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1843. Photocatalytic CO2 reduction over mesoporous TiO2 photocatalystsMartin Reli, Peter Nadrah, Miroslava Filip Edelmannová, Rudolf Ricka, Andrijana Sever Škapin, Urška Lavrenčič Štangar, Kamila Kočí, 2024, original scientific article Abstract: In this study, we investigated different synthesis methods (template-free and template-based) using copolymers of poly(ethylene oxide) and poly(propylene oxide) to enhance the CO2 reduction activity of mesoporous TiO2. Our main goal was to identify key factors affecting photocatalyst efficiency and selectivity. We compared the newly synthesized TiO2 photocatalysts with the commercial photocatalyst P25. Among the materials studied, TiO2-P123 in its pure anatase form demonstrated the highest photoreduction efficiency and CO2 selectivity. In contrast, TiO2-EG, TiO2-F127, and P25, which contained both rutile and anatase phases, exhibited decreased photoactivity due to the formation of a type II heterojunction between the phases and higher oxygen adsorption on rutile's surface. Additionally, we observed that the choice of chemicals for photocatalyst preparation significantly influenced the specific surface area. TiO2-P123, the most active photocatalyst, had the highest specific surface area, providing more reactive sites for improved light absorption efficiency and prolonged electron-hole pair lifetimes, resulting in enhanced photocatalytic activity. We also calculated apparent quantum yields to support our findings.
Keywords: CO2 reduction, TiO2, photocatalysis, mesoporous material, Sol-gel method
Published in DiRROS: 14.11.2023; Views: 505; Downloads: 55
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1846. Analiza stanja, težave z obnovo in usmeritve za gospodarjenje z borovimi sestoji v južnem delu GGO TolminAmbrož Blažko, 2023, professional article Abstract: V članku so predstavljeni rezultati digitalizacije površin borovih sestojev v južnem delu gospodarskega območja (GGO) Tolmin iz leta 1963 in primerjava stanja omenjenih gozdnih sestojev leta 1963 in dandanes. Podatki o stanju sestojev so razdeljeni v tri kategorije. Borovi sestoji, starejši od 60 let (nastali pred letom 1963), nekdanji borovi sestoji, kjer je že bila narejena premena, in mlajši borovi sestoji (do 60 let). Na splošno se je površina borovih sestojev v tem obdobju od leta 1963 do zdaj zmanjšala. Starost sestojev kaže, da je večina že dosegla sečno zrelost. Bori so marsikje opravili svoje poslanstvo predkulture. V mladju se pojavljajo toploljubni listavci. Zato so mnogi sestoji že primerni za posek (premeno), saj se njihova vitalnost in kakovost zmanjšujeta. Prav tako so požarno ogroženi.
Keywords: borovi sestoji, premena, toploljubni listavci, pomlajevanje, starostna struktura
Published in DiRROS: 14.11.2023; Views: 419; Downloads: 156
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1847. Popasenost travinja zaradi jelenjadi (Cervus elaphus L.) – poskus PoliceIztok Koren, 2023, original scientific article Abstract: Poskus ugotavljanja popasenosti travinja zaradi jelenjadi (Cervus elaphus L.) smo izvedli leta 2021 v predalpskem svetu severozahodne Slovenije, tj. pri naselju Police v Občini Cerkno. Postavili smo deset parov vzorčnih ploskev (ograjeno, neograjeno) in merili maso svežega travinja. Poskus smo ponovili enkrat. Na maso travinja značilno vpliva ograjenost (9,9 % variabilnosti), čas košnje (47,3 %), interakcija med časom košnje in prostorsko porazdelitvijo parov ploskev (5,6 %) ter razdalja parov ploskev do gozda (15,7 %). Največji delež popasenosti travinja je bil v drugi košnji - 53,0 %, v prvi pa 20,4 %. Med skupinama parov ploskev je bila razlika v popasenosti manjša: v prvem bloku je bila 31,6 %, v drugem pa 30,3 %. Skupni letni delež popasenosti je znašal 31 %. Rezultati poskusa so primerljivi z drugimi podobnimi raziskavami na območjih velikih populacijskih gostot jelenjadi.
Keywords: Slovenija, predalpski svet, jelenjad, popasenost travinja
Published in DiRROS: 14.11.2023; Views: 430; Downloads: 149
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1849. UV light causes structural changes in microplastics exposed in bio-solidsS. S. Alavian Petroody, Seyed Hossein Hashemi, Luka Škrlep, Branka Mušič, Cornelis A. M. van Gestel, Andrijana Sever Škapin, 2023, original scientific article Abstract: Bio-solids (biological sludge) from wastewater treatment plants are a significant source of the emission of microplastics (MPs) into the environment. Weakening the structure of MPs before they enter the environment may accelerate their degradation and reduce the environmental exposure time. Therefore, we studied the effect of UV-A and UV-C, applied at 70 °C, on three types of MPs, polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET), that are commonly found in sewage sludge, using three shapes (fibers, lines, granules). The MPs were exposed to UV radiation in bio-solid suspensions, and to air and water as control. The structural changes in and degradation of the MPs were investigated using Attenuated Total Reflectance–Fourier Transform Infrared Spectrometry (ATR-FTIR) and surface morphology was performed with SEM analysis. UV exposure led to the emergence of carbonyl and hydroxyl groups in all of the PP samples. In PE and PET, these groups were formed only in the bio-solid suspensions. The presence of carbonyl and hydroxyl groups increased with an increasing exposure time. Overall, UV radiation had the greatest impact on the MPs in the bio-solids suspension. Due to the surface-to-volume ratio of the tested samples, which influences the degradation rate, the fibers were more degraded than the other two plastic shapes. UV-A was slightly more effective at degrading the MPs than UV-C. These findings show that ultraviolet radiation in combination with an elevated temperature affects the structure of polymers in wastewater bio-solids, which can accelerate their degradation.
Keywords: microplastics, degradation, hydroxyl, carbonyl, ultraviolet light
Published in DiRROS: 14.11.2023; Views: 456; Downloads: 215
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1850. Infestation intensity by the invasive oak lace bug, Corythucha arcuata (Say) in mixed and pure oak standsGernot Hoch, Alex Stemmelen, Eötvös Csaba Béla, Werner Hinterstoisser, Miran Lanšćak, Srđan Stojnić, Máté Tóth, Marjana Westergren, Simon Zidar, Milica Zlatković, Nikola Zoric, Maarten De Groot, 2024, original scientific article Abstract: There has been accumulating evidence for effects of tree species composition on herbivory with many examples of lower damage by specialist feeders in tree species rich forests. In a joint study in five Central and Southeastern European countries, we studied the effect of tree species richness on infestation intensity of the oak lace bug, Corythucha arcuata (Say) (Heteroptera, Tingidae), an invasive pest on oak trees that has spread rapidly across the Balkan Peninsula and Central Europe. Intensity of infestation by C. arcuata on oaks was assessed on three or four study plots with high (pure stands) and three or four plots with low percentage of oak (mixed stands) in each country. Ordinal regression analysis showed that intensity of infestation of trees by C. arcuata differed between countries; no significant effect of stand type (mixed or pure) on infestation levels was detected. When analysing the percentage of trees in the highest infestation class, stand type had a significant effect with more intensive infestation in pure stands. We conclude that mixed stands will not prevent severe infestation but may help mitigating the impact of established C. arcuata populations.
Keywords: associational resistance, Corythucha arcuata, diversity, host tree concentration, invasive forest pest
Published in DiRROS: 14.11.2023; Views: 420; Downloads: 251
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