Heidi Lees

Tallinn University of Technology | TTU · Department of Energy Technology

A portable capillary electrophoretic system with contactless conductivity detection was used for fingerprint analysis of post-blast explosive residues from commercial organic and improvised inorganic explosives on various surfaces (sand, concrete, metal witness plates). Simple extraction methods were developed for each of the surfaces for subsequen...

A novel method based on capillary electrophoresis with pre-column derivatization and direct UV detection for the determination of thiodiglycol, thiodiglycol sulfoxide and thiodiglycol sulfone in water samples was developed. The lack of a UV chromophore of target analytes was overcome by derivatization with phthalic anhydride. The reactant concentra...

Novel, fast and simple methods based on RP-HPLC and MEKC with DAD are developed and validated for the qualitative and quantitative determination of five cyclic sulfur mustard (HD) degradation products (1,4-thioxane, 1,3-dithiolane, 1,4-dithiane, 1,2,5-trithiepane, and 1,4,5-oxadithiepane) in water samples. The HPLC method employs a C18 column and a...

MODUM project continued the work on monitoring of the chemical weapons (CW) dumped in the Baltic Sea started in previous projects. As a new aspect, on board analysis methods – headspace gas chromatography-mass spectrometry (GC–MS) and capillary electrophoresis (CE) – were developed and tested in laboratory conditions and during cruises. The GC–MS m...

Lignin is considered a valuable renewable resource for building new chemicals and materials, particularly resins and polymers. The aromatic nature of lignin suggests a synthetic route for synthesizing organic aerogels (AGs) similar to the aqueous polycondensation of resorcinol with formaldehyde (FA). The structure and reactivity of lignin largely d...

An alternative adsorbent from oil shale semi-coke material for removing chemical pollutants from aqueous solutions was investigated. For this purpose, enriched oil shales with different kerogen contents (57, 79 and 90 wt%) were pyrolyzed in nitrogen atmosphere at 600–900 °C at a heating rate of 10 °C/min and a hold time of 60 min. The surface p...

Finding a recycling method for waste materials is attracting increasing attention. In Estonia, semicoke from the shale oil industry is a material that can be used for adsorbent production. For this application, it is important to characterize the surface properties and enhance the porosity. In this study, different pyrolysis temperatures (from 500...

The European Union (EU) presented a uniform List of Waste (LoW) in 2000 and last updated the technical guidance in 2018. The respective local regulations for the classification of waste in Estonia were set in 2015. Due to the changes in the regulations, it was necessary to review the properties of solid wastes generated in Estonian oil shale indust...

Using woody biomass in thermochemical gasification can be a viable alternative for producing renewable energy. The type of biomass and the process parameters influence the producer gas composition and quality. This paper presents research on the composition of the producer gas from the gasification of three woody biomass species: spruce, alder, and...

In Estonia, oil shale ash was considered as hazardous waste until the end of 2019 mainly due to its high content of calcium oxide. This limited the use and export of the produced ash. During 2018 and 2019, a study on the overall hazardous potential of Estonian oil shale ash was conducted. In this paper, we present the computational ecotoxic analysi...

Oil shale is currently used for electricity and oil production. The production of the latter produces large quantities of residue, i.e. semi-coke, from which it could be possible to create valuable porous materials with high surface areas. These adsorbents could be used in a wide range of environmental and industrial applications. To produce adsorb...

Perfluoroalkyl substances are chemical pollutants whose levels in the environment should be monitored. This work implemented nonaqueous capillary electrophoresis with conductivity detection to achieve separation of perfluoroheptanoic acid, perfluorooctanoic acid, and perfluorooctanesulfonate within 5 min. The mixture of 3‐(N‐morpholino)propanesulfo...

It is important to understand the extent of transfer of explosive particles to different surfaces in order to better evaluate potential cross-contamination by explosives in crowded security controls such as those at airports. This work investigated the transfer of nine explosive residues (ANFO, dynamite, black powder, TNT, HMTD, PETN, NH4NO3, KNO3,...

This novel investigation focused on studying the transfer of explosive residues (TNT, HMTD, PETN, ANFO, dynamite, black powder, NH4NO3, KNO3, NaClO3) in ten consecutive fingerprints to two different surfaces – cotton fabric and polycarbonate plastic – by using multispectral imaging (MSI). Imaging was performed employing a reflex camera in a purpose...