1,721,063 research outputs found
Modified clay minerals for water cleaning and re-cycling
Full text linkA new technology for purification of organic-contaminated water employs a complex between micelles, or vesicles, of an organic cation and a clay mineral, such as montmorillonite (MMT). Micelles of octadecyltrimethylammonium (ODTMA), and benzyldimethylhexadecylammonium (BDMHDA) bromide were mostly used [1, 2]. Vesicles used were composed of didodecyldimethylammonium (DDAB) [3]. Both types of complexes have a very large surface area, large hydrophobic domains, and typically are designed to have a large excess of positive charge. They can be effective in the removal from water of anionic and neutral pollutants such as herbicides (anionic and hydrophobic ones), anionic detergents, antibiotics and other anionic drugs, and components of DOM (dissolved organic matter) such as fulvic and humic acids. DOM is not a pollutant per se, but treatment of water, e.g., by chlorination, results in production of trihalomethanes, which are carcinogenic. Noteworthy, DOM also promotes the migration of herbicides to ground water. The nature of the head group of the organic cation was shown to be critical [1].
In our work, we compared the behaviour of two micellar organoclays realized by using natural MMT and ODTMA and bovine serum albumin (BSA) as surfactants. The herbicides atrazine, and tribenuron-methyl, together with its main degradation product 2-methoxy-4-methylamino-6-methyl-1,3,5-triazine, and the non-steroidal anti-inflammatory (NSAID) drug diclofenac potassium were used as sorption models.
The micelle-clay complexes were prepared as suggested by Polubesova et al. [1, 2]. Column filters (about 20 cm) made of a mixture of quartz sand and micelle-clay complexes at 50:1 w/w ratio removed 80% to 98% of the herbicides and up to 99.9% of 2-methoxy-4-methylamino-6-methyl-1,3,5-triazine and diclofenac from initial solutions. Efficiency of removal with micelle-clay filtering was significantly enhanced comparing to results obtained by using activated carbon. A quartz-clay layer placed into the bottom of the filter was able to capture almost all the released surfactants from micelle-clay complexes avoiding their leaking out the filter. The adsorption of contaminants studied was more efficient on ODTMA-MMT and BSA-MMT than natural MMT, since the surfaces of the modified micelle clay are more hydrophobic than the natural MMT. The effectiveness of atrazine and tribenuron-methyl adsorption coupled with the complete removal of the tribenuron-methyl derivative and diclofenac potassium gives account of the usefulness of organoclay systems for the elimination of this kind of pollutant from water in cleaning processes
DETERMINATION OF PHARMACEUTICALS’ RESIDUES IN WASTEWATER OBTAINED WITH AN OPTIMIZED LC-FTICR MS METHOD
No full textThe presence of pharmacologically active molecules or their derivatives found in wastewater is a problem of wide interest (1,2). Pharmaceutical compounds (PhCs) and their metabolites, even if present in the order of μg/L and ng/L, can affect the bioconcentration factor, and then be subject to bioaccumulation and biomagnification showing toxic effects for both flora and fauna and mankind.
The high resolution liquid chromatography mass spectrometry (LC-MS) coupled to tandem mass spectrometry MS/MS has gained popularity in recent decades thanks to its versatility, specificity and selectivity, finding application as the preferred method for the analysis of PhCs in complex matrices such as waste and/or discharge water. (3,4)
Most methods developed in the past have focused on specific therapeutic classes, such as antibiotics for their potential resistance to biotic degradation.
In this work we focus on the development of an analytical multi-residual method by using LC-FT/ICR-MS and IRMPD for a particular class of pharmaceuticals chosen according to the 10 mostly diffused and consumed products in the Mediterranean area (4-8).
A solid phase extraction from spiked tap water followed by LC-FTICR MS determination has been proposed for the simultaneous analysis of these pharmaceuticals as in Figure 1: (peak 1) metformin hydrochloride (exact m/z 130.10872), (peak 2) amoxicillin (exact m/z 366.11182), (peak 3) caffeine (exact m/z 195.08765), (peak 4) erythromycin (exact m/z 734.46852), (peak 5) clarithromycin (exact m/z 748.48417), (peak 6) carbamazepine (exact m/z 237.10224), (peak 7) naproxen (exact m/z 231.10157), (peak 8) diclofenac sodium (exact m/z 294.00941), (peak 9) ibuprofen (exact m/z 205.12340), (10) aspirin (exact m/z 181.04954). In order to ascertain the identity of all chromatographic peaks, the measurements and interpretation of IRMPD-FTICR data was accomplished. All precursor ions were photon irradiated for 200 ms at 100% laser power by a 20 W continuous CO2 laser source at a wavelength of 10.6 μm.
The method optimized was applied to samples collected from influent and effluent from a Wastewater Treatment Plants (WWTP) in order to assess the efficiency of the plant for removing this kind of recalcitrant compounds. Among the PhCs considered in this study, only carbamazepine and clarithromycin were found in the effluent of the WWTP
DEGRADAZIONE OSSIDATIVA DEL MEPANIPYRIM, UNA ANILINO-PIRIMIDINA
No full textL’utilizzo degli agrofarmaci è ancora oggi il mezzo più semplice ed efficace per il controllo delle avversità delle piante. Rimane, pertanto, di estrema attualità considerare che i composti organici ad uso fito-farmacologico, una volta raggiunto il loro bersaglio (suolo, acqua, vegetali), sono soggetti a tutta una serie di possibili e complessi fenomeni di trasformazione biotica ed abiotica. La sostanza bio-attiva inalterata e/o i suoi prodotti di trasformazione e degradazione possono essere diffusi nell'ecosistema diventando spesso un pericolo per l'ambiente e per gli organismi non-bersaglio.
Uno dei processi abiotici più studiati è la degradazione che avviene ad opera delle radiazioni luminose. La fotodegrazione ed altri processi degradativi (chimici e biochimici) costituiscono le uniche vere vie di rimozione di un agrofarmaco dall’ambiente, in quanto tutti gli altri processi, che non comportano trasformazione della molecola madre, determinano solo uno spostamento dello xenobiotico da un comparto ambientale ad un altro.
Negli ultimi anni è stato mostrato un crescente interesse verso l’utilizzo dell’ozonolisi come possibile mezzo alternativo nell’eliminazione dei residui dei agrofarmaci. L’ozono (O3), infatti, è un gas altamente reattivo le cui eccellenti proprietà ossidative nei confronti di sostanze organiche ed inorganiche vengono ampiamente utilizzate anche nel trattamento di purificazione dell'acqua per uso potabile.
Per verificare le potenzialità dei processi di fotolisi ed ozonolisi nella depurazione di acque contaminate, in questo lavoro è stato studiata la degradazione in presenza di luce ed ozono del Mepanipyrim (fig.1), un fungicida appartenente alla famiglia delle anilino-pirimidine attivo contro la Muffa grigia (Botrytis cinerea) su vite, fragola e pomodoro. Con lo scopo di valutarne la cinetica di reazione e di identificarne i prodotti di degradazione in fase liquida, il Mepanipyrim è stato sottoposto a diversi trattamenti degradativi durante i quali ne è stata seguita la variazione di concentrazione in funzione del tempo di esposizione. I risultati ottenuti hanno messo in evidenza come l’ozonizzazione sia un processo più efficace nella degradazione del Mepanipirym rispetto alla fotolisi
Effectiveness of different photoadvanced oxidationdegradation processes (AOPs) on the abatement of mepanipyrim and its transformation products in water
No full textThis study aims to present the effectiveness of different advanced oxidation processes (AOPs) as photolysis (UV mercury arc and Xe-arc), ozone, ozone/Hg-UV, and photocatalysis (suspended and immobilized TiO2) for the degradation of the fungicide mepanipyrim in aqueous solutions. A well-known commercial product Pilkington ActiveTM Blue glass has been tested as immobilized TiO2 system. Experiments were performed in batch mode at laboratory scale and results were compared in terms of disappearance kinetics. Transformation products (TPs) were identified by Surveyor LC system coupled to a hybrid LTQ-FTICR (7-Tesla) mass spectrometer (MS). Simple mechanisms of degradation for different AOPs were proposed. New by-products formed during the degradation processes were identified. Since primarily hydroxy derivatives were identified in aqueous suspensions, the mechanism of degradation was probably based on hydroxyl radical attack. The greatest difference in the quality of transformation products was observed between the heterogeneous photocatalysis using suspended TiO2 and Pilkington ActiveTM Blue glass system. The inhibition percentage of bioluminescence from Vibro fischeri — as a toxicity parameter—increased during the irradiation time due to the residual concentration of the parent compound and transformation products generated.
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IDENTIFICAZIONE E VALUTAZIONE IN CROMATOGRAFIA LIQUIDA-SPETTROMETRIA DI MASSA DI GLUCOSILONATI IN BRASSICA OLERACEA L.
No full textDEGRADATION OF MEPANIPYRIM BY PHOTOCATALYTIC OZONATION
No full textThe occurrence of not easily degradable pesticides in the hydrosphere, due to intensive agricultural activities, is of particular concern for surface and groundwater quality. In this respect, it is advisable to strengthen existing technologies for the decontamination of water, with the aim of enhance the degradation methods for recalcitrant organic compounds. [1]
In our previous study, we have demonstrated that the application of advanced oxidation processes promises to be a profitable expedient for the rapid degradation and detoxification of persistent herbicides as imazethapyr. [2]
The capabilities of the oxidation processes to degrade organic pollutants in water and the variety of derivatives formed is illustrated here by the case of Mepanipyrim [N-(4-methyl-6-prop-1-ynylpyrimidin-2-yl)aniline], a widely used pyrimidinic fungicide. The purpose of this study was to simulate the production of degradation compounds, which can be arisen in water treatment plants where physical or chemical oxidation methods are normally used. Comparisons between different oxidation techniques can provide useful information on the mechanisms of these processes, and are of particular concern in the assessment of the most efficient experimental conditions for the destruction of organic pollutants. The advanced oxidation methods compared were ozonation (without application of any initiator), UV-photolysis and UV-O3 coupled treatment. Kinetics of reactions were determined. Numerous degradation products were identified and characterised through MS spectra analyses.
Toxicity tests on Microtox, Daphnia magna and Lactuca sativa were carried out on the mix of degradation products
Applicazione del metodo QueChERS per la determinazione di agrofarmaci residui in campioni di lattuga
No full textL’analisi multiresiduale di agrofarmaci ha subito una profonda evoluzione in linea con le trasformazioni tecnologiche avvenute in campo analitico. Dall’analisi del singolo principio attivo, all’analisi della classe chimica sino all’analisi della classe agronomica si è assistito ad un’evoluzione dei metodi analitici che hanno privilegiato sempre più la quantità di molecole da ricercarsi per singola analisi rispetto alla qualità analitica del dato finale.
Nella comunità europea il metodo QueChERS (quick, easy, cheap, effective, rugged, and safe), presentato la prima volta da Anastassiades nel 2002 alla IV edizione dell’EPRW tenutasi a Roma, è stato testato da più di 100 laboratori, che hanno dato vita ad una serie di ring-test annuali e negli Stati Uniti è stato validato come AOAC International Official Method 2007.
Questo lavoro, condotto su campioni di lattuga provenienti da un’azienda biologica del Metapontino, ha avuto lo scopo di evidenziare punti di forza e di debolezza del metodo QueChERS confermando e dissentendo su valutazioni riportate in bibliografia.
Per le determinazioni analitiche è stato adoperato un cromatografo liquido accoppiato ad uno spettrometro di massa a triplo quadrupolo e trappola ionica.
I risultati hanno confermato molte positività (es. alta percentuale di recuperi per una vasta gamma di agrofarmaci polari e volatili, ridottissimo numero di passaggi, utilizzo intelligente di solventi, riduzione del personale) e alcune negatività (es. fattori di concentrazione molto bassi con necessità di arricchire il campione e soprattutto un elevato effetto matrice), ed hanno confermato come il metodo necessiti, se utilizzato per analisi di routine, di monotorare continuamente i punti critici del metodo.
Alcune modifiche hanno già prodotto risultati positivi sfruttando le caratteristiche della cromatografia liquida che permette di evitare il problema degli elevati volumi di vaporizzazione di solventi organici propri della gas-cromatografia. Altre modifiche sono ancora in fase di sperimentazione
Stability and Removal of Dexamethasone Sodium Phosphate from Wastewater Using Different Techniques
No full textStability and removal of dexamethasone sodium phosphate (DSP) from wastewater produced at
Al-Quds University Campus were investigated. Kinetic studies in both pure water and
wastewater coming from secondary treatment (activated sludge) demonstrated that the antiinflammatory
DSP underwent degradation to its hydrolytic derivative, simply named
dexamethasone, in both media. The first order hydrolysis rate of DSP in activated sludge at 25°C
(3.80×10-6 s-1) was about 12-fold greater than in pure water (3.25×10-7 s-1). The overall
performance of the wastewater treatment plant (WWTP) installed in the University Campus was
also assessed showing that 90% of spiked DSP was removed together with its newly identified metabolites. In order to check for different tools to be used instead of ultra-filtration membranes,
the effectiveness of adsorption and filtration by micelle-clay preparation for removing DSP was
ascertained in comparison with activated charcoal. Batch adsorption in aqueous suspensions of
the micelle-clay composite and activated carbon was well described by Langmuir isotherm
showing the best results for micelle-clay material. Besides, filtration of DSP water solutions by
columns filled in with a mixture of sand and micelle-clay complex showed complete removal of
the drug at concentration higher than sand/activated-charcoal filled filters
Removal of Dexamethasone Sodium Phosphate (DSP) in liquid phase by Using Advanced Oxidation Processes (AOPs)
Full text linkThe 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
REPELLENT ACTIVITY OF SOLENACEAE ALKALOIDS AGAINST SPODOPTERA EXIGUA MOTHS
No full textEffect of alkaloid-containing extracts obtained from the leaves of potatoes were tested against Spodoptera exigua moths. The following effects were checked: effect of alkaloids in substratum on the number of eggs laid by females, hatching success, preferences of insects in choosing the soaked or
control substratum. We noticed significantly decreased egg-laying and limited hatching. When females had to chose between alkaloids-soaked substratum and the control ones, they preferred control ones. The observed changes
show concentration-dependence, too. Therefore, we assume, that these extracts
can have repellent and (limited) ovicidal activity. Our data suggest,
that the research on the effects of these substances on insects should be continued, with a wide variety of substances and techniques used
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