CN1868576B - Biologically modified diatomite adsorbent and preparation method thereof - Google Patents

Abstract

The invention relates to a biologically modified diatomite adsorbent and a preparation method thereof. The adsorbent is composed of a tannin-modified diatomite carrier and biological cells or biological organic components fixed thereon, and is used for adsorbing and removing diatomite in samples. Harmful substances such as proteins, heavy metals, iron, pesticide residues, and antibiotics can also be used to immobilize biological enzymes, biological cells, and biological macromolecules. The adsorbent of the invention has the advantages of high selectivity, strong enrichment capacity, low price, no pollution and the like.

Description

Biologically modified diatomite adsorbent and preparation method thereof

technical field

The present invention relates to biosorbent and its preparation method. In particular, it relates to a biologically modified diatomite adsorbent and a preparation method thereof.

Background technique

Adsorption is an important method for separating impurities in liquids or extracting useful substances in liquids, and is widely used in beverage preparation, industrial wastewater treatment, oil product manufacturing, pharmaceutical industry, and chemical analysis. The existing adsorbents are divided into inorganic adsorbents, organic adsorbents and biological adsorbents. The key to determining the applicability of an adsorbent lies in its chemical composition and surface properties.

Commonly used inorganic adsorbents include silica gel, alumina, activated carbon, diatomaceous earth, magnesium oxide, calcium carbonate, calcium phosphate, clay, perlite, vermiculite, expanded shale, and natural zeolite. Inorganic adsorbents can be used to adsorb various types of hydrocarbons, acids and their derivatives, alcohols, aldehydes, ketones, esters and nitro compounds, as well as to selectively adsorb molecules of different sizes or ions of different polarities. Easy to obtain and practical, it is the commonly used adsorbent for decolorization, odor removal and water treatment. Inorganic adsorbents have disadvantages such as poor selectivity, weak enrichment ability, and inability to adjust adsorption performance.

Organic adsorbents are divided into natural organic adsorbents and synthetic adsorbents. Natural organic adsorbents such as cellulose, starch, and sucrose have the advantages of being cheap, non-toxic, and easy to obtain. At present, many researchers have used them and modified them to develop a variety of adsorbents. Fanta et al. used different initiators and different monomers to graft and polymerize cross-linked starch, and developed adsorbents with different properties. Wang Yuting et al. used Fe ²⁺ and --H ₂ O ₂ as initiators to graft acrylonitrile onto the crosslinked starch backbone, and the grafted carboxylated starch developed could effectively remove Cd ²⁺ , Pb ²⁺ , Cu ²⁺ , Hg ²⁺ , Cr ³⁺ , etc. (Liu Minghua et al., Chemical Environmental Protection, 2001, 21(1): 1~5). However, a major drawback of organic adsorbents is the difficulty in regeneration. Synthetic adsorbents generally have a large specific surface area and sufficient adsorption capacity; they have different adsorption capacities for different substances to be separated, that is, they have sufficient resolution; they will not chemically react with eluents, solvents and sample components ; The adsorbent particles are uniform. The ability to regenerate is a major advantage of synthetic adsorbents. Commonly used synthetic adsorbents are polyurethane, polypropylene, and resins with a large number of meshes. The disadvantages of synthetic adsorbents are that it is difficult to make, high in cost, easy to age, and may cause residual chemical toxicity pollution to food and medicine.

In recent years, there have been many studies on the use of biological cells and natural organic matter adsorption at home and abroad. Foreign countries use biosorption to remove heavy metals in wastewater. Greene uses algae to remove gold in water (Geene Betal., Environ.Sci.Technol., 1986, 20:627～632), and Tsezo/Maranon uses fungi to adsorb uranium in water (Tsezos Metal, Biotechnol Bioeng., 1998, 32:545 ~550). Mark Spint etc. immobilized peat moss in a porous polymeric sulfone matrix and successfully applied it to remove metal ions such as Zn ²⁺ , Cd ²⁺ , Mg ²⁺ in acidic mine water (Mark Spintietal., Water Environment Research., 1995, 67 (6): 943-952). Biosorbent is a special ion exchanger in which microorganisms are used and biological cells play a major role. Studies have found that bacteria, fungi, algae and other microorganisms can adsorb or enrich heavy metals, not only on the surface of living microbial cells, but also on the surface of dead microbial cells. Exchange and combine with each other. The effect of using biosorbent to remove heavy metal ions in water is significantly higher than that of ordinary ion exchangers. The preparation of biosorbents is to immobilize microorganisms on the carrier in a certain way. Commonly used methods for immobilizing microbial cells include adsorption, covalent bonding, cross-linking and embedding.

There is no report on the biologically modified diatomite adsorbent.

Contents of the invention

The purpose of the present invention is to provide a biologically modified diatomite adsorbent. The adsorbent is composed of a tannin-modified diatomite carrier and biological cells or biological organic components fixed on it. It is used to adsorb and remove harmful substances such as proteins, heavy metals, iron, pesticide residues, and antibiotics in samples. It can also be used for Immobilize biological enzymes, biological cells and biological macromolecules.

Another object of the present invention is to provide a preparation method of the adsorbent.

The biologically modified diatomite adsorbent of the present invention is white or brown particles with a slight fragrance and a fineness of 20-100 mesh. The adsorbent is composed of a tannin-modified diatomite carrier and biological cells or biological Consists of organic components, wherein the tannin-modified diatomite carrier is composed of diatomite carrier particles and tannin immobilized thereon, the ratio of the amount of diatomite carrier particles, tannin and biological cells or biological organic components (by weight ) is 10:1~3:1~4.

In the present invention, the diatomite carrier particles are uniform particles obtained by calcining diatomite at 800°C, washing, drying, pulverizing and sieving, with a fineness of 20-100 mesh. Diatomite should be pure, light, fine-grained and porous diatomite, that is, the content of SiO ₂ should be 80-90% (dry basis, by weight), and the density after drying should be 0.4-0.7g/cm ³ , The diatomite has a porosity of 85-95%, and can absorb 1.5-4 times its own weight of water. After the diatomite is calcined and cleaned at 800 ° C, complex organic matter and soluble impurities are removed, but the natural diatom skeleton remains. Structure and unique shape, so the diatomaceous earth carrier is essentially a loose skeleton of _SiO2 .

Tannin is a tannin component extracted from natural plants. In the present invention, natural tannin adopts hydrolyzed tannin or condensed tannin with a molecular weight of 500-1000, such as pentagaltannin, oak bowl tannin, larch tannin, Black Vitex tannin, tea tannin, etc.

Biological cells or biological organic components are selected from protein molecules, peptide molecules or biological cells that have an affinity for the substances to be adsorbed, such as yeast cells, enzymes with biological activity, antibodies, etc. In practical applications, targeted biological cells or biological organic components can be selected according to different adsorbed target substances.

The present invention fixes the tannins on the diatomite. The present invention fixes the tannins on the diatomite carrier particles by bio-enzyme technology to make a tannin-modified diatomite carrier, and then will have affinity for the substances to be adsorbed. The biological cells or bio-organic components that interact with the tannins are fixed on the tannin-modified diatomite carrier to make a bio-modified diatomite adsorbent. Its preparation method comprises the following steps:

1. Calcinate diatomite at 800°C for 1 hour, cool it to room temperature, wash it with water, dry it, then crush it with airflow, and select uniform particles of 20-100 meshes by sieving to make diatomite carrier particles;

2. Mix 5% (by weight) aqueous solution of bio-organic molecules with diatomite carrier particles in a ratio of 3:1 (by weight), dry at 60-70°C for 3 hours and pass through a 20-100 mesh sieve to prepare into fine powder A;

3. Add 5%-15% (by weight) tannin aqueous solution to 5 times the amount of 40°C water, and then add 0.06%-0.2% oxidase in dry weight of tannin to make solution B;

4. Add the fine powder A to the solution B, heat it at 40°C for 1 hour, then centrifuge to remove the reaction solution, wash and dry the precipitate to make a tannin-modified diatomite carrier;

5. Dissolve biological cells or biological organic components in 8-15 times the amount of 40°C water, then add 50% glutaraldehyde (aqueous solution, volume ratio) and tannin-modified diatomite carrier of 5% of the weight of the carrier, After heat preservation at 40°C and reaction for 10 hours, centrifuge to remove the reaction solution, wash and dry the precipitate, and pass through a 20-100 mesh sieve to make a biomodified diatomite adsorbent;

Among the present invention, the dosage ratio (by weight) of diatomaceous earth carrier particle, tannin and biological cell or biological organic component is 10: 1～3: 1～4; 8000 protein, such as 2000-6000 collagen.

Beneficial effect

1. The present invention uses biological enzyme technology to fix natural tannin on the diatomite skeleton, and evenly combines tannin macromolecules on the adsorption surface of diatomite, and its surface action involves electrostatic interaction, van der Waals force, and hydrophobic interaction Force, hydrogen bonding, chelation, and spatial size and shape matching and other factors, rather than a single physical and chemical effect, the peptide bond of the protein can undergo multi-point chelation cross-linking with the tannin bound on the surface of the adsorbent Therefore, it has the advantages of easy fixation, good mass transfer performance, stable properties and high strength.

2. The present invention uses the diversity and selectivity of protein molecules to selectively immobilize suitable biological macromolecules that have an affinity for the adsorbed substances on the modified diatomite carrier, and the obtained adsorbent can be targeted Adsorption of target substances with high selectivity and strong enrichment ability.

3. The adsorbent of the present invention is made of natural raw materials, which is cheap and pollution-free.

Description of drawings

Fig. 1 is a flow chart of the preparation process of the biologically modified diatomite adsorbent of the present invention.

Detailed ways

The method of the present invention will be further described below by way of examples, but the present invention is not limited.

In the following preparation examples, the SiO ₂ content of diatomite is 80-90%, the density after drying is 0.5g/cm ³ , the porosity reaches 88%, and the diatomite can absorb 2.5 times its own weight of water.

Example 1

Calcinate diatomaceous earth at 800°C for 1 hour, cool to room temperature, wash with water, dry, then air-flow crush, sieve, select 10Kg of 20-mesh uniform particles; take 1.5Kg of collagen and dissolve it with 10 times the amount of water and add water to After 30Kg, mix with diatomite, dry at 65°C for 3 hours, and pass through a 20-mesh sieve to make fine powder A; take 2Kg of larch tannin and dissolve it in 18Kg of hot water, add 100Kg of 40°C warm water, and add 2g of polyphenol oxidase (polyhphenol oxidase referred to as PPO) to make solution B; add fine powder A to solution B, react at 40°C for 1 hour, centrifuge to remove the reaction solution, wash, and dry the precipitate to obtain 13kg of tannin-modified diatomite carrier; another 3kg of pancreatic Dissolve protease in 30kg of water at 40°C, add 650g of 50% glutaraldehyde and 13kg of tannin-modified diatomite carrier, keep warm at 40°C for 10 hours, centrifuge to remove the reaction solution, wash with water, dry the precipitate, and pass through a 20-mesh sieve. Obtain JM immobilized trypsin.

Example 2

Calcinate diatomaceous earth at 800°C for 1 hour, cool to room temperature, wash with water, dry, then air-flow crush, sieve, select 10Kg of 80-mesh uniform particles; take 1.5Kg of collagen and dissolve it with 10 times the amount of water and add water to After 30Kg, mix with diatomite, dry at 65°C for 3 hours, pass through an 80-mesh sieve to make fine powder A; take 1Kg of tea tannin, dissolve it in 19Kg of hot water, add 100Kg of 40°C warm water, and add 2g of polyphenol oxidase to make it Solution B; add fine powder A to solution B, react at 40°C for 1 hour, remove the reaction solution by centrifugation, wash, and dry the precipitate to obtain 12 kg of tannin-modified diatomaceous earth carrier; 2 kg of egg white that has an affinity with chlorogenic acid Dissolve the protein in 28kg of water at 40°C, add 500g of 50% glutaraldehyde and 10kg of the tannin-modified diatomite carrier prepared above, keep it warm at 40°C for 10 hours, remove the reaction solution by centrifugation, wash with water, and dry the precipitate , through 80-mesh sieve to obtain JM-LY chlorogenic acid-type adsorbent.

Example 3

Calcinate diatomaceous earth at 800°C for 1 hour, cool to room temperature, wash with water, dry, then air-flow crush, sieve, select 10Kg of 100-mesh uniform particles; take 1.5Kg of collagen and dissolve it with 10 times the amount of water and add water to After 30Kg, mix with diatomite, dry at 65°C for 3 hours, pass through a 100-mesh sieve to make fine powder A; take 3Kg of tea tannins, dissolve them in 17Kg of hot water, add 100Kg of 40°C warm water, and add 2g of polyphenol oxidase to prepare into solution B; add fine powder A to solution B, react at 40°C for 1 hour, centrifuge to remove the reaction solution, wash, and dry the precipitate to obtain 14kg of tannin-modified diatomite carrier; dissolve 4kg of gelatin protein in 27kg of water at 40°C, Add 500g of 50% glutaraldehyde and 10kg of the tannin-modified diatomite carrier prepared above, keep warm at 40°C for cross-linking reaction for 10 hours, centrifuge to remove the reaction solution, wash with water, dry the precipitate, and sieve to obtain JM tannin adsorption agent.

comparative example

Take two parts of 5kg honeysuckle and add 40kg of water respectively, extract at 90-100°C for 20 minutes, filter the extract and cool to 30°C, adjust the pH of one part of the extract to 7.5 and add 1kg of JM prepared in Example 2 -LY chlorogenic acid-type adsorbent, adjust pH to 7 and add 1kg D309 macroporous adsorption resin to another part of the extract, stir for 40 minutes, centrifuge to remove the original solution, and add 5Kg 2% citric acid solution to stir and elute , collected the filtrate by centrifugation, and eluted twice in this way; the two eluents were combined, concentrated, and dried to obtain the corresponding Silver Flower extract, and the JM-LY chlorogenic acid-type adsorbent was 223.5g. Resin adsorbate was 434.5g; the content of chlorogenic acid in the two powders were detected by ultraviolet spectrophotometry.

The results are shown in Table 1.

Table 1

Table 1 shows that the effect of extracting chlorogenic acid by the adsorbent of the present invention, including the yield and content of chlorogenic acid, is significantly better than that of common macroporous adsorption resins. It can be seen that the adsorbent of the present invention has high enrichment rate, high selectivity, etc. advantage.

Claims (7)

1. A bio-modified diatomite adsorbent, characterized in that the bio-modified diatomite adsorbent consists of a tannin-modified diatomite carrier and a material that has an affinity for the substance that needs to be adsorbed on it. Protein molecules or biological cells, wherein the tannin-modified diatomite carrier is composed of diatomite carrier particles and tannin immobilized on it by bio-enzyme technology, diatomite carrier particles, tannin and protein molecules or biological cells The dosage ratio is 10:1～3:1～4 by weight. 2. The biologically modified diatomite adsorbent according to claim 1, characterized in that the fineness of the biomodified diatomite adsorbent is 20-100 mesh. 3. The biologically modified diatomite adsorbent according to claim 1, characterized in that the fineness of the diatomite carrier particles is 20-100 mesh. 4. The biologically modified diatomite adsorbent according to claim 1, characterized in that the tannin is a hydrolyzed tannin or a condensed tannin with a molecular weight of 500-1000. 5. the preparation method of biologically modified diatomite adsorbent as claimed in claim 1, comprises the steps: (1) Calcining diatomite at 800°C for 1 hour, cooling to room temperature, washing with water, drying, crushing by air flow, and sieving to select uniform particles of 20-100 mesh to make diatomite carrier particles; (2) Mix 5% protein molecule aqueous solution by weight with diatomite carrier particles in a ratio of 3:1 by weight, dry at 60-70°C for 3 hours and pass through a 20-100 mesh sieve to make a fine powder A; (3) adding 5%-15% tannin aqueous solution by weight to 5 times the amount of 40°C water, and then adding 0.06%-0.2% oxidase of the dry weight of tannin to prepare solution B; (4) Add the fine powder A into the solution B, heat it at 40° C. for 1 hour, react and fix it for 1 hour, centrifuge to remove the reaction solution, wash and dry the precipitate to make a tannin-modified diatomite carrier; (5) dissolving protein molecules or biological cells in 8-15 times the amount of water at 40°C, then adding 5% of the carrier weight in 50% by volume glutaraldehyde aqueous solution and the tannin-modified diatoms made in step (4) The soil carrier is kept at 40°C for 10 hours, reacted and fixed for 10 hours, centrifuged to remove the reaction solution, washed and dried, and passed through a 20-100 mesh sieve to make a biomodified diatomite adsorbent. 6. the preparation method of biologically modified diatomite adsorbent according to claim 5 is characterized in that in step (1), diatomite is that _SiO content is 80-90% by weight, density after drying is 0.4～0.7 g/cm ³ , a porosity of 85-95%, and a diatomite that can absorb 1.5-4 times its own weight of water, wherein the content of SiO ₂ in the diatomite is calculated on a dry basis. 7. The preparation method of biomodified diatomite adsorbent according to claim 5, characterized in that said protein molecule is a protein molecule with a molecular weight of 2000-8000.

Images