Biochar Could Make Desalination More Cost Effective

ISU Grad Students Win DOE Grant to Study Concept

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Posted: Wednesday, June 18, 2014 3:00 pm

Imagine being able to desalinate water using a product derived from wood waste.

How could wood waste fit into water desalination? By applying a process called pyrolysis, which thermochemically processes biomass, such as wood waste.

Biochar, a charcoal-like substance, is a product of the pyrolysis, which involves heating biomass such as corn stover in the absence of oxygen, the products of which are bio-oil, gas and biochar. The bio-oil is used to create fuels and chemicals, but biochar, a black powder, is proving to be a useful product of the process as well. Scientists are demonstrating its worth as an additive to soil to improve the ability to retain moisture and nutrients.

Now biochar also is being studied for use in water desalination systems, after Advanced Renewable Technology International Inc., a company formed by Matt Kieffer, Bernardo del Campo and Juan Proano Aviles won a grant from the SBIR/STTR Programs Office within the U.S. Department of Energy. The three graduate students are studying mechanical engineering at Iowa State University and do research with the Bioeconomy Institute, also at Iowa State.

The project is expected to take nine months and is aimed at creating potable water at a reasonable cost.

Biochar is mostly carbon, so the three entrepreneurs came upon the idea of using it in desalination systems, in the way activated charcoal is currently used. Activated charcoal is essentially carbon with small pores that increase the amount of surface area available for adsorption.

The students are focusing on a technology called capacitive deionization (CDI), which uses electric current to perform electrolysis of salt ions in water. The separated ions are attracted by oppositely charged electrodes through electrostatic forces. Passing the water through a porous media such as activated charcoal traps the ions, removing the salt from the water. The company is proposing a multi-stage system, where water is passed through several activated charcoal filters, as well as a CDI stage.

Standard activated charcoal, however, is relatively expensive. Moreover, competing technologies, such as reverse osmosis, are energy intensive and not suitable for small scale operations. With their grant, the three students hope to prove that biochar can be a cost effective alternative.

“From the feedback from reviewers and from the literature, this technology is really attractive because it’s lower cost than what is used now,” Aviles said.

The graduate students will study various methods to activate the biochar – such as increasing its pore size – as well as how biochars made from different biomass, such as woods or various agricultural residues, work as activated charcoal. They also will try to determine if different biochars are more appropriate for absorbing different compounds found in various sources of water.

The three students worked together in the summer 2013 on a project in Nicaragua to introduce local farmers to the benefits of biochar. They spent three weeks near Matagalpa, Nicaragua, building a pyrolysis system to turn unwanted rice husks into biochar, which was then added to local fields to improve soil quality.

This friendship led to the development of the company. In addition to developing biobased technologies, the company also provides engineering consulting.

The three students have worked to improve their entrepreneurial skills. In the spring of 2014, they took a class taught by Peter Keeling, the industrial collaboration and innovation director for the NSF Engineering Research Center for Biorenewable Chemicals (CBiRC) at Iowa State. Keeling oversees CBiRC’s Biobased Foundry, which helps start-up companies by providing experienced support for the transition from technological innovation to business opportunity.

“It was a valuable experience,” Kieffer said. “Not just working with Peter, but also working with other students on campus that have been involved in entrepreneurship. “

As a result of the class, they wrote a business plan and entered two business competitions. The first, the Pappajohn New Venture Business Plan Competition gives Iowa students an opportunity to present a business plan and win $5,000 in start-up finances. The company was selected as a finalist at Iowa State and went on to the state competition.

In another competition held this spring, the Colorado Cleantech New Venture Challenge, the company had to make a presentation and discuss its business plan with venture capitalists, professors and representatives from the U.S. DOE. It won third place in the competition, a $150,000 grant.

“It was a good experience,” Kieffer said. “We learned a lot about our company and what we want to focus on and what attracts investors and customers.”

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