Effectiveness of conventional chlorine and ozone disinfection on reduction of antibiotic resistance was compared with less commonly applied heterogeneous photocatalytic process. For this purpose plasmid DNA isolated from a multi-resistant Escherichia coli (E. coli) HB101 was treated in two different concentrations with the three oxidation processes. Oxidative damage on the plasmid DNA was analyzed with gel electrophoresis by comparing the extent of conformational changes in the DNA structure. The effectiveness of the applied oxidant in reducing the risk of resistance transfer was also evaluated by comparing the ability of treated plasmid DNA to transform competent cells. Chlorine did not affect plasmid DNA structure at the studied doses, while ozone and photocatalytic treatment resulted in conformational changes and the damage increased with increasing oxidant doses. Transformation experiments confirmed a similar trend. Chlorine did not affect the transformability and the cell counts of competent cells transformed with chlorine treated plasmid DNA were similar to those transformed by non-treated plasmid DNA in the control experiments.

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An innovative strategy integrating the use of biosurfactant (BS) and persulphate activated by chelated iron for the decontamination of soil from an emerging pollutant chlorophene was studied in laboratory down-flow columns along with other persulphate activation aids including combined application of persulphate and hydrogen peroxide, and persulphate activation with sodium hydroxide. Although BS addition improved chlorophene removal by the persulphate treatment, the addition of chelated iron did not have a significant influence. Combined application of persulphate with hydrogen peroxide resulted in a significant (p≤.05) overall improvement of chlorophene removal compared with treatment with persulphate only. The highest removal rate (71%) of chlorophene was achieved with the base-activated persulphate, but only in the upper part (of 0.0-3.5 cm in depth) of the column. The chemicals at the applied dosages did not substantially influence the Daphnia magna toxicity of the effluent. Dehydrogenase activity (DHA) measurements indicated no substantial changes in the microbial activity during the persulphate treatment. The highest oxygen consumption and a slight increase in DHA were observed with the BS addition. The combined application of persulphate and BS at natural soil pH is a promising method for chlorophene-contaminated soil remediation. Hydroquinone was identified among the by-products of chlorophene degradation.

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Pentablock poly(L-lactide-co-∊-caprolactone) (PLLA/PCL), with a central fluorinated segment and four PLLA/PCL side chains was synthesized by sequential ring-opening polymerization (ROP) with stannous octoate catalyst in an environmentally benign and clean medium, scCO2. Copolymers of PLLA and PCL are extensively researched for biomedical applications. Fluorinated hydrocarbons are similarly promising for biomedicine, and especially for oxygen-carrying substitute applications. Initially, a fluorinated reactive triblock stabilizer (prepolymer, PCL-FLKT-PCL) with inner fluorinated segment and PCL side chains was synthesized in bulk from a tetraol fluorinated alcohol (FLKT) with a 99% conversion. The prepolymer was then utilized for the synthesis of copolymers in scCO2, where PLLA segments were successively incorporated to the ends of the prepolymer, forming a pentablock structure with four polyester side chains. Reactions were carried out at 75°C and 4000-4500 psi. Solubility studies of the prepolymer and the pentablock copolymer in scCO2 showed effective solubilization at the reaction temperature and pressure. The molecular weights of the products were measured with the aid of gel permeation chromatography; the prepolymer and the copolymer possessed average number molecular weights (Mn) in the range of 13 000 and 24 000 (for 96% conversion of LLA), respectively. Low poly-dispersity indexes were obtained: 1.34 for the prepolymer and 1.08-1.34 for the pentablock copolymer. Material characterization was carried out by 1H NMR, 13C NMR, 19F NMR, differential scanning calorimetry (DSC), gel permeation chromatography (GPC) and scanning electron microscopy (SEM).