Method for dye degradation in aqueous solution
A method of degrading a dye in an aqueous solution including contacting nanoparticles with the dye in the aqueous solution and irradiating the aqueous solution. The nanoparticles have a formula of Zn 1−2x Ce x Yb x O, x=0.01-0.1, and where at least 90 wt. % of the dye is degraded during the irradiating of the aqueous solution.
1 . A method for photodegrading a dye in purifying a dye-contaminated aqueous solution, comprising:
mixing nanoparticles with the dye-contaminated aqueous solution to form a mixture comprising the nanoparticles and the dye-contaminated aqueous solution;
contacting the nanoparticles with the dye in the dye-contaminated aqueous solution; and
irradiating the mixture comprising the nanoparticles and the dye-contaminated aqueous solution,
wherein the nanoparticles have a formula of Zn 1-2x Ce x Yb x O, x=0.01-0.03,
wherein at least 90 wt. % of the dye is degraded during the irradiating, and
wherein the nanoparticles have an average crystallite size of 50-55 nm.
2 . The method of claim 1 , wherein the nanoparticles have a unit cell volume of 47.62-47.75 Å 3 .
3 . The method of claim 1 , wherein the ZnO of the nanoparticles have a hexagonal crystal system, and wherein at least a portion of the Zn is replaced with Ce and Yb.
4 . The method of claim 1 , wherein the nanoparticles have a nanorod shape.
5 . The method of claim 4 , wherein the nanorod shape has a length of 150-250 nm.
6 . The method of claim 4 , wherein the nanorod shape has a width of 50-70 nm.
7 . The method of claim 1 , wherein the nanoparticles have a zeta potential of 10-20 mV.
8 . The method of claim 1 , wherein the nanoparticles have a bandgap of 3.21 to 3.25 eV.
9 . The method of claim 1 , wherein the nanoparticles further comprise 0.1-1 wt. % Yb 0.3 Ce 0.4 O 1.85 , based on the total weight of the nanoparticles.
10 . The method of claim 1 , wherein the dye is selected from the group consisting of methylene orange, methylene blue, methyl red, phenolphthalein, bromothymol blue, and congo red.
11 . The method of claim 1 , wherein the irradiating comprises light with a wavelength of 300-700 nm.
12 . A method of claim 1 , wherein the degrading of the dye has a rate constant of at least 0.02 min −1 .
13 . The method of claim 1 , wherein 0.1 to 10 mg/mL of the nanoparticles are present in the mixture comprising the nanoparticles and the dye-contaminated aqueous solution.
14 . The method of claim 1 , wherein the dye-contaminated aqueous solution has a temperature of 50 to 70° C. during the irradiating.
15 . The method of claim 1 , wherein the mixture comprising the nanoparticles and the dye-contaminated aqueous solution further comprises at least one ionic species selected from the group consisting of ions of alkali metals, alkaline earth metals, halides, carbonates, phosphates, and sulfates.
16 . The method of claim 1 , wherein the nanoparticles are made by a method comprising:
mixing separately three solutions of a zinc salt, an ytterbium salt, and a cerium salt each in water;
mixing together the three solutions at a temperature of 70-90° C. for 30-120 mins to form a reaction mixture;
adjusting the pH of the reaction mixture to 7 with a base to form a second reaction mixture;
evaporating the water from the second reaction mixture to form a gel;
combusting the gel to form a powder; and
calcining the powder at a temperature of 400 to 600° C.
17 . The method of claim 1 , wherein the irradiating is for less than 120 minutes.