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The final objective of this study is to produce chemical models of flotation- like systems, including oxidation products of magnetite (maghemite and hematite) together with apatite. This is started by investigating the acid base properties, surface complexation and surface characteristics of the systems hematite-H+ and maghemite-H+ (paper I), fluorapatite-OH- (paper II) and a mixed system of maghemite-fluorapatite-OH- (paper III). Synthetic minerals were prepared and characterised with BET, SEM, XRD, FT-IR and FT- Raman. The acid base properties were investigated using high precision emf potentiometric titrations and z-potential measurements. Titration data were interpreted using models based on the theory of surface complexation, assuming the formation of surface complexes with charge dependent formation constants. The constant capacitance model was applied to interpret titration data for all three systems. The obtained models will contribute to a better understanding of the reactions during the apatite/magnetite separation by flotation. The surface site density Ns (sites/nm2) for maghemite was found to be very low compared to other iron oxides. The mixed system of maghemite and fluorapatite was interpreted with two different models. FT-Raman together with the Ns (sites/nm2) value reveals that interactions occurred between the fluorapatite and maghemite particles in the system. These interactions have to be chemical or sterical, because both surfaces are negatively charged in the actual pH-range. / Godkänd; 2004; 20070127 (ysko)

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Liquid crystal monomers (LCMs) are byproducts that can be expected in LCD screens and they have been found to be released into the environment due to breakage and usage of LCD-products. The presence of these substances in other pieces of technology is likely but unknown. They are a new type of potentially hazardous environmental pollutants that has yet to be fully researched. Some LCMs that have been studied show tendencies for the ability to bioaccumulate and have possible effects on different organs in living organisms. This study serves to research if LCMs can be found in dust in Swedish homes, screen repair-shops, phone-shops, or electric areas at a recycling station. For this purpose, dust samples were collected at the mentioned locations. Swipe samples from screens located in these environments were also collected. The samples were later analyzed with gas chromatography coupled with mass spectrometry. LCMs were found in 6 out of 10 dust samples and in 3 out of 11 swipe samples. The swipe samples in which LCMs were found were not from home environments. Some LCMs seemed to be more common and some LCMs were more common in the same types of environments. / <p>Detta är en rapport.</p>

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Godkänd; 1997; 20070418 (ysko)

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Climate change is one of the greatest challenges of the 21st century and is the reason for several environmental changes on earth. One reason behind climate change includes the rise ingreenhouse gas emissions in the atmosphere due to the burning of coal, gas and oil, i.e. fossil fuels. Fossil fuels are currently the world’s primary source of energy and alternative solutions are there for necessary to mitigate climate change, for example by utilizing solar cells. Perovskite solar cells have gain a lot of attention due to its rapid improvement in power conversion efficiency. In parallel with the advances in performance and stability, the challenges of commercialization have arisen. Therefore scalable technology is required to facilitate for large-area fabrication as well as a quality improvement in the perovskite film. The purpose of this project was to characterize the optical properties and functions of the perovskite solar cell when using the precursor solution of Cs0.1FA0.9Pb(I0.9Br0.1)3 for semi-upscaled technique. Additionally, this project investigated different elements in the slot-die coater process to optimize the performance of the solar cell, including the fabrication process of the precursor solution, the size of the substrates and to optimize the functionality of the electron transport layer. Four different trials were conducted in this study using a solution-based technique from  Cs0.1FA0.9Pb(I0.9Br0.1)3 perovskite powder while varying different parameters in the cell design and geometric shapes of the substrates. These trials were compared to a reference trial using Cs0.1FA0.9PbI3 through solar cell characterization and material characterization, including current-voltage measurements, incident photon-to-current efficiency, X-ray diffraction, UV/vis/NIR spectrophotometry and scanning electron microscopy. The results show that the power conversion efficiency increased when adding bromide into the perovskite structure. Furthermore, a shift in the band gap was observed during the material characterization. Trial 4 consisted of using SnO2 as the electron transport layer, developing a powder perovskite and adding a 2D additive layer to the cell design, displayed the best performance. In conclusion, the addition of bromide in Cs0.1FA0.9Pb(I0.9Br0.1)3 did increase the performance of the solar cells and the band gap of the perovskite solar cells was tunable.

Chemicals entering the market have been steadily increasing. The Swedish Chemicals Agency is in control of the Swedish Products Register, which is storing information on chemicals  manufactured in, transferred, or imported into Sweden. Applied to the register comes the exposure index predicting exposure of chemicals. For this study, the exposure index was used to make a first prioritization of chemicals with potential of exposure to consumers, the list of suspects were further prioritized by in silico predicted physiochemical properties. Six synthetic antioxidants 2,4-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, 2,4,6-tris-tert-butyl-phenol, 2,2´-methylene-bis(4-methyl-6-tert-butylphenol), 4,4´-methylene-bis(2,6-di-tert-butylphenol), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenol) propionate), were selected for target analysis. Great care to background contamination is applied since the analytes are used in everyday objects such as food package and personal care products. Human serum samples was collected from “Blodcentralen” in Stockholm, Sweden. Previous analytical methods exist for individual and combination for a few analytes but lacks in combination of all selected analytes. A previous method for the extraction without clean-up of some of the analytes in serum were tested but lacked in efficiency for all analytes, hence an clean-up step for removal of lipids were added. A gas chromatography mass spectrometry method was developed for simultaneous analysis of the six analytes. Four of the target analytes were detected and three were quantified (2,4-di-tert-butylphenol 2.20-3.33 ng/mL, 2,6-di-tert-butyl-4-methylphenol 3.22-3.93 ng/mL and 2,4,6-tris-tert-butyl-phenol 0.054-0.104 ng/mL). 2,2´-methylene-bis(4-methyl-6-tert-butylphenol) was detected in high concentration but due to linearity problems (R2&lt;0.99) it was not quantified. To the best of my knowledge this is the first time that 2,4,6-tri-tert-butylphenol and 2,2´- methylene-bis(4-methyl-6-tert-butylphenol) have been detected in human serum.

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