Serpentine locks up Carbon Dioxide

Sep 02, 2004
Carbon dioxide sequestered in treated serpentine minerals

A common mineral can remove carbon dioxide from combustion gases, but in its natural state, it is glacially slow. Now, a team of Penn State researchers is changing serpentine so that it sequesters the carbon dioxide from fossil fuel burning in hours, not eons.
"Serpentine naturally sequesters carbon dioxide over geologic time, but it is too slow to help us," says Dr. M. Mercedes Maroto-Valer, assistant professor of energy and geo-environmental engineering and program coordinator for sustainable energy, the Energy Institute.

The metamorphic mineral serpentine -- or magnesium silicate hydroxide -- is composed of magnesium, silicon and oxygen and is plentiful. He researchers used material from the Cedar Hills quarry on the Pennsylvania/ Maryland border for this study, but the mineral is available in large quantities in many places. The U.S. deposits of the minerals that can be used for this process – serpentine and ovivine – can sequester all the carbon dioxide emissions produced from fossil fuels.

"Previous researchers investigating serpentine for use in sequestering carbon dioxide have crushed serpentine very finely, to sizes smaller than beach sand, but, even at these small sizes, it takes high temperatures to speed up the reaction, "says Maroto-Valer. "With our method, we do not need to crush it that fine and we do not need high temperatures. In fact, the reaction gives off heat. Our method is much less energy expensive."

The researchers, who also include John M. Andresen, director of the Consortium for Premium Carbon Products from Coal (CPCPC), the Energy Institute; Yinzhi Zhang, post doctoral fellow, the Energy Institute; Matthew E. Kuchta, graduate student in geo-environmental engineering, all at Penn State; and Dan J. Fauth, U.S. Department of Energy’s National Energy Laboratory in Pittsburgh, dissolved the crushed serpentine in sulfuric acid.

When serpentine dissolves in sulfuric acid, the silicon in the mineral becomes silicon dioxide, or sand, and falls to the bottom, while the magnesium becomes magnesium sulfate. Treating some of this magnesium sulfate with sodium hydroxide also creates some magnesium hydroxide. The researchers were able to convert large amounts of the serpentine’s magnesium to these chemicals providing large surface areas for reactions to occur in solution at room temperature.

Carbon dioxide passed through the solution of magnesium sulfate and magnesium hydroxide converts both to magnesium carbonate or magnesite, which becomes a solid and falls to the bottom. This solid can be used to manufacture construction blocks and there is also a small market for hydrated magnesium carbonate in the cosmetics industry. The silicon dioxide can be used to remove sulfur dioxide from the flue gases, which can subsequently be converted to sulfuric acid to use in the first part of the process.

"The high surface area of the silicon dioxide makes it a natural sorbent for capturing more carbon dioxide and sulfur dioxide," says Maroto-Valer.

The researchers have not yet tested the process on a working coal-fired stationary boiler, but they are working on developing a reactor in the laboratory that can continuously treat the flue gas. At the same time they would like to regenerate the sulfuric acid to minimize costs.

Because carbon dioxide will be the last gas in the emission stream treated, there are two options for commercial implementation. Fossil fuel burning plants could simply place a serpentine reactor as the last component of their emissions clean up and sequester carbon on site. Or, if the area is heavy with fossil fuel burning plants, each plant could pipe their carbon dioxide to a central treatment plant.

The U.S. Department of Energy supported this research. The researchers have applied for a U.S. patent for this process.

Explore further: Researchers discover low-grade nonwoven cotton picks up 50 times own weight of oil

add to favorites email to friend print save as pdf

Related Stories

How do we terraform Venus?

Jul 25, 2014

It might be possible to terraform Venus some day, when our technology gets good enough. The challenges for Venus are totally different than for Mars. How will we need to fix Venus?

Hot tropical oceans during Pliocene greenhouse warming

Jun 29, 2014

The impact of the greenhouse gas CO2 on the Earth's temperature is well established by climate models and temperature records over the past 100 years, as well as coupled records of carbon dioxide concentration ...

Earth's breathable atmosphere tied to plate tectonics?

Jun 20, 2014

The rise of oxygen is one of the biggest puzzle in Earth's history. Our planet's atmosphere started out oxygen-free. Then, around 3.5 billion years ago, tiny microbes called cyanobacteria (or blue-green algae) ...

An experiment recreates the crust of the moon Europa

Mar 14, 2014

Water, salts and gases dissolved in the huge ocean that scientists believe could exist below Europa´s icy crust can rise to the surface generating the enigmatic geological formations associated to red-tinged ...

Sorbents capturing CO2 will make power plants cleaner

Oct 18, 2013

When coal is used to generate electricity in power plants, carbon from the coal bonds with oxygen from air to make carbon dioxide (CO2). Due to concerns about how CO2 impacts global climate, scientists at ...

Recommended for you

Refocusing research into high-temperature superconductors

6 hours ago

Below a specific transition temperature superconductors transmit electrical current nearly loss-free. For the best of the so-called high-temperature superconductors, this temperature lies around -180 °C – a temperature ...

MRI for a quantum simulation

12 hours ago

Magnetic resonance imaging (MRI), which is the medical application of nuclear magnetic resonance spectroscopy, is a powerful diagnostic tool. MRI works by resonantly exciting hydrogen atoms and measuring ...

50-foot-wide Muon g-2 electromagnet installed at Fermilab

12 hours ago

One year ago, the 50-foot-wide Muon g-2 electromagnet arrived at the U.S. Department of Energy's Fermi National Accelerator Laboratory in Illinois after traveling 3,200 miles over land and sea from Long Island, ...

User comments : 0