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Ocena učinkovitosti hidrodinamske kavitacije za odstranjevanje bisfenolov iz odpadnih vod
Krištofelc, Nina (Avtor), Sollner Dolenc, Marija (Mentor) Več o mentorju... Povezava se odpre v novem oknu, Heath, Ester (Komentor)

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Izvleček
Z bisfenoli (BP) se srečujemo vsakodnevno z uporabo polikarbonatne plastike (posode za hrano, plastenke za pijačo, igrače, športni in medicinski pripomočki), epoksi smol (notranja prevleka vodovodnih cevi ter premazi notranjosti konzerv za hrano in pločevink za pijačo) in termičnega papirja (računi, vozovnice za javni prevoz, parkirni listki). Najpogosteje uporabljen BP je bisfenol A (BPA), vendar ga zaradi neželenih učinkov na zdravje ljudi in s tem povezanimi regulatornimi omejitvami v industriji zamenjujejo z drugimi BP. Široka uporaba BP se kaže v pogostejšem pojavljanju le teh v okolju. Do sedaj so v okolju detektirali BPA, BPAF, BPF, BPS, BPAP, BPB, BPP in BPZ. Glavni vir teh spojin v okolju predstavlja odpadna voda. BP so bili zaznani tako v dotoku v čistilne naprave kot iztoku iz njih, kar nakazuje, da trenutno uporabljani načini čiščenja odpadnih vod niso zadostni. Kavitacija je fizikalni pojav v tekočini, pri katerem pride do tvorbe, rasti in kolapsa zračnih mehurčkov. Pri hidrodinamski kavitaciji (HC) se mehurčki tvorijo v toku tekočine zaradi povečanja hitrosti tekočine zaradi geometrije pretočnega sistema oz. zmanjšanega pretoka, posledično pa se zniža tlak (npr. Venturijeva šoba, zaslonka z več luknjami, rotacijski generatorji). Ko se pretok ponovno poveča, se tlak normalizira, kar pripelje do kolapsa mehurčka. Pri razpadu mehurčkov se lokalno sprostijo velike količine energije. Oblikujejo se območja, podobna vročim točkam, na katerih temperatura naraste na 1000–10000 K in tlak na 100–5000 barov. Ekstremni pogoji vodijo v disociacijo vodnih molekul v radikale OH˙ in H˙, kar omogoča oksidativne reakcije in oksidativno razgradnjo snovi, ki so prisotne v tekočini. V magistrski nalogi smo preučevali odstranjevanje oziroma razgradnjo naslednjih BP s HC: BPA, BPB, BPC, BPC2, BPE, 22BPF, 24BPF, 44BPF, BPAF, BPS, BPAP in BPZ. Uporabili smo rotacijski generator HC. Učinkovitost HC v odpadni vodi iz laboratorijskih bioreaktorjev smo ovrednotili v različnih eksperimentalnih pogojih (čas, moč in temperatura kavitacije). Rezultati so pokazali, da HC ne odstrani izbranih BP iz odpadne vode v celoti, ampak zahteva kombinacijo z drugimi metodami čiščenja. Pomembno je poudariti, da učinkovitost HC za razgradnjo organskih onesnažil ni odvisna samo od eksperimentalnih pogojev kavitacije, ampak nanjo vplivajo tudi kompleksnost matrike, sestava reaktorja HC in fizikalno kemijske lastnosti preučevanih spojin. Optimalni eksperimentalni pogoji za razgradnjo preučevanih BP s HC glede na rezultate so 10 minut pri 9500 rpm in nenadzorovani temperaturi. V teh eksperimentalnih pogojih dosežemo naslednje deleže razgradnje BP: 54 %–63 % za BPB, BPC, BPZ in BPF, 38 %–49 % za 24BPF, BPE, BPAF, BPA BPC2 in BPAP, 15 %–24 % za 22BPF in BPS.

Jezik:Slovenski jezik
Ključne besede:bisfenoli, hidrodinamska kavitacija, odpadna voda, odstranjevanje
Vrsta gradiva:Magistrsko delo/naloga (mb22)
Organizacija:FFA - Fakulteta za farmacijo
Leto izida:2019
Število ogledov:336
Število prenosov:361
Metapodatki:XML RDF-CHPDL DC-XML DC-RDF
 
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Sekundarni jezik

Jezik:Angleški jezik
Naslov:Effectiveness assesment of hydrodynamic cavitation for bisphenols removal from wastewater
Izvleček:
We come across bisphenols (BP) daily by using polycarbonate plastics (food containers, drink bottles, toys, sports and medical equipment), epoxy resins (internal water pipe coating and protective coatings for the interiors and exteriors of food and beverage cans) and thermal paper (invoices, public transport tickets, parking tickets). The most commonly used BP is bisphenol A (BPA), but it is often replaced by other BPs due to its adverse effects on human health and the associated regulatory restrictions in the industry. The widespread use of BP is reflected in their greater occurrence in our environment. BPA, BPAF, BPF, BPS, BPAP, BPB, BPP and BPZ have been detected in the environment so far. The main source of these compounds in the environment is wastewater. BPs have been detected in both the infleunt as well as the effluent from treatment plants, which indicates that the currently wastewater treatment is not sufficient. Cavitation is a physical phenomenon in liquids, where the formation, growth and collapse of bubbles occurs. Hydrodynamic cavitation causes the bubbles to form in the fluid stream due to an increase in fluid velocity, which occurs due to the geometry of the flow system or rather the reduced flow. Consequently, the pressure is reduced (e.g. Venturi restriction, multiple hole orifice plates, rotation generators). Once the flow is increased again, the pressure normalizes which leads to the collapse of the bubble. When the bubbles break down, it leads to a localized release of large amounts of energy. Areas similar to hot spots start to form, with temperatures rising up to 1000–10000 K and the pressure up to 100–5000 bars. Extreme conditions lead to the dissociation of aqueous molecules into OH˙ in H˙ radicals. Strong oxidation conditions are created which enable the oxidative decomposition of substances present in the liquid. In the master’s thesis, we studied the removal or degradation of the following bisphenols with hydrodynamic cavitation: BPA, BPB, BPC, BPC2, BPE, 22BPF, 24BPF, 44BPF, BPAF, BPS, BPAP in BPZ. A rotation generator of hydrodynamic cavitation was used for the research. The efficiency of hydrodynamic cavitation in the waste water from laboratory bioreactors was evaluated under various experimental conditions (time, power and temperature of cavitation). The results showed that HC does not remove the selected BP from the waste water in its entirety, but rather requires assistance from other methods of purification. It is important to note that the efficiency of HC for degradation of organic pollutants depends not only on the experimental conditions of cavitation, but also on the complexity of the matrix, the composition of the HC reactor, and the physicochemical properties of the compounds studied. Optimal experimental conditions for the degradation of the studied BP with HC in terms of results are 10 minutes at 9500 rpm and uncontrolled temperature. Under these experimental conditions, the following degradation rates are achieved: 54 %–63 % for BPB, BPC, BPZ and BPF, 38 %–49 % for 24BPF, BPE, BPAF, BPA BPC2 and BPAP, 15 %–24 % for 22BPF and BPS.

Ključne besede:bisphenols, hydrodynamic cavitation, wastewater, degradation

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