Hemp Graphene

Just in from Beth Buczynski at Earth Techling:

Graphene has the potential to revolutionize nearly every energy-generating technology on the planet, from batteries to solar panels. It’s lighter and stronger than almost any other material on the planet. Here’s the problem: graphene is still extremely expensive to make, so while its potential is boundless its applications have been limited.
Now, researchers at the University of Alberta are working on a way to reduce the price of making a graphene-like nanomaterial using hemp fiber, an agricultural byproduct that’s usually sent to the landfill.

Image via Bogdan/Natrij

Graphene is an ideal material for batteries and supercapacitors, energy storage devices designed to deliver short burst of power. Because of its high cost, however, most manufacturers must choose commercial supercapacitors that use activated carbon electrodes instead.
University of Alberta chemical engineer David Mitlin knows that finding a way to make graphene cost-competitive with activated carbon could mean huge advances in technologies that create and store energy. So, Mitlin is working on a way to “transform waste from the cannabis plant into a carbon nanomaterial that had similar properties to graphene and with a much smaller price tag,” writes Katherine Bourzac for Chemical & Engineering News.
To do so, Mitlin and his team focused on a barklike layer of the hemp plant called the “bast”, a nanocomposite made up of layers of lignin, hemicellulose, and crystalline cellulose. “If you process it the right way, it separates into nanosheets similar to graphene,” Mitlin told CEN.
By super heating the processed bast, the researchers were able to produce a thin, porous materials capable of providing a quick path for charges to move in and out, an essential characteristic of any supercapacitor. Using this material as electrodes, Mitilin built a supercapacitor with more than twice the maximum power density of activated carbon.

INVITATION TO LIGNIN CONFERENCE

Just in from Michael Carus and Lena Scholz, an invite to a conference on lignin, tons of which are to be harvested from every acre of hemp. It is in the stalks, in both the bast and the hurds, but mostly in the latter. Other posts on lignin are found on this blog and will give context, including studies by the US gov on using lignin in paper and companies that research lignin use. Presently, it is a waste or by-product of cellulose production. Click on the tag for lignin to be taken to them.

(Lignin, by the way, is a macromolecule characterised by monolignols, the starting material being phenylalinine. It is common in trees and herbaceous plants, where is part of the cell walls, including the xylem fibres. After cellulose it is the most abundant organic compound, accounting for up to 33% of the dry mass of wood. It fills space between cellulose and pectin, giving rigidity, conducting water and providing defence against pathogens).

Dear scientists and experts,
we would like to invite you to the first worldwide event on sourcing and material use of Lignin, taking place in Toronto, Canada on the 17th and 18th of November. Nova-Institut is the European partner of the Conference.At the event, the relevant bio-based chemistry along with Lignin-based Products will be presented and discussed by leading experts in this field. Don't miss the most important Lignin-event of the year! Please find the attached agenda.For further information also visit http://www.bioautocouncil.com/conferences/international-lignin-biochemicals.aspxor contact directly: Ms. Vicki Leith (vleith@bioautocouncil.com) +1 519 827 1118. We look forward to seeing you in Toronto! With best regards,Michael Carus and Lena Scholz

LIGNIN

Lignin is a macromolecule characterised by monolignols, the starting material being phenylalinine. It is common in trees and herbaceous plants, where is part of the cell walls, including the xylem fibres. After cellulose it is the most abundant organic compound, accounting for up to 33% of the dry mass of wood. It fills space between cellulose and pectin, giving rigidity, conducting water and providing defence against pathogens.

Lignin has both a negative and a positive side; it must be removed from plants when processed for paper and textiles, but is in fact on its own a very commercial compound. Studies of its uses began in 1927, when the Marathon Corp. in Rothschild, Wisconsin took an interest in it; since then this firm has been renamed LignoTech USA, and is owned by a Norwegian company, Borregaard.

The commercial uses of lignin and its derivatives include raw materials for use in vanillin, ethanol, humic acid, environmentally friendly dust suppression agents, dispersants in high performance cement applications, textile dyes and agricultural chemicals.

When burned, methoxy phenols are formed, of which guaicol and syringol are responsible for the flavour of smoked foods.

(for related post, see note below on pectin)

PECTIN

Pectin is a heterosaccharide, found in the cell wall of plants. The term 'pectin' includes a number of compounds which vary in the order of the monosaccharides. Under acidic conditions, it forms a gel, most well known from its use in marmalade and other jams. In fruit it is a welcome ingredient, which breaks down during maturation to pectinic and pectic acids in the presence of the enzyme pectinose. In general, hard fruits contain more pectin than soft fruits.

In fibre plants, pectin is removed out of necessity so as to isolate the cellulose, which is the main compound in paper and textiles. Hot water is one way of removing pectin, which is why hot-water retting and boiling have been methods of the hemp farmer.

Today hot-water retting is being explored along with enzyme retting. The goal of researchers is the removal of pectin from the stem so as to produce a pure cellulose fibre, free from pectin and other substances, such as lignin.