Hydrochars can eliminate over 70 per cent of pollutants in waters

A new doctoral dissertation that will be examined at the Lappeenranta University of Technology, LUT involves the production of hydrochars, which can be used to clean pollutants from water.

In her dissertation, Sara-Maaria Alatalo produced hydrochars by modifying the properties of carbon. Ms Alatalo increased the carbon's porosity and made its surface more variable by altering the surface's functional groups i.e. division of oxygen, nitrogen and sulphur atoms on the surface. These properties are better suited for practical application such as water treatment, as they influence the effectiveness of the material's functions. Over 70 per cent of metals and colourants present in water were cleansed with the produced hydrochars. The results also demonstrated that hydrochars can be reused at least three times.

Hydrochar refers to carbon produced through the hydrothermal carbonization process. The process alters carbon in a closed container under high pressure in water that is at a temperature of approximately 200 Celsius. Biomasses are used as the method's input, and the method does not release carbon dioxide emissions, which makes the method environmentally friendly.

According to the dissertation, hydrothermal carbonization is simpler, faster and more cost effective than other carbon production methods. The dissertation achieved significant improvements in the porosity of carbon. Additionally, utilisation of source material properties made it simple to alter the functional groups for carbon. It was possible to control porosity and functional groups during the process without added stages, which made the process faster.

Hydrothermal carbonization is considered a promising method for the production of carbon materials for numerous uses, such as transport of pharmaceuticals, energy storage, chromatography as well as the treatment of water, air and gas.

Sara-Maaria Alatalo's, MSc (Chemistry) dissertation in the field of chemical technology is titled Hydrothermal carbonization in the synthesis of sustainable porous carbon materials. Ms Alatalo will defend her dissertation on 6 July 2016 at 12.00 noon in Mikkeli, at the Mikkeli University Consortium. Professor Niklas Hedin from Stockholm University, Sweden will be opponent. Professor Mika Sillanpää from the Lappeenranta University of Technology will act as custos.

The dissertation has been published in the University's Acta Universitatis Lappeenrantaensis research series (number 701). ISBN 978-952-265-963-7 and ISSN 1456-4491. The dissertation can be found on the Lappeenranta University of Technology LUTPub database at: http://urn.fi/URN:ISBN:978-952-265-964-4. A printed version of the dissertation may be purchased from the Aalef bookshop, tel. +358 44 744 5511 or kirjakauppa@aalef.fi as well as from the online shop LUT Shop at https://lutshop.lut.fi. The research has been funded by Tekes, the Finnish Foundation for Technology Promotion and the Land and Water Technology Foundation.

Information about the doctoral candidate:

Name: Sara-Maaria Alatalo

Year and place of birth: 1985 Haapavesi

Home municipality: Mikkeli

Education: MSc (Chemistry), University of Eastern Finland, 2011

Employment: Researcher, LUT, 2011-2016

More information:

Sara-Maaria Alatalo, researcher, telephone number, sara-maaria.alatalo@student.lut.fi