A method for preparing and applying a phenolic cross-linked soybean protein isolate adsorbent and lake.

Abstract

This invention discloses a method for preparing a soy protein isolate adsorbent and a lake. The method first involves mixing soy protein isolate with an alkaline solution and reacting at high temperature to obtain hydrolyzed soy protein isolate. Phenol and formaldehyde are then mixed and heated to obtain a phenolic resin. The hydrolyzed soy protein isolate is then reacted with the phenolic resin, followed by centrifugation and drying to obtain a modified soy protein isolate adsorbent. This adsorbent provides a novel material option for dye and metal ion treatment, and the derived bright lake can be applied in the coloring field, showing broad application prospects.

Description

Technical Field

[0001] This invention focuses on the field of bio-based functional materials, specifically involving a modified adsorbent made from soybean protein isolate as a key raw material. This adsorbent can be used for the adsorption of dyes and metal ions in industrial wastewater treatment, and can also be used to prepare lakes for dyeing biodegradable plastics by adsorbing dyes. It belongs to the fields of bio-based functional adsorbents and biodegradable plastic coloring technology.

[0002] Driven by environmental protection needs and the concept of sustainable development, traditional petroleum-based adsorbents and colorants face severe challenges. On the one hand, traditional petroleum-based adsorbents rely on non-renewable fossil resources, have high energy consumption and high pollution during production, and are prone to leaving residues after adsorption, causing secondary pollution. They also have technical defects such as limited adsorption selectivity, low adsorption capacity, and poor regeneration performance, which seriously restrict the efficiency of environmental governance. On the other hand, traditional petroleum-based colorants commonly used in the field of biodegradable plastics also rely on petroleum resources. Their prices are significantly affected by fluctuations in international oil prices, and their chemical structure is stable and difficult to degrade. When the plastic matrix degrades in the natural environment, the colorants will remain in the form of "microplastic particles," seeping into the soil and water and accumulating through the food chain, threatening the ecosystem and human health.

[0003] Soy protein isolate, as a natural and renewable bio-based raw material, provides an excellent foundation for simultaneously solving the green preparation challenges of adsorbents and lakes: Firstly, soybeans are widely cultivated and abundant, ensuring controllable raw material costs and a stable supply, thus eliminating dependence on petroleum resources; secondly, soy protein isolate is rich in active groups such as amino, carboxyl, and hydroxyl groups, endowing it with natural adsorption capabilities. Through modification and optimization, it can efficiently adsorb dyes and metal ions, and after adsorbing dyes, it can form stable lakes. Furthermore, these lakes exhibit excellent compatibility with bio-based biodegradable plastics, enabling simultaneous degradation with the plastic matrix. Using soy protein isolate as the core raw material, high-performance green adsorbents can be prepared, and environmentally friendly lakes can be derived from these adsorbents, forming a "dual-purpose" functional expansion. This provides a new solution in line with sustainable development principles for the fields of adsorbent materials and biodegradable plastic colorants.

[0004] Soybeans, as an agricultural crop, have a short growth cycle, allowing for a continuous supply of raw materials through agricultural cultivation. Adsorbents prepared based on soy protein isolate can naturally decompose through biodegradation after completing their adsorption function, avoiding the secondary pollution and waste accumulation problems associated with traditional adsorbents. This naturally renewable characteristic creates a closed loop in the production and use of adsorbents, significantly reducing the environmental burden.

[0005] Adsorbents prepared based on soy protein isolate can naturally decompose through biodegradation after completing their adsorption mission, avoiding secondary pollution and waste accumulation problems like traditional adsorbents. The derived lakes avoid the residual risks of traditional petroleum-based colorants, achieving environmental compatibility with biodegradable plastics throughout their entire lifecycle. To simultaneously overcome the technical bottlenecks of traditional adsorbents and the environmental challenges of coloring biodegradable plastics, and to meet the dual needs of industrial wastewater purification and green coloring, this invention aims to develop an adsorbent and lake preparation process using soy protein isolate as the core raw material. This addresses the multiple limitations of traditional materials in terms of environmental friendliness and performance stability, promoting environmental governance and the high-quality development of bio-based materials. Summary of the Invention

[0006] The preparation method proposed in this invention is simple and efficient, with precise and controllable process parameters at each stage, and easily achievable reaction conditions. It also fully utilizes the inexpensive and readily available nature of bio-based soy protein isolate to significantly reduce production costs. The modified soy protein isolate adsorbent prepared by this method possesses excellent pollutant adsorption performance, good mechanical strength, and outstanding environmental stability. It exhibits highly efficient adsorption capacity for dyes and metal ions, while also possessing good regeneration performance and wide applicability. The lake obtained after adsorbing dyes using this adsorbent possesses excellent coloring performance, good material compatibility, and outstanding environmental degradability, and exhibits highly efficient dyeing ability for biodegradable plastics.

[0007] To achieve the objectives of this invention, the following technical solutions are provided: A method for preparing an adsorbent using soy protein isolate as a raw material, characterized by the following steps: Soy protein isolate is mixed with an alkaline solution and reacted at high temperature to obtain hydrolyzed soy protein isolate. Phenol and formaldehyde are mixed and heated to obtain phenolic resin. The hydrolyzed soy protein isolate is reacted with the phenolic resin, and the mixture is centrifuged and dried to obtain a modified soy protein isolate adsorbent.

[0008] Furthermore, the alkaline solution used to prepare hydrolyzed soy protein isolate is a sodium hydroxide or potassium hydroxide solution.

[0009] Furthermore, the temperature for preparing hydrolyzed soy protein isolate is 80~100℃.

[0010] Furthermore, the mass ratio of phenolic resin to hydrolyzed soy protein isolate in the preparation of the soy protein isolate adsorbent is 1:1 to 20.

[0011] The reaction conditions for preparing the soybean protein isolate adsorbent are as follows: temperature 60-100℃ and time 1-20 h.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The adsorbent preparation method using soy protein isolate as the core raw material significantly reduces costs. Soybeans are a widely cultivated crop globally, and their massive yield provides an abundant raw material base for soy protein isolate production, ensuring a stable supply and facilitating large-scale production.

[0013] The prepared modified soybean protein isolate adsorbent can be used for industrial wastewater treatment, meeting the purification needs of different media and environments, and ensuring the removal of dyes and heavy metal ions from complex industrial wastewater. The unique modification process endows the protein adsorbent with abundant active groups and a porous structure, comprehensively improving its adsorption performance and exhibiting excellent selective adsorption, enabling precise and targeted removal of pollutants. Simultaneously, using this adsorbent to adsorb dyes can yield brightly colored lakes. This method adheres to green and environmentally friendly principles, using natural and renewable raw materials, and generating no harmful byproducts during the preparation process. Throughout the entire life cycle of the adsorbent—from use and disposal to degradation—it does not cause environmental pollution, contributing to the environmental protection industry's move towards green and sustainable development. Attached image description: Figure 1 is a graph showing the adsorption capacity of SPI to pCFR in a ratio of 1:0.2 over time in Example 1 of the present invention. Figure 2 (a) shows the adsorption capacity over time under different SPI and pCFR ratios in Example 1 of the present invention; (b) shows the adsorption capacity comparison chart corresponding to different material ratios in Example 1 of the present invention. Detailed Implementation

[0014] The present invention will be further described below through specific embodiments. The following examples are intended to illustrate the invention and not to further limit it. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims. Example

[0015] 5.021g of soy protein isolate was weighed and mixed thoroughly with 50ml of distilled water. The pH was adjusted with sodium hydroxide, and the mixture was heated at 98℃ for 10 hours to obtain hydrolyzed soy protein isolate. 2.030g of phenol and 5.576ml of formaldehyde were weighed, the pH was adjusted to 10 with sodium hydroxide, and the mixture was heated for 1 hour. The temperature was then adjusted to 80℃, and the reaction was allowed to proceed for 2 hours to obtain phenolic resin. Hydrolyzed soy protein isolate and phenolic resin were mixed at a 10:1 ratio (specifically, 40.132g of hydrolyzed soy protein isolate and 4.037g of phenolic resin were mixed). The pH was adjusted to 5 with acetic acid, and the mixture was reacted for 3 hours to obtain a liquid. After centrifugation and cold drying, a modified soy protein isolate adsorbent was obtained. Experiments showed that the adsorbent could complete adsorption within 6 hours, demonstrating excellent adsorption performance.

[0016] Kinetic analysis was performed on the adsorption contact time of malachite green and Congo red. The pseudo-first-order and pseudo-second-order kinetic models are shown in the equations. Eq. (3) and Eq. (4): (3) (4) Here t is time (Min), q e and q t K1 and K2 are the adsorption rates of malachite green at equilibrium and time (mg / g), and k1 and k2 are the adsorption rate constants of the pseudo-first-order and pseudo-second-order kinetic models, respectively.

[0017] The adsorption results of malachite green at initial concentrations can be analyzed isothermally using linearized Langmuir and Freundlich isotherm equations. Eq. (5) and Eq. (6): (5) (6) In the formula, q e For malachite green adsorption equilibrium (mg / g), q max The maximum adsorption concentration of malachite green (mg / g), c e Here, b is the equilibrium concentration of malachite green (mg / L), b is the Langmuir constant, and k is the equilibrium concentration of malachite green. f n is Freundlich's constant.

Claims

1. A method for preparing adsorbents and lakes using soy protein isolate as raw material, characterized by the following steps: Soy protein isolate is mixed with an alkaline solution and reacted at high temperature to obtain hydrolyzed soy protein isolate. Phenol and formaldehyde are mixed and heated to obtain phenolic resin. Hydrolyzed soy protein isolate is reacted with phenolic resin, and after centrifugation and drying, modified soy protein isolate adsorbent is obtained.

2. The method for preparing an adsorbent and a lake as described in claim 1, characterized in that... The alkaline solution used to prepare hydrolyzed soy protein isolate is a sodium hydroxide and potassium hydroxide solution.

3. The method for preparing an adsorbent and a lake as described in claim 1, characterized in that... The temperature for preparing hydrolyzed soy protein isolate is 80~100℃.

4. The method for preparing an adsorbent and a lake as described in claim 1, characterized in that... The mass ratio of phenolic resin to hydrolyzed soy protein isolate in the preparation of soy protein isolate adsorbent is 1:1~20.

5. The method for preparing an adsorbent and a lake as described in claim 1, characterized in that... The reaction conditions for preparing soybean protein isolate adsorbent are a temperature of 60-100℃ and a time of 1-20 h.

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