[{"command":"openDialog","selector":"#drupal-modal","settings":null,"data":"\u003Cdiv id=\u0022republish_modal_form\u0022\u003E\u003Cform class=\u0022modal-form-example-modal-form ecl-form\u0022 data-drupal-selector=\u0022modal-form-example-modal-form\u0022 action=\u0022\/en\/article\/modal\/6957\u0022 method=\u0022post\u0022 id=\u0022modal-form-example-modal-form\u0022 accept-charset=\u0022UTF-8\u0022\u003E\u003Cp\u003EHorizon articles can be republished for free under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.\u003C\/p\u003E\n \u003Cp\u003EYou must give appropriate credit. We ask you to do this by:\u003Cbr \/\u003E\n 1) Using the original journalist\u0027s byline\u003Cbr \/\u003E\n 2) Linking back to our original story\u003Cbr \/\u003E\n 3) Using the following text in the footer: This article was originally published in \u003Ca href=\u0027#\u0027\u003EHorizon, the EU Research and Innovation magazine\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003ESee our full republication guidelines \u003Ca href=\u0027\/horizon-magazine\/republish-our-stories\u0027\u003Ehere\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003EHTML for this article, including the attribution and page view counter, is below:\u003C\/p\u003E\u003Cdiv class=\u0022js-form-item form-item js-form-type-textarea form-item-body-content js-form-item-body-content ecl-form-group ecl-form-group--text-area form-no-label ecl-u-mv-m\u0022\u003E\n \n\u003Cdiv\u003E\n \u003Ctextarea data-drupal-selector=\u0022edit-body-content\u0022 aria-describedby=\u0022edit-body-content--description\u0022 id=\u0022edit-body-content\u0022 name=\u0022body_content\u0022 rows=\u00225\u0022 cols=\u002260\u0022 class=\u0022form-textarea ecl-text-area\u0022\u003E\u003Ch2\u003ESystem to rid space station of astronaut exhalations inspires Earth-based CO2 removal\u003C\/h2\u003E\u003Cp\u003EIn order to limit global warming to 1.5\u02daC above pre-industrial levels and avoid some of the worse impacts of climate change, it means \u003Ca href=\u0022https:\/\/www.ipcc.ch\/news_and_events\/pr_181008_P48_spm.shtml\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Eeliminating all 42 billion tonnes of annual CO2 emissions\u003C\/a\u003E by 2050.\u003C\/p\u003E\u003Cp\u003EOne way of doing this is to cut emissions. Another is to design materials that can remove the CO2 that is already in the atmosphere or before it\u2019s expelled. The problem is that no one has quite worked out how best to do this \u2013 yet.\u003C\/p\u003E\u003Cp\u003EThe air filter system in space inspired Professor Stefano Brandani and Dr Giulio Santori from the University of Edinburgh, UK, to develop a way of capturing and concentrating CO2 directly from the atmosphere. This ambitious strategy \u2013 to build a so-called artificial tree \u2013 would see CO2 captured to be stored in large underground reservoirs.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022tw-text-center tw-text-blue tw-font-bold tw-text-2xl lg:tw-w-1\/2 tw-border-2 tw-border-blue tw-p-12 tw-my-8 lg:tw-m-12 lg:tw--ml-16 tw-float-left\u0022\u003E\n \u003Cspan class=\u0022tw-text-5xl tw-rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n \u003Cp class=\u0022tw-font-serif tw-italic\u0022\u003E\u0026#039;If you could capture CO2 from the air, this will allow you compress it and to store it in a nearby geological facility.\u0026#039;\u003C\/p\u003E\n \u003Cfooter\u003E\n \u003Ccite class=\u0022tw-not-italic tw-font-normal tw-text-sm tw-text-black\u0022\u003EDr Giulio Santori, University of Edinburgh, UK\u003C\/cite\u003E\n \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EZeolite\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EThe CO2 breathed by astronauts aboard the ISS is captured by using a sponge-like mineral called a zeolite, which has tiny pores to lock in a CO2 molecule. On the space station, the zeolites empty their CO2 when exposed to the vacuum of space.\u003C\/p\u003E\u003Cp\u003EAs part of a project called ACCA, Dr Santori is hacking the system so it will work on Earth. This is more challenging. \u2018There is so much more CO2 to capture and concentrations are more dilute to begin with on Earth, so it is much more energy intensive,\u2019 he explained. \u2018The starting concentration of CO2 on the ISS is one order of magnitude higher.\u2019\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EThe new system works by having a series of zeolite adsorption beds. Each takes in CO2, concentrates it a little and releases it when heated up. \u2018It is like a sponge. You regenerate the material using heat. When it is cold, it takes in a lot (of CO2),\u2019 said Dr Santori.\u003C\/p\u003E\u003Cp\u003EThis CO2 then moves into a new adsorption bed, which again pushes the gas molecules closer. The gas is thereby compressed more at each step, without the need for moving parts like vacuum pumps. Temperature changes are the engine of this process. Heating and cooling the spongy material causes it to release the gas, and take up more.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EWith five beds of zeolites, emptied with heat \u2013 which could be waste heat from an industrial facility \u2013 and cooled at ambient temperature, CO2 could be captured at a purity of above 95%, with little energy consumed. \u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u2018If you could capture CO2 from the air, this will allow you compress it and to store it in a nearby geological facility,\u2019 said Dr Santori, who believes that large-scale carbon capture and storage is the ideal strategy for decreasing CO2 in the atmosphere.\u003C\/p\u003E\u003Cp\u003EIn the long term, zeolites could be used in stations that could capture CO2 directly from the air \u2013 but this is a long way off as compressing CO2 is just part of the problem.\u0026nbsp;Because CO2 is very dilute in ambient air, technology such as giant fans would be needed to suck it towards the stations without spending too much energy or money \u2013 something that is still too high a hurdle for current technologies. Prof. Brandani said: \u2018The issue is how much it costs and who then owns the CO2.\u2019\u003C\/p\u003E\u003Cp\u003EA nearer-term option is to focus on stripping CO2 from the waste gases produced by industry before it is released into the atmosphere.\u003C\/p\u003E\u003Cp\u003ECO2 spews from fossil-fuelled power plants, but industries such as steel and cement emit lots of CO2 as well. The chemical reactions needed to turn limestone into cement, for example, set free CO2 gas and cement-making alone releases \u003Ca href=\u0022https:\/\/www.iea.org\/newsroom\/news\/2018\/april\/cement-technology-roadmap-plots-path-to-cutting-co2-emissions-24-by-2050.html\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003E7% of all global carbon emissions\u003C\/a\u003E.\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@alignleft@\u0022\u003E\n\u003Cimg alt=\u0022The CO2 breathed by astronauts aboard the ISS is captured by using a sponge-like mineral called a zeolite. Image credit - Pictures are in the public domain \u0022 height=\u0022451\u0022 src=\u0022\/research-and-innovation\/sites\/default\/files\/hm\/IMCEUpload\/Zeolites_min_struct.jpg\u0022 title=\u0022The CO2 breathed by astronauts aboard the ISS is captured by using a sponge-like mineral called a zeolite. Image credit - Pictures are in the public domain \u0022 width=\u0022990\u0022\u003E\n\u003Cfigcaption class=\u0022tw-italic tw-mb-4\u0022\u003EThe CO2 breathed by astronauts aboard the ISS is captured by using a sponge-like mineral called a zeolite. Image credit - Pictures are in the public domain\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMembranes\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EThe idea is to install membranes that trap CO2, which can then be concentrated and compressed for storage. \u2018Membranes are efficient and can save energy compared to other systems,\u2019 said Professor Marco Giacinti Baschetti at the University of Bologna, Italy.\u003C\/p\u003E\u003Cp\u003EIn traditional strategies used by industries such as coal plants, CO2 is captured in special liquids or solid sponge-like structures, but these must then be heated up to release the CO2. This is not needed with membranes. All existing technologies, however, are costly. Current membrane materials are not durable enough and do not separate CO2 well enough to be economically sensible.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EProf. Baschetti runs a project called NANOMEMC\u003Csup\u003E2 \u003C\/sup\u003Ewhich is developing a number of different membranes for CO2 capture. In November, the team is to test a new membrane in a Colacem cement facility in Italy.\u003C\/p\u003E\u003Cp\u003EDeveloped by project scientists at the Norwegian University of Science and Technology, the membrane is made of hollow fibres, about a millimetre thick, and covered with an extremely thin layer of nanocellulose and polymer mixed with artificial amino acids. The nanocelluose, which is made of miniscule fibres from wood, allows CO2 to permeate, while blocking other gases. The amino acid grabs onto CO2 and pulls it across the membrane.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u2018Cement plants generate CO2 from combustion and from making cement, so their flue gas is high in CO2,\u2019 said Prof. Baschetti. \u2018We will feed this gas through our membrane to separate out CO2, but of course when you do this in industry, some dust and impurities will be present. We want to see if our membrane can still work properly with this real flue gas.\u2019 The membrane will also be tested at the University of Sheffield, UK.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EThis project has not placed all its betting chips on one membrane. \u2018We started in the lab and screened more than 60 types of membranes,\u2019 said Dr Maria-Chiara Ferrari, a scientist on the project at the University of Edinburgh, UK.\u0026nbsp; There are around four membrane candidates leading the way that are based on facilitated transport \u2013 this is when a carrier molecule helps hook onto CO2 and ferry it across the membrane.\u003C\/p\u003E\u003Cp\u003EWhile it sounds promising, the technology is still at a very early \u2013 and small \u2013 stage. The membranes made so far in the lab fit in the palm of a hand, whereas the test membranes will be around the size of an A4 page. \u2018A full real plant will need hundreds of thousands of square metres and the complete separation unit will occupy around three shipping containers in volume,\u2019 Dr Ferrari explained.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThe research in this article was funded by the EU. 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