Title Fotorazgradnja neonikotinoida u prisutnosti sulfatnih radikala Title (english) Photodegradation of nenonicotinoids in the presence of sulfate radicals Author Ana Grčić Mentor Vesna Tomašić (mentor)Committee member Vesna Tomašić (predsjednik povjerenstva)Committee member Marin Kovačić (član povjerenstva)Committee member Marina Duplančić (član povjerenstva)Granter University of Zagreb Defense date and country 2022-09-12, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Od početka 1990-ih neonikotinoidni pesticidi imaju široku primjenu kao učinkovita sredstva protiv insekata štetnih za biljke. Zbog bioakumulacije i niske biorazgradivosti neki od neonikotinoida često se mogu pronaći u površinskim i podzemnim vodama, što predstavlja opasnost za ljude i okoliš. Zbog toga se javlja potreba za razvojem i primjenom naprednih tehnologija za njihovu razgradnju ili drugi oblik uklanjanja iz okoliša. Dostignuća u području heterogene fotokatalize značajno pridonose remedijaciji okoliša, međutim usprkos velike djelotvornosti takvih procesa još uvijek postoji potreba za svladavanjem određenih izazova i prepreka njihovoj primjeni u realnim sustavima. U ovom radu ispitana je fotokatalitička razgradnja acetamiprida u rotacijskom fotoreaktoru. Poseban naglasak dan je na utjecaj primijenjenih persulfata na učinkovitost fotorazgradnje navedene modelne komponente. Fotorazgradnja je provedena u šaržnim uvjetima rada, primjenom imobiliziranog sloja fotokatalizatora TiO2 koji je prethodno modificiran djelovanjem UVC zračenja s ciljem smanjenja energijskog procjepa. Početna koncentracija acetamiprida iznosila je 10 ppm, a protok recirkulacije reakcijske smjese koji je ostvaren pomoću recirkulacijske pumpe iznosio je 200 mL/min. Fotokatalizator je bio izložen djelovanju UV-zračenja, pri čemu je cijev fotoreaktora rotirala kontroliranom brzinom od 200 okretaja/min. Ukupno vrijeme trajanja reakcije (odnosno zračenja) iznosilo je 4 sata, uz dodatnih 30 minuta potrebnih za postizanje ravnotežne adsorpcije modelne komponente na površinu fotokatalizatora. Razgradnja acetamiprida praćena je primjenom tekućinske kromatografije visoke učinkovitosti (HPLC) periodičnim uzimanjem uzoraka volumena 1 mL. Na temelju dobivenih rezultata može se zaključiti da se razgradnja acetamiprida uspješnije provodi u prisutnosti TiO2-UVC fotokatalizatora u odnosu na fotolitičku razgradnju. Prisutnost persulfata (PS), npr. kalijevog persulfata (K2S2O8) te peroksimonosulfata (PMS), npr. kalijevog peroksimonosulfata (KHSO5) dovodi do značajnog poboljšanja ukupne učinkovitosti fotorazgradnje acetamiprida. Provedena je kinetička analiza primjenom empirijskog kinetičkog modela za reakciju prvog reda koji je uvršten u model kotlastog reaktora, uz korijen srednjih kvadratnih odstupanja kao kriterij slaganja pri čemu je nađeno dobro slaganje eksperimentalnih i teorijskih rezultata. Također su izračunate karakteristične konstante brzine fotorazgradnje i karakteristična vremena poluraspada.
Abstract (english) Since the early 1990-s, neonicotinoid pesticides have been widely used as an effective agent against insects harmful to plants. Due to bioaccumulation and low biodegradability, some of the neonicotinoids can often be found in surface and underground water, which can poses a great danger to people and the environment. Consequently, there is a need for the development and application of advanced technologies for their degradation or other form of their removal from the environment. Achievements in the field of heterogeneous photocatalysis contribute significantly to environmental remediation, however, despite the great effectiveness of such processes, there is still a need to overcome certain challenges and obstacles realted to their application in real systems. This paper examined the photocatalytic degradation of acetamiprid in a rotating photoreactor. Special emphasis is given to the influence of applied persulfates on the photodegradation efficiency of the mentioned model component. Photodegradation was carried out in batch conditions, using an immobilized layer of TiO2 photocatalyst that was previously modified by UVC radiation with the aim of reducing the energy gap. The initial concentration of acetamiprid was 10 ppm and the reaction mixture circulated through the system using a recirculation pump at a flow rate of 200 ml/min. The photocatalyst was exposed to UV radiation, while the photoreactor tube rotated at a controlled speed of 200 revolutions/min. The total duration of the reaction (i.e. radiation) was 4 hours, with an additional 30 minutes needed to achieve equilibrium adsorption of the model component on the surface of the photocatalyst. The degradation of acetamiprid was monitored using high-performance liquid chromatography (HPLC) with periodic sampling of 1 mL volume. Based on the obtained results, it can be concluded that the degradation of acetamiprid is carried out more successfully in the presence of TiO2-UVC photocatalyst compared to photolytic degradation. The presence of persulfate (PS), eg potassium persulfate (K2S2O8) and peroxymonosulfate (PMS), eg potassium peroxymonosulfate (KHSO5) leads to a significant improvement in the overall photodegradation efficiency of acetamiprid. A kinetic analysis was carried out using an empirical kinetic model for the first-order reaction, which was included in the model of the boiler reactor, with the root mean square deviation as measure of the differences between values, whereby a good match between experimental and theoretical results was found. Characteristic photodegradation rate constants and characteristic half-lives were also calculated.
Keywords
heterogena fotokataliza
neonikotionidi
acetamiprid
PMS
PDS
TiO2
Keywords (english)
heterogeneous photocatalysis
neonicotinoids
acetamiprid
PMS
PDS
TiO2
Language croatian URN:NBN urn:nbn:hr:149:309718 Project Number: IP-2018-01-8669 Study programme Title: Chemical Engineering - Undergraduate study Type of resource Text File origin Born digital Access conditions Access restricted to students and staff of home institution Terms of use Created on 2023-02-23 14:07:28
