CN112479283A

CN112479283A - Novel water purifying agent and water purifying method

Info

Publication number: CN112479283A
Application number: CN202011424858.2A
Authority: CN
Inventors: 禤耀明; 刘华; 邓艺海
Original assignee: Foshan Zhongke Yuanming Environmental Protection Technology Co ltd
Current assignee: Foshan Zhongke Yuanming Environmental Protection Technology Co ltd
Priority date: 2020-12-08
Filing date: 2020-12-08
Publication date: 2021-03-12

Abstract

The invention discloses a novel water purifying agent and a water purifying method, wherein the novel water purifying agent comprises the following components in percentage by weight: 5-30% of polymeric ferric sulfate; 3-20% of polyaluminium sulfate; 10-50% of ferrous sulfate; 10-40% of molecular sieve; 3-10% of activated carbon. According to the invention, through reasonably optimizing and improving the formula and optimizing the water purification step, the inertial thinking that the pH value of the Fenton reaction must be adjusted by strong acid at the early stage is broken, so that compared with the Fenton reaction, the novel water purifying agent disclosed by the invention has the following advantages: 1. acid is not needed, and the pH value of the water body can be reduced or even adjusted without adding strong alkali in the later period, so that the danger is reduced; 2. the water purification cost is reduced; 3. the linearity of the COD reduction value and the medicament use amount is good; 4. the water purification step is simplified, and the water purification efficiency is improved; 5. can remove phosphorus.

Description

Novel water purifying agent and water purifying method

Technical Field

The invention relates to the field of wastewater treatment, and mainly relates to a novel water purifying agent and a water purifying method.

Background

At present, the industrial wastewater COD is removed, the standard discharge is realized, and the Fenton reaction is needed to be used in many cases. The Fenton reaction is a high-grade oxidation reaction under an acidic condition, hazardous chemicals such as sulfuric acid, hydrochloric acid and the like are required in the Fenton reaction process, and when the concentration of some organic matters difficult to oxidize is lower than a certain value, the concentration of the organic matters is further reduced, and the COD value is reduced. Therefore, the fenton method has the following disadvantages: 1) using an acid; 2) the linearity of the reduction value of COD and the dosage of the medicament is not good; 3) phosphorus cannot be removed.

Accordingly, the prior art is yet to be improved and developed.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention provides a novel water purifying agent and a water purifying method, wherein the novel water purifying agent is optimized and improved based on the fenton reaction, and aims to solve the problem that the fenton reaction requires acid.

The technical scheme of the invention is as follows:

a novel water purifying agent comprises the following components in percentage by weight:

5-30% of polymeric ferric sulfate;

3-20% of polyaluminium sulfate;

10-50% of ferrous sulfate;

10-40% of molecular sieve;

3-10% of activated carbon.

The novel water purifying agent is characterized in that the molecular sieve is a molecular sieve with the pore diameter ranging from 6.68 nm to 7.75 nm.

The novel water purifying agent is characterized in that the aperture range of the active carbon is 10-20A⁰Activated carbon in between.

A method of purifying water, comprising the steps of:

dissolving the novel water purifying agent into water to prepare a water purifying agent solution with the concentration of 10-20%;

pumping the water purifying agent solution into the wastewater by using a metering pump, and pumping the hydrogen peroxide solution into the wastewater by using another metering pump to fully mix the water purifying agent solution, the hydrogen peroxide and the wastewater;

adding a PAM solution into a water body, and uniformly stirring;

and (4) precipitating in a sedimentation tank, discharging the supernatant after the detection index of the supernatant is qualified, and discharging the precipitate after filter pressing.

The water purification method comprises the following steps of fully mixing the water purifier solution, the hydrogen peroxide and the wastewater:

and detecting the pH value of the water body, adding NaOH to adjust the pH value of the water body to be neutral if the pH value is acidic, and not adding NaOH if the pH value is neutral.

The water purifying method comprises the step of determining the addition amount of the water purifying agent solution and the addition amount of the hydrogen peroxide according to the COD value in the wastewater.

According to the water purification method, when the concentration of the PAM solution is 0.1%, the addition amount of the PAM solution accounts for 0.5-1% of the weight of the wastewater.

Has the advantages that: the novel water purifying agent and the water purifying method are optimized and improved based on the Fenton reaction, break the inertial thinking that the pH value of the Fenton reaction must be adjusted by strong acid in the early stage through reasonably optimizing and improving the formula and optimizing the water purifying step, and have the following advantages: 1. acid is not used, so that the danger of using acid is avoided; 2. the water purification cost is reduced; 3. the linearity of the COD reduction value and the medicament use amount is good; 4. the water purification steps are simplified, the water purification efficiency is improved, and the types of reagents in the water body are reduced; 5. can remove phosphorus.

Detailed Description

The present invention provides a novel water purifying agent and a water purifying method, and the present invention will be described in further detail below in order to make the objects, technical solutions and effects of the present invention clearer and clearer. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a novel water purifying agent which comprises the following components in percentage by weight:

5-30% of polymeric ferric sulfate;

3-20% of polyaluminium sulfate;

10-50% of ferrous sulfate;

10-40% of molecular sieve;

3-10% of activated carbon.

The polyferric sulfate is a new-type high-effective inorganic high-molecular coagulant with molecular weight up to 1X 10⁵It is non-toxic, harmless, stable in chemical property and can be mixed with water. In the water treatment process, the polyferric can be quickly hydrolyzed to form a large amount of positive multi-nuclear complex ions, the surface charges of the colloidal particles are neutralized, the colloidal particles are strongly adsorbed, and the particles are condensed to form flocs to settle through the adhesion, bridging, crosslinking and sweeping actions, so that the water is clarified.

Polyaluminium chloride is a water purifying material, an inorganic polymer coagulant, also called polyaluminium for short, and is called PAC for short, and is an inorganic polymer water treatment agent with large molecular weight and high charge, which is produced by the bridging action of hydroxide ions and the polymerization action of polyvalent anions.

Under the acidic condition, the ferrous sulfate is matched with hydrogen peroxide to generate strong oxidation. The ferrous sulfate is preferably added in a ferrous sulfate solution, which may be 30% in concentration.

The molecular sieve and the active carbon can absorb the organic matters with certain molecular weight after oxidation, and the organic matters are changed into stable matters to be settled. Wherein, preferably, the invention also provides the pore diameter requirements of the molecular sieve and the activated carbon, the molecular sieve with the pore diameter of 6.68-7.75 nm is selected, and the pore diameter of 10-20A is selected⁰Activated carbon in between.

Under the acidic environment, ferrous sulfate in the formula and added hydrogen peroxide act together to oxidize organic molecules in the wastewater into molecules suitable for molecular sieve and active carbon pore size adsorption, and the molecular sieve and the active carbon adsorbing the organic molecules are subjected to rapid flocculation and precipitation under the action of polyferric oxide and polyaluminium oxide, so that water-slag separation is facilitated. The novel water purifying agent provided by the invention is particularly effective for subsequent advanced treatment of organic matters which are difficult to treat at the later stage of industrial wastewater treatment and high-difficulty industrial wastewater, and can match organic matter molecules with the pore diameters of the molecular sieve and the active carbon only by proper oxidation without thorough oxidation, thereby achieving the purpose of removing COD in wastewater.

The invention also provides a water purification method adopting the novel water purifying agent, which comprises the following steps:

weighing raw materials, adding raw material powder into a powder mixer, and uniformly mixing to obtain the novel water purifying agent;

dissolving the novel water purifying agent in water to prepare a water purifying agent solution with the concentration of 10-20%;

detecting the pH value of the water body of the effluent, adding NaOH to adjust the pH value of the water body to be neutral if the pH value is acidic, and not adding NaOH if the pH value is neutral (because no strong acid is added in the step of the invention, the pH value of the water body does not exceed the effluent requirement, and if the pH value meets the effluent requirement, the step is not needed);

adding a PAM solution into a water body, and uniformly stirring; the PAM solution is added, so that the flocculation deposition speed can be effectively accelerated, and the wastewater treatment efficiency is improved; the addition amount of the PAM solution is about one hundred thousand parts of the mass concentration of the dry PAM in the water body, namely when the concentration of the PAM solution is 0.1 percent, the addition amount of the PAM solution accounts for 0.5 to 1 percent of the weight of the wastewater;

In the water purification method, the addition amount of the water purifying agent solution and the addition amount of the hydrogen peroxide are adjusted according to the COD value in the water body, and the higher the COD value is, the more the water purifying agent solution is needed. In addition, because the organic matters contained in each kind of wastewater are different, the dosage of the water purifying agent solution and the hydrogen peroxide solution can be influenced; moreover, the method of the invention has no amplification effect, and the dosage obtained by small experiments can be amplified for use. Therefore, the amounts of the water purifying agent solution and the hydrogen peroxide solution for each wastewater can be determined based on the calculation method of the fenton reaction in combination with a bench test.

In addition, strong acid is not required to be added in advance to reduce the pH value of the water body, and the pH value of the water body can be reduced or even increased again without adding NaOH in the later period.

According to the invention, through reasonably optimizing and improving the formula and optimizing the water purification step, the inertial thinking that the pH value of the Fenton reaction must be adjusted by strong acid at the early stage is broken, so that compared with the Fenton reaction, the novel water purifying agent disclosed by the invention has the following advantages: 1. acid is not needed, and the pH value of the water body can be reduced or even adjusted without adding strong alkali in the later period, so that the danger is reduced; 2. the water purification cost is reduced; 3. the linearity of the COD reduction value and the medicament use amount is good; 4. the water purification step is simplified, and the water purification efficiency is improved; 5. can remove phosphorus.

The present invention is further illustrated by the following specific examples.

Example 1: purifying black and odorous water body for pig raising

First, test purpose

By selecting a certain black and odorous water body as a test object, the COD value of the test object is 330mg/L, the total phosphorus is 25mg/L, and two groups of comparison tests are respectively carried out by using a Fenton method and a water purifying agent method, so that the advantages and the disadvantages of the two methods are compared when the COD of the effluent is less than or equal to 100 mg/L.

Second, test section

2.1, reagents

H₂SO₄(30%), hydrogen peroxide (27.5%), ferrous sulfate solution: 30% of NaOH solution: 30% of an anionic PAM solution: 0.1% of water purifying agent solution: the mass fraction is 20%.

2.2 testing apparatus

D60 desk-top four-parameter water quality analyzer and COD (H/L) prefabricated reagents; one ten-thousandth electronic balance and one percentile electronic balance; one pH meter.

2.3, a detection method: rapid digestion spectrophotometry HJ924-2017

Third, testing step

3.1 Fenton method

3.1.1, accurately weighing 1000g of sample wastewater on an electronic scale.

3.1.2, calculating the weight of the needed ferrous sulfate heptahydrate solution and the needed hydrogen peroxide, and accurately weighing the ferrous sulfate heptahydrate solution and the hydrogen peroxide by using a small beaker on an electronic balance (ten thousands of places).

3.1.3 with H₂SO₄Adjusting the pH value of the waste water to be within the range of 3-4.

3.1.4, adding the weighed ferrous sulfate solution and hydrogen peroxide into the wastewater with the adjusted pH value.

3.1.5, after being evenly stirred for 20 minutes, the pH value is adjusted to be neutral by NaOH.

3.1.6, adding a proper amount of PAM solution, and stirring for about 30s until a flocculent state is obtained.

3.1.7, standing for 60min, and taking supernatant to detect indexes.

3.1.8, if the detection index COD is less than or equal to 100mg/L, repeating the small test for three times according to the steps to verify the medicament test effect, otherwise, re-testing the optimal medicament proportion.

3.2 Water purification method

3.2.1, accurately weighing 1000g of sample wastewater on an electronic scale.

3.2.2, preparing a water purifying agent, which comprises the following components in percentage by weight:

30% of polymeric ferric sulfate;

20% of polyaluminium sulfate;

25% of ferrous sulfate;

20% of molecular sieve;

5 percent of activated carbon.

And dissolving the water purifying agent in water to obtain a water purifying agent solution with the concentration of 20%. Calculating the weight of the required water purifying agent solution and the hydrogen peroxide, and accurately weighing the prepared water purifying agent solution and the hydrogen peroxide by using a small beaker on an electronic balance (ten thousands of units).

3.2.3, respectively pouring the weighed water purifying agent solution and hydrogen peroxide into the sample wastewater.

3.2.4, after being evenly stirred for 20min, the pH value is adjusted to be neutral by NaOH (if the pH value meets the water outlet requirement, the step is omitted).

3.2.5, adding PAM (polyacrylamide) solution with proper amount, stirring for about 30s, and stopping when the floccule appears.

3.2.6, standing for 60min, and taking supernatant to detect indexes.

3.2.7, if the detection index COD is less than or equal to 100mg/L, repeating the small test for three times according to the steps to verify the medicament test effect, otherwise, re-testing the optimal medicament proportion.

Fourth, recording test data

4.1 when the pH value of the black and odorous water body is 7, the COD is 330mg/L and the total phosphorus is 25mg/L, the water purifying agent method and the Fenton method are compared in repeated tests, and the results are shown in Table 1.

TABLE 1

4.2 conclusion of the test

The comparison of the two data sets shows that: in both methods, the COD can be reduced to the environmental water requirement, and secondly, when the treatment effect is equivalent, the advantages of the novel water purifying agent are shown in the table 2.

TABLE 2

Processing method	Fenton method	Novel water purifying agent	Remarks for note
				Whether or not to use acids	Is that	Whether or not
Whether or not to use a base	Is that	Without or in small quantities
				Kind of medicament	5 kinds of	3 kinds of	Solutions containing PAM
Safety in operation	Has a certain danger	Secure
				Cost of treatment	25.44	14.34

See the following compositional analysis for processing costs. And (3) cost analysis: when the wastewater treated by the two methods reaches the standard and has the effect, the treatment cost per ton of water is calculated and shown in the table 3.

TABLE 3

Remarking: 1. market reference for each required reagent: the price of 30 percent acid per ton is 600 yuan; 2950 yuan per ton of water purifying agent (solid), 300 yuan per ton of ferrous sulfate (solid), 2000 yuan per ton of 27.5% hydrogen peroxide and 1100 yuan per ton of 32% alkali liquor. 2. Table 3 the selected addition rates were determined by averaging the data from the test chart of table 1.

Example 2: purification of paper mill effluent

First, test purpose

The method is characterized in that waste water after biochemical air flotation in a certain paper mill is selected as a test object, COD values of the test object are 66mg/L, 110mg/L and 140mg/L respectively, and three groups of comparison tests are carried out by using a water purifying agent (20% water aqua) and a Fenton method respectively, so that the advantages and the disadvantages of the two methods are compared when the COD of effluent is less than or equal to 50 mg/L.

Second, test section

2.1, reagents

The same as in example 1.

2.2 testing apparatus

The same as in example 1.

2.3, a detection method: rapid digestion spectrophotometry HJ924-2017

2.4, test Water quality index, as shown in Table 4.

TABLE 4

	First group	Second group	Third group
				pH	6.95	6.82	6.91
COD(mg/L)	66	110	140

Third, testing step

3.1 Fenton method

The same as in example 1.

3.2 Water purification method

3.2.1, accurately weighing 1000g of sample wastewater on an electronic scale.

25% of polymeric ferric sulfate;

15% of polyaluminium sulfate;

35% of ferrous sulfate;

15% of molecular sieve;

10 percent of activated carbon.

3.2.5 adding PAM solution, stirring for about 30s, and stopping.

3.2.6, standing for 100min, and taking supernatant to detect indexes.

3.2.7, if the detection index COD is less than or equal to 50mg/L, repeating the small test for three times according to the steps to verify the medicament test effect, otherwise, re-testing the optimal medicament proportion.

Fourth, recording test data

4.1 when the pH of the papermaking wastewater was 6.95 and the COD was 66mg/L, the water purification method was compared with the Fenton method, and the results are shown in Table 5.

TABLE 5

4.2 when the pH of the paper-making waste water is 6.82 and the COD is 110mg/L, the test record of the medicament is compared with Fenton, and the result is shown in Table 6.

TABLE 6

4.3 when the pH of the paper-making waste water was 6.91 and the COD was 140mg/L, the chemical test record was compared with that of Fenton, and the results are shown in Table 7.

TABLE 7

4.4 conclusion of the test

As can be seen by comparing the above three sets of data: both methods can reduce COD to the environmental effluent requirement, and secondly, when the treatment effect is comparable, the advantages of the novel water purifying agent of the invention are shown in Table 8.

TABLE 8

Processing method	Fenton method	Novel water purifying agent	Remarks for note
				Whether or not to use acids	Is that	Whether or not
Whether or not to use a base	Is that	Without or in small quantities
				Sludge amount (g)	0.3228	0.3306	When the COD of the raw water is 66mg/L
Kind of medicament	5 kinds of	3 kinds of	Solutions containing PAM
				Safety in operation	Has a certain danger	Secure
Cost of treatment 1	1.88	1.78	When the COD of the raw water is 66mg/L
				Cost of treatment 2	3.12	2.86	When the COD of the raw water is 110mg/L
Cost of treatment 3	3.36	3.15	When the COD of the raw water is 140mg/L

For processing costs, the following cost analysis is referred to. And (3) cost analysis: when the wastewater treated by the two methods reaches the standard and has the effect, the treatment cost per ton of water is measured and calculated, and the table 9 shows.

TABLE 9

Remarking: 1. market reference for each required reagent: the price of 30 percent acid per ton is 600 yuan; 2950 yuan per ton of water purifying agent (solid), 300 yuan per ton of ferrous sulfate (solid), 2000 yuan per ton of 27.5% hydrogen peroxide and 1100 yuan per ton of 32% alkali liquor. 2. The selected addition ratios in Table 9 were determined by averaging the data from the test charts of tables 5-7.

Example 3: purification of coking wastewater

First, test purpose

By selecting certain coking wastewater as a test object, the COD value of the test object is 253mg/L and 490mg/L respectively, and two groups of comparison tests are carried out by using a Fenton method and a water purifying agent method respectively, so that the advantages and the disadvantages of the two methods are compared when the COD of the effluent is less than or equal to 100 mg/L.

Second, test section

2.1, reagents

The same as in example 1.

2.2 testing apparatus

The same as in example 1.

2.3, a detection method: rapid digestion spectrophotometry HJ924-2017

2.4, test Water quality index, as shown in Table 10.

Watch 10

	First group	Second group
			pH	8.1	8.1
COD(mg/L)	253	490

Third, testing step

3.1 Fenton method

The same as in example 1.

3.2 Water purification method

3.2.1, accurately weighing 1000g of sample wastewater on an electronic scale.

20% of polymeric ferric sulfate;

20% of polyaluminium sulfate;

30% of ferrous sulfate;

20% of molecular sieve;

10 percent of activated carbon.

3.2.4, after stirring evenly for 20min, adjusting the pH value to be neutral by NaOH (if the pH value meets the effluent requirement, the step is omitted)

3.2.5 adding PAM solution, stirring for about 30s, and stopping.

3.2.6, standing for 90min, and taking supernatant to detect indexes.

Fourth, recording test data

4.1 when the coking wastewater has a pH of 8 and a COD of 253mg/L, the water purification method and the Fenton method were compared in a repeated test, and the results are shown in Table 11.

TABLE 11

4.2 when the pH of the paper-making waste water was 8 and the COD was 490mg/L, the chemical test record was compared with that of Fenton, and the results are shown in Table 12.

TABLE 12

4.3 conclusion of the test

The comparison of the two data sets shows that: both methods can reduce COD to the environmental effluent requirement, and secondly, when the treatment effect is comparable, the advantages of the novel water purifying agent of the invention are shown in Table 13.

Watch 13

Processing method	Fenton method	Novel water purifying agent	Remarks for note
				Whether or not to use acids	Is that	Whether or not
Whether or not to use a base	Is that	Without or in small quantities
				Kind of medicament	5 kinds of	3 kinds of	Solutions containing PAM
Safety in operation	Has a certain danger	Secure
				Cost of treatment 1	29.25	4.39	When the COD of the raw water is 253mg/L
Cost of treatment 2	39.4	8.2	When the COD of the raw water is 490mg/L

For processing costs, the following cost analysis is referred to. When the wastewater treated by the two methods reaches the standard and has the effect, the treatment cost per ton of water is measured and calculated, and the analysis is shown in the table 14.

TABLE 14

Remarking: 1. market reference for each required reagent: the price of 30 percent acid per ton is 600 yuan; 2950 yuan per ton of water purifying agent (solid), 300 yuan per ton of ferrous sulfate (solid), 2000 yuan per ton of 27.5% hydrogen peroxide and 1100 yuan per ton of 32% alkali liquor. 2. The selected addition ratio in Table 14 was determined by averaging the data in the test charts in tables 11 and 12.

From the data of examples 1-3, it can be seen that compared with Fenton reaction, the novel water purifying agent provided by the invention not only reduces the water purifying cost, but also simplifies the water purifying step while ensuring the water purifying result.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.

Claims

1. The novel water purifying agent is characterized by comprising the following components in percentage by weight:

5-30% of polymeric ferric sulfate;

3-20% of polyaluminium sulfate;

10-50% of ferrous sulfate;

10-40% of molecular sieve;

3-10% of activated carbon.

2. The novel water purifying agent according to claim 1, wherein the molecular sieve is a molecular sieve having a pore size in the range of 6.68 to 7.75 nm.

3. The novel water purifying agent according to claim 1, wherein the activated carbon has a pore size of 10-20A⁰Activated carbon in between.

4. A water purification method is characterized by comprising the following steps:

dissolving the novel water purifying agent as claimed in any one of claims 1 to 3 in water to prepare a water purifying agent solution having a concentration of 10 to 20%;

adding a PAM solution into a water body, and uniformly stirring;

5. The water purification method of claim 4, wherein the water purifying agent solution, the hydrogen peroxide and the wastewater are fully mixed, and the method further comprises the following steps:

6. The water purification method according to claim 4, wherein the amount of the water purifying agent solution and the amount of the hydrogen peroxide solution are determined based on the COD value in the wastewater.

7. The water purification method of claim 4, wherein when the concentration of the PAM solution is 0.1%, the PAM solution is added in an amount of 0.5-1% by weight based on the wastewater.