Luciane Calabria's research while affiliated with Universidade de Caxias do Sul (UCS) and other places

The present study has investigated the influence of the filtration step of the liquid-liquid extraction (LLE) on the quantitative analysis of di-n-butyl phthalate (DnBP) in the wastewater treatment system of the University of Caxias do Sul (WWTS-UCS). During five months, five wastewater samples from the inflow and outflow points were collected and submitted to LLE with and without the filtration step. The organic extracts were analyzed by Gas Chromatography with Flame Ionization Detection (GC/FID). The DnBP removal in the filtered samples was 36%, and the median DnBP concentration at the outflow point was 17.45 μg/mL. For the unfiltered samples, the DnBP removal was 39%, and the median DnBP concentration at the outflow point was 21.45 μg/mL. According to these results, an important fraction of the contaminant is retained in the LLE filtration step leading to considerable errors in the quantification of the target compounds.

The herein developed approach an attractive tool for environment friendly, low coast, preparation of biodegradable materials with tunable controlled release of active molecules; • The revelation of phases through immersion in selective solvent for the PLA revealed the presence of a porous head office and highly ordinate of SPI in the which the domains of PLA are dispersed; • In the studies of controlled liberation the analyzed blends demonstrated a retard of approximately 8 times, comparatively to the liberation only of the nutrient that ended how being potentially efficient for the proposed study. Therefore, the agrochemicals incorporation in the blends production becomes viable, because when incorporate in the blend it doesn't interfere directly either in the characteristics physics of the polymeric in your morphologic properties, providing liberation controlled efficient.  The experiments were performed under continuously stirring during 180 h in a Becker containing 100 mL of Mili-Q water and 1.6 ± 0.2 g of the sample. The release of NPK from biopolymer blends produced an important increase in conductivity due to the presence of NPK salts in solution.  However, in this case it takes 8 times longer to reach the same conductivity values of pure NPK (Figure 2), corroborating the slow controlled release. Figure 2. Solution conductivity during NPK release in water: SPI/PLA blends, SPI/PLA blends containing NPK, and pure NPK.

In this work a simple gravimetric method was described for the study of di-(2-ethylhexyl) phthalate (DEHP) in wastewater samples from the inflow and outflow points of the sewage treatment plant (ETE) at the University of Caxias do Sul (UCS). The organic phase of the sample was precipitated by adding concentrated HCl. The precipitate was filtered in glass columns packed with treated cotton. After drying, the columns containing the precipitate were carefully weighted and extracted with n-hexane. After solvent evaporation, the organic extract was re-diluted and analyzed by Gas Chromatography with Flame Ionization Detection (GC/FID). The average rate of DEHP removal was 27.50%. The median DEHP concentration was 6.01 g mL -1 at the outflow point. This DEHP concentration is well above the maximum concentration level reported in the literature.