Atmospheric pressure photoionization mass spectrometry as a tool for the investigation of the hydrolysis reaction mechanisms of phosphite antioxidants

The hydrolysis reaction mechanism of phosphite antioxidants is investigated by liquid chromatography-mass spectrometry (LC/MS). The phosphites were chosen because they differed in chemical structure and phosphorus content. Dopant assisted-atmospheric pressure photoionization (DA-APPI) is chosen as the ion source for (lie ionization of the compounds. [it our previous work, DA-APPI was shown to offer an attractive alternative to atmospheric pressure chemical ionization (APCI) since it provided background-ion free mass spectra and higher sensitivity [M. Papanastasiou, et al., Polymer Degradation and Stability 91 (11) (2006) 2675-2682]. In positive ion mode, the molecules are generally detected in their protonated form. In negative ion mode, the phosphites are unstable and only fragment ions are observed: these however, are characteristic of each phosphite and may be used for the identification of the analytes in complex mixtures. The analytes under investigation are exposed to accelerated humid ageing conditions and their hydrolytic pathway and stability is investigated. Different substituents around the phosphorus atom are shown to have a significant effect on the stability of the phosphites, with phenol substituents producing very hydrolytically stable structures. Alkanox P24 and PEP-36 follow a similar hydrolytic pathway via the scission of the first and then the second P-O-phenol bonds, eventually leading to the formation of phenol, Phosphorous acid and pentaerythritol as end products. HP-10 exhibits a rather different Structure and the products detected suggest scission of either the P-O-hydrocarbon or one of the P-O-phenol bonds. A phenomenon similar to that of autocatalysis is observed for all phosphites and is attributed to the formation of dialkyl phosphites as intermediate products. (C) 2008 Elsevier B.V. All rights reserved.

SnO(2)-based materials for pesticide degradation

This study presents the results of the degradation of the pesticide atrazine using electrochemical and photo-assisted electrochemical degradation techniques using SnO(2)-containing electrode of nominal composition electrodes of composition Ti/Ru(x)Sni-(x)O(2) (where X = 0.10, 0.15, 0.20, 0.25 and 0.30). The materials were characterized ex situ and in situ in order to correlate the observed atrazine removal rates with electrode morphology/composition. The results obtained demonstrate the effectiveness of the photo-assisted electrochemical degradation. Using purely electrochemical methods the rate of atrazine removal is almost zero at all the electrodes studied. However, the application of photo-assisted degradation results in almost complete atrazine removal in 1 h of electrolysis. The efficiency of atrazine degradation does not seem to be greatly affected by the electrode material or by SnO(2) content, but the overall COD removal is dependent on the SnO(2) content. Overall, the SnO(2)-containing electrodes do not reach the level of COD removal (maximum similar to 21%) seen for the Ti/Ru(0.3)Ti(0.2)O(2) electrode. An interesting correlation between the morphology factor (phi) and chemical oxygen demand removal is observed. (C) 2010 Elsevier B.V. All rights reserved.

Study of photo-assisted electrochemical degradation of carbaryl at dimensionally stable anodes (DSA (R))

This paper presents the results concerning the degradation of the pesticide carbaryl comparing two methods: electrochemical (EC) and photo-assisted electrochemical (PAEC). The experimental variables of applied current density, electrolyte flow-rate and initial carbaryl concentration were investigated. The results demonstrate that the electrochemical degradation of carbaryl was greatly enhanced when simultaneous UV light was applied. The greatest difference between the PAEC and EC method was apparent when lower current densities were applied. The extent of COD removal was much enhanced for the combined method, independent of the applied current density. It should be noted that the complete removal of carbaryl was achieved with out the need to add NaCl to the reaction mixture, avoiding the risk of chlorinated organic species formation. (C) 2009 Elsevier B.V. All rights reserved.

Heterogeneous photocatalytic degradation of acid dyes in aqueous TiO2 suspensions: Kinetics and toxicity

This work assesses the photocatalytic (TiO2/UV) degradation of a simulated acid dye bath (Yellow 3, Red 51, Blue 74, and auxiliary chemicals). Color and phytotoxicity removal were monitored by spectrophotometry and lettuce (Lactuca sativa) seeds as the test organism, respectively. Mineralization was determined by DOC analyses. Photocatalytic, photolytic, and adsorption experiments were performed, showing that adsorption was negligible. After 240 minutes of irradiation, it was achieved 96% and 78% of color removal with photocatalysis and photolysis, respectively. 37% of mineralization occurred with photocatalysis only. The dye bath was rendered completely non-toxic after 60 minutes of photocatalytic treatment; the same result was only achieved with photolysis after 90 minutes. A kinetic model composed of two first-order in series reactions was used. The first photocatalytic decolorization rate constant was k(1) = 0.062 min(-1) and the second k(2) = 0.0043 min(-1), approximately two times greater than the photolytic ones.

On the activation and physical degradation of boron-doped diamond surfaces brought on by cathodic pretreatments

The electrochemical activation and physical degradation of boron-doped diamond (BDD) electrodes with different boron doping levels after repeated cathodic pretreatments are reported. Galvanostatic cathodic pretreatment passing up to -14000 C cm(-2) in steps of -600 C cm(-2) using -1 A cm(-2) caused significant physical degradation of the BDD surface, with film detachment in some areas. Because of this degradation, a great increase in the electrochemically active area was observed in Tafel plots for the hydrogen evolution reaction (HER) in acid media. The minimum cathodic pretreatment needed for the electrochemical activation of the BDD electrodes without producing any observable physical degradation on the BDD surfaces was determined using electrochemical impedance spectroscopy (EIS) measurements and cyclic voltammetry: -9 C cm(-2), passed at -1 A cm(-2). This optimized cathodic pretreatment can be safely used when electrochemical experiments are carried out on BDD electrodes with doping levels in the range between 800 and 8000 ppm.

Photo-assisted electrochemical degradation of the commercial herbicide atrazine

This paper presents a degradation study of the pesticide atrazine using photo-assisted electrochemical methods at a dimensionally stable anode (DSA (R)) of nominal composition Ti/Ru(0.3)Ti(0.7)O(2) in a prototype reactor. The effects of current density, electrolyte flow-rate, as well as the use of different atrazine concentrations are reported. The results indicate that the energy consumption is substantially reduced for the combined photochemical and electrochemical processes when compared to the isolated systems. It is observed that complete atrazine removal is achieved at low current densities when using the combined method, thus reducing the energy required to operate the electrochemical system. The results also include the investigation of the phytotoxicity of the treated solutions.

Photo-assisted electrochemical degradation of real textile wastewater

In the present study, photo-assisted electrochemical degradation of real textile wastewater was performed. Degradation assays were performed at constant current (40 mA cm(-2)) in a combined electro/photochemical flow-cell using a Ti/Ru(0.3)Ti(0.7)O(2) DSA(R) type electrode. The results show that the method is capable of removing color and chemical oxygen demand (COD) from the effluent. Additionally, the effect of initial pH and type of supporting electrolyte (Na(2)SO(4) or NaCl) was investigated. The principal figures of merit used in this study were COD removal and color removal (605 nm). The results show that up to 72% color and up to 59% COD removal in 120 min is possible under the operating conditions employed. Studies of the phytotoxicity of the wastewater before and after the photo-assisted degradation assays are also presented and the results demonstrate that the toxicity of the effluent is dependent on the length of electrolysis time and the treatment procedure employed.

Degradation of alachlor herbicide by gamma radiation from cobalt-60 in aqueous and alcohol solution

Alachlor has been widely used in agriculture all over the world. It is suggested that it may be a carcinogen and an environmental estrogen. The aim of this work was to verify the degradation the alachlor by gamma radiation. Gamma radiation from (60)Co was used to degrade the alachlor herbicide in water and methanol solution. The alachlor in water and alcohol solution in the concentration of 100 mgL(-1) was irradiated with doses of 0.25-50 kGy, at dose rate 5-6 and 2.7 kGyh(-1). High performance liquid chromatography was used as an analytical technique to determine the degradation rate of herbicide studied.

Heterogeneous photocatalytic degradation of reactive dyes in aqueous TiO(2) suspensions: Decolorization kinetics

This work assesses the photocatalytic (TiO(2)/UV) degradation of a simulated reactive dye bath (Black 5, Red 239, Yellow 17, and auxiliary chemicals). Color removal was monitored by spectrophotometry. Mineralization was determined by DOC analyses. Photocatalytic, photolytic, and adsorption experiments were performed, showing that adsorption was negligible. After 30 min of irradiation, it was achieved 97% and 40% of color removal with photocatalysis and photolysis, respectively. No mineralization occurred within 30 min. A kinetic model composed of two, first-order in-series reactions was used. The first photocatalytic decolorization rate constant was k(1) = 2.6 min(-1) and the second k(2) = 0.011 min(-1). The fast decolorization of Reactive Black 5 dye is an indication that the number of azo and vinylsulfone groups in the dye molecule maybe a determining factor for the increased photolytic and photocatalytic color removal and degradation rates. (C) 2008 Elsevier B.V. All rights reserved.

TiO(2)-PHOTOCATALYZED DEGRADATION OF PHENOL IN SALINE MEDIA IN AN ANNULAR REACTOR: HYDRODYNAMICS, LUMPED KINETICS, INTERMEDIATES, AND ACUTE TOXICITY

The photocatalytic degradation of phenol in aqueous suspensions of TiO(2) under different salt concentrations in an annular reactor has been investigated. In all cases, complete removal of phenol and mineralization degrees above 90% were achieved. The reactor operational parameters were optimized and its hydrodynamics characterized in order to couple mass balance equations with kinetic ones. The photodegradation of the organics followed a Langmuir-Hinshelwood-Hougen- Watson lumped kinetics. From GC/MS analyses, several intermediates formed during oxidation have been identified. The main ones were catechol, hydroquinone, and 3-phenyl-2-propenal, in this order. The formation of negligible concentrations of 4-chlorophenol was observed only in high salinity medium. Acute toxicity was determined by using Artemia sp. as the test organism, which indicated that intermediate products were all less toxic than phenol and a significant abatement of the overall toxicity was accomplished, regardless of the salt concentration.

Sjuksköterskans upplevelser av den palliativa vården vid användadet av Liverpool Care Pathway

Syftet var att studera hur den palliativa vården upplevs av sjuksköterskor vid användandet av Liverpool Care Pathway. Studien baserades på data från sex informanter på särskild boende/korttidsboende i en kommun i Dalarna. Studien har en kvalitativ design med innehållsanalys enligt Graneheim och Lundman. Analys av insamlad data resulterade i de tre kategorierna: Tydliga kriterier ger trygghet i vården, Omvårdnadsarbetet har utvecklats och tydligare information. Resultatet visade att tydliga kriterier vid användningen av Liverpool Care Pathway i den kommunala vården gav den palliativa patienten trygghet i omvårdnaden vid livets slut samt klara kriterier som gjorde att personalen tillämpade lika arbetsätt i den palliativa vården. Att stanna kvar i hemmet vid livet slut var en självklarhet för den palliativa patienten när Liverpool Care Pathway var infört i kommunen. Information till anhöriga och patienten i livets slut hade underlättats då Liverpool Care Pathway tillhandahöll tydlig information om den palliativa patientens status. Studiens resultat visade att den palliativa vårdens dokumentation kvalitetssäkrats och utvecklats genom att Liverpool Care Pathway införts i den kommunala vården. 

Sjuksköterskors upplevelser av att vårda patienter i livets slutskede enligt Liverpool Care Pathway (LCP)

Syfte: Att beskriva sjuksköterskors upplevelser av att vårda patienter i livets slutskede enligt en vårdplan utformad som en journal med riktlinjer för vård i livets slutskede, den så kallade Liverpool Care Pathway (LCP). Metod: Studien är utförd som en litteraturöversikt. Artiklarna söktes via databaserna CINAHL, PubMed, MedLine, SAGE Journals och Scopus. Tolv artiklar valdes ut för kvalitétsgranskning enligt en förutbestämd granskningsmall. Elva artiklar godkändes och utgjorde grunden för resultatet. Resultat: En tydlig effekt av införandet av LCP var att sjuksköterskorna upplevde ett ökat självförtroende och en ökad kunskap i vårdandet. Detta bidrog till förbättringar gällande symtomkontroll samt ifrågasättande av fortsatt rutinmässig behandling. LCP anågs vara en bra utgångspunkt för samtal och undervisning i möten med patienter och anhöriga. LCP upplevdes ge ramar och gemensamma utgångspunkter i teamarbetet runt patienten vilket bidrog till en bättre planering och tydligare mål i vårdandet. Trots alla positiva upplevelser kände en del sjuksköterskor att de kunde uppstå svårigheter i vårdandet enligt LCP. Brister i vårdmiljön ansågs av sjuksköterskorna göra att målen med vården inte kunde tillgodoses. Tidsbrist och underbemanning ledde ofta till att patienter i livets slutskede fick en lägre prioritet. Vidare ansågs kriterierna vara för hårda enligt vissa sjuksköterskor gällande införande av LCP.

Sjuksköterskors erfarenhet av att vårda patienter i livets slutskede enligt Liverpool Care Pathway (LCP) : En litteraturöversikt

Syfte: Att redogöra för sjuksköterskors erfarenhet av att vårda patienter i livets slutskede enligt Liverpool Care Pathway (LCP). Metod: Litteraturstudien baseras på tio vetenskapliga artiklar med kvalitativ ansats. De vetenskapliga artiklarna söktes i databaserna CINAHL, PubMed och World of Science. Inklusionskriterier var att artiklarna skulle vara primärkällor, vara skrivna på svenska eller engelska samt publicerade mellan år 2003-2013. Ytterligare inklusionskriterier var att sjuksköterskorna skulle ha erfarenhet av LCP, samt att de vetenskapliga artiklarna erhöll medel eller hög poäng vid granskningen och var godkänd av en etisk kommitté. Studier från hela världen inkluderades. Huvudresultat: Ett flertal studier visade att LCP bidrog till ett ökat självförtroende och tydligare riktlinjer för den palliativa vården. Sjuksköterskorna upplevde en förbättrad symtomkontroll och förbättrad vård efter införandet av LCP. Sjuksköterskorna var positiva till dokumentationen i LCP och det framgick också att LCP hade förbättrat och underlättat kommunikationen med närstående. LCP erbjöd stöd och vägledning i vården men det framgick också att det fanns oklarheter vad beträffar diagnostiserande av en patient som döende. Slutsats: Syftet med litteraturstudien var att undersöka sjuksköterskors erfarenhet av att vårda patienter i livets slutskede enligt Liverpool Care Pathway. Det framgick att det fanns bristande kunskaper om palliativ vård, men att införandet av LCP gett sjuksköterskor stöd och vägledning samt förbättrat kunskapen om palliativ vård. En vårdplan som LCP kan vara ett stöd för sjuksköterskan i omvårdnaden av patienter inom palliativ vård, men en sådan vårdplan kan aldrig ersätta sjuksköterskans kliniska kompetens. Det är därför viktigt att sjuksköterskor erbjuds fortlöpande utbildning inom palliativ vård, samt att en vårdplan som LCP används utifrån ett kritiskt förhållningssätt.  

Photochemical degradation of 2,4-D and atrazine in well-defined media

Atrazine and 2,4-D are common herbicides used for crop, lawn, and rangeland management. Photochemical degradation has been proposed as one safe and efficient remediation strategy for both 2,4-D and Atrazine. In the presence of iron(llI) and hydrogen peroxide these herbicides decay by both thermal and light induced oxidation. Past studies have focused primarily on sun light as an energy source. This work provides a mechanistic description of herbicide degradation incorporating intermediate degradation products produced in the dark and under well-defined light conditions.