A new simpler and reliable method for determining mineral oil in sewage sludge: Influence of biogenic compounds for the quantitative analysis of C10-C40 hydrocarbons.

The characterization of organic contaminants in sewage sludge is a fundamental step to address the relevant most appropriate management practice. In this perspective, C10-C40 hydrocarbon content was considered in Italy a crucial parameter to be considered, in spite of its irrelevance in the literature. The very complex mixture of organic substances of both biogenic and anthropogenic origin the sludge is made up of makes sewage sludge a matrix of uniqueness nature, and the analytic determination of hydrocarbon content through conventional procedures may be subjected to overestimation. In this work, optimization of two conventional protocols for the determination of mineral oil (EN14039 and IRSA CNR gravimetric method) were run with attention to anthropogenic compounds potentially affecting the C10-C40 mineral hydrocarbons determination. Effects from the first manipulations of sewage sludge samples to extraction procedure and clean-up operations were investigated. A new simple procedure was set up and tested on 30 samples from different wastewater treatment plants (WWTPs). Through a simple extraction with hexane (12 mL per 2 g of dried sludge, acidified with HCl conc.) at room temperature for 2 h, followed by a clean-up on Florisil column (10 mL-2 g) a confident determination of C10-C40 were obtained with respect to conventional optimized procedures. Variability within the range 0.06-9.49% was calculated with respect to the average value determined using three different methods, with an average value of 2.48 ± 2.37%, demonstrating the robustness of the determination. Up to 3% of the total hydrocarbons were identified as naturally occurring, namely terpenes, squalenes and deoxygenized sterols, passed through the clean-up Florisil column. A significant incidence (up to 75%) of the final overall C10-C40 content was found to be related to the C10-C20 component, originally present in the commercial polyelectrolytes in emulsion, widely used for conditioning before mechanical dewatering.

An integrated photocatalytic/enzymatic system for the reduction of CO2 to methanol in bioglycerol-water.

A hybrid enzymatic/photocatalytic approach for the conversion of CO2 into methanol is described. For the approach discussed here, the production of one mol of CH3OH from CO2 requires three enzymes and the consumption of three mol of NADH. Regeneration of the cofactor NADH from NAD(+) was achieved by using visible-light-active, heterogeneous, TiO2-based photocatalysts. The efficiency of the regeneration process is enhanced by using a Rh(III)-complex for facilitating the electron and hydride transfer from the H-donor (water or a water-glycerol solution) to NAD(+). This resulted in the production of 100 to 1000 mol of CH3OH from one mol of NADH, providing the possibility for practical application.

Cerium-based binary and ternary oxides in the transesterification of dimethylcarbonate with phenol.

Diphenyl carbonate (DPC) plays a key role in phosgene-free carbonylation processes. It can be produced by transesterification of dimethyl carbonate (DMC) with phenol in the presence of catalysts. Methyl phenyl carbonate (MPC) is first produced that is then converted into DPC by either disproportionation or further transesterification with phenol. Cerium-based bimetallic oxides (with the heterometal being niobium, iron, palladium, or aluminum) are used as catalysts in the transesterification of DMC to synthesize MPC. The catalytic activity is affected by the type and concentration of the heterometal. XPS, IR and elementary analyses are employed to characterize the new catalysts. Differently from pure oxides, the mixed oxides produce a significant increase of the conversion and selectivity towards MPC.

The use of solar energy can enhance the conversion of carbon dioxide into energy-rich products: stepping towards artificial photosynthesis.

The need to cut CO2 emission into the atmosphere is pushing scientists and technologists to discover and implement new strategies that may be effective for controlling the CO2 atmospheric level (and its possible effects on climate change). One option is the capture of CO2 from power plant flue gases or other industrial processes to avoid it entering the atmosphere. The captured CO2 can be either disposed in natural fields (geological cavities, spent gas or oil wells, coal beads, aquifers; even oceans have been proposed) or used as a source of carbon in synthetic processes. In this paper, we present the options for CO2 utilization and make an analysis of possible solutions for the conversion of large volumes of CO2 by either combining it with H2, that must be generated from water, or by directly converting it into fuels by electrolysis in water using solar energy. A CO2-H2-based economy may address the issue of reducing the environmental burden of energy production, also saving fossil carbon for future generations. The integration of CO2 capture and utilization with CO2 capture and storage would result in a more economically and energetically viable practice of CO2 capture.

Catalytic synthesis of hydroxymethyl-2-oxazolidinones from glycerol or glycerol carbonate and urea.

Oxazolidinones have been synthesized by reacting glycerol carbonate or glycerol with urea in the presence of γ-Zr phosphate as a catalyst. The conversion yield of the polyol or its carbonate depends on the temperature. Below 408 K the selectivity is 100 % with a conversion of up to 25 %, whereas increasing the temperature means that conversion yield grows, but the selectivity decreases, which makes the separation process more difficult. Starting from glycerol carbonate, two isomers, 6 and 6', are formed with a quasi 1:1 molar ratio because urea can attack the carbonate moiety on both sides of the carboxylic CO moiety. From glycerol the formation of the 6' isomer is preferred: the ratio of 6'/6 is close to 7. The oxazolidinones formed act as templates because they interact through hydrogen bonding with glycerol. The intensity of the interaction depends on the 6 or 6' isomer: DFT calculations showed that the energy was 22.6 kcal mol(-1) for 6-oxazolidinone and 25.7 kcal mol(-1) for 6'-oxazolidinone.

Synthesis, characterization, and use of Nb(V)/Ce(IV)-mixed oxides in the direct carboxylation of ethanol by using pervaporation membranes for water removal.

New catalytic systems based on ceria have been used in the direct carboxylation of ethanol. The catalytic behavior of Al(2)O(3) and Nb(2)O(5) loaded ceria is compared, the latter showing a better performance. A morphological and structural study has been carried out on Nb(2)O(5)/CeO(2) catalysts in order to explain their behavior in catalysis. Pervaporation membranes have been used for water separation. The synthesis of diethylcarbonate (DEC) has been carried out either in a liquid phase (ethanol) pressurized with CO(2) or in supercritical conditions. A set-up has been developed that allows the production of quite pure DEC (>90%) with recycling of CO(2) and ethanol.

Synthesis and X-ray characterization of [RhCl(C2H4)(PiPr3)]2. Multinuclear NMR and DFT investigation of its solid-state and solution reaction with dihydrogen. Ethene and propene hydrogenation by the solid Rh-hydrides.

[RhCl(C(2)H(4))(PiPr(3))](2) has been synthesised and structurally characterised. It shows an unusual planar Rh(2)Cl(2) system, with the two phosphine and the two ethene molecules disposed trans to each other. It easily reacts with dihydrogen in solution and in the solid state to afford ethane and a dimeric complex of formula [RhCl(H)(2)P](2). The latter exhibits a high fluxionality both in solution and in the solid state making impossible the identification of a single limiting structure even at 183 K. 25 different hydride structures are possible, four of which have very low interconversion barriers (1-3 kcal mol(-1)) and cannot be blocked even at 183 K. A multinuclear NMR study and HECTOR experiments have allowed to identify the most probable structures that interconvert at 198 K. The solid hydrides are able to hydrogenate quite selectively ethene and propene at room temperature. A TON higher than 5600 and a TOF of 97 h(-1) was observed with ethene (for propene the values were 5200 and 79, respectively). Toluene was hydrogenated to methylcyclohexane at 323 K under an atmospheric pressure of H(2) with a TOF h(-1) equal to 15.