Abstract:
Various industries like textile, plastic, pulp, and paper produce dye-containing waste waters
that have harmful effect on the environment as well as human health. Developing a method to
abate the pollution problem by dyes is therefore crucial. To this effect, single, binary and
ternary nanocomposites were synthesized by different methods such as precipitation, solvothe
rmal and simple solution methods. The as-synthesized nanocomposites were characterized by
various techniques, including powder X-ray diffraction (XRD), Fourier Transforms Infrared
Spectroscopy (FTIR), Photoluminescence (PL),Scanning electron microscopy (SEM) and
UV–Vis diffuse reflectance to determine the structures, surface functional groups,
recombination rate, morphology and band gap energies respectively. Photocatalytic
degradation activities of the as synthesized nanocomposites under visible light irradiation
were evaluated in aqueous solution comprising model pollutant (Methyl orange dye) as well
as a real sewage sample solution collected from Bahirdar Textile Share Company. The
results showed that the degradation efficiency of ternary nanocomposite rGO/UiO66/Ag3PO4
(RUA3) exhibited a relatively higher efficiency on the photodegradation of Methyl
Orange (MO) compared to the binary and single counterparts. The percent degradation of
MO and real sample solution under visible light irradiation are found to be 88.09 and 63.64
respectively. The enhanced photocatalytic property of the ternary composite could be
attributed to high surface area, enhanced visible light absorption, efficient charge transfer
process, as well as the synergetic effect among rGO, UiO-66 and Ag3PO4. The effect of key
parameters such as solution pH, initial dye concentration and photocatalyst load were also
examined. The result showed that at optimum pH (4), catalyst load (0.2 g L
-1
) and initial
dye concentration 10 ppm, the nanocomposite possessed very good MO degradation and ads
orption effecincy. Mechanism of photocatalytic degradation of methyl orange (MO) was
investigated by using different scavengers. The addition of AgNO3 to the photocatalyst system
is much suppressed. Generally MOF-based ternary composites have great potentiality in environmental remediation fields.
