Lubricating industry naturally

Sesame oil might make a viable and sustainable alternative to mineral oil as an industrial lubricant, according to research published in the International Journal of Agricultural Resources, Governance and Ecology.

Sabarinath Sankaran Nair, Kumarapillai Prabhakaran Nair, and Perikinalil Krishnan Rajendrakumar of the Department of Mechanical Engineering at the National Institute of Technology, Calicut, Kerala, India, explain that there is a pressing need to find alternatives to the mineral oils currently produced by the petrochemicals industry from fossil reserves of crude oil. Sustainable alternative feedstocks that might be grown as agricultural crops could offer a potentially less polluting alternative especially in the face of dwindling resources.

There are countless plant-derived oils any one of which might have particularly properties desirable in an industrial lubricant. The team, however, has tested the physicochemical, rheological, thermal, oxidative, and tribological properties of sesame oil and compared it positively with coconut oil, sunflower oil, and a commercially available mineral oil. The team reports that sesame oil has excellent thermal and tribological properties and high viscosity and has a better coefficient of friction.

However, the oxidative stability of sesame oil is not as high as mineral oil and this will need improving through reformulation of oil derived from sesame seeds with additives, or perhaps even through genetically modified plants for improved oil stability. Nevertheless, even without such changes, the team points out that it is stable as a lubricant base stock at a wide range of temperatures.

“With further development, it can become an eco-friendly substitute for its mineral oil counterparts in near future,” the team concludes.

Nair, S.S., Nair, K.P. and Rajendrakumar, P.K. (2017) ‘Evaluation of physicochemical, thermal and tribological properties of sesame oil (Sesamum indicum L.): a potential agricultural crop base stock for eco-friendly industrial lubricants’, Int. J. Agricultural Resources, Governance and Ecology, Vol. 13, No. 1, pp.77–90.

A better life outback

Desert lands cover about a quarter of the Earth’s land mass and are home to some half a billion people and yet they are commonly portrayed as extreme places with marginalized communities. The people who live there are perceived as living in hardship and isolation and surviving largely due to subsidies from the “mainstream” economy. New research published in the International Journal of Sustainable Development suggests that for some desert regions, particularly Australia’s “outback”, there is huge potential given appropriate infrastructure and investment for desert regions to become places of great prosperity and wellbeing.

Digby Race of the Cooperative Research Centre for Remote Economic Participation, in Alice Springs and The Australian National University, in Canberra and colleagues from other universities, report that there is great potential for 200,000 people who live in Australia’s vast desert area which covers about 3.6 million square kilometers. However, the team asserts, “The multi-dimensional nature of the debate about the future of Australia’s desert region often leaves policy makers with little overarching synthesis to guide public policy.”

The desert region of Australia includes the traditional homelands of many Aboriginal peoples, the team points out, and over the last century or so has developed a mixed economy based on pastoral operations, government education and health services, gas and mining operations, and tourism. However, the Aboriginal peoples commonly remain marginalized by mainstream society. The researchers have now drawn together research on climate change, energy, housing and transport to provide an analysis that spans disciplines of how Australia’s desert region could become a highly livable and prosperous area for existing and new residents. It is, of course, hoped that such development would be in concert with the preferred lifestyles of the Aboriginal peoples.

“While there will always be uncertainty about future conditions and challenges, investing in strategies that are culturally appropriate, have little regret (low risk) and provide multiple benefits appears the best pathway,” the team suggests. “That is, investing in the connectivity and mobility of remote communities, creating a coordinated transport system, transitioning to renewable energy, and building super energy efficient housing can all be elements of re-designing the livability of desert Australia.”

Race, D., Dockery, A.M., Havas, L., Joyce, C., Mathew, S. and Spandonide, B. (2017) ‘Re-imagining the future for desert Australia: designing an integrated pathway for enhancing liveability’, Int. J. Sustainable Development, Vol. 20, Nos. 1/2, pp.146–165.

How to reclaim battery metals

Rechargeable lithium ion batteries power our phones and tablets they drive us from A to B in electric vehicles, and have many applications besides. Unfortunately, the devices that they power can fail and the batteries themselves are commonly only usable for two to three years. As such, there are millions batteries that must be recycled. Research published in the International Journal of Energy Technology and Policy describes a new way to extract the lithium and the cobalt that make up the bulk of the metal components of these batteries.

According to Ataur Rahman of the Department of Mechanical Engineering, at the International Islamic University Malaysia and colleague in the Department of Economics, Rafia Afroz, explain that the price of both lithium and cobalt is rising as demand for lithium ion batteries which require both metals for their construction are increasingly in demand. They have investigated a recycling technology that can extract with reasonable efficiency the metals from scrap batteries.

The team’s hydrometallurgical method can recover both cobalt and lithium in their laboratory-scale tests from standard 48.8 Wh lithium batteries. This involves first baking the battery in an oven at 700 Celsius to “calcinate” the cobalt, lithium and copper components to destroy organic compounds, such as plastics and foams. The calcined material carrying metal and metal compounds (salts and oxides) is then treated with strong acid, hydrochloric acid and sulfuric acid, to leach out the metal ions. The team experimented with using hydrogen peroxide as a reducing agent to see whether that reagent would improve the leaching process. They were able to extract the lithium with almost 50 percent efficiency and the cobalt with almost 25 percent efficiency.

Given that each of these metals represent 41% of the weight of a 48.8 Wh battery and 8.5% of the weight, these are useful extraction rates that would on balance, given the heating and acid use, represent a commercially viable approach to recycling the electrodes from such batteries. The leached metals could then be used in the manufacture of new batteries or elsewhere in industry. The contaminated liquid waste could be further treated to make it safe for disposal under recycling regulations.

Rahman, A. and Afroz, R. (2017) ‘Lithium battery recycling management and policy’, Int. J. Energy Technology and Policy, Vol. 13, No. 3, pp.278-291.