several CN-based materials immersed in an irradiated water/triethanolamine (TEOA) solution and found that for the analyzed settings, the water splitting reaction was accelerated by almost one order of magnitude in the presence of the CN aerogel, when compared to bulk CN. Moreover, it was found that the aerogel catalysts exhibit good cycling stability, ensuring a good long-term reactivity of the material.

Apart from their application in solar-to-chemical energy conversion, the authors also see great potential for the CN aerogels in fields such as separation and sensing.

More details: Honghui Ou et al. Carbon Nitride Aerogels for the Photoredox Conversion of Water, Angewandte Chemie (2017). DOI: 10.1002/ange.201705926. http://onlinelibrary.wiley.com/doi/10.1002/anie.201705926/abstract

Read more at: https://www.analytik-news.de/Presse/2017/480.html

SEM image of (a) pure silica aerogel,
(b) resin without AAm monomer & 5 wt % aerogel)
and (c) resin with AAm monomer & 5 wt % aerogel).

Researchers of the University of Tehran (Iran) have attempted to boost the insulating behavior of two different acrylic resins by incorporating silica aerogels. Both resins were produced using methyl methacrylate, 2-ethylhexyl acrylate and acrylic acid monomers, but one resin additionally contained named acrylamide (AAm).

Unsurprisingly, the thermal properties of the resins were improved by the addition of silica aerogel. However, the mechanical properties (e.g. hardness and pull-off strength), which are a key factor for the application of resins as coating films, were shown to deteriorate in the presence of silica aerogels for the resin without AAm. In contrast to that, the resin containing AAm exhibited outstanding mechanical features, which was related to the formation of hydrogen bonds between the aerogel and the acrylamide monomers, ensuring a more homogeneous dispersion of aerogel particles in the resin (see SEM image on the right). The authors therefore concluded that the acrylic resin modified with acrylamide and silica aerogel particles can be used as an insulating roof coating to reduce the thermal losses in buildings.

It will be interesting to witness whether further developments in this field will transform aerogel containing paints to an integral part of energy efficient infrastructure.

More details: Karami et al. Improvement of thermal properties of pigmented acrylic resin using silica aerogel, Journal of Applied Polymer Science (2017). DOI: 10.1002/app.45640 http://onlinelibrary.wiley.com/doi/10.1002/app.45640/full

Read more at: http://www.farbeundlack.de/Wissenschaft-Technik/Rohstoffe/Lackbindemittel/Verbessert-Silica-Aerogel-die-thermischen-Eigenschaften-von-Acrylharz

Source: IDTechEx

IDTechEx has released an extensive report on the global aerogel market, discussing present day as well as future developments in the field.

It not only covers market analyses and forecasts, but also gives an elaborate introduction to aerogel properties and manufacturing techniques. Moreover, aerogel products and their applications are summarized and SWOT analyses for the different material types are presented. Last but not least, the report also features profiles of key aerogel manufacturers.

The authors of the 123-page report claim to have issued “the most comprehensive and authoritative view of the global aerogel market”, based on the company’s “interview-based primary research”.

While not all chapters might be of a particular interest to all readers, the broad approach of this report certainly offers the opportunity for both  researchers and entrepreneurs to dive into the field of aerogels.

Full report: https://www.idtechex.com/research/reports/aerogels-2017-2027-technologies-markets-and-players-000507.asp?viewopt=showall

Report sample pages: IDTechEx_Samplepages_Aerogels20172027TechnologiesMarketsandPlayers

An initial determination of the US International Trade Commission (ITC) has found two Asian aerogel manufacturers guilty of infringing on several of Aspen Aerogel’s patents.

The ruling came more than a year after the complaint by Aspen Aerogels (filed in May 2016), asserting Nano Tech Co. (South Korea) and Guangdog Alison High-Tech Co. (China) are importing patented insulants into the US. The motions of both companies, stating the invalidity of the Aspen Aerogels patent claims, have been rejected by Judge McNamara. A final ruling on the matter is expected in January 2018.

With Aspen Aerogel announcing to spend almost 4 % of their projected annual revenue on expenses associated with patent enforcement in their financial outlook for 2017, it becomes clear the significance this matter has for the company. The outcome of the investigation will therefore be decisive for the future strategy of the company in terms of protection of their intellectual property.

Read more at: https://www.printedelectronicsworld.com/articles/12910/initial-results-emerge-from-the-aspen-aerogel-patent-infringement-case

Read more at: http://www.wbjournal.com/article/20171002/NEWS01/171009994/northborough-manufacturer-wins-preliminary-ruling-in-asian-patent-case

Silver nanowire aerogel on flower.

Researchers from the Lawrence Livermore National Laboratory (California, USA) have recently manufactured monolithic aerogels consisting of silver nanowires (AgNW). The newly devised production technique, consisting of freeze-casting and sintering, facilitates tunable aerogel properties (e.g. bulk densities, pore structure, and conductivity). Due to its electrical conductivity, applications for the new material range from fuel cells to medical devices.

Although the discovered aerogel structures are of an outstanding quality, the researchers are already aiming at enhancing the material features.The researchers hope to further increase the electrical conductivity by reducing the average pore size and nanowire diameter, while at the same time increasing the length of the nanowires. Of course this prospect only boosts the likelihood of finding silver nanowire aerogels in future applications.

More details: Fang Qian et al. Ultralight Conductive Silver Nanowire Aerogels, Nano Letters (2017). DOI: 10.1021/acs.nanolett.7b02790

Read more at: https://phys.org/news/2017-10-ultralight-silver-nanowire-aerogel-boon.html