阅读说明：本技术 一种黄豆提取物水解产物缓蚀剂及其制备方法和应用 (Soybean extract hydrolysate corrosion inhibitor and preparation method and application thereof ) 是由 李杰兰 金怡宁 李倩娜 王笑梅 杨雪 于 2020-10-16 设计创作，主要内容包括：本发明公开了一种黄豆提取物水解产物缓蚀剂及其制备方法和应用。上述缓蚀剂以黄豆为原料,制备包括如下步骤：黄豆加水充分浸泡后搅拌粉碎,将抽滤后的滤液蒸干获得黄豆提取物,提取物中加入木瓜蛋白酶进行水解,控制水解条件获得不同水解度的水解产物缓蚀剂。本发明制备的缓蚀剂对盐酸溶液中的碳钢具有良好的缓蚀性能,在碳钢设备酸洗领域具有较大的应用前景。另外,本发明制备的缓蚀剂具有原料价廉易得、环境友好、制备方法工艺简单、适合规模化生产等优点。(The invention discloses a soybean extract hydrolysate corrosion inhibitor and a preparation method and application thereof. The corrosion inhibitor takes soybeans as raw materials, and the preparation method comprises the following steps: fully soaking soybeans in water, stirring, crushing, evaporating filtrate after suction filtration to obtain a soybean extract, adding papain into the extract for hydrolysis, and controlling hydrolysis conditions to obtain hydrolysate corrosion inhibitors with different hydrolysis degrees. The corrosion inhibitor prepared by the invention has good corrosion inhibition performance on carbon steel in a hydrochloric acid solution, and has a wide application prospect in the field of carbon steel equipment pickling. In addition, the corrosion inhibitor prepared by the invention has the advantages of cheap and easily available raw materials, environmental friendliness, simple preparation method and process, suitability for large-scale production and the like.)

1. A soybean extract hydrolysate corrosion inhibitor is characterized in that the active component of the inhibitor is mainly a papain hydrolysate of a soybean extract; the soybean extract hydrolysate corrosion inhibitor is in a powder shape.

2. The method for preparing the soy extract hydrolysate corrosion inhibitor of claim 1, comprising the steps of:

soaking soybeans in water for 10-14h, wherein the mass ratio of the feed liquid is 1:10, crushing by using a crusher, stirring for 2h, filtering by using 150-mesh filter cloth, performing suction filtration on the obtained filtrate, and drying the filtrate obtained by suction filtration in a 50 ℃ oven to obtain light yellow soybean extract powder;

preparing a soybean extract into a solution with the protein content of 5-10%, heating at 85 ℃ for 20min, cooling to 50 ℃, adding papain with the concentration of 2000-32000U/g for hydrolysis for 60min, maintaining the pH value at 6.91 in the hydrolysis process, and drying the hydrolysate to obtain soybean extract hydrolysate powder.

3. The method according to claim 2, wherein the concentrations of papain to be added are 2000U/g, 4000U/g, 8000U/g, 16000U/g, and 32000U/g, respectively.

4. The method according to claim 3, wherein the concentration of papain added is 32000U/g.

5. The method of claim 2, wherein the soybeans are soaked for 12 hours.

6. The method of claim 2, wherein the hydrolysate drying condition is 50 ℃.

7. The use of the soy extract hydrolysate corrosion inhibitor of claim 1, wherein the soy extract hydrolysate is used as a corrosion inhibitor for a3 steel in hydrochloric acid solution.

8. The use as claimed in claim 7, wherein the addition amount of the corrosion inhibitor as the hydrolysate of the soybean extract is 400mg/L, the concentration of the hydrochloric acid solution is 1.0-3.0mol/L, the temperature of the hydrochloric acid solution is 20-60 ℃, and the soaking time of the A3 steel is 6-72 h.

9. The use of claim 8, wherein the soy extract hydrolysate corrosion inhibitor is added in an amount of 400mg/L, the hydrochloric acid solution concentration is 1.0mol/L, the hydrochloric acid solution temperature is 40 ℃, and the A3 steel immersion time is 48 h.

Technical Field

The invention relates to the technical field of metal corrosion inhibitor production, in particular to a soybean extract hydrolysate corrosion inhibitor for inhibiting corrosion of A3 steel in a hydrochloric acid solution, and a preparation method and application thereof.

Background

The corrosion phenomenon of metal materials is ubiquitous, and the economic loss caused by metal corrosion accounts for 2-4% of the total value of national economic production in each country every year. The metal corrosion causes economic loss and waste of resources and energy, and the addition of the corrosion inhibitor in a corrosive environment is one of the effective methods for solving the corrosion problem.

Carbon steel is widely applied in modern production and life, hydrochloric acid is widely applied in the fields of acid cleaning and descaling, acidification oil extraction and the like, carbon steel equipment is seriously corroded, some corrosion inhibitors are greatly limited due to the defects of high toxicity, poor biodegradation and the like, and the development of the high-efficiency, low-toxicity and environment-friendly corrosion inhibitor for carbon steel in a hydrochloric acid medium has very high practical application value.

Amino acid compounds have the characteristics of no toxicity and easy degradation, and various scholars conduct a great deal of research on corrosion inhibition performance of amino acids and derivatives. The amino acid has various types, the side chain structures in different types of amino acid molecules and hydrophilic groups and hydrophobic groups contained in the side chain structures have obvious influence on the corrosion inhibition effect of the side chain structures, and the amino acid derivatives are mainly researched by grafting the amino acid and other organic matters together and endowing the molecules with more special groups and structures which are beneficial to adsorption and corrosion inhibition. The soybean is rich in protein, the basic structural unit of the soybean is various in amino acid types, and peptide bonds in the protein are broken to form short-chain polypeptide, so that the novel idea for synthesizing the novel corrosion inhibitor with various amino acid structures is provided. The invention provides a brand-new way for deep processing of soybeans while hydrolyzing the soybean extract by enzymolysis to obtain the hydrolysate corrosion inhibitor, and the invention has good application prospect and social and economic values.

Disclosure of Invention

The invention aims to provide a preparation method and application of a soybean extract hydrolysate corrosion inhibitor. The corrosion inhibitor can be applied to a carbon steel corrosion inhibitor in a hydrochloric acid solution, and has high corrosion inhibition efficiency. In addition, the preparation method of the invention has the following advantages: the raw materials are cheap and easy to obtain, the operation is simple, the conditions are easy to control, and the method is suitable for large-scale production and the like.

The technical scheme of the invention is as follows: a soybean extract hydrolysate corrosion inhibitor contains papain hydrolysate of soybean extract as active ingredient; the soybean extract hydrolysate corrosion inhibitor is in a powder shape.

The preparation process of the soybean extract hydrolysate corrosion inhibitor comprises the following steps:

soaking soybeans in water for 10-14h, wherein the mass ratio of the feed liquid is 1:10, crushing by using a crusher, stirring for 2h, filtering by using 150-mesh filter cloth, performing suction filtration on the obtained filtrate, and drying the filtrate obtained by suction filtration in a 50 ℃ oven to obtain light yellow soybean extract powder.

In order to facilitate hydrolysis reaction, the soybean extract is prepared into a solution with the protein content of 5-10%, the solution is heated at 85 ℃ for 20min, the temperature is reduced to 50 ℃, papain with the concentration of 2000U/g-32000U/g is added for hydrolysis for 60min, NaOH solution is dripped into the hydrolysis solution to maintain the pH value to be 6.91, and the hydrolysis solution is dried to prepare the hydrolysis product powder of the soybean extract.

Furthermore, the concentrations of the added papain are 2000U/g, 4000U/g, 8000U/g, 16000U/g and 32000U/g respectively. Preferably, the concentration of papain added is 32000U/g.

Furthermore, the soaking time of the soybeans is preferably 12 hours.

Further, the drying condition of the hydrolysate is 50 ℃.

The invention also claims that the hydrolysate of the soybean extract can be used as a corrosion inhibitor of A3 steel in hydrochloric acid solution.

The addition concentration of the soybean extract hydrolysate corrosion inhibitor is 400mg/L, the concentration of the hydrochloric acid solution is 1.0-3.0mol/L, the temperature of the hydrochloric acid solution is 20-60 ℃, and the soaking time of A3 steel is 6-72 h.

Preferably, the addition concentration of the soybean extract hydrolysate corrosion inhibitor is 400mg/L, the concentration of a hydrochloric acid solution is 1.0mol/L, the temperature of the hydrochloric acid solution is 40 ℃, and the soaking time of A3 steel is 48 hours.

The principle of the invention is as follows: the corrosion inhibitor is an adsorption film type corrosion inhibitor, and the corrosion inhibition effect is that the corrosion inhibitor molecules replace water molecules adsorbed on the iron surface, so that FeOOH is reduced⁺Thereby inhibiting the occurrence of corrosion reactions; meanwhile, atoms such as N, O in polar groups contained in corrosion inhibitor molecules have lone pair electrons and can form a complex with the empty d orbit of iron ions, so that chemical adsorption is generated, or physical adsorption is generated on the surface of A3 steel through electrostatic interactionA compact and firm adsorption film is formed, and the charge state of the surface of the A3 steel is influenced; in addition, the micromolecule soybean extract hydrolysate polypeptide has shorter peptide chain, the number of hydrophilic groups exposed at the end group is increased, the active adsorption sites are increased, the intermolecular gap of the metal surface adsorption film is reduced, the coverage is increased, the adsorption film is firmer and more compact, and the double electric layer structure of the metal/solution interface is improved, so that the obvious corrosion inhibition effect is generated. The corrosion inhibitor has a remarkable inhibiting effect on corrosion of A3 steel in a hydrochloric acid solution, and provides a new way for high-added-value development of soybeans.

The invention has the beneficial effects that: 1) according to the invention, natural plant seeds, namely soybeans are used as raw materials, an extract is obtained by a water extraction method, proteins in the extract are macromolecules rich in various amino acid structures, the steric hindrance is large, the adsorption of corrosion inhibitor molecules on the surface of A3 steel is not facilitated, the protein macromolecules are converted into micromolecular polypeptides after the soybean extract is hydrolyzed by papain, the steric hindrance effect is reduced, the adsorption capacity of a hydrolysate on the surface of A3 steel is improved, the corrosion inhibition performance is enhanced, the hydrolysis product molecules obtained with the larger hydrolysis degree are smaller, and the corrosion inhibition performance is better; 2) the invention has the advantages of biodegradable raw materials, wide sources, reproducibility, no toxicity, no pollution, low price, easy obtainment and the like; 3) when the corrosion inhibitor is added into 1mol/L hydrochloric acid solution at room temperature and 400mg/L, the corrosion inhibition efficiency on A3 steel can reach 94.36%, the corrosion inhibitor has good corrosion inhibition effect on A3 steel in the hydrochloric acid solution, and the corrosion inhibitor has good development prospect in corrosion prevention of A3 steel.

Drawings

FIG. 1 is an infrared spectrum of a hydrolyzate of soybean extract.

FIG. 2 is a comparison graph of the corrosion inhibition effect of the soybean extract hydrolysate on carbon steel, wherein a is a scanning electron microscope photo of carbon steel after being soaked in a hydrochloric acid solution without the addition of the soybean extract hydrolysate for 6 hours, and b is a scanning electron microscope photo of carbon steel after being soaked in a hydrochloric acid solution with the addition of the soybean extract hydrolysate for 6 hours.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and examples. It is also to be understood that the following examples are intended to illustrate the present invention and are not to be construed as limiting the scope of the invention, and that the particular materials, reaction times and temperatures, process parameters, etc. listed in the examples are exemplary only and are intended to be exemplary of suitable ranges, and that insubstantial modifications and adaptations of the invention by those skilled in the art in light of the foregoing description are intended to be within the scope of the invention.

Example 1:

preparation of soybean extract hydrolysate corrosion inhibitor: cleaning high-quality plump semen glycines, soaking for 12 hr, peeling, pulverizing, stirring, filtering, vacuum filtering, and oven drying the filtrate at 50 deg.C to obtain semen glycines extract. Preparing the soybean extract into a solution with the protein content of 5%, heating in a water bath at 85 ℃ for 20min, adding 32000U/g of papain for hydrolysis for 60min, (controlling the pH to be 6.91 in the hydrolysis process, and being beneficial to calculating the hydrolysis degree under the pH, the hydrolysis degrees are different, and the corrosion inhibition effect is different), and drying the hydrolysate in a drying oven at 50 ℃ to obtain the soybean extract hydrolysate with the hydrolysis degree of 8.06%. Performing infrared spectrum characterization on the hydrolysate of the soybean extract, wherein the obtained spectrogram is shown in figure 1: at 3270 and 3280cm^-1Occurrence of-NH₂Has an absorption peak of 2925cm^-1An asymmetric stretching vibration peak of-CH-is shown, and is 1632cm^-1And 1536cm^-1The absorption peak is indicated as C ═ O stretching vibration in-COOH-, at 1046cm^-1The vicinity is a C-N stretching vibration peak. It is known that the hydrolysate of soybean extract contains polar groups centered on atoms such as N, O, such as-NH₂-CH-, C ═ O, and the like, and thus the soybean extract hydrolysate has a potential corrosion inhibition effect. Because the electronegativity of the neutral atoms in the polar groups is relatively large and the neutral atoms have lone pair electrons, the neutral atoms can form a complex with the empty d orbit of the iron ions, so that chemical adsorption is generated, or physical adsorption is generated through electrostatic action to form a compact and firm adsorption film.

The invention carries out the weight loss experiment according to GB10124-88 'method for testing uniform corrosion in a metal material laboratory in full immersion test'. The corrosion inhibitor prepared according to example 1 and having a hydrolysis degree of 8.06% from a soybean extract hydrolysate has a corrosion inhibition rate at 20 ℃ to A3 steel in a hydrochloric acid solution of 1mol/L as shown in Table 1.

TABLE 1

As can be seen from Table 1, the optimum concentration of the corrosion inhibitor is 400 mg/L. In addition, the corrosion topography of the surface of the A3 steel subjected to the weight loss test is characterized, and a Scanning Electron Microscope (SEM) in fig. 2 shows that the surface of the A3 steel in a hydrochloric acid solution without the corrosion inhibitor is uneven, very rough and seriously corroded; after the corrosion inhibitor is added, the surface of the A3 steel is not obviously corroded, the surface becomes flat, the roughness is small, and a uniform film layer is attached, so that the soybean extract hydrolysate is adsorbed on the surface of the A3 steel to inhibit the corrosion.

Example 2:

this example examined the corrosion inhibiting effect of papain at various concentrations on soy extract hydrolysates.

Preparation of soybean extract hydrolysate corrosion inhibitor: cleaning high-quality plump semen glycines, soaking for 12 hr, peeling, squeezing, stirring, filtering, vacuum filtering, and oven drying the filtrate at 50 deg.C to obtain semen glycines extract. Preparing the soybean extract into a solution with the protein content of 5%, heating in a water bath at 85 ℃ for 20min, adding papain with different concentrations of 2000U/g, 4000U/g, 8000U/g, 16000U/g and 32000U/g, hydrolyzing for 60min, controlling the pH value in the hydrolysis process to be 6.91, and drying the hydrolysate in a drying oven at 50 ℃ to obtain the hydrolysate of the soybean extract. The above papain with different concentrations can obtain hydrolysis products with hydrolysis degrees of 1.79%, 2.69%, 6.72%, 7.17% and 8.06%, respectively, and the obtained hydrolysis product with hydrolysis degree of 8.06% has the best corrosion inhibition effect when the enzyme is added at 32000U/g.

Example 3:

this example examined the corrosion inhibiting properties of soy extract hydrolysates of different degrees of hydrolysis.

The soybean extract hydrolysate with different degrees of hydrolysis prepared by the method of example 2 is used as the corrosion inhibitor, and when the adding concentration of the corrosion inhibitor is 400mg/L at 20 ℃, the corrosion inhibition rate of the soybean extract hydrolysate with the degrees of hydrolysis of 1.79%, 2.69%, 6.72%, 7.17% and 8.06% in 1mol/L hydrochloric acid solution to A3 steel is 90.51%, 92.24%, 92.78%, 94.21 and 94.36% respectively.

Example 4:

this example investigates the effect of different hydrochloric acid solution temperatures on corrosion inhibition performance.

The soybean extract hydrolysate with the hydrolysis degree of 8.06 percent prepared by the method of example 1 is used as a corrosion inhibitor, and when the addition concentration of the corrosion inhibitor is 400mg/L at the temperature of 20 ℃, 30 ℃, 40 ℃, 50 ℃ and 60 ℃, the corrosion inhibition rate of the corrosion inhibitor on A3 steel in 1mol/L hydrochloric acid solution is 94.36 percent, 94.45 percent, 96.12 percent, 92.56 percent and 91.38 percent respectively.

Example 5:

this example investigates the effect of different soaking times on corrosion inhibition performance.

The soybean extract hydrolysate with the hydrolysis degree of 8.06 percent prepared by the method of example 1 is used as a corrosion inhibitor, the adding concentration of the corrosion inhibitor at 20 ℃ is 400mg/L, and the corrosion inhibition rate of the corrosion inhibitor on A3 steel in 1mol/L hydrochloric acid solution is 94.36 percent, 95.23 percent and 97.12 percent when the reaction time is 6 hours, 24 hours and 48 hours respectively.