| Autor: |
Ianăși C; Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University Timişoara, 2 Victoriei Square, 300006 Timisoara, Romania., Nemeş NS; Research Institute for Renewable Energies-ICER, Politehnica University Timisoara, 138 Gavril Musicescu Street, 300501 Timisoara, Romania., Pascu B; Research Institute for Renewable Energies-ICER, Politehnica University Timisoara, 138 Gavril Musicescu Street, 300501 Timisoara, Romania., Lazău R; Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University Timişoara, 2 Victoriei Square, 300006 Timisoara, Romania., Negrea A; Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University Timişoara, 2 Victoriei Square, 300006 Timisoara, Romania., Negrea P; Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University Timişoara, 2 Victoriei Square, 300006 Timisoara, Romania., Duteanu N; Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University Timişoara, 2 Victoriei Square, 300006 Timisoara, Romania., Ciopec M; Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University Timişoara, 2 Victoriei Square, 300006 Timisoara, Romania., Plocek J; Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, v.v.i, Husinec-Řež 1001, 25068 Řež, Czech Republic., Alexandru P; 'Coriolan Dragulescu' Institute of Chemistry, Romanian Academy, 24 Mihai Viteazu Bvd., 300223 Timisoara, Romania., Bădescu B; Doctoral School, 'Victor Babeș' University of Medicine and Pharmacy, 2 Eftimie Murgu Street, 300041 Timisoara, Romania., Duda-Seiman DM; Department of Cardiology, 'Victor Babeș' University of Medicine and Pharmacy, 2 Eftimie Murgu Street, 300041 Timisoara, Romania., Muntean D; Multidisciplinary Research Centre on Antimicrobial Resistance, Department of Microbiology, 'Victor Babeş' University of Medicine and Pharmacy, 2 Eftimie Murgu Street, 300041 Timișoara, Romania. |
| Abstrakt: |
Bismuth oxides were synthesized from bismuth carbonate using the sol-gel method. Studies have described the formation of Bi 2 O 3 , as a precursor of HNO 3 dissolution, and intermediate oxides, such as Bi x O y when using H 2 SO 4 and H 3 PO 4 . The average size of the crystallite calculated from Scherrer's formula ranged from 9 to 19 nm, according to X-ray diffraction. The FTIR analysis showed the presence of specific Bi 2 O 3 bands when using HNO 3 and of crystalline phases of "bismuth oxide sulphate" when using H 2 SO 4 and "bismuth phosphate" when using H 3 PO 4 . The TG curves showed major mass losses and specific thermal effects, delimited in four temperature zones for materials synthesized with HNO 3 (with loss of mass between 24% and 50%) and H 2 SO 4 (with loss of mass between 45% and 76%), and in three temperature zones for materials synthesized with H 3 PO 4 (with loss of mass between 13% and 43%). Further, the thermal stability indicates that materials have been improved by the addition of a polymer or polymer and carbon. Confocal laser scanning microscopy showed decreased roughness in the series, [Bi x O y ] N > [Bi x O y -6% PVA] N > [Bi x O y -C-6% PVA] N , and increased roughness for materials [Bi x O y ] S , [Bi x O y -6% PVA] S , [Bi x O y -C-6% PVA] S , [Bi x O y ] P , [Bi x O y -6% PVA] P and [Bi x O y -C-6% PVA] P . The morphological analysis (electronic scanning microscopy) of the synthesized materials showed a wide variety of forms: overlapping nanoplates ([Bi x O y ] N or [Bi x O y ] S ), clusters of angular forms ([Bi x O y -6% PVA] N ), pillars ([Bi x O y -6% PVA] S -Au), needle particles ([Bi x O y -Au], [Bi x O y -6% PVA] S -Au, [Bi x O y -C-6% PVA] S -Au), spherical particles ([Bi x O y -C-6% PVA] P -Pt), 2D plates ([Bi x O y ] P -Pt) and 3D nanometric plates ([Bi x Oy-C-6% PVA] S -Au). For materials obtained in the first synthesis stage, antimicrobial activity increased in the series [Bi x O y ] N > [Bi x O y ] S > [Bi x O y ] P . For materials synthesized in the second synthesis stage, when polymer (polyvinyl alcohol, PVA) was added, maximum antimicrobial activity, regardless of the microbial species tested, was present in the material [Bi x O y -6% PVA] S . For the materials synthesized in the third stage, to which graphite and 6% PVA were added, the best antimicrobial activity was in the material [Bi x O y -C-6% PVA] P . Materials synthesized and doped with metal ions (gold or platinum) showed significant antimicrobial activity for the tested microbial species. |
