Absorpcijske in fotokatalitske lastnosti tankih plasti cink-aluminijevih plastovitih dvojnih hidroksidov

Trobec, Klemen (author), Cerc Korošec, Romana (mentor)

Plastoviti dvojni hidroksidi (LDH, angl. layered double hydroxides) so raznoliki materiali z značilno plastovito strukturo. Zaradi delne zamenjave dvovalentnih kovinskih kationov s trivalentnimi so sestavljeni iz pozitivno nabitih plasti hidroksida, med plasti pa se za izenačitev naboja interkalirajo anioni. Tovrstna struktura tem materialom omogoča izmenjavo interkaliranih anionov, kar uporabljamo za določene aplikacije. Nekateri LDH so tudi polprevodniki, kar jim daje fotokatalitske lastnosti. S toplotno obdelavo iz LDH dobimo mešane kovinske okside. Namen mojega diplomskega dela je bila sinteza cink-aluminijevih LDH z interkaliranimi kloridnimi ioni, ter cink-aluminijevih LDH z interkaliranimi karbonatnimi ioni. Sintezo smo izvedli z metodo soobarjanja pri konstantnem pH. Iz pripravljenih LDH smo s peptizacijo pripravili sol, iz katerega smo s tehniko potapljanja pripravili tanke plasti, ki smo jih nato toplotno obdelali. Strukturo pripravljenih LDH v praškasti obliki in tankih plasti smo preverili z metodo rentgenske praškovne difrakcije. Določili smo sorpcijske in fotokatalitske lastnosti tankih plasti, ki smo jih termično obdelali pri 600 °C. V raztopino barvila Plasmocorinth B znane začetne koncentracije smo potopili pripravljene plasti in z UV-Vis spektrofotometrijo spremljali časovno odvisnost zniževanja koncentracije barvila. Potek absorpcije smo določali v temi, fotokatalitsko učinkovitost pa med izpostavitvijo opisanega sistema UV ali vidni svetlobi. Izkazalo se je, da so toplotno obdelane tanke plasti Zn-Al LDH z interkaliranimi karbonatnimi ioni učinkovit sorbent in deloma tudi fotokatalizator. Toplotno obdelane plasti Zn-Al LDH z interkaliranimi kloridnimi ioni so slab sorbent, a zelo učinkovit fotokatalizator.

• Language: Slovenian
• Keywords: plastoviti dvojni hidroksidi, tanke plasti, sorpcija, fotokataliza
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2022
• PID: 20.500.12556/RUL-143486
• COBISS.SI-ID: 138788099
• Publication date in RUL: 22.12.2022

TROBEC, Klemen, 2022, Absorpcijske in fotokatalitske lastnosti tankih plasti cink-aluminijevih plastovitih dvojnih hidroksidov [online]. Bachelor’s thesis. [Accessed 18 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=143486

Secondary language

• Language: English
• Title: Absorption and photocatalytic properties of zinc-aluminium layered double hydroxide thin films

Abstract

Layered double hydroxides (LDH) are diverse materials with a characteristic layered structure. As a result of the partial exchange of divalent cations with trivalent ones, they consist of positively charged hydroxide layers, while anions are intercalated between the layers to neutralize the charge. This structure gives these materials the ability to exchange intercalated anions, which can be used for certain applications. Some LDHs are also semiconductors, which leads to their photocatalytic properties. We can produce mixed metal oxides by calcination of LDHs. The aim of my diploma work was to synthesize zinc-aluminium LDH with intercalated chloride ions, and zinc-aluminium LDH with intercalated carbonate ions. The synthesis was carried out by the coprecipitation method at constant pH. Sols were prepared from the synthesized LDHs by peptization, from which thin films were prepared by dip-coating technique. The thin films were then thermally treated. The structure of the prepared LDHs was determined by X-ray diffraction. The sorption and photocatalytic properties of the thin films, thermally treated at 600°C, were determined. The prepared thin films were immersed in a solution of Plasmocorinth B dye of known concentration. Then the change of dye concentration with increasing time was monitored using UV-Vis spectrophotometry. Sorption process was performed in the dark, while the determination of photocatalytic properties was performed by irradiating the described system with UV or visible light. It was found that calcined thin films of Zn-Al LDH, intercalated with carbonate ions, are an effective sorbent and a partially effective photocatalyst. Thermally treated thin films of Zn-Al LDH with intercalated chloride ions are an ineffective sorbent, but a very effective photocatalyst.

• Keywords: layered double hydroxide, thin films, sorption, photocatalysis