A method for treating polyvinyl alcohol-containing aqueous dyeing and finishing wastewater for recycling

Abstract

The present application belongs to the technical field of polyvinyl alcohol recycling, and discloses a treatment method for recycling and reusing polyvinyl alcohol-containing aqueous dyeing and finishing wastewater. The polyvinyl alcohol-containing aqueous dyeing and finishing wastewater is concentrated by using a ceramic membrane until the concentration of polyvinyl alcohol in the wastewater reaches 8% or above. The concentrated wastewater is directly used in the production of special glue for paper tubes or rubber cotton mop heads. The present application has achieved a breakthrough in the core technology of the concentration process of polyvinyl alcohol-containing aqueous dyeing and finishing wastewater and the backwashing of the ceramic membrane, thereby improving the concentration efficiency, reducing the energy consumption, greatly prolonging the replacement cycle of the ceramic membrane, and achieving the possibility of recycling. After 6 years of research, the inventors' team has realized the industrial application of the recycling of polyvinyl alcohol-containing aqueous dyeing and finishing wastewater, greatly alleviating the environmental protection pressure of the treatment of polyvinyl alcohol-containing aqueous dyeing and finishing wastewater in the production process of embroidery and linen industries, promoting the recovery and healthy development of the embroidery and linen industries, and achieving remarkable social and economic benefits.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyvinyl alcohol recycling, and particularly relates to a treatment method for recycling and reusing polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater. BACKGROUND

[0002] Polyvinyl alcohol (PVA) is a high molecular material that is easily soluble in water and has good orientation performance, and is widely used in the manufacturing of water-soluble fibers and the production of various adhesives, PVA optical films, and PVB vehicle laminated glass. The water-soluble fibers are used to make non-woven fabrics as embroidery base cloth, and are used in textile linen, wool spinning, and towel products to achieve lightness, softness, and fluffiness. High-strength PVA water-soluble fibers are added during yarn spinning, and after the fabric is made, 20%-40% of the water-soluble fibers are dissolved in boiling water in the first process of dyeing to achieve the effect of thinning, softening, and fluffing the fabric. According to statistics, 20,000 tons of PVA fibers are used to make non-woven fabrics as embroidery base cloth, and another 20,000 tons are used in linen, wool spinning, and towel products. This results in a large amount of PVA dissolved in the water bodies of various dyeing plants. Since the molecular weight of PVA is as high as 80,000 or more, the COD value of 1% content after being dissolved in water is above 25,000, and the decomposition time is 80 days under bacterial conditions. With the strict requirements of environmental protection on water environment, many enterprises have to close down and change production due to the inability to properly treat such wastewater. SUMMARY

[0003] The purpose of the present application is to provide a treatment method for recycling and reusing polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater, which has the effect of recycling and reusing polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater.

[0004] The above technical purpose of the present application is achieved by the following technical solution: a treatment method for recycling and reusing polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater, which uses a ceramic membrane to concentrate the polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater until the concentration of polyvinyl alcohol in the wastewater reaches 8% or more.

[0005] The present application further provides that the concentrated wastewater is directly used in the production of paper tube special glue or cotton mop head.

[0006] The present application further provides that a penetrating agent is added before the concentration of the polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater.

[0007] The present application further provides that the penetrating agent is a fatty alcohol ring-opening ethylene oxide, and 0.5-1 kg of penetrating agent is added per 10 tons of wastewater.

[0008] The further setting of the application is that after the ceramic membrane is used for a period of time, the ceramic membrane is back-flushed in turn by using the A component back-flushing liquid and the B component back-flushing liquid, the A component back-flushing liquid comprises one or more of sulfonic acid, phosphorous acid, ethylenediaminetetraacetic acid, aniline acid, hydroxylamine carboxylic acid and citric acid, and the B component back-flushing liquid is hydrogen peroxide; the A component is added into 60-80 DEG C water to back-flush the ceramic membrane, 25 kg of the A component is added into each ton of water, and the flushing time is 1 hour or above; then the B component is added into 60-80 DEG C water to back-flush the ceramic membrane, 25 kg of the B component is added into each ton of water, and the flushing time is 1 hour or above; and the ceramic membrane after water removal can be applied to the concentration treatment of the polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater again.

[0009] The further setting of the application is that the A component is added into 60-80 DEG C water to back-flush the ceramic membrane until the ceramic membrane efficiency is recovered to 60% or above, and then the B component is added into 60-80 DEG C water to back-flush the ceramic membrane until the ceramic membrane efficiency is recovered to 95% or above.

[0010] The further setting of the application is that the polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater is the dyeing and finishing wastewater of the embroidery industry.

[0011] The further setting of the application is that the polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater is the dyeing and finishing wastewater of the linen industry.

[0012] The further setting of the application is that the polyvinyl alcohol content in the polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater is 0.5-3%.

[0013] The beneficial effect of the application is that.

[0014] 1. The polyvinyl alcohol water-soluble fiber is used in different scenes such as embroidery, linen, wool cloth and towel, and the substances and polyvinyl alcohol content in the wastewater are different. According to the sample detection of the dyeing and finishing wastewater of various industries and in combination with the characteristics of large wastewater amount of the embroidery industry and the linen industry, the polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater in the embroidery industry and the linen industry is recycled.

[0015] 2. The polyvinyl alcohol-containing water-soluble dyeing and finishing wastewater with the polyvinyl alcohol content of 0.5%-3% is concentrated by using the ceramic membrane. The concentration mechanism is that the high molecular weight of polyvinyl alcohol and the low molecular weight of water are used to intercept the high molecular polyvinyl alcohol by using the ceramic membrane to achieve the concentration effect. The polyvinyl alcohol content in the wastewater is uniformly increased to 8% or above. When the concentration reaches the above, the dyeing and finishing wastewater can be directly used for the production of special glue for paper tubes and rubber cotton mop heads, so that the recycling is realized.

[0016] 3. When using ceramic membranes to concentrate polyvinyl alcohol (PVA) water-soluble dyeing and finishing wastewater, the PVA molecular weight reaches over 80,000, and its content becomes very sticky after reaching 5%. As the concentration gradually increases, the separation efficiency of the ceramic membrane decreases rapidly, resulting in high energy consumption and reduced economic efficiency. This invention, through research on the application of concentrated wastewater in the production of paper tube adhesive and PVC-coated mop heads, adds a penetrant to the wastewater without affecting its subsequent use. The penetrant is a fatty alcohol-conjugated ethylene oxide (FAO), chemically known as fatty alcohol polyoxyethylene ether. Its function is to fully dissolve PVA, increasing the number of free water molecules, making them easier to separate, thereby improving the separation efficiency of the ceramic membrane and reducing energy consumption during the concentration process. This ensures economic efficiency even when the PVA content in the dyeing and finishing wastewater reaches 8%. Furthermore, the FAO does not affect the direct application of the concentrated wastewater to the production of paper tube adhesive and PVC-coated mop heads.

[0017] 4. After a period of use, the ceramic membrane's separation efficiency gradually declines due to the high viscosity of polyvinyl alcohol and other low-molecular-weight substances clogging it, resulting in high energy consumption and low efficiency. The inventors initially backwashed the ceramic membrane using ordinary strong acids or gunshot wounds, finding that backwashing only restored about 60% of the efficiency. This was clearly unsuitable for large-scale production and even resulted in a short lifespan for the ceramic membrane, rendering it economically worthless. The inventors then conducted individual analyses of the deposits inside the ceramic membrane after one cycle of use, and formulated component A and component B backwash solutions based on the characteristics of these deposits. After numerous experiments, the backwashing effect enabled the ceramic membrane to recover 95% or more of its efficiency. The replacement cycle of the ceramic membrane can now be extended from one year to four years or more.

[0018] 5. This invention achieves breakthroughs in the core technologies of concentration process and ceramic membrane backwashing for polyvinyl alcohol water-soluble dyeing and finishing wastewater, improving concentration efficiency, reducing energy consumption, and greatly extending the replacement cycle of ceramic membranes, resulting in good economic efficiency and realizing the possibility of recycling.

[0019] 6. After six years of research, the inventors of this invention have achieved the industrial application of recycling and reusing polyvinyl alcohol water-soluble dyeing and finishing wastewater. This has greatly alleviated the environmental pressure of treating polyvinyl alcohol water-soluble dyeing and finishing wastewater in the production processes of industries such as embroidery and linen, promoted the recovery and healthy development of industries such as embroidery and linen, and yielded significant social and economic benefits. Detailed Implementation

[0020] The technical solutions in the embodiments will be clearly and completely described below. Apparently, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0021] Embodiment: A treatment method for recycling and reusing polyvinyl alcohol-containing aqueous dyeing and finishing wastewater, the polyvinyl alcohol-containing aqueous dyeing and finishing wastewater is dyeing and finishing wastewater of the embroidery industry or dyeing and finishing wastewater of the linen industry, the polyvinyl alcohol content is 0.5-3%, a penetrating agent is added to the polyvinyl alcohol-containing aqueous dyeing and finishing wastewater, the penetrating agent is a fatty alcohol epoxide, and 0.5-1 kg of the penetrating agent is added to every 10 tons of the polyvinyl alcohol-containing aqueous dyeing and finishing wastewater. Then, ceramic membranes are used to concentrate the polyvinyl alcohol-containing aqueous dyeing and finishing wastewater, until the polyvinyl alcohol content reaches 8% or above, to obtain concentrated dyeing and finishing wastewater, which can be directly applied to the production of special glue for paper tubes or glue cotton mop heads.

[0022] After the ceramic membranes are used for a period of time, the ceramic membranes are backwashed in turn by using an A component backwashing liquid and a B component backwashing liquid, the A component backwashing liquid comprises one or more of sulfonic acid, phosphorous acid, ethylenediaminetetraacetic acid, aniline acid, hydroxylamine carboxylic acid and citric acid, and the B component backwashing liquid is hydrogen peroxide; the A component is added to 60-80 DEG C water to backwash the ceramic membranes, 25 kg of the A component is added to every ton of water, the washing time is 1 hour or above, until the ceramic membrane efficiency is restored to 60% or above, then the B component is added to 60-80 DEG C water to backwash the ceramic membranes, 25 kg of the B component is added to every ton of water, the washing time is 1 hour or above, until the ceramic membrane efficiency is restored to 95% or above, and the ceramic membranes after water removal can be applied to the concentration treatment of the polyvinyl alcohol-containing aqueous dyeing and finishing wastewater again.

[0023] Embodiment of the present application: The present application is essentially to realize the industrial application of recycling and reusing polyvinyl alcohol-containing aqueous dyeing and finishing wastewater, the applicant and the inventor team invest equipment in Zhejiang, and apply the technology of the present application to collect and reuse the water-soluble wastewater of embroidery bottom water-soluble fibers, and supply the PVA concentrated solution obtained after concentration to paper tube special glue manufacturers, and nearly 400,000 tons of PVA concentrated solution has been provided for three large paper tube special glue manufacturers in Zhejiang in the past six years, including Ningbo Yonggu Chemical Co., Ltd. (the largest paper tube glue manufacturer in China at present) and Tongxiang Tongheng Adhesive Co., Ltd.

[0024] The applicant and the inventor team invest 6 sets of equipment in Shantou Longbo Printing and Dyeing Co., Ltd. in Guangdong, and apply the technology of the present application to recycle PVA in the water-soluble solution of embroidery cloth, and a factory producing 10 million mop heads per year is correspondingly built, and the production line has been put into use.

[0025] The application and the inventor team collect, treat and reuse all the polyvinyl alcohol aqueous dyeing and finishing wastewater of hemp textile fabrics of Jingzhou Jiayuan Textile Co., Ltd. Jingzhou Jiayuan Textile Co., Ltd. is a leading enterprise in the ramie industry, and the market share of ramie cloth is 70%. The application and the inventor team invest 6 machine groups to treat the wastewater, and the treated PVA aqueous solution is supplied to the 2000 million / year mop head production factory which has been built, the factory normally produces, and the excess part is supplied to enterprises such as Hunan Haokai Daily Necessities Co., Ltd. and Henan Shanghai Quanyu Technology Co., Ltd. to produce mop heads.

[0026] The technology of the application is applied in industry, greatly alleviates the environmental protection pressure of polyvinyl alcohol aqueous dyeing and finishing wastewater treatment, promotes the recovery and healthy development of the embroidery and hemp textile industry, and has remarkable social and economic benefits.

Claims

1. A treatment method for recycling and reusing polyvinyl alcohol-containing aqueous dyeing and finishing wastewater, characterized by comprising the following steps: The polyvinyl alcohol content in the polyvinyl alcohol-containing aqueous dyeing and finishing wastewater is 0.5-3%, and the ceramic membrane is used to concentrate the polyvinyl alcohol-containing aqueous dyeing and finishing wastewater until the polyvinyl alcohol concentration in the wastewater reaches 8% or above; ​ The penetrating agent is added before the concentration of the polyvinyl alcohol-containing aqueous dyeing and finishing wastewater, and the penetrating agent is a fatty alcohol ring-opening ethylene oxide; After the ceramic membrane is used for a period of time, the ceramic membrane is backwashed in turn by using an A component backwashing liquid and a B component backwashing liquid, the A component backwashing liquid comprises one or more of sulfonic acid, phosphorous acid, ethylenediaminetetraacetic acid, aniline acid, hydroxylamine carboxylic acid and citric acid, and the B component backwashing liquid is hydrogen peroxide; the A component is added to 60-80℃ water to backwash the ceramic membrane, 25kg of the A component is added per ton of water, and the washing time is 1 hour or above; then the B component is added to 60-80℃ water to backwash the ceramic membrane, 25kg of the B component is added per ton of water, and the washing time is 1 hour or above; and the ceramic membrane after the water is drained is used again for the concentration treatment of the polyvinyl alcohol-containing aqueous dyeing and finishing wastewater. The A component is added to 60-80℃ water to backwash the ceramic membrane until the ceramic membrane efficiency is restored to 60% or above, and then the B component is added to 60-80℃ water to backwash the ceramic membrane until the ceramic membrane efficiency is restored to 95% or above.

2. The method for treating polyvinyl alcohol-containing aqueous dyeing and washing wastewater for recycling according to claim 1, characterized in that: The concentrated wastewater is directly applied to the production of paper tube special glue or cotton mop head.

3. The method for treating polyvinyl alcohol-containing aqueous dyeing and washing wastewater for recycling according to claim 1, characterized in that: 0.5-1kg of the penetrating agent is added per 10 tons of wastewater.

4. The method according to any one of claims 1 to 3, wherein the treatment method for recycling and reusing polyvinyl alcohol-containing aqueous dyeing and finishing wastewater is characterized by: The polyvinyl alcohol-containing aqueous dyeing and finishing wastewater is dyeing and finishing wastewater of the embroidery industry.

5. The method according to any one of claims 1 to 3, wherein the treatment method for recycling and reusing polyvinyl alcohol-containing aqueous dyeing and finishing wastewater is characterized by: The polyvinyl alcohol-containing aqueous dyeing and finishing wastewater is dyeing and finishing wastewater of the linen industry.