As demand for oil increases, so does its extraction and, consequently, the frequency of production-related accidents. This necessitated advancements in oil separation and absorption techniques to make sure that environmental disasters can be prevented.

An efficient way to remove oil and solvents from contaminated waters are absorbents, which directly remove the oil in the deployed surroundings. Additionally, they facilitate the possibility of recycling the absorbed oil after recollection. However, common absorbing materials utilized for the cleaning of oil spills are known to have a low environmental compatibility.

Died water droplets on top of hydrophobic cotton cellulose aerogel

In light of these facts, researchers from the National University of Singapore have synthesized novel environmentally benign cotton-cellulose aerogels which exhibit promising oil absorption characteristics. The monolithic pure cotton (PC) and cellulose-cotton (CC) aerogels were manufactured using a freeze-drying technique. In order to ensure hydrophobicity of the materials (see figure on the right), the aerogels were silanized using methyltrimethoxysilane. Thereafter, the absorption capacity of the aerogels was investigated for different solvents (e.g. dichloromethane, motor oil, ethanol).

The synthesized PC and CC aerogels were able to absorb all utilized solvents to large extents with loading capacities of up to 100 g/g being measured. Additionally it was discovered that absorption capacities increase with solvent density. In order to analyze the recyclability of the aerogels, two different recycling techniques were investigated. These experiments revealed that distillation cycling guarantees a superior sustaining of the absorbing performance when compared to squeeze cycling.

The intriguing findings of the authors once again highlight that aerogels can be applied in areas reaching beyond the field of insulation.

More details: Hanlin Cheng et. al; Cotton aerogels and cotton-cellulose aerogels from environmental waste for oil spillage cleanup, Materials & Design Volume 130, 15 September 2017, Pages 452-458. https://doi.org/10.1016/j.matdes.2017.05.082

Although monolithic aerogels of numerous types and forms have been produced using a broad palette of techniques, it remains a challenge to accurately tailor the micro- and macrostructure of the resulting three-dimensional structures. Recently, researchers from Kansas State University (USA) have presented a 3D-printing freeze drying technique promising just that.

Different aerogel geometries produced using the 3DFAP production technique

The so-called 3D freeze assembling printing (3DFAP) technique facilitates the fabrication of monolithic aerogels of various macrostructures (see figure on the right). Using this process, the team of researchers was able to produce silver nanowire aerogels (SNWA), that have ultra-low density (1.3 mg/cm³) and high electrical conductivity (0.24 S/cm), while also exhibiting outstanding mechanical features such as good compressive resistance and tunable Poisson ratios (even negative). Experiments investigating the effect of mechanical stress on material resistance revealed outstanding cyclic stability. Furthermore, the different structures were found to exhibit extremely high mechanical resilience, even under tensile stress.

In light of these promising results, the authors conclude that through facilitating the manipulation of the aerogel macrostructure, the novel production technique offers the possibility to manufacture three-dimensional aerogel structures for applications in the fields of sensing, energy storage or catalysis. They are also convinced that the 3DFAP technique can be applied to produce other 3D nanomaterial architectures.

More details: Pengli Yan et. al; 3D Printing Hierarchical Silver Nanowire Aerogel with Highly Compressive Resilience and Tensile Elongation through Tunable Poisson’s Ratio, Small Volume 13, Issue 38 October 11, 2017. http://onlinelibrary.wiley.com/doi/10.1002/smll.201701756/abstract

Read more at: http://www.advancedsciencenews.com/3d-printing-tunable-poisson-ratio-metallic-aerogels/

Owing to their unique characteristics, graphene aerogels are considered promising materials for a wide range of applications in fields such as energy storage, catalysis, and sensing. A research team from the Tsinghua University (China) has successfully demonstrated that another item can be added to this impressive list — adsorption and pre-concentration of air pollutants. Hierarchical porous graphene aerogels (HPGAs) synthesized via self-assembly, freeze drying and subsequent calcination have been shown to possess outstanding characteristics for extracting chemical warfare agents (CWAs) from ambient air.

Morphological structure images of hierarchical porous graphene aerogel (HPGA) at different magnifications.

The researchers found that the graphene aerogels, composed of a porous three-dimensional pore network (see Figure above), exhibited a good thermal and mechanical stability. Adsorption experiments with sarin, a highly toxic nerve agent, showed that the HPGAs display outstanding adsorption/desorption behavior in a wide range of operation conditions (e.g. desorption temperature, relative humidity). Furthermore, repeated cycling of the graphene aerogels did not result in a drop in adsorption efficiency or a change in material morphology, underlining the high resilience of HPGAs.

Given those intriguing results, the authors hypothesize that graphene aerogels could be efficient materials for the removal of other hazardous gases from air and hence might prove to be a promising alternative in cases of industrial accidents or terrorist attacks.

More details: Qiang Han, Liu Yang, Qionglin Liang and Mingyu Ding; Three-dimensional hierarchical porous graphene aerogel for efficient adsorption and preconcentration of chemical warfare agents, Carbon Volume122, October 2017, pages 556-563. https://doi.org/10.1016/j.carbon.2017.05.031

Aerogels, long familiar only to researchers and pioneers,  are now making their way into consumer products. One such example is the newly introduced Life-Pocket^TM  by the Norwegian company Helly Hansen.

Helly Hansen Life-Pocket

It is rumored that when the Canadian Skiing Team was asked which improvements they hoped for in skiing apparel, they explicitly demanded for an insulated smartphone chest pocket, which facilitates a longer battery lifetime. With the aim of making the pro-skiers innermost wish a reality, the team at Helly Hansen found a partner which had a solution at hand — PrimaLoft (USA), a company focused on insulation for outerwear, gloves and footwear.

Using “Primaloft Aerogel Gold” insulating material, the designers at Helly Hansen have created a pocket which protects the battery of cell phones even in the most extreme weather conditions (-28.0 °C / -18.4 ℉). This high performance insulation composite (CLO ratings: 1.29-2.00) is a pressure resistant material encapsulated in a waterproof membrane that can be used for insulating pockets, shoes and gloves.

Since the aerogel is only located on the outside of the jacket, body warmth is utilized to maintain a certain temperature inside the chest pocket and hence prevent temperature-related performance decrease of smartphone batteries. According to the company, jackets equipped with the Life-Pocket^TM  and the Life-Pocket+^TM keep phones two or three times warmer than regular ski jackets, respectively.  

Initial hands-on tests of the product showed a significant increase in battery life, demonstrating that the aerogel-insulated pocket delivers on its promise (more details).

It will be interesting to see whether the unique characteristics of aerogel materials begin to attract a broader interest from product designers.

Read more at: https://www.hellyhansen.com/news/the-life-pocket-saving-battery-life-in-cold-environments/

Read more at: https://www.airfreshing.com/news-helly-hansen-life-pocket

Read more at: https://gearjunkie.com/aerogel-helly-hansen-lifepocket-powder-suit

Read more at: https://gearjunkie.com/primaloft-gold-aerogel-insulation