Nova argamassa constituída por resíduos de rocha magmática e nanopartículas de óxido de zinco para ação antimicrobiana e fotocatalítica

Abstract

The application of nanotechnology in the construction sector has enabled the incorporation of new properties into traditional materials in an efficient and innovative manner. Among these features is photocatalysis, which imparts self-cleaning and antimicrobial properties to materials, making them fundamental for reducing pollutants present in liquid effluents and representing an interesting alternative to the emerging environmental crisis—water pollution. In this specific context, the research focuses on developing a photocatalytic mortar using powdered magmatic rock (gray andorinha granite) as a partial substitute for natural sand. This residue acts as a precursor to photocatalytic properties, containing titanium dioxide and iron oxide, which have the potential to facilitate photocatalysis. Test specimens were produced with partial substitutions of natural sand by crushed residue in proportions of 15%, 30%, and 30% combined with the addition of ZnO-NP nanoparticles (0.33%) to intensify photocatalytic activity. A control sample was prepared without the addition of residue or ZnO-NP. The photocatalytic efficiency of the developed mortars was tested by degrading methylene blue in mortar plates immersed in an aqueous solution and exposed to sunlight for four hours. The results showed that samples containing the residue exhibited superior photocatalytic performance compared to the control, demonstrating the efficacy of the residue in dye degradation. The sample RR-30/NP-1 showed one of the best photocatalytic performances, with efficiency surpassing that of the control (81.37%), degrading 88.68% of the methylene blue dye. Additionally, the use of powdered magmatic rock significantly increased the compressive strength of the mortar. After 56 days of curing, the RR-15, RR-30, and RR-30/NP-1 samples exceeded the reference samples, whose strengths were: 76.61 MPa for the control, 88.22 MPa for the RR-15 sample, 80.59 MPa for the RR-30 sample, and 102.15 MPa for the RR-30/NP-1 sample, highlighting their superiority over the control. Therefore, the developed material exhibits characteristics that promote sustainability by providing environmental advantages through its application in effluent treatment and the reuse of industrial residues, reducing the extraction of natural resources. In this way, this work aligns with three objectives outlined in the United Nations' 2030 Agenda: “Industry, Innovation, and Infrastructure,” “Responsible Consumption and Production,” and “Clean Water and Sanitation.”