Comparison of UV/H2O2 and UV/TiO2 for the degradation of metaldehyde: Kinetics and the impact of background organics

Autin, Olivier; Hart, Julie; Jarvis, Peter; MacAdam, Jitka; Parsons, Simon A.; Jefferson, Bruce

doi:10.1016/j.watres.2012.07.057

Cited by 53 publications

(43 citation statements)

References 38 publications

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“…This is particularly pertinent in the case of pesticides, where several widelyused active substances regularly cause water quality problems in a number of drinking water catchments (Kennedy 2010;Kennedy et al 2009;Defra 2012). These problems are especially acute for compounds that are not removed significantly by current water treatment technologies, such as metaldehyde (Autin et al 2012) and clopyralid (Tizaoui et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Identifying Adaptation Options and Constraints: The Role of Agronomist Knowledge in Catchment Management Strategy

Dolan

Parsons

Howsam

et al. 2014

Water Resour Manage

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Water suppliers in parts of Europe currently face occasional Drinking Water Directive compliance challenges for a number of pesticide active substances including metaldehyde, clopyralid and propyzamide. Water Framework Directive (WFD) Article 7 promotes a prevention-led (catchment management) approach to such issues. At the same time, European pesticide legislation is driving reduced active substance availability. In this context, embedding agronomic drivers of pesticide use into catchment management and regulatory decision making processes can help to ensure that water quality problems are addressed at source without imposition of disproportionate cost on either agriculture or potable water suppliers. In this study agronomist knowledge, perception and expectations of current and possible future pesticide use was assessed and the significance of this knowledge to other stakeholders involved with pesticide catchment management was evaluated. This was then used to provide insight into the possible impacts of active substance restrictions and associated adaptation options. For many arable crops, further restrictions on the range of pesticides available may cause increased use of alternatives (with potential for "pollution swapping"). However, in many cases alternatives are not available, too costly or lack a proven track record and other adaptation options may be selected which catchment managers need to be able to anticipate.

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Section: Introductionmentioning

confidence: 99%

Identifying Adaptation Options and Constraints: The Role of Agronomist Knowledge in Catchment Management Strategy

Dolan

Parsons

Howsam

et al. 2014

Water Resour Manage

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“…Degradation products were not detected during metaldehyde photocatalysis with UV/TiO 2 [12], although volatile by-products in this system, if present, would probably have been lost during the sample treatment carried out, which involving sample preconcentration with styrene divinylbenzene cartridges. This is because of the high volatility of the possible degradation products and limited adsorption onto the stationary phase due to the short hydrocarbon skeleton of the possible degradation products.…”

Section: Immobilisation Of Slgo Onto Cellulose Tape and An Assessmentmentioning

confidence: 87%

“…For example, Busquets et al noted the improved adsorption of metaldehyde using "tailored" activated carbon beads (i.e. with controlled surface chemistry and pore size distribution) synthesised from phenolic resin [10,11], while Autin et al reported successful photodegradation of metaldehyde using UV/H 2 O 2 and UV/TiO 2 (although the effectiveness of metaldehyde removal was significantly reduced by the presence of background organic matter) [12]. Bing and Fletcher report the destruction of metaldehyde using sulfonic acid functionalized mesoporous silica [13], and ion exchange resins with sulfonic acid groups in a system that can also adsorb any acetaldehyde generated [14] , while Nabeerasool et al report effective removal of metaldehyde using a coupled batch adsorption/ electrochemical regeneration technique, based on low capacity graphitic material (Arvia TM process) [8].…”

Section: Introductionmentioning

confidence: 99%

Graphene oxide-based degradation of metaldehyde: Effective oxidation through a modified Fenton’s process

Nguyen

Busquets

Ray

et al. 2017

Chemical Engineering Journal

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A modified graphene oxide-based Fenton's reaction has been investigated for the degradation of a challenging emerging contaminant which is not effectively removed in conventional water treatment. Metaldehyde, used as the challenge molecule in this study, is a common molluscicide that (like many highly soluble contaminants) has frequently breached European regulatory limits in surface waters. The new method involves graphene with higher hydrophilic characteristics (Single-Layer Graphene Oxide, SLGO) as a system that participates in a redox reaction with hydrogen peroxide and which can potentially stabilize the •OH generated, which subsequently breaks down organic contaminants. The modified Fenton's reaction has shown to be effective in degrading metaldehyde in natural waters (>92% removal), even at high contaminant concentrations (50 mg metaldehyde/L) and in the presence of high background organic matter and dissolved salts. The reaction is relatively pH insensitive. SLGO maintained its catalytic performance over 3 treatment cycles when immobilized. Its performance gradually decreased over time, reaching around 50% of starting performance on the 10 th treatment cycle. X-ray Photoelectron Spectroscopy (XPS) analysis of modifications caused in SLGO by the oxidizing treatment indicated that the oxidation of C-C sp 2 to carbonyl groups may be the cause of the decrease in performance. The proposed modified Fenton's process has the potential to substitute traditional Fenton's treatment although regeneration of the nanocarbon is required for its prolonged use. Highlights: SLGO and H 2 O 2 can degrade metaldehyde-contaminated water  pH and total organic carbon are not critical in the modified Fenton's process  SLGO has been immobilized and can be re-used  Regeneration of SLGO is needed to improve cost-effectiveness 4

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“…36 The kinetics of the heterogeneous photocatalytic reactions is typically correlated to the LangmuirHinschelwood model. 34,37,38 Considering that the concentration of reactive species (RS) formed in the reaction sites must quickly achieve a stationary regimen, 39,40 remaining nearly constant during all the photocatalytic process, the rate law can be expressed by equation 1: (3) which, considering that is k app , the apparent rate constant of the reaction, can be rewritten as (4) Vol. 27, No.…”

Section: Control Experimentsmentioning

confidence: 99%

“…34,37,38 Considering that the concentration of reactive species (RS) formed in the reaction sites must quickly achieve a stationary regimen, 39,40 remaining nearly constant during all the photocatalytic process, the rate law can be expressed by equation 1:…”

mentioning

confidence: 99%

Efficient Mineralization of Paracetamol Using the Nanocomposite TiO₂/Zn(II) Phthalocyanine as Photocatalyst

França¹,

Santos²,

Silva³

et al. 2016

Journal of the Brazilian Chemical Society

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The photocatalytic performance of a composite based on the association of TiO 2 and 2.5 wt.% of zinc(II) phthalocyanine (TiO 2 /ZnPc) was evaluated towards the mineralization of paracetamol and compared to that observed for the bare oxide in different pH and H 2 O 2 concentrations. The results show that the photocatalytic performances were influenced by the pH, with maximum efficiency around the isoelectric point. Mineralization efficiencies between 86-91% was obtained using TiO 2 /ZnPc in pH 5.5-6.8, with 33 mg L -1 of H 2 O 2 , ca. 15% higher than that observed with TiO 2 . The mineralization efficiencies using bare TiO 2 and TiO 2 /ZnPc were respectively 112 and 18% lower in the absence of H 2 O 2 . The better performance of TiO 2 /ZnPc is related to its extended light absorption and non-uniform coating of the TiO 2 surface by ZnPc aggregates. Above pH 6.8, the mineralization efficiencies decrease for both photocatalysts, although the consumption of H 2 O 2 remains above 90%, due to its decomposition in alkaline pH.Keywords: mineralization, paracetamol, heterogeneous photocatalysis, role of pH and hydrogen peroxide, TiO 2 /zinc(II) phthalocyanine nanocomposite IntroductionSince initial studies by Fujishima and Honda, 1 heterogeneous photocatalysis 2 has attracted considerable attention due to its many technological applications, such as H 2 production, 3-5 CO 2 reduction, 6-8 environmental remediation, 9-12 among others. TiO 2 has been widely used in heterogeneous photocatalysis due its low cost, low toxicity, chemical and photochemical stability, usually expressive photocatalytic activity and versatility. 2,10,12,13 Its main limitation as photocatalyst is related to the lack of absorption in the visible region, which limits its use under solar irradiation. Several strategies have been employed to overcome this limitation, including doping 3 and production of nanocomposites. 9,[12][13][14] TiO 2 -based photocatalysis has been specially used in environmental remediation for the removal of recalcitrant and hazardous organic pollutants in wastewater. 9,15 The radicals produced from its excitation by light are able to efficiently oxidize organic pollutants leading in some cases to a complete mineralization of the organic matter.Paracetamol (N-acetyl-p-aminophenol, PCT), Figure 1a, among other pharmaceutical products, their metabolites, pesticides, hormones and herbicides, 9,16-20 is calling attention due to its persistence in the environment and the inability of the sewage treatment plants in removing this contaminant, which may result in bioaccumulation and harmful consequences for ecosystems. 17,[20][21][22] Although PCT is metabolized mainly by the liver, up to 68% of this drug tends to be excreted in the urine when ingested within permitted levels. [21][22][23][24] It should be emphasized that one of the routes of paracetamol metabolism produces highly toxic metabolites able to bind covalently to cysteine present in proteins. 23,25Figure 1. Chemical structure of PCT (a) and Zn(II) phthalocyanine (b). França e...

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Comparison of UV/H2O2 and UV/TiO2 for the degradation of metaldehyde: Kinetics and the impact of background organics

Cited by 53 publications

References 38 publications

Identifying Adaptation Options and Constraints: The Role of Agronomist Knowledge in Catchment Management Strategy

Identifying Adaptation Options and Constraints: The Role of Agronomist Knowledge in Catchment Management Strategy

Graphene oxide-based degradation of metaldehyde: Effective oxidation through a modified Fenton’s process

Efficient Mineralization of Paracetamol Using the Nanocomposite TiO₂/Zn(II) Phthalocyanine as Photocatalyst

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Comparison of UV/H2O2 and UV/TiO2 for the degradation of metaldehyde: Kinetics and the impact of background organics

Cited by 53 publications

References 38 publications

Identifying Adaptation Options and Constraints: The Role of Agronomist Knowledge in Catchment Management Strategy

Identifying Adaptation Options and Constraints: The Role of Agronomist Knowledge in Catchment Management Strategy

Graphene oxide-based degradation of metaldehyde: Effective oxidation through a modified Fenton’s process

Efficient Mineralization of Paracetamol Using the Nanocomposite TiO2/Zn(II) Phthalocyanine as Photocatalyst

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Efficient Mineralization of Paracetamol Using the Nanocomposite TiO₂/Zn(II) Phthalocyanine as Photocatalyst