Title Razgradnja imidakloprida u pločastom fotoreaktoru Title (english) Degradation of imidacloprid in the flate plate photoreactor Author Martina Koren Mentor Vesna Tomašić (mentor)Committee member Željka Ujević Andrijić (predsjednik povjerenstva)Committee member Vesna Tomašić (član povjerenstva)Committee member Vanja Kosar (član povjerenstva)Granter University of Zagreb Defense date and country 2019-07-11, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Pesticidi su toksične kemijske tvari čija je uloga uništavanje ili kontrola populacije štetnika. Međutim, njihova intenzivna primjena može uzrokovati bioakumulaciju u okolišu. Heterogena kataliza u novije vrijeme postaje sve atraktivnija tehnologija koja se primjenjuje za obradu otpadnih voda i onečišćenog zraka s ciljem uklanjanja različitih postojanih organskih spojeva. Cilj ovog istraživanja je razvoj učinkovitog heterogenog fotokatalizatora koji može uspješno razgraditi neonikotinoidni insekticid imidakloprid (C9H10C1N5O2). Istraživanje je provedeno u pločastom fotoreaktoru s recirkulacijom reakcijske smjese, uz TiO2 kao fotokatalizator, koji je prethodno izložen djelovanju UVC zračenja. Difuznom refleksijskom spektroskopijom (UV/Vis-DRS) uzorka fotokatalizatora potvrđeno je da se na taj način smanjuje širina zabranjene zone, Eg, na vrijednost od 2,6 eV, što odgovara valnoj duljini od 476 nm. To je omogućilo da se istraživanja mogu provoditi u vidljivom dijelu elektromagnetskog spektra. Istraživanja obuhvaćaju fotolitičku te fotokatalitičku razgradnju imidakloprida na imobiliziranom sloju fotokatalizatora uz primjenu UVA, UVC zračenja te komercijalne Arcadia lampe kojom je simulirano Sunčevo zračenje. Utvrđeno je da do fotolitičke razgradnje dolazi samo uz primjenu UVC lampe (200-280 nm), dok do fotokatalitičke razgradnje dolazi i djelovanjem UVA (320-400 nm) i Arcadia lampe. Fotokatalitičkom razgradnjom uz djelovanje UVA lampe postignuta je konverzija od 96,97% nakon 9,5 sati reakcije. Razvijena je metoda imobilizacije fotokatalizatora prethodno aktiviranog djelovanjem UVC zračenja na površinu nosača, a najboljim nosačem fotokatalitički aktivnog sloja pokazalo se staklo. Dodatak komerijalnog mineralnog veziva Procol omogućio je pripremu mehanički stabilnog imobiliziranog sloja fotokatalizatora. Provedena je kinetička analiza i predložen je odgovarajući kinetički model. Rezultati pokazuju da u početnom periodu razgradnje (t < 150 min) reakcija slijedi model pseudo-nultog reda, dok pri višim reakcijskim vremenima dolazi do prelaska u kinetički model reakcije pseudo-prvog reda. Na temelju postignutog slaganja eksperimentalnih rezultata i rezultata prema predloženom složenom modelu te dobivenih normaliziranih srednjih kvadratnih odstupanja zaključeno je da se predloženi model može koristiti za uspješno opisivanje eksperimentalnog sustava pri radnim uvjetima korištenim u ovom radu.
Abstract (english) Pesticides are toxic chemicals whose role is to destroy or control the pests populations. However, their intensive use can cause bioaccumulation in the environment. Heterogeneous catalysis has become increasingly attractive technology for the treatment of wastewater and contaminated air, with the aim of removing various persistent organic compounds. The aim of this study is to develop an effective heterogeneous photocatalyst which can successfully degrade neonicotinoid insecticide imidacloprid (C9H10C1N5O2). The study was performed in a plate photoreactor with recirculation of the reaction mixture, with TiO2 as a photocatalyst, previously exposed to pre-treatment by UVC radiation. The diffusive reflection spectroscopy (UV / Vis-DRS) photocatalyst sample was verified to reduce the width of the forbidden zone, Eg, to a value of 2.6 eV, corresponding to a wavelength of 476 nm. This has allowed the research to be conducted in the visible part of the electromagnetic spectrum. The experiments include photolytic and photocatalytic digestion of imidacloprid on an immobilized photocatalyst layer using UVA, UVC radiation, and commercial Arcadia lamps, whose function is to simulate solar radiation. It was found that photolytic degradation occurs only with the use of UVC lamps (200-280 nm), while photocatalytic degradation occurs with UVA (320-400 nm) and Arcadia lamps. Photocatalytic degradation with UVA lamp operation resulted in a 96.97% conversion after 9.5 hours of reaction. Immobilization method was developed for loading thepreviously pretreated photocatalyst on the support and glass was shown as the best support. The commercial mineral binder Procol was added to prepare mechanically stable immobilized photocatalyst layer. Kinetic analysis was performed and an appropriate kinetic model was proposed. The results show that in the initial degradation period (t <150 min) the reaction follows a pseudo-zero order, while at higher reaction times there is a transition to the kinetic model of the pseudo-first reaction. Based on the agreement between experimental values and theoretical values predicted by the proposed complex kinetic model and the normalized mean square deviations, it can be concluded that proposed model can be efficientlly used for description of the experimental system under working conditions used in this paper.
Keywords
heterogena fotokataliza
fotoliza
imidakloprid
pločasti fotoreaktor
TiO2
Keywords (english)
heterogeneous photocatalysis
photolysis
imidacloprid
plate flat photoreactor
TiO2
Language croatian URN:NBN urn:nbn:hr:149:099435 Project Number: IP-2018-01-8669 Study programme Title: Chemical Engineering - Graduate 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 2022-02-22 10:07:51
