Although some formulations (out of 28) presented very slow decomposition rate of methyl orange
, others were rapid, but they left behind porous TiO2 skeleton that are suitable for long-term and high-speed photocatalytic applications.
It is clearly concluded that the obtained ZnO nanocatalysts represent an excellent candidate with the commercial ZnO catalyst with high catalytic activity in the degradation of the methyl orange
dye (MO) as well as paraquat herbicide.
It is evident that methyl orange
is better adsorbed than Eriochrome Black T.
0.5 g CA0, CA1, CA2, CA3, CA4, CA5, CE (CA4 without amino protection), and activated carbon powder (ACP) were put into 50 mL 37.57 mg/L methyl orange
As to methyl orange
degradation, the photocatalytic activity of immobilized PU/Ti[O.sub.2] was showed as follows (Figure 9).
Aliquots (3 mL) of each flask were withdrawn at different time intervals (1, 2, 3 and 4 days) and the optical density was measured at 618 nm for malachite green, 462 nm for methyl orange
and 485 nm for Congo red.
0.5 g of the catalyst was weighed and added into the hydrogenation flask containing a solution of 150 mL methyl orange
was purchased from Jining Chemical Engineering Research Institute.
The highest photodegradation of methyl orange
under visible light was achieved by C-doped Ti[O.sub.2] (0.0% Ag) photocatalyst probably due to the high surface area for adsorption of the contaminant and also enhanced visible light absorption.
The mechanism on photodecolorization of azo dyes with methyl red and methyl orange
as a model of compound is illustrated in Figures 6 and 7, respectively.
The following chemicals were of analytical reagent grade and used without further purification: ferric nitrate (Sigma Aldrich Reagent Co., Ltd.), calcium hypochlorite (Shun Chemical Reagent Co., Ltd.), potassium hydroxide (Chongqing Chuandong Reagent Co., Ltd.), and methyl orange
(ChengDu Kelong Chemical Co., Ltd.).
ZnONPs were one pot fabricated by direct precipitation; their photocatalytic activity for environmental application was carefully investigated by using decoloring methyl orange
(MeOr) under sunlight.