CN115650448B - Composite flocculant based on modified diatomite and application thereof - Google Patents

Abstract

This case involves a composite flocculant based on modified diatomite, including 20 to 40 parts of modified diatomite, 10 to 15 parts of inorganic flocculant and 0.1 to 0.5 parts of microbial flora; wherein, the modified diatom The soil is firstly treated with sodium hydroxide, then treated with polyethylene glycol, coated with aluminum, and finally coated with polyethylenediamine. The surface modification of diatomite in this case can effectively increase the pore size and pore volume of diatomite; can effectively remove metal ions in water; can effectively adsorb impurities such as nitrogen and phosphorus in water; prolong the service life and increase the adsorption site It also has a certain degree of adsorption to the organic matter in the water body; through the adsorption of modified diatomite, the impurity pollutants in the water body are gathered, and then the inorganic flocculant and microbial flora assist in the flocculation, precipitation and degradation of the pollution in the water body , Effectively reduce metal ions and organic matter in wastewater.

Description

A kind of composite flocculant based on modified diatomite and its application

technical field

The invention relates to the field of water treatment, in particular to a modified diatomite-based composite flocculant and its application.

Background technique

Water is one of the most important natural resources for human survival and an indispensable resource for all ecosystems. Although my country has a vast territory and numerous rivers and seas, the per capita water resources in the country are very low. Especially with the rapid development of the economy, a large amount of domestic sewage, industrial wastewater and agricultural wastewater have seriously polluted the water environment, and even affected the lives of animals, plants and human beings. In the face of increasingly stringent environmental protection standards and requirements, and in order to reduce the energy and resource requirements required in the sewage treatment process and reduce the potential risk of secondary pollution, it is necessary to develop new and efficient water treatment processes and water treatment agents.

Commonly used sewage treatment methods are: ion exchange method, precipitation method, suspension method, adsorption method, flocculation method, biological method, etc. The flocculation method can destabilize and gather various solutes, suspended particles or colloids in the aqueous solution to form flocs through the flocculant, so as to accelerate the sedimentation. It is a simple and efficient wastewater treatment method, and is usually combined in industry. Biological method and adsorption method are used.

Most commercial organic synthetic flocculants are based on petroleum, which are produced after chemical processing and are non-renewable resources. At present, people turn to look for natural resources in nature to replace organic synthetic flocculants.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention proposes a composite flocculant based on natural resource diatomite combined with inorganic flocculants and biological flora. Compared with traditional flocculants, the flocculation effect is better good.

To achieve the above object, the present invention provides the following technical solutions:

A composite flocculant based on modified diatomite, comprising 20-40 parts of modified diatomite, 10-15 parts of inorganic flocculant and 0.1-0.5 parts of microbial flora; wherein, the modified diatomite The preparation process is as follows:

1) Weigh a certain amount of diatomaceous earth into a conical flask, add sodium hydroxide solution, shake at a constant temperature of 40°C for 2-3 hours; Calcined for 2-3 hours to obtain powder;

2) After the powder is cooled, place it in an aqueous solution of polyethylene glycol, disperse it evenly with ultrasonic vibration, heat it to 60°C, and then add sodium metaaluminate to it. The amount of sodium metaaluminate is 1.5% of the mass of the powder. % to 2.5%, stirred at constant temperature for 1 hour to obtain slurry;

3) Add polyethylenediamine to the slurry, raise the temperature to 80-90°C, and stir for 1-2 hours; after cooling to room temperature, separate the solid from the liquid, dry and grind the solid to obtain the modified diatomite.

Preferably, the concentration of the sodium hydroxide solution is 10M, and the volume to mass ratio of the sodium hydroxide solution to diatomaceous earth is 4ml:1g.

Preferably, the mass of polyethylene glycol in the step 2) is 1-1.5% of the mass of the powder.

Preferably, the polyethylenediamine is used in an amount of 70-100% of the mass of the powder.

Preferably, the inorganic flocculant is one or more combinations of polyaluminum sulfate, polyaluminum silicate, polyferric silicate, ferric chloride and polyaluminum chloride.

Preferably, the microbial flora is at least two of yeast, lactic acid bacteria, Bacillus subtilis and nitrifying bacteria.

Preferably, the composite flocculant further includes 1-3 parts of a coagulant aid, and the coagulant aid is polyacrylamide or chitosan.

Compared with prior art, the beneficial effect of the present invention is:

Diatomite has a porous structure and a large specific surface area. In this case, it is first treated with sodium hydroxide, which can effectively increase the pore size of diatomite; after calcination, impurities are further removed and the pore volume is increased; polyethylene glycol is added Increase the steric hindrance, and then increase the contact area when mixed with sodium metaaluminate, which can effectively remove metal ions in the water body; use aluminum to coat it, and the aluminum is positively charged, so the surface of the modified diatomite is electrically charged. Changes can effectively adsorb impurities such as nitrogen and phosphorus in the water body; finally, the addition of polyethylenediamine forms a protective layer on the surface of diatomite, which prolongs the service life on the one hand, and increases the adsorption sites on the other hand, which also has a certain effect on the organic matter in the water body. A certain degree of adsorption.

Through the adsorption of modified diatomite, the impurities and pollutants in the water body are gathered, and then the inorganic flocculant and microbial flora assist in the flocculation, sedimentation and degradation of the pollution in the water body, effectively reducing the metal ions and organic matter in the wastewater.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as there is no conflict with each other.

Example 1:

A composite flocculant based on modified diatomite, including 20 parts of modified diatomite, 10 parts of inorganic flocculant (polyaluminum sulfate and polyaluminum silicate 1:1), 0.1 part of microbial flora; wherein, the The preparation process of the modified diatomite is as follows:

1) Weigh a certain amount of diatomaceous earth into an Erlenmeyer flask, add 10M sodium hydroxide solution according to the mass volume ratio of 1g:4ml, shake at a constant temperature at 40°C for 2-3 hours; after the end, filter and wash with water until neutral , after drying, calcining at 350-400°C for 2-3 hours to obtain powder;

2) After the powder is cooled, place it in an aqueous solution of polyethylene glycol containing 1% of the powder mass, disperse it evenly by ultrasonic oscillation, heat to 60°C, and then add sodium metaaluminate, sodium metaaluminate The dosage is 1.8% of the mass of the powder, and stirred at constant temperature for 1 hour to obtain a slurry;

3) Add 70% polyethylenediamine to the slurry, heat up to 80-90°C, stir for 1-2 hours; cool to room temperature, separate the solid from the liquid, dry and grind the solid to obtain the modification diatomite.

Example 2:

A composite flocculant based on modified diatomite, including 30 parts of modified diatomite, 12 parts of inorganic flocculants (polyferric silicate, ferric chloride and polyaluminum chloride 1:1:2), 0.2 parts Microflora and 1 part of chitosan; Wherein, the preparation process of the modified diatomite is as follows:

1) Weigh a certain amount of diatomaceous earth into an Erlenmeyer flask, add 10M sodium hydroxide solution according to the mass volume ratio of 1g:4ml, shake at a constant temperature at 40°C for 2-3 hours; after the end, filter and wash with water until neutral , after drying, calcining at 350-400°C for 2-3 hours to obtain powder;

2) After the powder is cooled, place it in an aqueous solution of polyethylene glycol containing 1.2% of the mass of the powder, disperse it evenly by ultrasonic oscillation, heat it to 60°C, and then add sodium metaaluminate, sodium metaaluminate The dosage is 1.8% of the mass of the powder, and stirred at constant temperature for 1 hour to obtain a slurry;

3) Add 80% polyethylenediamine to the slurry, heat up to 80-90°C, and stir for 1-2 hours; after cooling to room temperature, separate the solid from the liquid, dry and grind the solid to obtain the modification diatomite.

Example 3:

A composite flocculant based on modified diatomite, including 40 parts of modified diatomite, 15 parts of inorganic flocculant (polyaluminum silicate, polyferric silicate and polyaluminum chloride 2:1:1), 0.2 Part microbial flora and 1 part chitosan; Wherein, the preparation process of described modified diatomite is as follows:

1) Weigh a certain amount of diatomaceous earth into an Erlenmeyer flask, add 10M sodium hydroxide solution according to the mass volume ratio of 1g:4ml, shake at a constant temperature at 40°C for 2-3 hours; after the end, filter and wash with water until neutral , after drying, calcining at 350-400°C for 2-3 hours to obtain powder;

2) After the powder is cooled, place it in an aqueous solution of polyethylene glycol containing 1.5% of the powder mass, disperse it evenly by ultrasonic oscillation, heat it to 60°C, and then add sodium metaaluminate, sodium metaaluminate The dosage is 2.5% of the mass of the powder, and stirred at constant temperature for 1 hour to obtain a slurry;

3) Add 100% polyethylenediamine to the slurry, heat up to 80-90°C, and stir for 1-2 hours; after cooling to room temperature, separate the solid from the liquid, dry and grind the solid to obtain the modification diatomite.

Comparative example 1:

Same as Example 3, the difference lies in the preparation of the modified diatomite. After step 2), the slurry is directly separated from the solid and liquid, and the solid is dried and ground to obtain the modified diatomite.

Comparative example 2:

Same as Example 3, the difference is that the same amount of unmodified diatomite is used to replace the modified diatomite.

Comparative example 3:

The modified diatomite was removed, and the remaining components were the same as in Example 3.

Product Effect Test

The simulated wastewater was treated with the composite flocculants prepared in Examples 1-3 and Comparative Examples 1-3.

The composition of the simulated wastewater is shown in Table 1:

Table 1

Element <![CDATA[Fe²⁺]]> <![CDATA[Zn²⁺]]> <![CDATA[Cd²⁺]]> Ammonia nitrogen Total Phosphorus COD Concentrationmg/L 90 80 60 70 100 300

Add 50 mg of composite flocculant to 1L of simulated wastewater, stir and mix evenly, let it stand for a day, and test the removal rate of ions and COD in wastewater. The results are shown in Table 2.

Table 2

<![CDATA[Fe²⁺/%]]> <![CDATA[Zn²⁺/%]]> <![CDATA[Cd²⁺/%]]> Ammonia nitrogen/% Total Phosphorus/% COD/% Example 1 88.5 90.1 87.2 94.1 94.5 92.5 Example 2 89.1 90.5 88.1 95.8 95.1 93.8 Example 3 89.9 91.6 88.8 97.2 96.6 95.1 Comparative example 1 72.6 70.3 65.3 82.5 82.2 80.1 Comparative example 2 69.5 66.5 60.2 81.5 82.0 82.1 Comparative example 3 65.1 60.3 58.7 75.3 70.1 76.4

It can be seen from the above table that the modified diatomite-based composite flocculant of the present invention has a good removal effect on heavy metal ions, ammonia nitrogen, total phosphorus and organic matter.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Therefore, the invention is not limited to the specific details without departing from the general concept defined by the claims and their equivalents.

Claims (6)

1. A composite flocculant based on modified diatomite, characterized in that it comprises 20 to 40 parts of modified diatomite, 10 to 15 parts of inorganic flocculants and 0.1 to 0.5 parts of microbial flora; wherein, the The preparation process of modified diatomite is as follows: 1) Weigh a certain amount of diatomaceous earth into a conical flask, add sodium hydroxide solution, shake at a constant temperature of 40°C for 2-3 hours; after the end, filter, wash with water until neutral, dry at 350-400°C Calcined for 2-3 hours to obtain powder; 2) After the powder is cooled, place it in an aqueous solution of polyethylene glycol, disperse it evenly with ultrasonic vibration, heat it to 60°C, and then add sodium metaaluminate to it. The dosage of sodium metaaluminate is 1.5% of the mass of the powder. % to 2.5%, stirred at constant temperature for 1 hour to obtain slurry; 3) Add polyethylenediamine to the slurry, raise the temperature to 80-90°C, and stir for 1-2 hours; after cooling to room temperature, separate the solid from the liquid, dry and grind the solid to obtain modified diatomite; The dosage of the polyethylenediamine is 70-100% of the mass of the powder; the microbial flora is at least two kinds of yeast, lactic acid bacteria, bacillus subtilis and nitrifying bacteria. 2. the composite flocculant based on modified diatomite as claimed in claim 1, is characterized in that, the concentration of described sodium hydroxide solution is 10M, and its volume mass ratio with diatomite is 4ml: 1g. 3. The composite flocculant based on modified diatomite as claimed in claim 1, characterized in that, the quality of polyethylene glycol in the step 2) is 1 to 1.5% of the powder mass. 4. the composite flocculant based on modified diatomite as claimed in claim 1, is characterized in that, described inorganic flocculant is polyaluminum sulfate, polyaluminum silicate, polyferric silicate, ferric chloride and polychloride One or more combinations of aluminum oxides. 5. The composite flocculant based on modified diatomite according to claim 1, characterized in that, the composite flocculant also includes 1 to 3 parts of coagulant aid, and the coagulant aid is polyacrylamide or shell polysaccharides. 6. The application of the composite flocculant based on modified diatomite according to any one of claims 1-5 in the simultaneous removal of heavy metal ions and organic pollutants in wastewater.