CN1214995C - Decolouring method of printing and dyeing waste water - Google Patents

Abstract

The invention provides a decolorization method of printing and dyeing wastewater, comprising the following steps: adjusting the pH value of the wastewater to be acidic; adding natural manganese potassium ore, and stirring for several hours. In the method, the greater the acidity of the reaction solution, the faster the reaction proceeds; the more the amount of natural manganese-potassium ore and the smaller the particle size, the more conducive to the decolorization reaction; adding electrolyte calcium nitrate to the waste water is helpful for the decolorization reaction; Illumination is also conducive to the decolorization reaction. The decolorizing agent used in the decolorizing method of the present invention has easy-to-obtain natural manganese-potassium ore raw materials, low cost, no secondary pollution, wide application range and obvious decolorizing effect. In addition, natural manganese and potassium ore can be reused after treating printing and dyeing wastewater.

Description

A kind of decolorization method of printing and dyeing wastewater

Technical field:

The invention belongs to the technical field of wastewater treatment, in particular to a decolorization method for printing and dyeing wastewater.

Background technique:

Today, the annual output of synthetic dyes in the world is about 1 million tons, of which my country accounts for about 20%. Most of the raw materials input into dye production are aromatic compounds and heterocyclic compounds, so that most of the wastewater discharged during the production process is organic matter with aromatic groups such as benzene, naphthalene, anthracene, and quinone as the parent, with chromogenic groups, The color is very dark, with a chroma of 500-500,000, and has a strong sense of pollution. If it is discharged directly, it will cause serious pollution to water sources. Therefore, it is of great significance to study the treatment of dye wastewater to protect the ecological environment and human health. At present, the commonly used dye wastewater treatment methods in industry include flocculation precipitation method, electrolysis method, oxidation method, adsorption method and biodegradation method. However, these methods generally have the disadvantages of high cost, short timeliness and secondary pollution.

At present, most of the researches on the degradation of printing and dyeing wastewater by manganese oxides at home and abroad are artificially synthesized products, and there is no report on the oxidative degradation of printing and dyeing wastewater by using natural manganese potassium ore.

Invention content:

The purpose of the present invention is to provide a method for decolorizing printing and dyeing wastewater with low cost, wide application range and no secondary pollution.

Technical scheme of the present invention is as follows:

A method for decolorizing printing and dyeing wastewater, comprising the following steps:

(1) Adjust the pH value of the wastewater to be acidic (if the printing and dyeing wastewater itself is already acidic, this step can be omitted);

(2) Add natural manganese potassium ore, stir and react for several hours.

In the method, the greater the acidity of the reaction solution, the faster the reaction will proceed, and the effect will be the best when the pH value of the wastewater is adjusted to be below 4.

The more the natural manganese ore is used and the smaller the particle size is, the more favorable the decolorization reaction is, and the recommended particle size is 160-200 mesh.

In the method, the electrolyte calcium nitrate is added to the waste water to facilitate the decolorization reaction. Illumination is also conducive to the decolorization reaction.

The main mechanism of the decolorization method of the present invention is: natural manganese ore will show good oxidation-reduction property because of containing the Mn ⁴⁺ and Mn ²⁺ of changing valence, when manganese ore reacts with some easily oxidized or reduced molecules or ions During the chemical reaction, there are two properties. One is that Mn ⁴⁺ easily obtains electrons and is reduced to low-priced Mn ³⁺ or Mn ²⁺ , while the ions or molecules interacting with it lose electrons and are oxidized. Second, low-valence Mn ²⁺ can react with certain high-valence cations and reduce them to low-valence ions. A redox reaction occurs between the natural manganite and the dye, which decolorizes it.

The decolorization method of the invention is widely used and has good decolorization effects on different dye wastewaters. Utilize the method of the present invention, adopt the natural manganese potassium ore sample that adopts from Xiangtan manganese ore, to the X-3B, K-2BP, X-BR, X-R, K-BR, K-GN, X- that Tianjin Xinxin dyestuff factory produces 8B, K-G, X-GN, M-3RE and other ten kinds of dyes commonly used in industry have been used in the decolorization test, and all of them have good results.

1. Experimental research on X-3B dye was carried out.

The natural manganese and potassium ore samples used were collected from Xiangtan manganese ore, washed with tap water, dried naturally, crushed, sieved and other pretreatments before use. Printing and dyeing wastewater was prepared from 500ppm dye stock solution and deionized water. The dye X-3B used was a common industrial dye produced by Tianjin Xinxin Dye Factory. The pH was adjusted by _HNO3 and NaOH. The reagents used in the experiments were of analytical grade, and the water used was deionized water. The instruments used in the experiment mainly include HP-8453 UV-Vis spectrophotometer, 80-2B centrifuge, PHS-2C digital acidity meter, HZS-H water bath constant temperature oscillator, etc.

Experimental process: Add a certain amount and a certain particle size of mineral samples into a 100ml Erlenmeyer flask, then add 50ml, 20mg/L printing and dyeing wastewater, and the pH of the solution is adjusted by HNO ₃ and NaOH. Then put it into a constant temperature oscillator in a water bath, shake for a certain period of time at 25°C (the error does not exceed +1°C), and 200r/min. After taking it out, filter it with a 0.2 micron microporous membrane immediately, and measure the dye with a UV spectrophotometer. concentration. Calculate the decolorization rate of the dye.

Within a certain concentration range, the concentration of X-3B and its absorbance conform to the Lambert-Beer law:

A＝εbc

ε is the molar absorptivity, and its unit is L.mol ^-1 .cm ^-1 , b is the thickness of the liquid layer (in cm), and c is the molar concentration expressed in mol.L ^-1 . This experiment uses this principle to measure the absorbance of the solution at 559 nanometers with a HP-8453 UV-Vis spectrophotometer within a certain concentration range to obtain the concentration of different X-3B solutions. Calculate the dye decolorization rate according to the following formula, and the decolorization rate of the dye at time t is expressed as:

      st = ((c0-ct)/c0) × 100%

Among them, st represents the decolorization rate of X-3B at a certain moment; c0 and ct represent the concentration of the dye at the initial moment and the middle t moment, respectively.

Experimental results:

When the dosage of 160-200 mesh manganese potassium ore is 0.2g, the reaction pH value is 3, the reaction temperature is 25°C, the oscillation speed is 200r/min, and the reaction is half an hour, the X-3B printing and dyeing wastewater with an initial concentration of 20mg/l The decolorization rate is almost 100%. At the same time, we found that the pH value of the medium, sample amount and particle size, coexisting electrolyte, reaction time, and light had an impact on the dye decolorization reaction. The pH value of the medium is the most important influencing factor, and the relationship between it and the X-3B decolorization rate is shown in Figure 1, as can be seen from Figure 1, the greater the acidity of the reaction solution, the faster the reaction; when pH>3, the pH The small change of the value has a great influence on the decolorization rate of X-3B, and the decolorization rate increases with the decrease of pH; when PH=3, the decolorization rate can reach 99.48% after 20 minutes of reaction; when pH<3, the change of pH value Little effect on decolorization rate. The more samples used and the smaller the particle size, the more favorable the decolorization reaction; the coexistence of electrolyte calcium nitrate is conducive to the decolorization reaction, while the presence of sodium phosphate is not conducive to the decolorization reaction. Illumination is also conducive to the decolorization reaction. Manganese ore can also be reused, and Table 1 shows the decolorization results of manganese ore when it is reused.

Table I: usage count 1 2 3 Concentration of X-3B after reaction (mg/l) 0.21 0.36 0.45 Decolorization rate (%) 98.94 98.19 97.75

2. The decolorization effect of manganese potassium ore on the remaining nine dyes

pH=2.5, 160-200 mesh manganese potassium ore dosage 0.5g, waste water dosage 50ml, dye concentration 20ppm, shaking reaction for 5 hours, the results are shown in Table 2:

Table II: dye K-2BP X-BR XR K-BR K-GN X-8B KG X-GN M-3RE Decolorization rate (%) 93.15 98.94 84.14 89.11 100.00 99.46 100.0 97.54 99.02

Advantages and positive effects of the present invention: the decolorizing agent used in the decolorizing method of the present invention is easy to obtain natural manganese-potassium ore raw materials, has low cost, no secondary pollution, wide application range, and obvious decolorizing effect. In the south of my country, there are very rich manganese oxide ore resources distributed along the north latitude 23° belt, which is 1500km long from east to west, 220km wide from north to south, and has an oxidation depth of 50-60m. In addition, natural manganese and potassium ore can be reused after treating printing and dyeing wastewater.

Description of drawings:

Figure 1 The relationship between the pH value of wastewater and the decolorization rate of X-3B.

Detailed ways:

50ml of printing and dyeing wastewater of X-3B (a common industrial dye produced by Tianjin Xinxin Dye Factory) with an initial concentration of 20mg/l was placed in a 100ml Erlenmeyer flask, and its pH value was adjusted to 3 with HNO3 _and NaOH. The natural manganese and potassium ore is collected from Xiangtan manganese ore, washed with tap water, naturally dried, crushed and sieved to obtain 160-200 mesh manganese and potassium ore, and the dosage is 0.2g. Put the Erlenmeyer flask into a constant temperature shaker in a water bath, shake at 200r/min for half an hour at 25°C, and the decolorization rate of X-3B is almost 100%.

Claims (9)

1. decolorization of dyeing method may further comprise the steps in order:

(1) regulates the pH value of waste water to being acid;

(2) add natural cryptomelane, the stirring reaction several hrs gets final product.

2. decoloring method as claimed in claim 1, the pH value that it is characterized in that described waste water is below 4.

3. decoloring method as claimed in claim 1 or 2, the particle diameter that it is characterized in that described natural cryptomelane is the 160-200 order.

4. decoloring method as claimed in claim 1 or 2 is characterized in that also adding ionogen nitrocalcite in waste water.

5. decoloring method as claimed in claim 3 is characterized in that also adding ionogen nitrocalcite in waste water.

6. decoloring method as claimed in claim 1 or 2 is characterized in that decolouring and carries out under illumination condition.

7. decoloring method as claimed in claim 3 is characterized in that decolouring and carries out under illumination condition.

8. decoloring method as claimed in claim 4 is characterized in that decolouring and carries out under illumination condition.

9. decoloring method as claimed in claim 5 is characterized in that decolouring and carries out under illumination condition.