Preparation of nano-tin oxide particle and its fluid-investigation on their physico-chemical properties

Abstract

A new synthesis route towards nano-SnO2 particle and Sn(OH)4 nanofluid was developed. They were synthesized by a redox reaction using nitrobenzene as an oxidizing agent. The nano-SnO2 was characterized with XRD, SEM, EDX, FT-IR, and UV-vis; the Sn(OH)4 nanofluid was characterized with FT-IR, UV-vis and DLS. The grain size of the rutile-type nano-SnO2 was calculated to be 4.5 nm using XRD. The lattice parameters of the nanoparticle were found to be 4.745 and 3.182 Å for a0 and c0, respectively. The morphology of the nano-SnO2 was investigated using SEM which supported the XRD results. The particle size dispersion pattern of Sn(OH)4 nanofluid was examined by DLS and average size distribution of the nanofluid was found to be around 150 nm. Many exciting physico-chemical properties of the fluid were determined in this research. The developed nanofluid was very stable and durable and did not show any apparent physical as well as chemical change after more than two years. In addition, the fluid did not agglomerate after addition of acids or bases. Further, transparent conducting oxide (TCO) was developed from the synthesized nanofluid. Morphology and surface of the TCO were investigated by SEM as well as metallography and optical microscopy (MOM). The thermal conductivity of the fluid was studied. The thermal conductivity of the nanofluid was investigated to be 0.667 W. m-1. K-1 and thermal conductivity was increased by 10.39% for 3% w/w density of the fluid with respect to pure water. The viscosity of the nanofluid was also investigated and was found to be 1.576 × 10-3 Kg.m-1.s-1 at 30 0C. Furthermore, a new synthesis procedure of Ag-doped SnO2 nanoparticles was developed using the nanofluid as a starting material. Following the procedure, two Ag doped SnO2 {I-2, Ag-SnO2 (Ag:Sn = 1:3) and I-3, Ag-SnO2 (Ag:Sn = 1:5)} nanomaterials were synthesized and they were characterized with XRD, SEM, EDX, FT-IR, and UV-vis. The grain sizes of Ag and SnO2 in Ag-SnO2 (Ag:Sn = 1:3) was recorded as 11.03 and 5.82 nm, respectively while the grain sizes of the same nanomaterials were 22.28 and 5.80 nm in Ag-SnO2 (Ag:Sn = 1:5). The lattice parameters were also calculated for Ag-SnO2 (Ag:Sn = 1:3) and these were 4.0676 Å for Ag, 4.745 and 3.182Å (a0 and c0) for SnO2. The same parameters for Ag-SnO2 (Ag:Sn = 1:5) were 4.080Å for Ag, 4.736 and 3.185 Å (a0, c0) for SnO2. The antimicrobial activity of the developed four nanomaterials; nano-SnO2, Sn(OH)4 nanofluid and Ag doped SnO2 particles were tested. Nano-SnO2, Sn(OH)4 nanofluid did not show any activity. On the other hand, Ag-doped SnO2 particles exhibited positive activities against the microbes. Antimicrobial activities of these two nanomaterials, therefore, were intensively investigated on four microbes: EP-10 (Bacterial pathogen), P-25 (Strawberry pathogen), CG-12, Fungus (Strawberry pathogens), and CG-33, Fungus (Strawberry pathogens). These Ag-doped SnO2 nanomaterials not only showed robust effect but also possessed selectivity properties against the microbes. From this research, the developed four nanomaterials opened a new window for further research in the field of materials science, nanotechnology and biotechnology.