Evaluation of Silver-Modified ZnAl-Layered Double Hydroxide Coatings for Photocatalytic Self-Cleaning of Mortar Substrates

Rizescu, Claudiu Eduard; Zaulet, Ionut; Gheboianu, Anca Irina; Ion, Rodica Mariana

doi:10.2478/bsmm-2025-0012

Abstract

The preservation of stone and mortar elements in cultural heritage structures is increasingly challenged by environmental degradation, pollution, and biological fouling. Photocatalytic coatings represent a promising approach for developing self-cleaning and pollutant-degrading surfaces. In this study, a silver-modified ZnAl-layered double hydroxide (Ag@ZnAl-LDH) was synthesized via coprecipitation and applied as a coating on mortar substrates. The structural and compositional characteristics of the prepared materials were investigated using X-ray diffraction (XRD) and wavelength-dispersive X-ray fluorescence (WDXRF). The XRD pattern confirmed the formation of a ZnAl-LDH phase (JCPDS 48-1022) with carbonate as the main interlayer anion, along with additional reflections attributed to ZnO (JCPDS 99-0111) and silver-containing species. The photocatalytic activity was evaluated through the degradation of methylene blue under natural illumination (700 W/m²), monitored via CIELAB colorimetric parameters. The results demonstrated that Ag@ZnAl-LDH coatings promote the photodegradation of organic dyes, indicating potential for developing functional, self-cleaning coatings for the protection of heritage materials.

References

C. Esposito Corcione, C. Ingrosso, F. Petronella, R. Comparelli, M. Striccoli, A. Agostiano, M. Frigione, M.L. Curri, A designed UV–vis light curable coating nanocomposite based on colloidal TiO2 NRs in a hybrid resin for stone protection, Prog. Org. Coatings. 122 (2018) 290–301. https://doi.org/10.1016/j.porgcoat.2018.05.020.
Search in Google Scholar Back to article
L. Graziani, E. Quagliarini, A. Osimani, L. Aquilanti, F. Clementi, C. Yéprémian, V. Lariccia, S. Amoroso, M. D’Orazio, Evaluation of inhibitory effect of TiO2 nanocoatings against microalgal growth on clay brick façades under weak UV exposure conditions, Build. Environ. 64 (2013) 38–45. https://doi.org/10.1016/j.buildenv.2013.03.003.
Search in Google Scholar Back to article
J.M. Herrmann, C. Duchamp, M. Karkmaz, B.T. Hoai, H. Lachheb, E. Puzenat, C. Guillard, Environmental green chemistry as defined by photocatalysis, J. Hazard. Mater. 146 (2007) 624–629. https://doi.org/10.1016/j.jhazmat.2007.04.095.
Search in Google Scholar Back to article
M.A. Ali, I.M. Maafa, Recent literature review of Cerium-containing photocatalysts used for methylene blue degradation, J. Hazard. Mater. Adv. 16 (2024) 100486. https://doi.org/10.1016/j.hazadv.2024.100486.
Search in Google Scholar Back to article
J.C. Shen, H.Y. Zeng, C.R. Chen, S. Xu, A facile fabrication of Ag2O-Ag/ZnAl-oxides with enhanced visible-light photocatalytic performance for tetracycline degradation, Appl. Clay Sci. 185 (2020) 105413. https://doi.org/10.1016/j.clay.2019.105413.
Search in Google Scholar Back to article
M. Hadnadjev-Kostic, T. Vulic, R. Marinkovic-Neducin, D. Lončarević, J. Dostanić, S. Markov, D. Jovanović, Photo-induced properties of photocatalysts: A study on the modified structural, optical and textural properties of TiO2–ZnAl layered double hydroxide based materials, J. Clean. Prod. 164 (2017) 1–18. https://doi.org/10.1016/j.jclepro.2017.06.091.
Search in Google Scholar Back to article
S. Nayak, K. Kumar Das, K. Parida, Indulgent of the physiochemical features of MgCr-LDH nanosheets towards photodegradation process of methylene blue, J. Colloid Interface Sci. 634 (2023) 121–137. https://doi.org/10.1016/j.jcis.2022.12.050.
Search in Google Scholar Back to article
E.M. Seftel, M. Niarchos, C. Mitropoulos, M. Mertens, E.F. Vansant, P. Cool, Photocatalytic removal of phenol and methylene-blue in aqueous media using TiO2@LDH clay nanocomposites, Catal. Today. 252 (2015) 120–127. https://doi.org/10.1016/j.cattod.2014.10.030.
Search in Google Scholar Back to article
F. Cavani, F. Trifirò, A. Vaccari, Hydrotalcite-type anionic clays: Preparation, properties and applications., Catal. Today. 11 (1991) 173–301. https://doi.org/10.1016/0920-5861(91)80068-K.
Search in Google Scholar Back to article
H. Fan, J. Zhu, J. Sun, S. Zhang, S. Ai, Ag/AgBr/Co-Ni- NO3 layered double hydroxide nanocomposites with highly adsorptive and photocatalytic properties, Chem. - A Eur. J. 19 (2013) 2523–2530. https://doi.org/10.1002/chem.201203408.
Search in Google Scholar Back to article
R. He, S. Liu, R. Wang, T. Fu, R. Zhang, Q. Zhang, Y. Zhou, In situ modification of melamine sponge by MgAl- LDH with super-hydrophobicity and excellent harsh environment tolerance for high flux emulsion separation, Sep. Purif. Technol. 291 (2022) 120916. https://doi.org/10.1016/j.seppur.2022.120916.
Search in Google Scholar Back to article
A. Mills, M. McFarlane, Current and possible future methods of assessing the activities of photocatalyst films, Catal. Today. 129 (2007) 22–28. https://doi.org/10.1016/j.cattod.2007.06.046.
Search in Google Scholar Back to article
R.S. Sonawane, S.G. Hegde, M.K. Dongare, Preparation of titanium(IV) oxide thin film photocatalyst by sol–gel dip coating, Mater. Chem. Phys. 77 (2002) 744–750.
Search in Google Scholar Back to article
E.A. El-Sharkawy, A.Y. Soliman, K.M. Al-Amer, Comparative study for the removal of methylene blue via adsorption and photocatalytic degradation, J. Colloid Interface Sci. 310 (2007) 498–508. https://doi.org/10.1016/j.jcis.2007.02.013.
Search in Google Scholar Back to article
T.T.T. Le Hoang, N. Insin, N. Sukpirom, Catalytic activity of silver nanoparticles anchored on layered double hydroxides and hydroxyapatite, Inorg. Chem. Commun. 121 (2020) 108199. https://doi.org/10.1016/j.inoche.2020.108199.
Search in Google Scholar Back to article
G. Taglieri, J. Otero, V. Daniele, G. Gioia, L. Macera, V. Starinieri, A.E. Charola, The biocalcarenite stone of Agrigento (Italy): Preliminary investigations of compatible nanolime treatments, J. Cult. Herit. 30 (2018) 92–99. https://doi.org/10.1016/j.culher.2017.11.003.
Search in Google Scholar Back to article
Y. Yang, L. Yan, J. Li, J. Li, T. Yan, M. Sun, Z. Pei, Synergistic adsorption and photocatalytic reduction of Cr(VI) using Zn-Al-layered double hydroxide and TiO2 composites, Appl. Surf. Sci. 492 (2019) 487–496. https://doi.org/10.1016/j.apsusc.2019.06.229.
Search in Google Scholar Back to article
C.M. Chou, Y.C. Chang, P.S. Lin, F.K. Liu, Growth of Cu-doped ZnO nanowires or ZnO-CuO nanowires on the same brass foil with high performance photocatalytic activity and stability, Mater. Chem. Phys. 201 (2017) 18–25. https://doi.org/10.1016/j.matchemphys.2017.08.023.
Search in Google Scholar Back to article
M.I. Din, R. Khalid, J. Najeeb, Z. Hussain, Fundamentals and photocatalysis of methylene blue dye using various nanocatalytic assemblies- a critical review, J. Clean. Prod. 298 (2021) 126567. https://doi.org/10.1016/j.jclepro.2021.126567.
Search in Google Scholar Back to article
J. Zita, J. Krýsa, A. Mills, Correlation of oxidative and reductive dye bleaching on TiO2 photocatalyst films, J. Photochem. Photobiol. A Chem. 203 (2009) 119–124. https://doi.org/10.1016/j.jphotochem.2008.12.029.
Search in Google Scholar Back to article

Evaluation of Silver-Modified ZnAl-Layered Double Hydroxide Coatings for Photocatalytic Self-Cleaning of Mortar Substrates

Abstract

Paradigm

My account