Efficient and environment-friendly printing and dyeing sewage decolorizing agent and preparation method thereof

Abstract

The invention provides an efficient and environment-friendly printing and dyeing sewage decolorizing agent which is mainly prepared from the following raw materials in parts by mass: 10-17 parts of nanoscale silicon dioxide, 5-12 parts of concentrated sulfuric acid, 8-13 parts of a polyacrylamide emulsion, 5-17 parts of lignosulfonate, 3-10 parts of a metal ion chelating agent and 10-25 parts of deionized water. The decolorizing agent provided by the invention has good adsorption performance and chemical stability, and is low in cost and high in decolorizing efficiency on printing and dyeing sewage.

Description

Technical Field

[0001] The invention relates to the field of sewage treatment technology, and in particular to a highly efficient and environmentally friendly printing and dyeing sewage decolorizing agent and a preparation method thereof. Background Art

[0002] With the speed of modernization, the textile industry has also developed rapidly in recent years. However, rapid development has also brought environmental problems. During the printing and dyeing process, sewage is discharged. This sewage has become one of the sources of environmental pollution due to its high chroma, high chemical oxygen demand (COD) and complex chemical composition.

[0003] Traditional printing and dyeing wastewater decolorization technologies mainly include adsorption, oxidation, and coagulation and sedimentation. The adsorption method uses adsorbents to adsorb pigment molecules in wastewater, but the adsorbents are expensive and difficult to regenerate, which limits their wide application. The oxidation method uses oxidants to oxidize and decompose the pigment molecules in wastewater, but this treatment method is extremely inefficient and may also produce toxic by-products, causing secondary pollution to the environment. The coagulation and sedimentation method uses coagulants to condense suspended matter and colloidal substances in wastewater into flocs and precipitate them, but this method has limited effect on the removal of color from wastewater, and the use of coagulants may also cause a certain burden on the environment.

[0004] In view of the many problems existing in traditional decolorization technology, a new type of decolorization agent is currently needed on the market to solve the problems of the above decolorization technology.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first purpose of the present invention is to provide an efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater, which has low cost, significant decolorizing effect and excellent environmental performance, and effectively reduces the pressure caused by printing and dyeing wastewater on the environment.

[0007] The second purpose of the present invention is to provide a method for preparing an efficient and environmentally friendly printing and dyeing wastewater decolorizer. The preparation method is simple to operate, and the entire operation process is efficient and environmentally friendly, achieving a green economy.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are specially adopted: The invention provides a highly efficient and environmentally friendly printing and dyeing wastewater decolorizer, which is mainly prepared from the following raw materials, measured by weight: 10-17 parts of nano-scale silicon dioxide, 5-12 parts of concentrated sulfuric acid, 8-13 parts of polyacrylamide emulsion, 5-17 parts of lignin sulfonate, 3-10 parts of metal ion chelating agent and 10-25 parts of deionized water.

[0009] Preferably, as a further specific embodiment, 11-16 parts of nano-silicon dioxide, 6-11 parts of concentrated sulfuric acid, 9-11 parts of polyacrylamide emulsion, 8-16 parts of lignin sulfonate, 5-9 parts of metal ion chelating agent, and 14-22 parts of deionized water are used.

[0010] Preferably, as a further specific embodiment, 15 parts of nano-scale silicon dioxide, 10 parts of concentrated sulfuric acid, 10 parts of polyacrylamide emulsion, 15 parts of lignin sulfonate, 8 parts of metal ion chelating agent, and 20 parts of deionized water.

[0011] Preferably, the lignin sulfonate is at least one of sodium lignin sulfonate and calcium lignin sulfonate.

[0012] Preferably, the metal ion chelating agent is at least one of ethylenediaminetetraacetic acid, gluconic acid and angiotensin triacetic acid.

[0013] Among the above materials, nano-scale silicon dioxide plays a vital role as a matrix material in the highly efficient and environmentally friendly printing and dyeing sewage decolorant. Its high specific surface area and excellent adsorption performance enable it to effectively adsorb the pigment molecules in the sewage, thereby achieving an excellent decolorization effect. At the same time, nano-scale silicon dioxide has good chemical stability and is not easily decomposed or denatured by the influence of conditions such as pH and temperature in the sewage environment, which ensures the stability and durability of the printing and dyeing sewage decolorant of the present invention during long-term use. In addition, the particle size of nano-scale silicon dioxide is small, and it is easy to be evenly dispersed in the sewage, which improves the contact between the printing and dyeing sewage decolorant and the pigment molecules, and further improves the decolorization efficiency of the present invention.

[0014] Concentrated sulfuric acid plays multiple roles in the decolorizing agent for printing and dyeing wastewater of the present invention. As a strong acid, concentrated sulfuric acid can adjust the pH value of the decolorizing agent, so that the present invention is more suitable for the treatment of printing and dyeing wastewater. By adjusting the pH value of the decolorizing agent for printing and dyeing wastewater, it is beneficial for adsorption and precipitation of pigment molecules by adsorption materials such as nano-scale silicon dioxide. Concentrated sulfuric acid can also promote the dissolution and dispersion of organic matter of lignin sulfonate, so that they can better play the role of dispersion and surface activity, thereby improving the overall performance of the decolorizing agent for printing and dyeing wastewater.

[0015] As a flocculant, polyacrylamide emulsion plays a bridging role in the decolorizing agent for printing and dyeing wastewater. The molecular chain of polyacrylamide emulsion contains polar groups, which can chemically react / physically adsorb with pigment molecules and suspended matter in printing and dyeing wastewater, connecting them to form larger particles or flocs. The addition of polyacrylamide emulsion significantly improves the flocculation effect and sedimentation rate of the decolorizing agent for printing and dyeing wastewater of the present invention, thereby achieving purification treatment of printing and dyeing wastewater.

[0016] As a surfactant and dispersant, lignin sulfonate can effectively reduce the surface tension of sewage, increase the dispersion of pigment molecules in the water, and facilitate the adsorption and removal of pigment molecules by nano-silicon dioxide. Moreover, lignin sulfonate is a natural active ingredient extracted from specific plants, and has affinity and degradation ability for a variety of dyes, thereby further enhancing the decolorization effect of the printing and dyeing wastewater decolorizer.

[0017] Metal ion chelating agents play an important role in removing heavy metal ions in the printing and dyeing wastewater decolorizing agent of the present invention. Printing and dyeing wastewater usually contains heavy metal ions such as copper and zinc, which will affect the performance of the printing and dyeing wastewater decolorizing agent and may also cause secondary pollution to the environment. Metal ion chelation can efficiently combine with these ions to form stable chelates, thereby effectively discharging ions from the printing and dyeing wastewater. The present invention can significantly improve the environmental friendliness of the present invention when treating printing and dyeing wastewater by adding metal ion chelating agents to the printing and dyeing wastewater decolorizing agent; at the same time, the metal ion chelating agent can also actively promote the precipitation process of pigment molecules in the printing and dyeing wastewater, further enhancing the overall decolorization effect of the printing and dyeing wastewater decolorizing agent of the present invention.

[0018] In addition to providing an efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater, the present invention also provides a method for preparing the efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater, comprising the following steps: Add concentrated sulfuric acid and stir, and add nano-silicon dioxide and deionized water while continuing to stir; Then add polyacrylamide emulsion and lignin sulfonate and continue stirring; Finally, metal ion chelating agent and deionized water are added for aging and then stirred continuously.

[0019] Preferably, in the step of simultaneously adding nano-sized silicon dioxide and deionized water during the continuous stirring process, the adding time is controlled to be 1-30 minutes.

[0020] Preferably, in the step of adding nano-silicon dioxide and deionized water simultaneously during the continuous stirring process, the temperature is controlled at 80-85° C. and the reaction time is controlled at 3-5 h.

[0021] Preferably, in the step of adding the polyacrylamide emulsion and the lignin sulfonate and continuously stirring, the temperature is controlled at 75-80° C. and the continuous stirring time is 0.5-1.5 h.

[0022] Preferably, in the step of adding the metal ion chelating agent and deionized water for aging and then continuously stirring, the temperature is controlled at 75-80°C, the aging time is 2-4h, and the stirring is continuously performed to 20-25°C.

[0023] In the present invention, through the above-mentioned carefully designed preparation steps and control of preparation parameters, the prepared high-efficiency and environmentally friendly printing and dyeing wastewater decolorizer exhibits excellent performance. The preparation method of the present invention is simple and easy, has more raw material sources, relatively low cost, and can be widely produced and applied.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) The printing and dyeing wastewater decolorizer of the present invention can efficiently adsorb and decompose colored substances in printing and dyeing wastewater through the synergistic effect of nano-silicon dioxide, polyacrylamide emulsion and lignin sulfonate by carefully designing the ratio of raw materials, thereby achieving a significant decolorization effect. This efficient decolorization performance helps to reduce the pollution caused by printing and dyeing to the environment.

[0025] (2) The raw materials used in the present invention, such as nano-silicon dioxide, lignin sulfonate and metal ion chelating agent, are all environmentally friendly materials. No harmful chemicals are used in the preparation process. Therefore, the entire product of the present invention has excellent environmental performance. In addition, the printing and dyeing wastewater decolorizing agent of the present invention can also effectively reduce the discharge of heavy metal ions and other harmful substances in the printing and dyeing wastewater, further reducing the pressure on the environment.

[0026] (3) The raw materials of the printing and dyeing wastewater decolorizer of the present invention are from a variety of sources and are relatively cheap. The preparation process is simple and does not require complicated equipment and operations. The entire operation process is efficient and environmentally friendly. DETAILED DESCRIPTION

[0027] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0028] Example 1 Take 6g of concentrated hydrochloric acid and add it to the reactor and start stirring. During the stirring process, add 17g of nano-silicon dioxide and 11g of deionized water into the reactor. The addition is completed within 27min. The temperature is controlled at 81°C and the reaction time is 3.5h. Then, 13 g of polyacrylamide emulsion and 16 g of sodium lignin sulfonate were added into the reactor and stirred continuously. The temperature was controlled at 76°C and the stirring time was continued for 0.7 h. Finally, 9 g of aminotriacetic acid and the remaining 11 g of deionized water were added to the reactor, and the temperature was controlled at 76°C. After aging for 2.5 h, the temperature was naturally lowered to 20°C with continuous stirring.

[0029] Example 2 Take 11g of concentrated hydrochloric acid and add it to the reactor and start stirring. During the stirring process, add 17g of nano-silicon dioxide and 7g of deionized water into the reactor. The addition is completed within 22 minutes. The temperature is controlled at 80°C and the reaction time is 4.5 hours. Then, 11 g of polyacrylamide emulsion and 17 g of calcium lignin sulfonate were added into the reactor and stirred continuously. The temperature was controlled at 80°C and the stirring time was continued for 1.1 h. Finally, 10 g of ethylenediaminetetraacetic acid and the remaining 5 g of deionized water were added to the reactor, and the temperature was controlled at 75°C. After aging for 3.5 h, the temperature was naturally lowered to 22°C with continuous stirring.

[0030] Example 3 Take 12g of concentrated hydrochloric acid and add it to the reactor and start stirring. During the stirring process, add 11g of nano-silicon dioxide and 12.5g of deionized water into the reactor. The addition is completed within 20min. The temperature is controlled at 85℃ and the reaction time is 4h. Then, 12 g of polyacrylamide emulsion and 8 g of calcium lignin sulfonate were added into the reactor and stirred continuously. The temperature was controlled at 76°C and the stirring time was continued for 0.7 h. Finally, 6 g of gluconic acid and the remaining 12.5 g of deionized water were added to the reactor, and the temperature was controlled at 76°C. After aging for 4 hours, the temperature was naturally lowered to 21°C with continuous stirring.

[0031] Example 4 Take 5g of concentrated hydrochloric acid and add it to the reactor and start stirring. During the stirring process, add 10g of nano-silicon dioxide and 5g of deionized water into the reactor. The addition is completed within 25min. The temperature is controlled at 80℃ and the reaction time is 3h. Then, 8 g of polyacrylamide emulsion and 5 g of sodium lignin sulfonate were added into the reactor and stirred continuously. The temperature was controlled at 75°C and the stirring time was continued for 0.5 h. Finally, 3 g of EDTA and the remaining 5 g of deionized water were added to the reactor, and the temperature was controlled at 75°C. After aging for 2 h, the temperature was naturally lowered to 25°C with continuous stirring.

[0032] Example 5 Take 10g of concentrated hydrochloric acid and add it to the reactor and start stirring. During the stirring process, add 15g of nano-silicon dioxide and 10g of deionized water into the reactor. The addition is completed within 30 minutes. The temperature is controlled at 83°C and the reaction time is 5 hours. Then, 10 g of polyacrylamide emulsion and 5 g of sodium lignin sulfonate were added into the reactor and stirred continuously. The temperature was controlled at 78°C and the stirring time was continued for 1.5 h. Finally, 8 g of gluconic acid and the remaining 10 g of deionized water were added to the reactor, and the temperature was controlled at 78°C. After aging for 4 hours, the temperature was naturally lowered to 25°C with continuous stirring.

[0033] Example 6 Take 8g of concentrated hydrochloric acid and add it to the reactor and start stirring. During the stirring process, add 12g of nano-silicon dioxide and 8g of deionized water into the reactor. The addition is completed within 20min. The temperature is controlled at 85℃ and the reaction time is 4h. Then, 9 g of polyacrylamide emulsion and 10 g of calcium lignin sulfonate were added into the reactor and stirred continuously. The temperature was controlled at 80°C and the stirring time was continued for 1 h. Finally, 5 g of aminotriacetic acid and the remaining 8 g of deionized water were added to the reactor, and the temperature was controlled at 80°C. After aging for 3 hours, the temperature was naturally cooled to 23°C with continuous stirring.

[0034] Comparative Example 1 The specific implementation method is consistent with Example 5, except that the mass fraction of nano-scale silicon dioxide is changed to 2g.

[0035] Comparative Example 2 The specific implementation method is consistent with Example 5, except that the mass fraction of nano-scale silicon dioxide is changed to 24g.

[0036] Comparative Example 3 The specific implementation method is consistent with Example 5, except that the mass fraction of the polyacrylamide emulsion is changed to 30 g.

[0037] Comparative Example 4 Choose the common sewage decolorizing agents on the market, which mainly include oxidative decolorizing agents and flocculation decolorizing agents.

[0038] Experimental Example 1 Corresponding experiments were conducted at a sewage treatment station of a large printing and dyeing enterprise to determine the efficient and environmentally friendly printing and dyeing sewage decolorizing agent of the present invention, and the decolorizing effect and COD removal rate were determined. The experimental results are shown in Table 1.

[0039] Table 1. Experimental data

[0040] Based on the above data, the following conclusions can be drawn: Through the records of the above data, it can be clearly seen that nano-silicon dioxide plays an important role in the printing and dyeing sewage decolorant of the present invention. In Examples 1-6, significant decolorization effects are shown. Compared with the common printing and dyeing sewage decolorization agent on the market, that is, Comparative Example 4, it can be learned that when the dosage of the agent is 100ppm, the chromaticity removal rate reaches more than 98.3%, and the COD removal rate is also more than 86.2%; while in Comparative Example 4, at the same 100ppm dosage of the agent, the chromaticity removal rate and the COD removal rate are not more than 83%, even if the dosage of the agent is increased to 150ppm, the chromaticity removal rate and the COD removal rate are also far lower than the level of the embodiment. This further proves the superiority of the efficient and environmentally friendly printing and dyeing sewage decolorant of the present invention in decolorization and COD removal.

[0041] By comparing the data of Comparative Examples 1 and 2 with those of Examples 1 to 6, it can be seen that the mass fraction of nano-scale silicon dioxide has a direct impact on the decolorization effect. When the mass fraction of nano-scale silicon dioxide is too much or too little, the decolorization effect and COD removal rate are significantly reduced, indicating that there is an optimal ratio range between the nano-scale silicon dioxide and other raw materials in the printing and dyeing wastewater decolorizer of the present invention.

[0042] As one of the raw materials of the present invention, polyacrylamide emulsion acts together with nano-silicon dioxide to decolorize printing and dyeing wastewater. Comparison of the data of Comparative Example 3 with those of Examples 1 to 6 shows that when the mass fraction of polyacrylamide emulsion increases and exceeds the proportional range, the decolorization and COD removal effects are poor, especially when compared with the data of Example 5. Excessive polyacrylamide emulsion will destroy the synergistic effect with the raw materials in the printing and dyeing wastewater decolorizer of the present invention, resulting in a decrease in the flocculation effect of the pigment molecules and suspended matter in the printing and dyeing wastewater, and destroying the decolorization stability of the printing and dyeing wastewater decolorizer.

[0043] It can be seen from Examples 1 to 6 and Comparative Examples 1 to 4 that the decolorizing agent of the present invention cannot be prepared by simply knowing the raw materials of the agent. When preparing the printing and dyeing wastewater decolorizing agent of the present invention, the distribution ratio of each component needs to be controlled within a certain range to ensure the best decolorization and purification effect.

[0044] It can be seen from Examples 1 to 6 that the highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater of the present invention achieves synergistic effects among the components by reasonably matching the components of concentrated hydrochloric acid, nano-scale silicon dioxide, polyacrylamide emulsion, lignin sulfonate and metal ion chelating agent; the adsorption effect of nano-scale silicon dioxide is combined with the flocculation effect of polyacrylamide emulsion and lignin sulfonate, which effectively improves the purification efficiency of printing and dyeing wastewater. At the same time, the decolorization and COD removal efficiency are further optimized by adjusting the dosage of each component and the reaction conditions. It is obvious that Example 5 has the highest chroma removal rate (99.2%), and its COD removal rate is also relatively high (89.5%); while Example 6 has the highest COD removal rate (90.6%), but its chroma removal rate is the same as Example 5 (98.3%); measured by the comprehensive performance of chroma removal rate and COD removal rate, the performance of Example 5 and Example 6 are very close and excellent, but considering that the chroma removal rate is more important for the application effect of printing and dyeing wastewater scenarios, Example 5 is considered to be the embodiment with the best overall effect in the present invention with the highest chroma removal rate and relatively high COD removal rate.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater, characterized in that: The invention is mainly prepared from the following raw materials in parts by mass: 10-17 parts of nano-scale silicon dioxide, 5-12 parts of concentrated sulfuric acid, 8-13 parts of polyacrylamide emulsion, 5-17 parts of lignin sulfonate, 3-10 parts of metal ion chelating agent and 10-25 parts of deionized water.

2. The highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater according to claim 1, characterized in that: Calculated by mass: 11-16 parts of nano-silicon dioxide, 6-11 parts of concentrated sulfuric acid, 9-11 parts of polyacrylamide emulsion, 8-16 parts of lignin sulfonate, 5-9 parts of metal ion chelating agent, and 14-22 parts of deionized water.

3. The highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater according to claim 1, characterized in that: In parts by mass: 15 parts of nano-scale silicon dioxide, 10 parts of concentrated sulfuric acid, 10 parts of polyacrylamide emulsion, 15 parts of lignin sulfonate, 8 parts of metal ion chelating agent, and 20 parts of deionized water.

4. The highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater according to any one of claims 1 to 3, characterized in that: The lignin sulfonate is at least one of sodium lignin sulfonate and calcium lignin sulfonate.

5. The highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater according to any one of claims 1 to 3, characterized in that: The metal ion chelate is at least one of ethylenediaminetetraacetic acid, gluconic acid and aminotriacetic acid.

6. A method for preparing a highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: Add concentrated sulfuric acid and stir, and add nano-silicon dioxide and deionized water while continuing to stir; Then add polyacrylamide emulsion and lignin sulfonate and continue stirring; Finally, metal ion chelating agent and deionized water are added for aging and then stirred continuously.

7. The method for preparing the highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater according to claim 6, characterized in that: In the step of simultaneously adding nano-scale silicon dioxide and deionized water during the continuous stirring process, the adding time is controlled to be 1-30 minutes.

8. The method for preparing the highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater according to claim 6, characterized in that: In the step of adding nano-scale silicon dioxide and deionized water simultaneously during the continuous stirring process, the temperature is controlled at 80-85° C. and the reaction time is controlled at 3-5 hours.

9. The method for preparing the highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater according to claim 6, characterized in that: In the step of adding the polyacrylamide emulsion and the lignin sulfonate and continuously stirring, the temperature is controlled at 75-80° C. and the continuous stirring time is 0.5-1.5 h.

10. The method for preparing the highly efficient and environmentally friendly decolorizing agent for printing and dyeing wastewater according to any one of claims 6 to 9, characterized in that: In the step of adding the metal ion chelating agent and deionized water for aging and then continuously stirring, the temperature is controlled at 75-80° C., the aging time is 2-4 hours, and the stirring is continuously performed until the temperature reaches 20-25° C.

Images