No abstract

Surface‐attached, photo‐crosslinked gel films of a N‐isopropylacrylamide copolymer were investigated in ethanol/water mixtures using a combination of surface plasmon resonance/optical waveguide spectroscopy with reversed WKB analysis. The solvent quality of the pure good solvents drops in their mixture and this co‐nonsolvency effect shifts the transition temperature (Tc) in the µm‐thin gel films from 32.8 °C in pure water to 29.7 °C with only 0.25 vol.‐% ethanol. Between 20 and 70% ethanol and >10 °C (the practical temperature limit) the layers existed only in the collapsed state. A reentrant Tc of 40.2 °C was found at 70% ethanol while at higher ethanol volume fraction no Tc could be recorded.magnified image

A water solubilization method for hydrophobic CdSe-ZnS quantum dots (QDs) is exhibited in this paper. The thermo-sensitive and photo-cross-linkable poly(N-isopropylacrylamide) (PNiPAm) copolymer is used for extraction of the hydrophobic QDs in dichloromethane and transferring them to water. This was accomplished via a solvent-induced phase separation process based on the amphiphilic nature of PNiPAm and their interactions with the different solvents. In addition, the functional ferrocene-containing PNiPAm is also used for the water solubilization of the hydrophobic QDs and the hydrogel/QDs particles demonstrate the chemical redox-controlled switch on−off property.

No abstract

The aim of this article is to discuss the problem of drilling waste remediation. Analyses and research showed that material stored in waste pits could be classified as soil with a high level of petroleum impurities (total petroleum hydrocarbons [TPH] = 102,417-132,472 mg kg(-1) dry mass). While preparing the complex technology of soil decontamination (which included primary reclamation, basic bioremediation and inoculation with biopreparations based on indigenous bacteria and fungi), laboratory tests indicated the use of an ex-situ method was fundamental. Remediation was controlled with a chromatographic method of qualitative and quantitative determination of petroleum hydrocarbons. Based on analytical data, there was the possibility to determine the effectiveness of consecutive purifying phases. Laboratory tests, following 135 days of basic bioremediation stimulated by optimum conditions to activate the growth of indigenous micro-organisms, resulted in a decrease in the TPH content, which was in the range of 52.3-72.5%. The next phase of soil decontamination lasted 135 days and involved the use of inoculation with biopreparations based on indigenous micro-organisms and fungi. This process enabled a TPH decrease of 93.8- 94.3%. Laboratory biodegradation research was done with the use of the biomarker C30-17α(H)21β(H)-hopane to normalize analyte (TPH, Σn-C8-n-C22 and Σn-C23-n-C36) concentrations. The calculated first-order biodegradation constants enable estimation of the purification stage dynamics and the effectiveness of the applied biopreparations. Furthermore, they represent the biodegradation degree of individual n-alkanes in subsequent stages of the soil purification process.