CN109437377B

CN109437377B - Preparation method of sewage treatment flocculant

Info

Publication number: CN109437377B
Application number: CN201811485505.6A
Authority: CN
Inventors: 陈伟; 陈建平
Original assignee: Hunan Linghui Environmental Protection New Material Technology Co ltd
Current assignee: Hunan Linghui Environmental Protection New Material Technology Co ltd
Priority date: 2018-12-05
Filing date: 2018-12-05
Publication date: 2021-05-11
Anticipated expiration: 2038-12-05
Also published as: CN109437377A

Abstract

The invention provides a preparation method of a sewage treatment flocculant, which comprises the steps of firstly, uniformly mixing diallyl bromide pyrrolium salts and diallyl bromide piperidinium salts to obtain a mixture, then adding a certain amount of calcium silicate and kieselguhr into the mixture, and uniformly mixing to obtain the flocculant. The sewage treatment flocculant has the advantages of multiple functional groups, large generated floc, high flocculation speed, short time required by the treatment process, good treatment effect, less consumption, small sludge production amount, 90 percent of turbidity removal rate of domestic sewage and 80 percent of COD removal rate.

Description

Preparation method of sewage treatment flocculant

Technical Field

The invention belongs to the field of sewage purification, and particularly relates to a preparation method of a sewage treatment flocculant.

Background

With the proliferation of population and the development of modern industry and agriculture, the water consumption is increased sharply in recent years, especially the development of industry, a large amount of industrial water is needed, and then the produced industrial wastewater is increased day by day, so that the pollution of water is accelerated, and therefore how to treat sewage effectively and cheaply becomes urgent.

The flocculation precipitation method is that a certain amount of flocculant is added into the wastewater to carry out physical and chemical reaction, thereby achieving the purpose of water purification, and is an economic and simple water quality treatment method commonly used at home and abroad at present. The core and key of the flocculation precipitation method is the selection of a flocculating agent, and the property of the flocculating agent directly influences the quality of a flocculation effect. With the increase of water pollution, the simple inorganic salt flocculant can not meet the requirement of the existing water treatment, and the appearance of the polymeric flocculant is changed from a single type to a composite type, so that the water treatment efficiency is greatly improved.

At present, the research on the organic polymeric flocculant is mainly natural polymeric compounds, most researches are starch, chitosan and microbial extracellular polymeric compounds, however, the research, production and application of the organic polymeric flocculant in China are still in the development stage and still belong to weak links. The technical gap is large and mainly appears as follows: the serialization level is low, the special varieties are few, and the commercialized products only comprise two categories of polyacrylamide and polyacrylic acid; the yield is low, the economic scale is not formed, and some foreign industrialized varieties are still not in the passing of China; the production is lagged behind, and the overall quality level is not high. Therefore, the search for efficient and economic flocculating agents is always a technical problem of research in the field.

Disclosure of Invention

The invention aims to provide a high-efficiency and economic flocculating agent which can effectively reduce the turbidity and the chemical oxygen demand of domestic sewage.

The preparation method of the sewage treatment flocculant comprises the following steps:

(1) uniformly mixing diallyl bromide pyrrolium salt and diallyl bromide piperidinium salt according to the weight ratio of (1-3) to (1-2) to obtain a mixture;

(2) mixing the mixture with calcium silicate and diatomite according to a weight ratio of 10: (4-5): and (3-7) uniformly mixing to obtain the sewage treatment flocculant.

Preferably, the sewage treatment flocculant further comprises 2-amino-3-methylpyridine, wherein the weight ratio of the mixture to the 2-amino-3-methylpyridine is 10: (0.08-0.15), preferably 10: 0.1.

preferably, the weight ratio of the diallyl pyrrolium bromide to the diallyl piperidinium bromide is 1: 1.

Preferably, the weight ratio of the mixture to the calcium silicate and the diatomite is 10: 4.5: 5.

preferably, the calcium silicate is a synthetic porous calcium silicate.

Wherein, the preparation of the brominated diallyl pyrrolium salt comprises the following steps:

(1) taking diallylamine and 1, 4-dibromobutane according to the molar ratio of (2-4) to (1-3) and the volume ratio of (5-8): (1-3) taking K₂CO₃Solutions and alkali solutions;

(2) reacting diallylamine with K₂CO₃Adding the solution into a reaction container, heating to 60-70 ℃, alternately dropwise adding 1, 4-dibromobutane and an alkali solution into the reaction container, and continuing to react for 3-6h after dropwise adding is finished;

(3) after the reaction is finished, standing and separating the solution in the reaction container to obtain a water phase and an oil phase;

(4) concentrating the water phase, adding absolute ethyl alcohol for dissolving, and filtering;

(5) and (3) carrying out secondary concentration on the filtrate, adding acetone for crystallization, filtering, washing the filtered crystal with acetone again, and drying in vacuum to obtain the brominated diallyl pyrrolium salt.

The preparation of the diallyl piperidine onium bromide comprises the following steps:

(1) taking diallyl amine and 1, 5-dibromopentane according to the mol ratio of (2-4) to (1-3) and according to the volume ratio of (5-8): (1-3) taking K₂CO₃Solutions and alkali solutions;

(2) reacting diallylamine with K₂CO₃Adding the solution into a reaction container, heating to 60-70 ℃, alternately dropwise adding 1, 5-dibromopentane and an alkali solution into the reaction container, and continuing to react for 3-6h after dropwise adding is finished;

(5) and (3) carrying out secondary concentration on the filtrate, adding acetone for crystallization, filtering, washing the filtered crystal with acetone again, and drying in vacuum to obtain the brominated diallyl piperidinium salt.

Preferably, the molar ratio of diallylamine to 1, 4-dibromobutane is 3: 2.

Preferably, the molar ratio of the diallylamine to the 1, 5-dibromopentane is 3: 2.

And (3) taking the reaction vessel in the step (2) as a reaction kettle, and respectively placing 1, 5-dibromopentane and an alkali solution into a constant-pressure dropping funnel when dripping.

Wherein, K is₂CO₃The mass fraction of the solution was 40%.

The alkali solution is NaOH solution, and the concentration is 1 mol/L.

Preferably, said K₂CO₃The volume ratio of the solution to the alkali solution is 7: 2.

Preferably, the heating temperature of the reaction kettle is 65 ℃.

In the step (2), the dropping alternation time of the 1, 4-dibromobutane or the 1, 5-dibromopentane and the alkali solution is 30 to 90s, preferably 60 s.

The time for standing and liquid separation in the step (3) is 15 min.

The crystallization with acetone in step (5) is carried out at a low temperature of 10-20 deg.C, preferably 15 deg.C.

And (5) vacuum drying for 8h at the temperature of 60 ℃.

According to research, the invention discovers that the flocculation effect of the composite flocculant obtained by adopting the diallyl bromide piperidinium salt and matching with the conventional inorganic flocculant diatomite and the synthetic porous calcium silicate is superior to that of the inorganic flocculant, the turbidity removal rate and the COD removal rate are higher when domestic sewage is treated, and the treatment requirement in the aspect of domestic sewage can be met. Further research finds that the addition of the diallyl bromide pyrrolium salt can further improve the turbidity removal rate and COD removal rate of the domestic sewage, and can be applied to the field of industrial wastewater treatment, and possible reasons are that the diallyl bromide pyrrolium salt and the diallyl bromide piperidinium salt have high positive charge density and more functional groups, and the positive charge groups contained in the diallyl bromide pyrrolium salt and the diallyl bromide piperidinium salt promote colloidal particles to aggregate into floccules through the electric neutralization effect of the positive charge groups on negative charge organic colloids in the sewage and the excellent bridging and coagulating function of macromolecules, and the floccules are separated from the suspension of the colloidal particles.

However, the relative molecular mass of the diallyl pyrrolium bromide and the diallyl piperidinium bromide is low, so that only small and compact flocs can be formed in the suspended matters during flocculation, and the coagulation effect is poor. In order to improve the flocculation effect, those skilled in the art generally combine the organic polymeric flocculant with high relative molecular mass, and utilize the cationic group in the molecular structure of the organic polymeric flocculant with high relative molecular mass to adsorb to negatively charged suspended particles and the like through electrostatic action, so as to coagulate, flocculate and settle the suspended particles, thereby improving the flocculation effect. Thus, in general, the flocculation effect is not enhanced by the addition of low molecular weight substances.

According to the invention, 2-amino-3-methylpyridine with small molecular weight is added into the components, and the flocculant obtained by matching with diallyl bromide pyrrolium salt, diallyl bromide piperidinium salt, diatomite and synthetic porous calcium silicate has a better effect, wherein the turbidity removal rate of domestic sewage reaches 90%, and the removal rate of COD reaches 80%. The inventor researches and discovers that the reason that the condition can be caused is that 2-amino-3-methylpyridine can form a certain tiny field in sewage when the sewage is treated, so that suspended matters in the sewage are separated from water preliminarily, after the diallyl bromide pyrrolium salt, the diallyl bromide piperidinium salt, diatomite and synthetic porous calcium silicate are added, the strong adsorbability of the synthetic porous calcium silicate is utilized, diatomite is used as a coagulant aid, floc generated when cationic functional groups of the diallyl bromide pyrrolium salt and the diallyl bromide piperidinium salt are flocculated is larger, the flocculation speed is high, the floc can be separated from the suspension quickly, the time required by the treatment process is short, the treatment effect is good, the using amount is small, and the sludge generation amount is small.

The invention has the beneficial effects that:

1. according to the invention, two monomers of diallyl bromide pyrrolium salt and diallyl bromide piperidinium salt are adopted, and diatomite and synthetic porous calcium silicate are matched, so that the turbidity removal rate of the obtained sewage treatment flocculant on domestic sewage reaches 90%, the COD removal rate reaches 80%, and after micromolecule 2-amino-3-methylpyridine is added, the treatment effect is better.

2. The sewage treatment flocculant disclosed by the invention is simple and convenient to prepare, safe and environment-friendly, and cannot cause secondary pollution.

3. The calcium silicate of the invention adopts a synthetic porous calcium silicate material, has the adsorption performance 10-15 times that of activated carbon, has small bulk density, soft and light quality, high specific surface area, low abrasion value, weak negative charge strength and higher oil absorption and water absorption, and has an ion storage function.

4. The flocculant has the advantages of multiple functional groups, large generated floc, high flocculation speed, short time required by the treatment process, good treatment effect, less consumption and less sludge generation amount.

Detailed Description

Example 1

0.15mol of diallylamine and 70mL of 40 mass percent K are added into a reaction kettle₂CO₃And adding 0.1mol of 1, 4-dibromobutane and 20mL of NaOH solution with the concentration of 1mol/L into two constant-pressure dropping funnels respectively, and alternately dropping the 1, 4-dibromobutane and the NaOH solution at the time interval of 60 s. Keeping the reaction temperature at 65 ℃, and continuing to react for 4 hours after the materials are added. The reaction solution was transferred to a separatory funnel, and after standing for 15min, liquid was separated. Concentrating the separated water phase by rotary evaporation, adding anhydrous ethanol solution after the water in the solution is dried by rotationDecomposing and filtering until the inorganic salt is white, recovering the filtered inorganic salt crystal, performing rotary evaporation and concentration on the filtrate again, and basically spin-drying the absolute ethyl alcohol. Then adding acetone into the solution after rotary evaporation, and crystallizing at 15 ℃. Standing for 8h, filtering, washing the filtered crystal with acetone until the crystal is colorless, and drying under vacuum at 60 ℃ for 8h to obtain the monomer of the brominated diallyl pyrrolium salt.

0.15mol of diallylamine and 70mL of 40 mass percent K are added into a reaction kettle₂CO₃And adding 0.1mol of 1, 5-dibromopentane and 20mL of NaOH solution with the concentration of 1mol/L into two constant-pressure dropping funnels respectively, and alternately dropping the 1, 5-dibromopentane and the NaOH solution at the time interval of 60 s. Keeping the reaction temperature at 65 ℃, and continuing to react for 4 hours after the materials are added. The subsequent treatment and the preparation method of the monomer of the brominated diallyl pyrrolium salt are carried out to obtain the monomer of the brominated diallyl piperidinium salt.

10g of diallyl bromide pyrrolium salt and 10g of diallyl bromide piperidinium salt are mixed to obtain a mixture, 4.5g of synthetic porous calcium silicate and 5g of diatomite are added into the mixture and uniformly mixed to obtain the sewage treatment flocculant.

The turbidity removal rate and COD removal rate of the obtained product were measured and the results are shown in Table 1.

Example 2

0.15mol of diallylamine and 70mL of 40 mass percent K are added into a reaction kettle₂CO₃And adding 0.1mol of 1, 4-dibromobutane and 20mL of NaOH solution with the concentration of 1mol/L into two constant-pressure dropping funnels respectively, and alternately dropping the 1, 4-dibromobutane and the NaOH solution at the time interval of 30 s. Keeping the reaction temperature at 60 ℃, and continuing to react for 4 hours after the materials are added. The reaction solution was transferred to a separatory funnel, and after standing for 15min, liquid was separated. And (3) carrying out rotary evaporation concentration on the separated water phase, adding absolute ethyl alcohol to dissolve after water in the solution is dried, filtering until inorganic salt is white, recovering the filtered inorganic salt crystal, carrying out rotary evaporation concentration on the filtrate again, and basically carrying out rotary evaporation drying on the absolute ethyl alcohol. Then adding acetone into the solution after rotary evaporation, and crystallizing at 10 ℃. After the mixture is kept stand for 6 hours,and (3) filtering, washing the filtered crystals with acetone until the crystals are colorless, and drying the crystals for 8 hours in vacuum at the temperature of 60 ℃ to obtain the monomer of the brominated diallyl pyrrolium salt.

0.15mol of diallylamine and 70mL of 40 mass percent K are added into a reaction kettle₂CO₃And adding 0.08mol of 1, 5-dibromopentane and 14mL of NaOH solution with the concentration of 1mol/L into two constant-pressure dropping funnels respectively, and alternately dropping the 1, 5-dibromopentane and the NaOH solution at the time interval of 30 s. Keeping the reaction temperature at 60 ℃, and continuing to react for 4 hours after the materials are added. The subsequent treatment and the preparation method of the monomer of the brominated diallyl pyrrolium salt are carried out to obtain the monomer of the brominated diallyl piperidinium salt.

The diallyl bromide pyrrolium salt and the diallyl bromide piperidinium salt are mixed according to the weight ratio of 3:2 to obtain a mixture, and adding the following components in parts by weight: 40 percent of synthetic porous calcium silicate, 30 percent of diatomite and 0.8 percent of 2-amino-3-methylpyridine are evenly mixed to obtain the sewage treatment flocculant.

Example 3

0.15mol of diallylamine and 70mL of 40 mass percent K are added into a reaction kettle₂CO₃And adding 0.15mol of 1, 4-dibromobutane and 30mL of NaOH solution with the concentration of 1mol/L into two constant-pressure dropping funnels respectively, and alternately dropping the 1, 4-dibromobutane and the NaOH solution at intervals of 90 s. Keeping the reaction temperature at 70 ℃, and continuing to react for 4 hours after the materials are added. The reaction solution was transferred to a separatory funnel, and after standing for 15min, liquid was separated. And (3) carrying out rotary evaporation concentration on the separated water phase, adding absolute ethyl alcohol to dissolve after water in the solution is dried, filtering until inorganic salt is white, recovering the filtered inorganic salt crystal, carrying out rotary evaporation concentration on the filtrate again, and basically carrying out rotary evaporation drying on the absolute ethyl alcohol. Then adding acetone into the solution after rotary evaporation, and crystallizing at the temperature of 20 ℃. Standing for 10h, filtering, washing the filtered crystal with acetone until the crystal is colorless, and vacuum drying at 60 deg.C for 8h to obtain brominated dieneA monomer of propyl pyrronium salt.

0.15mol of diallylamine and 70mL of 40 mass percent K are added into a reaction kettle₂CO₃And adding 0.1mol of 1, 5-dibromopentane and 20mL of NaOH solution with the concentration of 1mol/L into two constant-pressure dropping funnels respectively, and alternately dropping the 1, 5-dibromopentane and the NaOH solution at intervals of 90 s. Keeping the reaction temperature at 70 ℃, and continuing to react for 4 hours after the materials are added. The subsequent treatment and the preparation method of the monomer of the brominated diallyl pyrrolium salt are carried out to obtain the monomer of the brominated diallyl piperidinium salt.

The diallyl bromide pyrrolium salt and the diallyl bromide piperidinium salt are mixed according to the weight ratio of 2: 1 to obtain a mixture, and adding the following components in parts by weight: 50 percent of synthetic porous calcium silicate, 70 percent of diatomite and 1.5 percent of 2-amino-3-methylpyridine are evenly mixed to obtain the sewage treatment flocculant.

Example 4

Diallyl pyrrolium bromide and diallyl piperidinium bromide were prepared as in example 1.

10g of diallyl bromide pyrrolium salt and 10g of diallyl bromide piperidinium salt are mixed to obtain a mixture, 4.5g of synthetic porous calcium silicate, 5g of diatomite and 0.1g of 2-amino-3-methylpyridine are added into the mixture and uniformly mixed to obtain the sewage treatment flocculant.

Comparative example 1

The diallylpiperidinium bromide was prepared as in example 1.

4.5g of synthetic porous calcium silicate and 5g of diatomite are uniformly mixed and added into the domestic sewage to be treated, 20g of diallyl bromide piperidinium salt is added into the mixture, and the turbidity removal rate and the COD removal rate of the domestic sewage are measured, and the results are shown in Table 1.

Comparative example 2

Diallyl piperidinium bromide and diallyl pyrrolidinium bromide were prepared as in example 1.

4.5g of synthetic porous calcium silicate and 5g of diatomite are uniformly mixed and added into domestic sewage to be treated, 10g of diallyl bromide piperidinium salt and 10g of diallyl bromide pyrrolidinium salt are added into the sewage, and the turbidity removal rate and the COD removal rate of the domestic sewage are measured, and the results are shown in Table 1.

TABLE 1 decontamination effect Table

	Turbidity removal rate	COD removal rate
			Example 1	94％	86％
Example 2	92％	83％
			Example 3	91％	80％
Example 4	96％	88％
			Comparative example 1	72％	67％
Comparative example 2	79％	73％

As is clear from comparison of examples 1 to 3, example 1 is the most preferable example, and therefore the experimental conditions are the most preferable.

As is clear from comparison between example 1 and comparative example 1, the addition of two onium salts, namely, diallylpiperidinium bromide and diallylpyrrolium bromide, to domestic sewage provides a better treatment effect on domestic sewage than the addition of only one diallylpiperidinium bromide, because the addition of diallylpyrrolium bromide results in a higher positive charge density and an increase in functional groups, and the neutralization of the electrical properties of the negatively charged organic colloids in sewage by the positively charged groups contained therein and the excellent bridging and aggregation function of the macromolecules, promotes aggregation of the colloidal particles into flocs, which are separated from the suspension, and thus provides a better treatment effect.

It can be seen from the comparison of example 1 and comparative example 2 that the flocculant obtained by uniformly mixing the diallyl bromide piperidinium salt and the diallyl bromide pyrrolidinium salt and then uniformly mixing the diallyl bromide piperidinium salt and the calcium silicate and the diatomite according to the method of the present invention has a better treatment effect on domestic sewage because the components are uniformly mixed and interact with each other to form a stable complex system, and the components are matched with each other after being added into the domestic sewage to fully exert the effect, so that the treatment effect is better.

Comparing example 1 with example 4, it is understood that the flocculant obtained by adding a small molecule of 2-amino-3-methylpyridine to example 4 and then blending it with diallylpyrrolium bromide, diallylpiperidinium bromide, diatomaceous earth and synthetic porous calcium silicate is more effective, and the reason is probably that 2-amino-3-methylpyridine forms a certain fine field in wastewater during wastewater treatment to primarily separate suspended matters from water, and that the flocculant generated during flocculation of cationic functional groups of diallylpyrrolium bromide and diallylpiperidinium bromide is larger by utilizing the strong adsorption property of synthetic porous calcium silicate and the diatomaceous earth as a coagulant aid after adding the diallylpyrrolium bromide, diallylpiperidinium bromide, diatomaceous earth and synthetic porous calcium silicate, the flocculation speed is high, and the flocculant can be quickly separated from the suspension, so that the treatment effect is better.

Claims

1. The preparation method of the sewage treatment flocculant is characterized by comprising the following steps of:

(2) mixing the mixture with calcium silicate and diatomite according to a weight ratio of 10: (4-5): (3-7) uniformly mixing to obtain the sewage treatment flocculant;

also comprises 2-amino-3-methylpyridine, wherein the weight ratio of the mixture to the 2-amino-3-methylpyridine is 10: (0.08-0.15).

2. The method for preparing sewage treatment flocculant according to claim 1, wherein the weight ratio of the diallyl pyrroliumbromide to the diallyl piperidinium bromide is 1: 1.

3. The method of claim 1, wherein the weight ratio of the mixture to the calcium silicate and the diatomaceous earth is 10: 4.5: 5.

4. the method according to claim 1, wherein the weight ratio of the mixture to the 2-amino-3-methylpyridine is 10: 0.1.

5. the method of claim 1, wherein the preparation of the diallyl pyrrolium bromide salt comprises the steps of:

6. The method of claim 1, wherein the preparation of the diallyl piperidinium bromide flocculant comprises the steps of:

7. The method according to claim 5, wherein the alkali solution in the step (2) is NaOH solution, and the dropping alternation time of the 1, 4-dibromobutane and the NaOH solution is 30-90 s.

8. The method according to claim 6, wherein the alkali solution in the step (2) is NaOH solution, and the dropping alternation time of the 1, 5-dibromopentane and the NaOH solution is 30-90 s.