Photocatalytic Degradation of Monolinuron and Linuron in an Aqueous Suspension of Titanium Dioxide Under Simulated Solar Irradiation

The photocatalytic degradation of two phenylurea herbicides, monolinuron (MLN) and linuron (LN), was investigated in an aqueous suspension of TiO2 using simulated solar irradiation. The objective of the study was to compare their photocatalytic reactivity and to assess the influence of various parameters such as initial pesticide concentration, catalyst concentration and photonic flux on the photocatalytic degradation rate of MLN and LN. A comparative study of the photocatalytic degradation kinetics of both herbicides showed that these two compounds have a comparable reactivity with TiO2/simulated sun light. Under the operating conditions of this study, the photocatalytic degradation of MLN and LN followed pseudo first-order decay kinetics. The kobs values indicated an inverse dependence on the initial herbicide concentration and were fitted to the Langmuir-Hinshelwood equation. Photocatalytic degradation rates increased with TiO2 dosage, but overdoses did not necessarily increase the photocatalytic efficiency. The degradation rate of MLN increased with radiant flux until an optimum at 580 W m‑2 was reached and then decreased. Under these conditions, an electron-hole recombination was favored. Finally, the photocatalytic degradation rate depended on pH, where an optimum was found at a pH value close to the pH of the point of zero charge (pH = 6).La dégradation photocatalytique de deux herbicides, le monolinuron (MLN) et le linuron (LN), a été étudiée dans une suspension de TiO2 au contact de lumière solaire simulée. L’objectif de cette étude est de comparer leur photoréactivité et d’évaluer l’influence de différents paramètres tels que la concentration initiale en pesticide, la concentration en catalyseur et le flux photonique sur la cinétique de dégradation du monolinuron. L’étude comparative de la dégradation des deux herbicides a montré que les deux composés présentent une réactivité comparable avec le système TiO2/lumière simulée. Dans les conditions opératoires de cette étude, la dégradation photocatalytique du LN et du MLN suit une cinétique de pseudo ordre 1. La pseudo-constante kobs est inversement proportionnelle à la concentration initiale en pesticide et peut être décrite par une équation de Langmuir-Hinshelwood. L’étude de l’influence de la concentration en TiO2 a permis de montrer que la cinétique de dégradation du MLN augmente avec la dose de catalyseur, mais un surdosage n’est pas nécessaire pour augmenter l’efficacité du procédé. Cette étude a permis également de montrer que la pseudo‑constante d’ordre 1 de dégradation du MLN augmente linéairement avec le flux lumineux jusqu’à 580 W m-2 puis décroît. Dans ces conditions, la recombinaison des électrons trous est favorisée. Enfin, la cinétique de dégradation du MLN en fonction du pH passe par un optimum de pH proche du pH de point de charge nulle (pH = 6)

Accelerated bacterial reduction on Ag–TaN compared with Ag–ZrN and Ag–TiN surfaces

Ag–TaN sputtered on polyester (PES) accelerated >6 times the bacterial inactivation kinetics compared to TaN–PES under actinic light irradiation. Direct current pulsed magnetron sputtering (DCP) was used to sputter Ag–TaN–PES and TaN–PES. Complete bacterial reduction by Ag–TaN occurred within 20 min compared to Ag–TiN (100 min) and Ag–ZrN (90 min). The co-sputtering of Ag and Ta on PES was carried out in an Ar/N2 10% atmosphere. By ion-coupled plasma mass-spectrometry (ICP–MS) a reduced Ag-release was observed for Ag–TaN samples compared to Ag–PES samples within the disinfection period. The redox catalysis by the Ag-species during the bacterial disinfection was followed by X-ray photoelectron spectroscopy (XPS). A bacterial reduction mechanism is suggested consistent with the experimental findings. The nitride films were characterized by surface science methods

Showing Israel the red card. Activists engaged in pro-Palestinian sport-related campaigns

© 2017 Informa UK Limited, trading as Taylor & Francis Group. This article explores the motivations of activists involved in pro-Palestinian sports-based campaigns. The activists’ intention is to bring pressure to bear upon Israel until it complies with international law and supports the rights of Palestinian people under the universal principles of human rights. In response to expressions of pro-Palestinian solidarity, the Israeli state and its supporters are interpreting such activity as a ‘new’ manifestation of ‘old’ antisemitism. In seeking to assess whether such activity is informed by antisemitism, 10 semi-structured interviews were conducted with activists to examine their motives. Their political biographies were explored as were their views on the use of sport as platform to express support for the Palestinian people and/or their displeasure at Israeli participation in international sport. One central theme was the activists’ responses to the suggestion that they were motivated by antisemitism. A qualitative content analysis of the interview transcripts revealed a shared observation that the accusation of antisemitism was a ‘shameless tactic’ employed by those seeking to cover up the ongoing injustices experienced by the Palestinian people. Sport was seen as a legitimate platform for political activity, to raise public awareness and to put pressure on the Israeli state. The findings contribute to a better understanding of activist motivations, the use of sport as a political platform and the challenges facing sport and its governing bodies

Israel and a sports boycott: Antisemitic? Anti-Zionist?

The paper identifies and summarises the debates that surround the place of Israel in international sport and assesses how that place is increasingly being contested. The long-standing conflict between Israel and Palestine has begun to manifest in the world of sport with the paper sketching the debates of those calling for, and those opposed to, sport sanctions/boycott of Israel until the ‘Palestinian Question’ is resolved. Five related tasks are addressed: first, to summarise the call for sanctions/boycott emanating from the Boycott, Disinvestment and Sanctions movement. Second, to explore how this call is establishing itself in the world of sport. The responses of those opposed to any form of sanction/boycott are then considered. The confusion that surrounds the term antisemitism is addressed and the relationship between (anti-) Zionism and antisemitism unpacked. The discussion concludes with an assessment of the claim made by the Israeli state, and its supporters, that any action against the country’s participation in international sport would be an act of antisemitism. Offering a timely, integrated summary of the heated debates that surround the Israel/Palestine conflict, the paper contributes to a wider discussion on the relationship between sport and politics