World's first biologically-activated aerosols: for carbon capture without the need for storage

Lead Research Organisation: University of Sheffield
Department Name: Chemical & Biological Engineering

Abstract

Our ambitious aim is to make aerosols that are "biologically activated" with photosynthetic algae that can capture CO2 from industry.

Steelmaking is critical to everyone's lives in everything from the containers for food we eat to the cars we drive and the buildings in which we live. Over 1.8 bn tonnes of steel are produced annually to maintain our modern lifestyles: we cannot live without steelmaking, yet it is arguably twice as much about making CO2 as it is about making steel (approximately 2 tonnes of CO2 per tonne of steel). Each Blast Furnace has the same carbon footprint of around 350,000 people and there are some 900 furnaces globally. Steelmaking is thought to consume 8% of the world's energy. These facts make steelmaking a major contributor to climate change. There is a nascent strategy within UK steelmaking to pioneer the capture of their CO2 using biological engineering, with small-scale pilots taking place at our collaborator's site in Port Talbot.

Although biological CO2 fixation provides a potential solution to capture carbon as well as produce a biomass resource, the associated efficiencies and costs are currently prohibitive. For example, if scaled up, current algal-based CO2-capture technology would require multiple football pitch size tanks to have a significant impact upon CO2 emission from a typical Blast Furnace. Hence, a completely new way of administering biological carbon fixation is required.

We are aware of three separate fundamental aspects that have provided inspiration for our proposed solution. Firstly, a very recent study used empirical evidence and modelling to link the generation of a mega-algal bloom to 715 million tonnes of CO2 produced during a wildfire event off the coast of Australia. This means, CO2 capture at high scales is possible in the natural environment. Secondly, we know that bio-aerosols exist in nature, where bacteria can be transported over long distances- although this work has been undertaken largely to look at pathogen transport. There has been work to show that respiratory illnesses might be linked to toxins from cyanobacteria blooms for oceans and lakes. This then provides a link to the current dust capture technology used at Port Talbot during steel manufacturing: aerosols.

We propose to repurpose our "Optomec AJ300" £0.5 M printed electronics machine and use its ink chambers to "atomise" microalgae into aerosols. These chambers become laboratories for our studies of the interaction between aerosol algae and gasses. The chambers have optical access for hyperspectral imaging and gas sensing. The printing afforded by the machine will allow efficient recovery of the aerosols "printing" them onto glass slides or any other substrate we desire, for further study. The work proposed is very high risk, as we do not know the parameters that would enable microalgae to survive the aerosolization process, what strains to use, how long they would be able to fix CO2 etc. However, if successful, the potential reward is high- as "biologically activated" aerosols could be used beyond CO2 capture, targeting others gases, volatile organic compounds and even warfare agents.

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