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.
