Degradation kinetics of isoproturon and its subsequent products in contact with TiO2 functionalized silica nanofibers

A challenge for the photodegradation of (organic) micro-pollutants in waste water treatment is the mechanistic and kinetic understanding beyond the degradation of the initial (parent) harmful product, e.g. the phenylurea herbicide isoproturon (IPU). By combining liquid chromatography-mass spectrometry and kinetic Monte Carlo modeling, we demonstrate that upon optimizing the dip-coating conditions (0.34 mol L (-1) TiO2 solution at a coating speed of 160 mm min( -1)) for the functionalization of a superhydrophilic electrospun silica nanofibrous membrane (i) hydroxylation is a dominant reaction pathway and (ii) once IPU reacts on the surface of the TiO(2 )nanoparticles, further hydroxylation occurs sufficiently fast, with complete IPU removal under the detection limit (5-10 mg Lsolution(-1)) as a result of UV irradiation within 8 h. As hydroxylation is dominant, degradation intermediates with a higher water solubility are formed and therefore a decreased toxicity is obtained upon reintroducing the treated solution into the environment. This is confirmed by respirometry, with an increase in the oxygen uptake rate of an activated sludge from 5.9 mg O(2 )g(activated) ( -1)(sludge) h (-1 )for an untreated 10 mg L-1 IPU solution to 8.2 mg O-2 g(activated sludge) (-1) h( -1) for a solution irradiated for 8 h, in line with a blank solution

Increasing the Dissolution Rate of Polystyrene Waste in Solvent-Based Recycling

Solvent-based recycling of plastic waste is a promising approach for cleaning polymer chains without breaking them. However, the time required to actually dissolve the polymer in a lab environment can take hours. Different factors play a role in polymer dissolution, including temperature, turbulence, and solvent properties. This work provides insights into bottlenecks and opportunities to increase the dissolution rate of polystyrene in solvents. The paper starts with a broad solvent screening in which the dissolution times are compared. Based on the experimental results, a multiple regression model is constructed, which shows that within several solvent properties, the viscosity of the solvent is the major contributor to the dissolution time, followed by the hydrogen, polar, and dispersion bonding (solubility) parameters. These results also indicate that cyclohexene, 2-pentanone, ethylbenzene, and methyl ethyl ketone are solvents that allow fast dissolution. Next, the dissolution kinetics of polystyrene in cyclohexene in a lab-scale reactor and a baffled reactor are investigated. The effects of temperature, particle size, impeller speed, and impeller type were studied. The results show that increased turbulence in a baffled reactor can decrease the dissolution time from 40 to 7 min compared to a lab-scale reactor, indicating the importance of a proper reactor design. The application of a first-order kinetic model confirms that dissolution in a baffled reactor is at least 5-fold faster than that in a lab-scale reactor. Finally, the dissolution kinetics of a real waste sample reveal that, in optimized conditions, full dissolution occurs after 5 min

Missionary Church in the service of the neighbour. Christians among Muslims

De nos jours, la présence chrétienne en milieu musulman est délicate et, à certains endroits, carrément dangereuse. L’auteur montre que plusieurs communautés chrétiennes de l’Antiquité ont cherché à témoigner de leur foi dans des milieux semblables. Comme Pierre dans les Actes des Apôtres nous aussi, nous avons besoin d’une «conversion vocationnelle» pour comprendre ce que Dieu attend de nous quand nous rencontrons des gens qui entendent rester fidèles à leur propre tradition religieuse. Une telle conversion nous permet de discerner leur rôle dans le plan de Dieu et d’entrer en dialogue avec eux. Ouverts aux richesses religieuses qu’ils désirent partager avec nous, nous pouvons à notre tour témoigner de la foi en Jésus-Christ et en Dieu qui s’est manifesté en lui. Ce témoignage des uns et des autres, prenant le plus souvent la forme d’une vie commune faite de services réciproques, est une authentique forme de mission, même s’il ne convient pas de l’appeler ainsi. La thèse central de cet article peut être formulé comme suit: la mission s’adresse à tous, y compris aux personnes qui ne manifestent pas le moindre désir de devenir chrétiens. En les accueillant tels qu’ils sont et en cheminant avec eux, l’Église accomplit sa mission d’être au service de tous. Une telle mission est plus que nécessaire à une époque où les malentendus entre croyants de différentes religions semblent l’emporter.Dzisiaj obecność chrześcijan w środowisku muzułmańskim staje się kontrowersyjna, a czasem nawet niebezpieczna. Autor wykazuje, że poszczególne pierwotne wspólnoty chrześcijańskie żyjąc w podobnym środowisku – dawały świadectwo wiary. Podobnie jak Piotr w Dziejach Apostolskich, tak i my potrzebujemy „nawrócenia naszego powołania” byśmy zrozumieli czego Bóg oczekuje od nas, kiedy spotykamy ludzi, którzy pragną pozostać wierni własnej tradycji religijnej. Takie nawrócenie pozwoli nam rozeznać ich miejsce w planie Bożym i nawiązać z nimi dialog. Otwarci na bogactwo religijne, którym chcą się z nami dzielić, z naszej strony możemy dać świadectwo wiary w Jezusa Chrystusa. Świadectwo wiary jednych i drugich, które najczęściej przybiera formę życia wspólnotowego i wzajemnej pomocy jest autentyczną misją – nawet jeśli określenie to wydaje się nieadekwatne. Zasadniczą tezę artykułu można sformułować następująco: misja skierowana jest do wszystkich, również do tych, którzy nie wykazują żadnej woli stania się chrześcijanami. Akceptując ich jako takich i egzystując pośród nich, Kościół wypełnia swoją misję służenia wszystkim ludziom. Misja ta ma szczególną wymowę w czasach, kiedy nieporozumienia pomiędzy wyznawcami różnych religii przybierają na sile.Christians living among Muslims find themselves in controversial, at times even dangerous, situations. The author of this article shows that early Christian communities in similar circumstances were able to give witness to their faith. Like St Peter (in the Acts of the Apostles), we too need a ”conversion of our vocation” if we are to understand what God expects of us whenever we encounter people who want to remain faithful to their own religious tradition. If we undergo such conversion, we shall be able to recognise their part in God’s plan and enter into dialogue with them. While open to the treasures of their religion they want to share with us, we can reciprocate with the witness of our faith in Jesus Christ. Witness on both sides, often assuming a concrete shape in the communal life and mutual assistance, is the authentic mission – even if the term seems out of place here. The author’s main thesis may be formulated as follows: Mission is directed towards all people; also to those who do not indicate any desire to become Christian. By accepting them as they are and staying among them, the Church fulfills her mission to serve all people. It is especially telling at times when misunderstandings between followers of different religions lead to increased tension among them

Use and challenges of electrical resistivity tomography to study processes in agro-ecosystems

Sustainable management of agro-ecosystems requires a thorough understanding of the interaction between physical, chemical and biological processes at play. In addition, processes at pore scale are linked to field scale phenomena, but this connection is often poorly understood. Electrical resistivity tomography (ERT) is increasingly used in the context of agriculture since the measured resistivity distribution can be linked to soil moisture, soil structural characteristics or pore water salinity. Due to its minimally invasive character, its spatial coverage and its monitoring abilities, ERT can be used to study field heterogeneity and competition between plants, quantify water fluxes throughout a growing season or distinguish preferential flow pathways in soils. Is resolution is well-below classical soil imaging techniques such as X-ray CT or MRI, but its spatial coverage much larger. This highlights the potential of ERT to link our knowledge obtained from pore scale data to field scale processes. Nevertheless, a lot of challenges still remain. A Tikhonov-type regularization approach is often used to solve the ill-posed, inverse problem linked to ERT, resulting in a smoothed resistivity distribution. However, in reality strong contrasts can exist due to e.g. compacted soil layers due to ploughing, water infiltration fronts, etc. and in that case other operators have been proposed to regularize the inversion. Taking into account spatial heterogeneity of petrophysical characteristics and providing a realistic uncertainty estimation are additional challenges, which can be addressed using stochastic approaches. Monitoring data provides further elements to constrain the inverse problem: data can be replaced by data difference and regularization may incorporate the temporal dimension for instance. However, such constraints require their compatibility with the studied temporal process, which is not always straightforward. Several alternative strategies are being developed, such as coupled hydrogeophysical inversion, or stochastic approaches using a prior falsification/validation method following a Popper-Bayes philosophy. In this talk, we will address some of these challenges and give some recent applications in the field of agro-geophysics