Biologist and conservationist Edward O Wilson strongly feels that half of earth's surface must be set aside just for Mother Nature. Its feasibility is debatable, but then we can't close our eyes to the hard facts that a variety of human activities continuously pollute air and water two precious components for the sustenance of life on this planet. This great threat to our ecosystem need remedies in real time.
14 January issue of Nature carries a report by Alsbaiee et al from Cornell University on the use of beta cyclodextrin polymers as molecular filters for the instant removal of organic micro pollutants from water. This could indeed revolutionise water purification. Molecular pockets of cyclodextrin(CD) can trap organic molecules. If you string together thousands of CD molecules and knit them into a three dimensional polymeric network, then such a network can be used as a membrane or mat to filter off toxic solutes from water. This has been tried earlier but the performance was not upto the mark. In this context the standard is activated charcoal. The low efficiencies of CD polymers were mainly because of their very low surface area. Now Alsbaiee et al report the use of rigid aromatic groups to tie up chains of CD polymers to enhance the porosity and the surface area of the final product. The new improved version registered performance efficiencies several fold higher than activated carbon. Moreover the soiled filter could be easily regenerated by mild washing and reused.
Alsbaiee et al demonstrated that 85% of toxic molecules such as Bisphenol A and S, 2,4- dichlorophenol, 2-naphthol, 1-naphthyl amine, metolachlor, propranolol, ethyl oestradiol were removed within minutes. The process holds enormous promise and could revolutionise the way we currently purify polluted water.
Aanindeeta Banerjee et al from Dept. of Chemistry, Stanford University , California USA report their efforts to utilise atmospheric carbon dioxide through an environmentally friendly route. They steer clear of conventional chemical pathway, as that would involve high energy processes. Taking a clue from the Calvin biochemical cycle, where carbon centred nucleophile reacts with CO2 to from carboxylate anion, Banerjee et al achieved the following transformations using moderate conditions: 200-350 deg.C and molten salts as catalysts.
~~~C-H + CO2 ----------> ~~C-CO2H
~~~C-H +CO2 +ROH ----------> ~~C-CO2R + H2O
Keeping in mind the abundance of lignocellulose (inedible biomass), Banerjee et al demonstrate the conversion of 2-furoic acid into furan 2,5 dicarboxylic acid, which is an industrially important feedstock.
Tailpiece:
If we surrendered
To earth's intelligence,
We could rise up rooted, like trees
Rilke in Rilke's Book of Hours: Love Poems to God
Tailpiece:
If we surrendered
To earth's intelligence,
We could rise up rooted, like trees
Rilke in Rilke's Book of Hours: Love Poems to God
References:
1. Half Earth:Our Planet's fight for Life: Edward O Wilson Publisher Liveright 2016, iSBN-13:978-1631490828
1. Half Earth:Our Planet's fight for Life: Edward O Wilson Publisher Liveright 2016, iSBN-13:978-1631490828
2. Rapid removal of organic micro pollutants from water by a porous beta cyclodextrin polymer. Alsbaiee et al Nature Vo. 529 14 January 2016, pp 190-194
3. Carbon dioxide utilization via carbonate -promoted C-H carboxylation. Banerjee et al Nature Vol.531 , 10 March 2016, pp 215-219
