Resumen

RODRIGUEZ CRUZ, Paslinda; ZEA ALVAREZ, Julia; VERA GONZALES, Corina  y  TALAVERA NUNEZ, María Elena. “Evaluation of the coat of the Ignimbrite using Polisyloxan gel functioned with silver nanoparticles”. Rev. Soc. Quím. Perú [online]. 2021, vol.87, n.4, pp.353-369. ISSN 1810-634X.  http://dx.doi.org/10.37761/rsqp.v87i4.361.

The deterioration of buildings made with ignimbrite in the historic center of Arequipa is a problem caused by weathering, emission of industrial and biological pollutants, affecting its preservation. It was evaluated to apply to the ignimbrite, polysiloxane functionalized with silver nanoparticles (PXS-AgNPs), as a coating to reduce its porosity, prevent its degradation and give a protective effect to its surface.

Silver nanoparticles (AgNPs) were synthesized by reducing silver nitrate (AgNO3) with sodium borohydride (NaBH4), polysiloxane was synthesized by hydrolysis of chlorosilane in water and diethyl ether; which was functionalized with AgNPs, mixing aqueous solutions of PXS and AgNPs, obtaining a milky yellow gel. PXS-AgNPs were applied to the surface of the ignimbrite and adsorption tests were performed with 1ppm methylene blue solution, which was contrasted with ignimbrite without PXS-AgNPs. Finding in the ignimbrite with PXS-AgNPs a coverage percentage of 85.98% and in the ignimbrite without PXS-AgNPs a coverage percentage of 61.04%, with a difference of 36.65% adsorption, showing that with the PXS-AgNPs are enhanced protection of the ignimbrite.

Ignimbrite coated with PXS-AgNPs was characterized by SEM EDX observing a structure with crystallizations and a thin layer covering them of PXS-AgNPs; by EDX a signal is observed by the presence of silver; by FT/IR bands at 981 cm-1 and 1243 cm-1 of the siloxane; in the TGA analysis, an inflection at 362.65ºC of the melting point of the PXS, at 630.22ºC due to the decomposition of the PXS, which indicates that it has thermal resistance; in the ICP-mass analysis, 0.48 mg/K of Ag was found due to its presence in the PXS-AgNPs.

Regarding the antimicrobial activity of PXS-AgNPs, a decrease in total mesophiles was found from 3950 CFU/g in the ignimbrite without PXS-AgNPs to 125 CFU/g in the ignimbrite with PXS-AgNPs; fungi decreased from 4 CFU/g in the ignimbrite without PXS-AgNPs to 1 CFU/g in the ignimbrite with PXS-AgNPs, which demonstrates the effectiveness of PXS- AgNPs against microbial activity.

All the tests carried out demonstrate the effectiveness of PXS-AgNPs as a coating, both in the physicochemical aspect and in the microbial activity, improving the protection of the ignimbrite.

Palabras clave : Ignimbrite; composite; polysiloxane; silver nanoparticles.

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