CN106995225B

CN106995225B - Method for quickly removing aromatic N-alkyl dye

Info

Publication number: CN106995225B
Application number: CN201710239071.0A
Authority: CN
Inventors: 徐东波; 施伟东; 陈必义; 张正媛; 夏腾
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2017-04-13
Filing date: 2017-04-13
Publication date: 2020-01-24
Anticipated expiration: 2037-04-13
Also published as: CN106995225A

Abstract

The invention relates to the technical field of photocatalytic degradation, in particular to a method for quickly removing aromatic N-alkyl dye in dye sewage. The invention adds a certain amount of chloroauric acid (HAuCl) into dye sewage₄) The solution is used for rapidly removing the aromatic N-alkyl dye by using a photocatalyst under the irradiation of visible light.

Description

Method for quickly removing aromatic N-alkyl dye

Technical Field

Aromatic N-alkyl dyes including rhodamine B, methyl violet, methylene blue, malachite green and the like are widely applied to the industries of paper making, textile printing and dyeing, leather manufacturing, colored glass coloring, cell fluorescent coloring agent manufacturing, firework and firecracker manufacturing and the like. These industries produce large quantities of aromatic N-alkyl dye waste water that, if not properly disposed of, can be extremely harmful to human health and the ecological environment. The photocatalytic technology has been rapidly developed in recent years as a method for removing organic pollutants in water with low cost and high efficiency. Most of the photocatalysts have the advantages of no toxicity to the environment, good stability and excellent photocatalytic activity, and can be recycled, so that the photocatalyst has wide application in environmental protection, such as air purification, water disinfection and purification and the like. In the invention, a certain amount of chloroauric acid is added into an aromatic N-alkyl dye aqueous solution, and then the removal of the aromatic N-alkyl dye is studied under the irradiation of visible light by utilizing nano semiconductor photocatalysts such as bismuth tungstate, tungsten oxide, bismuth vanadate, bismuth oxychloride, potassium niobate, sodium tantalate and the like. Hitherto, no research has been found on removing aromatic N-alkyl dye contaminants by adding a chloroauric acid solution to an aromatic N-alkyl dye aqueous solution and then irradiating the solution with visible light using a semiconductor photocatalyst.

Disclosure of Invention

The invention aims to provide a method for quickly removing aromatic N-alkyl dye by adding a certain amount of chloroauric acid into an aromatic N-alkyl dye aqueous solution and then adding a certain amount of nano semiconductor photocatalyst under the irradiation of visible light.

The invention is realized by the following steps:

(1) adding the prepared aromatic N-alkyl dye aqueous solution with a certain concentration into a light reaction bottle, placing the light reaction bottle in a dark place, simultaneously opening circulating condensed water, and keeping at room temperature; and then dropwise adding the prepared chloroauric acid solution into a light reaction bottle, keeping the solution for a certain time under stirring, finally adding the nano semiconductor photocatalyst, continuing stirring the solution for a certain time, turning on a light source, and performing a photocatalytic experiment. And taking out 5 ml of solution every 1 minute, putting the solution into a 5 ml centrifuge tube, centrifuging, and taking the supernatant for absorbance measurement of an ultraviolet-visible spectrophotometer.

The stirring time is 30 min.

The aromatic N-alkyl dyes include rhodamine B, methyl violet, methylene blue and malachite green.

The concentration of the aromatic N-alkyl dye aqueous solution was 10 mg/L.

The concentration of the chloroauric acid solution is 8.93 millimoles per liter, and the volume ratio of the aromatic N-alkyl dye aqueous solution to the chloroauric acid solution is as follows: 100:0.4-1.3, and the optimal ratio is 100: 0.7.

The nano semiconductor photocatalyst comprises titanium dioxide, bismuth tungstate, tungsten oxide, bismuth vanadate, bismuth oxychloride, bismuth oxybromide, bismuth oxyiodide, potassium niobate, tin tantalate, barium tantalate, sodium niobate, sodium tantalate and the like.

The mass of the added catalyst is as follows: 100 mg of photocatalyst was added per 100 ml of the aqueous aromatic N-alkyl dye solution.

In the present invention, an aromatic N-alkyl dye is complexed with chloroauric acid to generate a complex having a positive charge, and the semiconductor photocatalyst has been reported to have a negative charge on the surface, such as titanium dioxide (Journal of alloys & Compounds,2016,679:470-484.), tin niobate (Nanoscale,2014,6:6335-45.), bismuth tungstate, etc., which are determined by us to have a negative charge on the surface (FIG. 2). The photocatalysts and the complex are mutually adsorbed in a solution under the electrostatic action, and no report is reported at present, and the aromatic N-alkyl dye is oxidized and decomposed under the further catalytic action of the semiconductor photocatalyst under the illumination, so that the aim of purifying a water body is fulfilled.

Drawings

FIG. 1 is X-ray diffraction and scanning electron microscope spectrogram of bismuth tungstate nanometer semiconductor photocatalyst.

FIG. 2 shows zeta potential measurements of bismuth tungstate.

FIG. 3 shows zeta potential tests of rhodamine B (RhB), Methyl Violet (MV), Methylene Blue (MB) and chloroauric acid complex.

FIG. 4 shows the ultraviolet-visible absorbance measurements of photocatalytic degradation experiments performed by adding bismuth tungstate into solutions of rhodamine B (RhB), Methyl Violet (MV) and Methylene Blue (MB), respectively.

FIG. 5 shows UV-visible absorbance measurements of photocatalytic degradation experiments performed in the absence of light when bismuth tungstate was added to a mixed solution containing 0.7ml of chloroauric acid and rhodamine B (RhB), Methyl Violet (MV), and Methylene Blue (MB).

FIG. 6 shows the UV-visible absorbance measurements of photocatalytic degradation experiments performed by adding bismuth tungstate into a mixed solution containing 0.7ml of chloroauric acid solution and rhodamine B (RhB), Methyl Violet (MV), and Methylene Blue (MB).

Detailed Description

Example 1 photocatalytic experiment was performed by adding bismuth tungstate to a mixed solution of chloroauric acid and rhodamine B

(1) Preparing 10 mg/L rhodamine B (RhB), Methyl Violet (MV) and Methylene Blue (MB) solutions, and placing the prepared solutions in a dark place.

(2) 0.7mL of the prepared 3.3 mg/L chloroauric acid solution was added to the photocatalytic reactor under stirring and held for 30 minutes. As shown in fig. 3, zeta potential testing of its complex showed it to be positively charged.

(3) Weighing 100 mg of self-made bismuth tungstate photocatalyst, wherein the bismuth tungstate can be successfully prepared as shown in an X-ray diffraction pattern in figure 1, and an electron scanning microscope shows that the bismuth tungstate has a layered flower-type structure. As shown in FIG. 2, the zeta potential test showed that it was negatively charged, and the photocatalyst was placed in the above-mentioned photocatalytic reactor, magnetically stirred for 30 minutes to uniformly disperse the photocatalyst, and the circulating water was opened to keep the temperature at room temperature.

(4) And turning on a light source to perform a photocatalytic experiment.

(5) And absorbing the photocatalytic degradation liquid in the reactor every 1 minute, and centrifuging the photocatalytic degradation liquid for measuring the ultraviolet-visible absorbance. After turning on the light source, the dye removal rate reached 100% as shown in fig. 6 and did not change any more after 1 minute.

(6) The ultraviolet-visible absorbance of the pure bismuth tungstate-degraded rhodamine B (RhB), Methyl Violet (MV) and Methylene Blue (MB) solution without adding chloroauric acid is measured as shown in a graph 4, and the dye removal rates are respectively 28.6%, 31.5% and 9.2% within 30 minutes.

(7) The ultraviolet-visible absorbance of the bismuth tungstate degraded rhodamine B (RhB), Methyl Violet (MV) and Methylene Blue (MB) solution under the condition of no illumination is measured as shown in a figure 5, and the adsorption equilibrium is reached within 10 minutes.

Example 2 adding bismuth tungstate into mixed solution of different chloroauric acid volumes and rhodamine B for photocatalytic experiment

The same procedure as in example 1 was repeated, except that the volumes of the chloroauric acid solutions added were changed to 0.4 ml, 1.0 ml and 1.3 ml, respectively.

Example 3 different photocatalysts were added to a mixed solution of chloroauric acid and rhodamine B for photocatalytic experiments

The specific embodiment is the same as example 1 except that bismuth tungstate is changed to one of the photocatalysts such as tungsten oxide, bismuth vanadate, bismuth oxychloride, potassium niobate, tin niobate, barium tantalate, sodium niobate, sodium tantalate, and the like.

EXAMPLE 4 different photocatalysts were added to a mixed solution of chloroauric acid and other N-alkyl dyes for photocatalytic experiments

The embodiment is the same as example 1 except that the N-alkyl dye is changed to malachite green, and the photocatalyst includes bismuth tungstate, tungsten oxide, bismuth vanadate, bismuth oxychloride, potassium niobate, tin niobate, barium tantalate, sodium niobate, sodium tantalate, or the like.

Claims

1. A method for rapidly removing an aromatic N-alkyl dye, comprising: adding chloroauric acid into an aromatic N-alkyl dye aqueous solution, and quickly removing the aromatic N-alkyl dye by using a nano semiconductor photocatalyst under the irradiation of visible light; the aromatic N-alkyl dye is rhodamine B, methyl violet or methylene blue; the concentration of the chloroauric acid solution is 3.3 mg/L, and the concentration of the aromatic N-alkyl dye aqueous solution is 10 mg/L; the volume ratio of the aromatic N-alkyl dye aqueous solution to the chloroauric acid solution is 100: 0.7; the nano semiconductor photocatalyst is bismuth tungstate; the aromatic N-alkyl dye and chloroauric acid are subjected to complexation to generate a complex with positive charges, and the complex and the nano semiconductor photocatalyst with negative charges on the surface are mutually adsorbed under the electrostatic action, and the aromatic N-alkyl dye is oxidized and decomposed under the catalysis of the semiconductor photocatalyst under the illumination, so that the aim of purifying a water body is fulfilled.

2. The method for rapidly removing the aromatic N-alkyl dye as claimed in claim 1, which comprises the following steps: adding the prepared aromatic N-alkyl dye aqueous solution with a certain concentration into a light reaction bottle, placing the light reaction bottle in a dark place, simultaneously opening circulating condensed water, and keeping at room temperature; and then dropwise adding the prepared chloroauric acid solution into a light reaction bottle, keeping the solution for a certain time under stirring, finally adding the nano semiconductor photocatalyst, continuing stirring the solution for a certain time, turning on a light source, and performing a photocatalytic experiment.

3. The method for rapidly removing an aromatic N-alkyl dye according to claim 2, wherein the stirring is kept for 30 min.

4. The method for rapidly removing the aromatic N-alkyl dye as claimed in claim 1 or 2, wherein the mass of the added nano semiconductor photocatalyst is as follows: 100 mg of photocatalyst was added per 100 ml of the aqueous aromatic N-alkyl dye solution.