Preparation method of waste cattle hair hydrolysis modified protein filler based on subcritical water

Abstract

The invention relates to a preparation method of a subcritical water-based waste cattle hair hydrolysis modified protein filler, which comprises the following steps: pretreatment: cleaning and soaking waste cattle hair to obtain a pretreatment solution; hydrolysis: adding the pretreatment liquid into a subcritical water treatment device, adding clear water, and heating to 180-200 DEG C for reaction; filtering: filtering the hydrolysate to obtain filtrate; modifying: adjusting the pH value of the filtrate to 8-10, adding sodium polyacrylate, and reacting to obtain a modified protein solution; and purifying, and drying the modified protein liquid to obtain the protein modified filler. According to the preparation of the filler, only water and waste cattle hair need to be added in the hydrolysis process, substances participating in the reaction are few, the hydrolysis cost is low, and secondary pollution cannot be caused.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of leather chemical industry and solid waste resource utilization, and particularly relates to a preparation method of waste cow hair hydrolysis modified protein filler based on subcritical water. BACKGROUND

[0002] With the improvement of environmental protection requirements, the leather industry is facing serious pressure of solid waste treatment. Waste cow hair is one of the main solid wastes in the leather-making process, and its annual production is huge worldwide. Waste cow hair is rich in keratin, and if not properly treated, it not only occupies land resources, but also breeds bacteria and produces odor during natural accumulation, increasing the COD load of leather-making wastewater and causing serious environmental pollution.

[0003] At present, the main methods for treating waste cow hair include alkali method, acid method, oxidation method and reduction method. The alkali method destroys the molecular structure of keratin by strong alkali solution to achieve hydrolysis, but has problems such as harsh hydrolysis conditions and easy alkaline pollution; the acid method uses acid solution to hydrolyze keratin, which has a fast hydrolysis speed, but the use of acid substances may cause equipment corrosion and neutralization problems; the oxidation method uses hydrogen peroxide and other oxidizing agents to strengthen the hydrolysis process, but may cause excessive oxidation of keratin, affecting the application performance; the reduction method uses reducing agents to reduce the intermolecular force of keratin to achieve hydrolysis, but the selection and use of reducing agents are high in cost.

[0004] These traditional methods generally have the disadvantages of low hydrolysis rate, unstable product quality, complex process, high cost, etc., and are difficult to meet the green, efficient and economic development needs of the leather industry. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art, and provides a preparation method of waste cow hair hydrolysis modified protein filler based on subcritical water, which realizes efficient resource utilization of waste cow hair and provides a green and efficient protein filler for the leather industry.

[0006] The present application adopts the following technical scheme: A preparation method of waste cow hair hydrolysis modified protein filler based on subcritical water, comprising the following steps: Pretreatment, washing and soaking the waste cow hair to obtain a pretreated liquid; Hydrolysis, adding the pretreated liquid into a subcritical water treatment device, adding water, and heating to 180-200 DEG C for reaction; Filtration, filtering the hydrolysis liquid to obtain a filtrate; Modification, adjusting the pH of the filtrate to 8-10, adding sodium polyacrylate, and reacting to obtain a modified protein liquid; Purification, drying the modified protein liquid to obtain a protein modified filler.

[0007] Furthermore, in the above pretreatment, the amount of waste ox hair used is 800-1200g, the amount of water used for washing is 3-4L, the amount of water used for soaking is 11-12L, and the soaking time is 2-4 hours.

[0008] Furthermore, in the above hydrolysis, the amount of water added is 8-11L, the heating time is 2-3 hours, and the reaction time is 120-150 minutes.

[0009] Furthermore, in the above filtration process, a 200-250 mesh screen is used for filtration.

[0010] Furthermore, in the above modification, baking soda was used to adjust the pH value, the reaction temperature was 70-90℃, and the reaction time was 60-90 minutes.

[0011] Furthermore, the above-mentioned protein-modified filler is a pale yellow solid with a molecular weight of 25,000-25,500 Da, a viscosity of 8-8.5 mPa·s, and a process hydrolysis rate of 96.4-96.8%.

[0012] As can be seen from the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages: 1. The filler of the present invention only requires the addition of water and waste cow hair during the hydrolysis process. The amount of substances involved in the reaction is small, the hydrolysis cost is low, and it will not cause secondary pollution. 2. This invention uses sodium polyacrylate to modify hydrolyzed protein, which is a low-cost and simple-to-operate modification material.

[0013] 3. The modified hydrolyzed protein of this invention has a suitable molecular weight, a network structure, stable structure, and good filling performance; 4. The entire process of this invention is green and environmentally friendly, with mild reaction conditions, eliminating the need for strong acids and alkalis, thus reducing equipment corrosion and environmental pollution; 5. This invention realizes the high-value-added resource utilization of waste cow hair, turning waste into treasure, which is in line with the concept of circular economy development. Attached Figure Description

[0014] Figure 1 The image shown is a physical picture of the protein-modified filler prepared according to the present invention. Detailed Implementation

[0015] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0016] Example 1: A method for preparing a subcritical water-based waste bovine hair hydrolyzed modified protein filler, comprising the following steps: Pretreatment: Take 800g of waste cow hair and wash it twice with 3L of room temperature water to remove impurities from the surface of the cow hair. After washing, soak the cow hair in 11L of room temperature water, stir and let it stand for 2 hours to obtain pretreatment solution A; Hydrolysis: Add hydrolysate A to a subcritical water treatment device, then add 8 L of clean water and seal. Heat to 180°C within 2 hours and react for 120 minutes. Cool to 70°C to obtain hydrolysate B.

[0017] Filtration: Filter hydrolysate B through a 200-mesh sieve to obtain filtrate C. Add filtrate C to the subcritical water treatment device.

[0018] Modification: In a subcritical water treatment device, sodium bicarbonate was added to adjust the pH to 8, the temperature was raised to 70°C, sodium polyacrylate was added, the device was sealed, and the reaction was allowed to proceed for 60 minutes. Immediately afterwards, the valve was opened, the hydrolysate was transferred to a container, and the container was placed in 2°C ice water to obtain modified protein solution D.

[0019] Purification: The modified protein solution D is poured into a spray dryer and dried into a solid, which is the protein-modified filler. Figure 1 As shown.

[0020] Example 2: A method for preparing a subcritical water-based waste bovine hair hydrolyzed modified protein filler, comprising the following steps: Pretreatment: Take 800g of waste cow hair and wash it twice with 3L of room temperature water to remove impurities from the surface of the cow hair. After washing, soak the cow hair in 11L of room temperature water, stir and let it stand for 2 hours to obtain pretreatment solution A; Hydrolysis: Add hydrolysate A to a subcritical water treatment device, then add 11L of clean water and seal. Heat to 180℃ within 2 hours and react for 120 minutes. Cool to 70℃ to obtain hydrolysate B.

[0021] Filtration: Filter hydrolysate B through a 200-mesh sieve to obtain filtrate C. Add filtrate C to the subcritical water treatment device.

[0022] Modification: In a subcritical water treatment device, sodium bicarbonate was added to adjust the pH to 10, the temperature was raised to 70°C, sodium polyacrylate was added, the device was sealed, and the reaction was allowed to proceed for 60 minutes. Immediately afterwards, the valve was opened, the hydrolysate was transferred to a container, and the container was placed in 2°C ice water to obtain modified protein solution D.

[0023] Purification: The modified protein solution D is poured into a spray dryer and dried into a solid, which is the protein-modified filler. Figure 1 As shown.

[0024] Table 1. Detection data of protein-modified fillers The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A method for preparing a subcritical water-based waste cattle hair hydrolyzed modified protein filler, characterized by, The method comprises the following steps: pretreatment, cleaning and soaking the waste cow hair to obtain a pretreatment liquid; hydrolysis, adding the pretreatment liquid into a subcritical water treatment device, adding clean water, and heating to 180-200 DEG C to react; filtration, filtering the hydrolysis liquid to obtain a filtrate; modification, adjusting the pH of the filtrate to 8-10, adding sodium polyacrylate, and reacting to obtain a modified protein liquid; purification, drying the modified protein liquid to obtain a protein modified filler.

2. The method of claim 1, wherein the subcritical water-based waste cattle hair hydrolyzed modified protein filler is prepared by the steps of: In the pretreatment, the amount of waste cow hair is 800-1200g, the amount of water for cleaning is 3-4L, the amount of water for soaking is 11-12L, and the soaking time is 2-4 hours. ​ 3. The preparation method of a subcritical water-based waste bovine hair hydrolyzed modified protein filler as described in claim 1, characterized in that: In the hydrolysis, the amount of clean water added is 8-11L, the heating time is 2-3 hours, and the reaction time is 120-150 minutes.

4. The preparation method of a subcritical water-based waste bovine hair hydrolyzed modified protein filler as described in claim 1, characterized in that: In the filtration, a 200-250 mesh screen is used for filtration.

5. The preparation method of a subcritical water-based waste bovine hair hydrolyzed modified protein filler as described in claim 1, characterized in that: In the modification, baking soda is used to adjust the pH value, the reaction temperature is 70-90 DEG C, and the reaction time is 60-90 minutes.

6. The preparation method of a subcritical water-based waste bovine hair hydrolyzed modified protein filler as described in claim 1, characterized in that: The protein modified filler has a light yellow solid appearance, a molecular weight of 25000-25500 Da, a viscosity of 8-8.5 mPa·s, and a process hydrolysis rate of 96.4-96.8%.

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