Innovative methods for the recycling and reuse of contaminated water: the Nanowat project

Proposals for the reuse of alternative waters are of growing interest for regions stressed by scarce water availability. Collection, treatment and redistribution are some of the phases that require different purification actions, actions related to the water origin (eg. gray, rain, and/or industrial waters). It is known that wastewater contains both chemical and microbiological contaminants and for this reason, it is essential to have reliable control tools for assessing both risks (chemical and microbiological) for which, often, there is a lack of clear and comprehensive reference standards. NANOWAT project ( Diffusion of nanotechnology based devices for water treatment and recycling) has focused attention on the development and diffusion in the Mediterranean area of new technologies for efficient water treatment based on natural and modified nano-materials, using either filtration and sedimentation, photo-degradation, photocatalysis and their combination. Pilot-scale mobile equipment for the treatment of different types of wastewater like pesticides, pharmaceuticals, and organic contaminants coming from industrial enterprises was developed and realized. In detail was carried out the filtration using both nano-structured clay-micelles and clay vesicles to facilitate the immobilization of organic pollutants, microfibers and micro-plastics and successively on the recalcitrants compounds, still contained in the liquid phase after filtration treatment, were performed new photo-catalytic processes based on TiO2 in suspension and/or on immobilized on glass. Results obtained were interesting and effective, however confirming the need to customize the wastewater purification procedure in relation to the type of contamination present

Progress on the removal of contaminants on surface and wastewater: report of case-studies

Contamination of the water sector represents a global issue known since the 1960s. However, the consequences are still not adequately known as a whole. There is insufficient information on the thousands of molecules released into the environment and, above all, their properties and the quantities produced, capable of determining the global effects of potential toxic actions on living organisms and the environment. For some time, scholars and researchers from the planet have been directing their activities to identify new integrated technologies and low energy consumption tools aimed at treating and reusing wastewater. For some time, our research group has been experimenting with removing traditional contaminants and emerging contaminants using hybrid techniques (filtration and Advanced Oxidation Processes). In this communication, we report some of our case studies, which have validated the effectiveness of the treatments

PHOTOCHEMICAL BEHAVIOUR OF OXYFLUORFEN: A DIPHENYL-ETHER HERBICIDE

The photochemical behaviour in different solvents of the herbicide oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene (CAS RN 42874–03–3)] was studied. Photochemical reactions were carried out by using a high pressure mercury arc and a solar simulator. Kinetic parameters and quantum yields were determined. Identification of the photoproducts was performed by GC-MS and the main compounds were confirmed by [1H] NMR. The photochemical reactions were also carried out in the presence of either a singlet or a triplet quencher, and in the presence of either a radical initiator or a radical inhibitor. Results indicate that the first excited singlet state can undergo both homolytic and heterolytic cleavage of the ethyl-oxygen bond in the side chain of oxyfluorfen. Moreover, the presence of reduction products in the reaction mixture is supposed to occur via a monoelectron transfer process with the formation of a transient exciplex during the reaction

Analysis of tomato glycoalkaloids by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

Steroidal glycoalkaloids (SGAs) extracted from tomato leaves and berries (Lycopersicon esculentum Mill.) were separated and identified using optimized reversed-phase liquid chromatography with electrospray ionization (ESI) and ion trap mass spectrometry (ITMS). The ESI source polarity and chromatographic conditions were evaluated. The ESI spectra contain valuable information, which includes the mass of SGAs, the mass of the aglycones, and several characteristic fragment ions. Cleavage at the interglycosidic bonds proximal to the aglycones is the most prominent process in the ESI process. A protonated molecule, [M+H]+, accompanied by a mixed adduct ion, [M+H+Na]2+, was observed for a-tomatine (i.e., m/z 1034.7 and 528.9) and dehydrotomatine (i.e., m/z 1032.6 and 527.9) in positive ion mode spectra. The structures of these tomato glycoalkaloids were confirmed using tandem mass spectrometry. The identification of a new a-tomatine isomer glycoalkaloid, named filotomatine (MW 1033), which shares a common tetrasaccharide structure (i.e., lycotretraose) with a-tomatine and dehydrotomatine, and soladulcidine as an aglycone, is described for the first time. It occurs in significant amounts in the extracts of wild tomato foliage. Multistage mass spectrometry both of the protonated molecules and of the doubly charged ions was used for detailed structural elucidation of SGAs. Key fragmentations and regularities in fragmentation pathways are described and the fragmentation mechanisms involved are propose

The mechanism of the amine-catalysed isomerizationof dialkyl maleate: A computational study

DFT at B3LYP/6-31G (d,p) level calculation results for the amine-catalysed isomerization of dimethyl maleate revealed that the mechanism proceeds via foursteps: (1) a concerted proton transfer from one amine molecule to another which subsequently enhances the addition of the adduct thus formed to the C-C double bond to yield INT1. (2) Abstraction of a proton from the -carbon of INT1 by a second amine molecule to give intermediate INT2. (3) Rotation about the C-C single bond followed by proton abstraction by an amine molecule to yield unstable INT3, and (4) an elimination of an amine molecule to yield the trans isomer, dimethyl fumarate. Furthermore, it was found that step 1 is the rate limiting step. However, the activation energy difference between steps 1 and 2 was significantly low and its value depends on the amine catalyst used. The activation energy was found to be lower in water when compared to that calculated in the gas phase. In addition, linear correlation was found between the amine-catalysed isomerization experimental rate and the pKa of the amine catalyst on one hand and the enthalpic and free activation energies on the other hand. The calculations also confirmed that the reaction is first order in dimethyl maleate, second order in the amine catalyst and overall third order. This study disproves three of the four different intermediates that were previously suggested to explain the amine catalysed isomerization of dialkyl maleates. The study verifies the intermediate suggested by Rappopor

Artificial Aging of Crude Oil and Water Remediation by AOPs

Crude oil in the environment is exposed to a series of weather-climatic factors (water, oxygen, solar irradiation) and microorganisms’ action that triggers chemical-physical processes of degradation (known as weathering). In a short time, the original composition of exposed oil can change significantly. In this work, our research team experimented with an Italian crude oil simulating solar irradiation to understand the modifications induced on its composition by artificial aging. Moreover, we studied the transformations deriving from different advanced oxidation processes (AOP) applied as remediation methods on liquid matrices contaminated by petroleum. For the last objective, we adopted different AOPs (photocatalysis, sonolysis, and sonophotocatalysis). as a photocatalyst, we used TiO2 immobilized on a non-woven fabric sheet. Crude oil and its water-soluble fractions were analyzed using GC-MS, 1H-NMR in a liquid state, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and fluorescence. The artificial oil aging induced significant modifications of oil composition with the formation of more oxidized species. All treatments used for the detoxification of polluted water samples, except sonolysis, showed a consistent reduction of organic content with the appearance of potentially toxic substances, confirming that the remediation processes experimented with cannot be applied in natural environments without a careful and repeated experimentation in controlled laboratory conditions

Artificial Aging of Crude Oil and Water Remediation by AOPs

Crude oil in the environment is exposed to a series of weather-climatic factors (water, oxygen, solar irradiation) and microorganisms’ action that triggers chemical-physical processes of degradation (known as weathering). In a short time, the original composition of exposed oil can change significantly. In this work, our research team experimented with an Italian crude oil simulating solar irradiation to understand the modifications induced on its composition by artificial aging. Moreover, we studied the transformations deriving from different advanced oxidation processes (AOP) applied as remediation methods on liquid matrices contaminated by petroleum. For the last objective, we adopted different AOPs (photocatalysis, sonolysis, and sonophotocatalysis). as a photocatalyst, we used TiO2 immobilized on a non-woven fabric sheet. Crude oil and its water-soluble fractions were analyzed using GC-MS, 1H-NMR in a liquid state, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and fluorescence. The artificial oil aging induced significant modifications of oil composition with the formation of more oxidized species. All treatments used for the detoxification of polluted water samples, except sonolysis, showed a consistent reduction of organic content with the appearance of potentially toxic substances, confirming that the remediation processes experimented with cannot be applied in natural environments without a careful and repeated experimentation in controlled laboratory conditions

ADSORPTION OF TRIBENURON-METHYL BY NATURAL AND MODIFIED CLAYS

This work deals with the purification of water containing residues of the herbicide tribenuron-methyl by means of a cleaning system based on a composite organo-clay mineral. Tribenuron-methyl suffers hydrolysis, for this reason it is important to clean the water not only from the mother molecule, but also from the products of its degradation. Experiments on adsorption/desorption of tribenuron-methyl and its metabolites by using natural and organo-micellar montmorillonite were performed. Desorption of the herbicide from the micelle clay-composite was done using acetonitrile

Establishing the occurrence of major and minorglucosinolates in Brassicaceae by LC-ESI-hybrid linearion-trap and Fourier-transform ion cyclotron resonancemass spectrometry

Glucosinolates (GLSs) are sulfur-rich plant secondary metabolites which occur in a variety of cruciferous vegetables and among various classes of them, genus Brassica exhibits a rich family of these phytochemicals at high, medium and low abundances. Liquid chromatography (LC) with electrospray ionization in negative ion mode (ESI-) coupled to a hybrid quadrupole lineariontrap (LTQ) and Fouriertransformioncyclotronresonancemass spectrometer (FTICRMS) was employed for the selective and sensitive determination of intact GLSs in crude sample extracts of broccoli (Brassica oleracea L. Var. italica), cauliflower (B. oleracea L. Var. Botrytis) and rocket salad (Eruca sativa L.) with a wide range of contents. When LTQ and FTICR mass analyzers are compared, the magnitude of the limit of detection was ca. 5/6-fold lower with the FTICR MS. In addition, the separation and detection by LC–ESI-FTICR MS provides a highly selective assay platform for unambiguous identification of GLSs, which can be extended to lower abundance (minor) GLSs without significant interferences of other compounds in the sample extracts. The analysis of Brassicaceae species emphasized the presence of eight minor GLSs, viz. 1-methylpropyl-GLS, 2-methylpropyl-GLS, 2-methylbutyl-GLS, 3-methylbutyl-GLS, n-pentyl-GLS, 3-methylpentyl-GLS, 4-methylpentyl-GLS and n-hexyl-GLS. The occurrence of these GLSs belonging to the saturated aliphatic side chain families C4, C5 and C6, presumably formed by chain elongation of leucine, homoleucine and dihomoleucine as primary amino acid precursors, is described. Based on their retention behavior and tandem MS spectra, all these minor compounds occurring in plant extracts of B. oleracea L. Var. italica, B. oleracea L. Var. Botrytis and E. sativa L. were tentatively identified

Removal of Dexamethasone Sodium Phosphate (DSP) in liquid phase by Using Advanced Oxidation Processes (AOPs)

The occurrence and the fate of pharmaceuticals residues in wastewater treatment and in the environment has attracted an increasing interest during the last decade and have posed a new challenge to professionals for wastewater recovery as well as to the pharmaceutical industry. The removal of many of pharmaceutical compounds, during municipal wastewater treatment, has showed to be incomplete and unsuitable. As a result, residues of these compounds have been detected in surface waters in concentrations ranging from the ng L-1 up to the mg L-1 level. Advanced Oxidation Processes (AOP) are commonly designed to produce hydroxyl radicals (HO•) that react efficiently with most organic compounds present in the water. Photo-catalysis has emerged as viable alternative for removing micro-pollutants and other organic contaminants from surface, ground and wastewater. The catalyst used in this study was the semiconductor titanium dioxide (TiO2) chosen for its properties: high resistance to corrosion, low toxicity and low costs. The aim of this work was the application of photo-catalysis for the degradation of dexamethasone sodium phosphate (9-fluoro-11β,17-dihydroxy-16α-methyl-21-(phosphonooxy) pregna- 1,4-diene-3,20-dione disodium salt). This pharmaceutical compound is one of the most potent corticosteroids with anti- inflammatory and immunosuppressive properties. It has been widely used to treat inflammation, allergy and diseases related to adrenal cortex insufficiency. DSP is also known to reduce neointimal hyperplasia in arteries and has been used for coating drug- eluting stents for local drug delivery to prevent restenosis. Photochemical reactions were carried out by using a solar simulator and kinetic parameters were determined. Identification of the photoproducts was performed by liquid chromatography system coupled to a hybrid linear quadrupole ion trap (LTQ) – Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer. The standard solution used as control in the darkness did not show any significant degradation during the experimental time. Data of the DSP degradation fitted well a pseudo first order kinetic curve and the half-life was 30 min. Four photoproducts have been successfully identified