Dead plants may work as well as living plants in mopping up carbon dioxide from admissions, a duo of Spanish scientists has found.
Reporting for the Royal Society of Chemistry on Mar 18, Yaundi Li writes that sawdust is showing promise as a porous solid, able to absorb carbon dioxide in its pores. Other solids, such as zeolites, are already used in this way, but most are hard to fabricate and can absorb only about 3 mmol of carbon dioxide per gram (3mmol CO2/g).
A research group at Spain’s National Institute of Carbon in Oviedo have been able to convert sawdust into a lower cost material that absorbs up to 50% more of the greenhouse gas per volume—potentially the largest ever carbon uptake at room temperature, in fact.
I’ll leave it to Yi to describes the process:
The two step synthesis involves hydrothermal carbonisation of the sawdust, creating a hydrochar, which is then activated using potassium hydroxide. The KOH treatment creates pores in the sawdust structure by oxidation of carbon and carbon gasification from K2CO3 decomposition. These pores are responsible for the material’s uptake capabilities, bestowing it with a capacity as high as 4.8mmol CO2/g. In addition, [the] material has good selectivity for CO2 over N2, fast adsorption rates and can be easily regenerated.
More work must be done in advance of commercialization. But the find is promising given that raw material is plentiful and the fabrication process is “not complex” according to Antonio Fuertes, the lead researcher, as quoted in the article.
Caption: Magnified image of sawdust before (left) and after
(right) being heated and activated showing the pores, via RSC.org.For the serious carbon scientists I know we have here in the GCCSI community, I waited until the end for the serious technical stuff, so as not to scare off too many layfolk. Here’s the abstract for Sevilla and Fuertes’ study. For more, click here to go to the full journal citation at Energy & Environmental Science.
Sustainable porous carbons have been prepared by chemical activation of hydrothermally carbonized polysaccharides (starch and cellulose) and biomass (sawdust). These materials were investigated as sorbents for CO2 capture. The activation process was carried out under severe (KOH/precursor = 4) or mild (KOH/precursor = 2) activation conditions at different temperatures in the 600–800 °C range. Textural characterization of the porous carbons showed that the samples obtained under mild activating conditions exhibit smaller surface areas and pore sizes than those prepared by employing a greater amount of KOH. However, the mildly activated carbons exhibit a good capacity to store CO2, which is mainly due to the presence of a large number of narrow micropores (<1 nm). A very high CO2 uptake of 4.8 mmol·g-1 (212 mg CO2·g-1) was registered at room temperature (25 °C) for a carbon activated at 600 °C using KOH/precursor = 2. To the best of our knowledge, this result constitutes the largest-ever recorded CO2 uptake at room temperature for any activated carbon. Furthermore, we observedthat these porous carbons have fast CO2 adsorption rates, a good selectivity for CO2–N2 separation and they can be easily regenerated.
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Greenhouse gas emissions from U.S. power plants surged by 5.6% in 2010, largest-ever increase in a single year | Global CCS Institute
Amidst increasingly acrimonious political fighting in Washington over the fate of U.S. environmental programs in general, and about climate policy in particular, carbon dioxide emissions from power plants have resumed their upward climb after a recession-related retreat. News of rising emissions is likely to intensify the tug-of-war over federal regulation of greenhouse gas emissions.
While official data for overall US emissions has not yet been released for 2010* by the Energy Information Administration (EIA), data from power plant emissions—which account for about 40% of total U.S. emissions—point to a return to upward growth in overall emissions as the economy heats up. With demand for electricity falling, overall emissions contracted by 6% during the recession of 2008 and 2009, bucking a trend of steady 0.4% annual growth since 1990. The retreat temporarily deflated the national debate on climate policy.
Now it looks like emissions are climbing again, in sync with the economic recovery. U.S. greenhouse gas emissions from power plants surged by 5.6%, after declining sharply in 2009. The rise last year is largest in a single year since the EPA began tracking the data 15 years ago, according to a study by the Environmental Integrity Project, a Washington, D.C.-based nonpartisan, nonprofit organization established in March 2002 by former EPA enforcement attorneys to advocate for more effective enforcement of environmental laws.
Reflecting the recovery the economy, growth in emissions mirrors increased demand for power. “Last year’s rise was driven in part by a 3.0% net increase in overall generation for the 12 months ending in November of 2010,” the report noted.
In 2010 carbon dioxide emissions from power plants grew to 2.42 billion metric tons, or gigatonnes, up from 2.30 gigatonnes in 2009, based on data from the EPA’s Clean Air Markets website. Total carbon emissions from power plants were still below the record of 2.57 gigatonnes set in 2007.
Across the U.S., 50 coal-fired power plants accounted for 750 million tons, or megatonnes, of carbon dioxide releases in 2010, nearly one-third of the nation’s total. Four power plants emitted over 20 megatonnes apiece in 2010, two in Georgia, one in Alabama, and one in Texas.
The heaviest emitting states were Texas with 257 million tons, nearly twice the volume of the number two state, Florida, where power plants released 130 million tons of carbon emissions. Rounding out the top-10 states were: Ohio, Indiana, Pennsylvania, Illinois, Kentucky, Georgia, Alabama, and Missouri.
The resurgence in emissions come amidst sustained opposition to new coal burning facilities, and a shift by utilities to replace older coal plants with natural gas.
Nearly 4.5 gigawatts of new coal-fired electric generation came on line in 2010, the study notes, about half of that in Texas.
But power companies have also announced plans to retire almost 12 gigawatts of coal-fired capacity in coming years, including the January announcement last month that Xcel would close nearly 900 megawatts of coal-fired capacity at four different power stations in Colorado.
* U.S. greenhouse gas data for 2009 was released in draft form on Feb. 15, 2011. http://www.epa.gov/climatechange/emissions/downloads11/US-GHG-Inventory-2011-Complete_Report.pdf
Will nuclear fears shift development to renewables and CCS? | Global CCS Institute
A week into Japan’s triple tragedy—earthquake, tsunami, and nuclear accident—the implications are still unfolding. Analysts are beginning to map out how the nuclear accident could affect global energy trends for nuclear, conventional energy, and carbon capture and sequestration (CCS). Continue reading Will nuclear fears shift development to renewables and CCS? | Global CCS Institute
US clean energy stimulus spending starts slow: CCS funding last out of the gate | Global CCS Institute
In 2009, when newly elected President Obama signed the American Recovery and Reinvestment Act, nearly $65 billion was allotted to fund green programs.
For the U.S.’s nascent clean energy industry, the funds were like finding fresh water on a long, parched journey. The funds promised to rejuvenate American cleantech industries, and help them catch-up with European players who had benefitted from more public funding, over a longer period. Continue reading US clean energy stimulus spending starts slow: CCS funding last out of the gate | Global CCS Institute
Carbon capture fares well in Obama’s 2012 federal budget proposal | Global CCS Institute
Round 1 in the US budgeting process has begun, with key green priorities such as carbon capture surviving with barely a scratch.
In the face of relentless pressure to cut public spending, President Obama proposed a U.S. federal budget for fiscal year 2012 that “essentially treads water on energy and the environment” as The New York Times’ John M. Broder put it. Continue reading Carbon capture fares well in Obama’s 2012 federal budget proposal | Global CCS Institute