Micron- and nanosized FAU-type zeolites from fly ash for antibacterial applications

Tosheva, Lubomira; Brockbank, Ava; Mihailova, Boriana; Sutula, Justyna; Ludwig, Joachim; Potgieter, J.H.

doi:10.1039/c2jm33180b

Cited by 34 publications

(30 citation statements)

References 36 publications

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“…The particles of FAZ zeolite do not appear to be well defined. SEM images of FSZ sample reveal formation of ultrafine (sub micron) particles with typical octahedral morphology associated with NaY zeolite [23]. The size distribution of zeolitic particles is seen to be ranging from 400 to 670 nm.…”

Section: Morphological Studiesmentioning

confidence: 92%

Ultrafine nanocrystalline mesoporous NaY zeolites from fly ash and their suitability for eco-friendly corrosion protection

et al. 2015

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Fly ash, an industrial waste from coal based thermal power stations and a vast resource for silica and alumina, remains underutilized. It consists of polycyclic aromatic hydrocarbons, metals, silica etc. which are toxic in nature and silica has also been classified as a carcinogenic material. So a definite need is to make a proper use of the fly ash in order to convert it into useful materials possessing enormous functionality. Preparation of uniform nanocrystalline mesoporous NaY zeolites from fly ash without use of organic structural directing agents is reported for the first time. Different ratios of fumed silica are added to fly ash for preparation of NaY zeolites. The effect of amount of water used during the crystallization process on particle size of the zeolite is reported. Detailed characterization of the prepared zeolites is carried out using XRD, FTIR, SEM EDAX and DLS. Si/Al ratio was calculated using NMR and EDAX data. Porosity, pore size distribution and pore volume were determined using nitrogen adsorption data. The particle size of zeolites was found to be in the range of 400-670 nm whereas the crystallite size calculated from the XRD data was in 9-13.4 nm range. The synthesized zeolites are found to possess high crystallinity (90-93 %). Formation of octahedral crystals is confirmed by SEM observations. BET analysis shows high surface areas and presence of mesopores. IR and NMR spectroscopy confirms the formation of NaY with increased silica content. The prepared zeolites exhibited good ion exchange capacities which were found to decrease with increase in Si/Al ratio. Unlike the common applications of zeolites in catalysis where high purity is desirable, the fly ash based zeolites were exchanged with zinc metal ion and applied as pigment in anticorrosive paint formulations. Corrosion resistance was evaluated using electrochemical impedance spectroscopy measurements. The results indicate that metal exchanged zeolite possesses good anticorrosive property and can be used as an alternate to the conventionally used toxic, lead and chromate based anticorrosive pigments.

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Section: Morphological Studiesmentioning

confidence: 92%

Ultrafine nanocrystalline mesoporous NaY zeolites from fly ash and their suitability for eco-friendly corrosion protection

et al. 2015

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“…80 Silver (Ag) has been highlighted among other inorganic metals due to introducing the most well-established antibacterial properties. To guarantee the long-term antibacterial activity of Ag NPs, they were incorporated to zeolite media, 79,[81][82][83][84][85][86][87][88][89][90] as zeolite particles could hold silver ions and protect their bacteriostatic properties which lie on their ion-exchangeable sites, and this depends on composition of the selected zeolite, eg, A zeolite, X zeolite, Y zeolite, etc. 30 Based on a research by Dong et al on the antibacterial properties of Ag-containing nanozeolites, E. coli cells were immediately destroyed upon exposure to water forms of ultra-small EMT-type zeolite containing Ag0 or Ag+ ion.…”

Section: Zeolite and Antibacterial Agentsmentioning

confidence: 99%

<p>Biomedical Applications of Zeolitic Nanoparticles, with an Emphasis on Medical Interventions</p>

Derakhshankhah¹,

Jafari²,

Sarvari³

et al. 2020

IJN

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The advent of porous materials, in particular zeolitic nanoparticles, has opened up unprecedented putative research avenues in nanomedicine. Zeolites with intracrystal mesopores are low framework density aluminosilicates possessing a regular porous structure along with intricate channels. Their unique physiochemical as well as physiological parameters necessitate a comprehensive overview on their classifications, fabrication platforms, cellular/ macromolecular interactions, and eventually their prospective biomedical applications through illustrating the challenges and opportunities in different integrative medical and pharmaceutical fields. More particularly, an update on recent advances in zeolite-accommodated drug delivery and the prevalent challenges regarding these molecular sieves is to be presented. In conclusion, strategies to accelerate the translation of these porous materials from bench to bedside along with common overlooked physiological and pharmacological factors of zeolite nanoparticles are discussed and debated. Furthermore, for zeolite nanoparticles, it is a matter of crucial importance, in terms of biosafety and nanotoxicology, to appreciate the zeolite-bio interface once the zeolite nanoparticles are exposed to the biomacromolecules in biological media. We specifically shed light on interactions of zeolite nanoparticles with fibrinogen and amyloid beta which had been comprehensively investigated in our recent reports. Given the significance of zeolite nanoparticles' interactions with serum or interstitial proteins conferring them new biological identity, the preliminary approaches for deeper understanding of administration, distribution, metabolism and excretion of zeolite nanoparticles are elucidated.

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“…The zeolite samples were compared directly in terms of their antimicrobial efficacy by semi-quantitative tests. Three different zeolite concentrations were selected for the tests based on our previous results [37]. The Ag zeolite samples at different concentrations were tested against E. coli and C. albicans.…”

Section: Antimicrobial Testsmentioning

confidence: 99%

Rapid screening of the antimicrobial efficacy of Ag zeolites

Tosheva

Belkhair

Gackowski

et al. 2017

Colloids and Surfaces B: Biointerfaces

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A semi-quantitative screening method was used to compare the killing efficacy of Ag zeolites against bacteria and yeast as a function of the zeolite type, crystal size and concentration. The method, which substantially reduced labor, consumables and waste and provided an excellent preliminary screen, was further validated by quantitative plate count experiments. Two pairs of zeolite X and zeolite beta with different sizes (ca. 200nm and 2μm for zeolite X and ca. 250 and 500nm for zeolite beta) were tested against Escherichia coli (E. coli) and Candida albicans (C. albicans) at concentrations in the range 0.05-0.5mgml. Reduction of the zeolite crystal size resulted in a decrease in the killing efficacy against both microorganisms. The semi-quantitative tests allowed convenient optimization of the zeolite concentrations to achieve targeted killing times. Zeolite beta samples showed higher activity compared to zeolite X despite their lower Ag content, which was attributed to the higher concentration of silver released from zeolite beta samples. Cytotoxicity measurements using peripheral blood mononuclear cells (PBMCs) indicated that Ag zeolite X was more toxic than Ag zeolite beta. However, the trends for the dependence of cytotoxicity on zeolite crystal size at different zeolite concentrations were different for the two zeolites and no general conclusions about zeolite cytotoxicity could be drawn from these experiments. This result indicates a complex relationship, requiring the necessity for individual cytotoxicity measurements for all antimicrobial applications based on the use of zeolites.

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Micron- and nanosized FAU-type zeolites from fly ash for antibacterial applications

Cited by 34 publications

References 36 publications

Ultrafine nanocrystalline mesoporous NaY zeolites from fly ash and their suitability for eco-friendly corrosion protection

Ultrafine nanocrystalline mesoporous NaY zeolites from fly ash and their suitability for eco-friendly corrosion protection

<p>Biomedical Applications of Zeolitic Nanoparticles, with an Emphasis on Medical Interventions</p>

Rapid screening of the antimicrobial efficacy of Ag zeolites

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