Heavy metal wastewater treatment agent and application thereof

Abstract

The invention discloses a heavy metal wastewater treatment agent and a use method thereof, and relates to the technical field of sewage treatment. The heavy metal treatment agent mainly comprises an agent A, an agent B and an agent C. The agent A is a liquid agent and comprises the following raw materials in parts by weight: 40-45 parts of a strong oxidant, 2-5 parts of a chelating agent and 2-5 parts of a catalyst. The agent B is a solid agent and is mainly a heavy metal adsorbent, nanoscale zero-valent iron is modified twice through a sulfydryl compound and a porphyrin compound, the adsorption capacity on heavy metal is improved, meanwhile, the electron transfer efficiency is improved, and the reduction performance of the nanoscale zero-valent iron is enhanced; and the agent C is a liquid agent and mainly comprises the following components: 1-5% of a flocculating agent and 0.1-0.2% of a coagulant aid. According to the treatment agent for the wastewater containing the heavy metal ions, provided by the invention, the removal efficiency of the heavy metal wastewater with relatively low pH value and complex components reaches 95% or above, and the effluent is stable and reaches the discharge standard.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sewage treatment, and particularly relates to a heavy metal wastewater treatment agent and application thereof. BACKGROUND

[0002] Heavy metals cannot be biodegraded, can be long-term retained in water bodies, and can be amplified under the biological action of a food chain, and are hundreds of times enriched, thus producing toxic effects on organisms in the food chain. In recent years, with the continuous development of industrialization, a large amount of wastewater containing heavy metals is generated, and if not properly treated, will seriously harm the environment and human health.

[0003] At present, a large amount of research has been conducted on the treatment of industrial heavy metal wastewater, and common heavy metal wastewater treatment methods can mainly include neutralization precipitation, sulfide precipitation, iron salt precipitation, ion exchange, adsorption and electrolysis, etc. A large amount of reagents are used in these methods, but the common heavy metal reagents have the characteristics of single composition, single effect, and inability to significantly reduce the influence of interferents on heavy metal removal, etc., resulting in low heavy metal removal efficiency. Therefore, it is of great significance to develop a high-efficiency, organic-matter-interference-resistant reagent for heavy metal removal.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] Based on the above problems, the first technical scheme of the present application is a heavy metal wastewater treatment agent, which comprises three components of reagent A, reagent B and reagent C.

[0006] The reagent A is a liquid reagent, and comprises a strong oxidant, a chelating agent and a catalyst.

[0007] The reagent B is a solid reagent, and is mainly a heavy metal adsorbent.

[0008] The reagent C is a liquid reagent, and comprises a flocculant and a coagulant aid.

[0009] Further, in the reagent A, the strong oxidant is potassium ferrate or potassium permanganate; the catalyst is sodium humate; the chelating agent is inorganic sodium pyrophosphate; and the mass ratio of the strong oxidant, the catalyst and the chelating agent is (40-45):(2-5):(2-5).

[0010] Further, in the reagent B, the heavy metal adsorbent is modified nano zero-valent iron, and the preparation method thereof is as follows:

[0011] A first modifier is obtained by mixing and reacting a first solution containing nano zero-valent iron powder and a second solution containing a mercapto modifier;

[0012] A second modifier is obtained by mixing and reacting the first modifier and a third solution containing an allyl porphyrin compound;

[0013] The secondary modifier is freeze-dried to obtain a black powder, i.e. the modified nano zero-valent iron.

[0014] Further, the mass ratio of the thiol modifier to the nano zero-valent iron is (0.2-0.5):1; and the mass ratio of the porphyrin compound to the nano zero-valent iron is (0.05-0.2):1.

[0015] Further, the flocculant in the medicament C is polymeric ferric sulfate or polymeric aluminum ferric silicate; and the coagulant is anionic polyacrylamide.

[0016] The second technical solution of the present application discloses the application of the above wastewater treatment agent in the treatment of wastewater containing heavy metals. The heavy metal wastewater is acidic wastewater with pH<5, containing one or more components of lead, zinc, arsenic, cadmium, copper, nickel, magnesium, or organic matter such as phenols, lipids, and sulfates.

[0017] Further, the application method of the wastewater treatment agent is specifically:

[0018] The medicament A is added to the wastewater, and after stirring and reaction until the solution ORP≥300mV, a primary precipitation is obtained.

[0019] The pH of the supernatant after the primary precipitation is adjusted to 10-11, the medicament B is added, and after stirring and reaction, a secondary precipitation is obtained.

[0020] The medicament C is added to the supernatant after the secondary precipitation, and after reaction and precipitation, the supernatant reaches the wastewater discharge standard.

[0021] Beneficial effects: (1) Through the pretreatment of organic matter, and the chelation, adsorption, and reduction of heavy metals, the removal efficiency of complex heavy metal ions is effectively improved.

[0022] (2) The zero-valent nano iron is modified by thiol compounds, which strengthens the adsorption performance of nano zero-valent iron on heavy metals. Compared with traditional sulfide modification, thiol compounds have the characteristics of oxidation resistance. Through secondary modification by porphyrin compounds, the electron transfer efficiency is improved, and the reduction performance of zero-valent nano iron is strengthened, so that the removal performance of heavy metals by the overall zero-valent nano iron is significantly improved.

[0023] (3) During the use of the medicament, the system is always in a high oxidation environment, which effectively reduces the occurrence of heavy metal complexation reaction, and the removal effect is better, and the amount of medicament used is less. DETAILED DESCRIPTION

[0024] The technical solutions will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort shall fall within the protection scope of the present application.

[0025] Unless otherwise defined, the technical terms in the specification have the same meanings as those generally understood by those skilled in the art, but if there is a conflict, the definitions in the specification shall prevail.

[0026] The first embodiment of the present application discloses a heavy metal wastewater treatment agent, which comprises three components of medicament A, medicament B and medicament C.

[0027] The medicament A is a liquid medicament, which comprises a strong oxidant of potassium ferrate or potassium permanganate, a catalyst of sodium humate and a chelating agent of pyrophosphoric acid. The mass ratio of the strong oxidant, the catalyst and the chelating agent is (40-45):(2-5):(2-5).

[0028] In the medicament A, the strong oxidant is used to remove organic matters in wastewater and to increase the ORP of the wastewater, so that the heavy metals are dispersed in the water in the form of ions. In order to increase the removal rate of the organic matters by the oxidant, a certain amount of sodium humate is added as the catalyst. The chelating agent is pyrophosphoric acid, which is an inorganic chelating agent. In addition to effectively adsorbing heavy metal ions, the chelating agent can effectively reduce the consumption of permanganate and the generation of MnO2.

[0029] The medicament B is a solid medicament, which is mainly a heavy metal adsorbent. The preparation method of the medicament B is as follows.

[0030] The first solution containing nano zero-valent iron powder and the second solution containing a mercapto-modified substance are mixed to obtain a primary modified substance.

[0031] The first modified substance and the third solution containing a porphyrin compound are mixed to obtain a secondary modified substance.

[0032] The secondary modified substance is freeze-dried to obtain a black powder, i.e., modified nano zero-valent iron.

[0033] In the embodiment, the solvent of the first solution is deionized water, the solvent of the second solution is alcohol, the pH of the second solution is 3-3.5, and the pH of the mixed solution also needs to be adjusted to 3-3.5 after the first solution and the second solution are mixed. The solvent of the third solution is an organic solvent, and the pH is 4-5. The mass ratio of the mercapto-modified substance to the nano zero-valent iron is (0.2-0.5):1, and the mass ratio of the porphyrin compound to the nano zero-valent iron is (0.05-0.2):1.

[0034] The present embodiment first modifies the nano zero-valent iron by a mercapto compound, strengthens the adsorption performance of the nano zero-valent iron on heavy metals, and compared with the traditional sulfide modification, the mercapto compound has the characteristics of anti-oxidation. Then the second modification is carried out by a porphyrin compound, which can improve the electron transfer efficiency and strengthen the reduction performance of the nano zero-valent iron, so that the removal performance of the modified nano zero-valent iron heavy metal adsorbent on heavy metals is significantly improved.

[0035] The medicament C is a liquid medicament, which comprises a flocculant polymeric ferric sulfate or polymeric aluminum ferric silicate and a coagulant anionic polyacrylamide; the mass ratio of the flocculant to the coagulant contained therein is (10-50):(1-2), and the rest is water; the anionic polyacrylamide has an analysis amount of 800-1000 million and a particle size of 20-100 mesh. The second technical solution of the present application discloses the application of the above-mentioned wastewater treatment agent in the treatment of wastewater containing heavy metals. The heavy metal wastewater is acidic wastewater containing one or more components of lead, zinc, arsenic, cadmium, copper, nickel, magnesium, or organic matters such as phenols, lipids, and sulfates, and has a pH value of less than 5.

[0036] Further, the application method of the wastewater treatment agent is specifically:

[0037] The medicament A is added to the wastewater, and after stirring and reaction until the solution ORP is greater than or equal to 300 mV, a first precipitation is carried out, which is mainly used for removing the organic matters in the wastewater by oxidizing and decomposing the organic matters or forming insoluble precipitates, etc., while maintaining a high ORP in the whole treatment system, so that the heavy metals exist in the water in the form of ions, and the formation of heavy metal complexes is prevented.

[0038] The pH of the supernatant after the first precipitation is adjusted to 10-11, the medicament B is added, and after stirring and reaction, a second precipitation is carried out, the reaction time is 1-1.5 h, and the precipitation time is 3-5 h. Through the adsorption and reduction of the modified nano iron, the heavy metal ions are adsorbed or insoluble precipitates are formed.

[0039] The medicament C is added to the supernatant after the second precipitation, and after reaction and precipitation, the supernatant reaches the sewage discharge standard.

[0040] Further, the concentration of the medicament A is 3-5%, the dosage is 0.1-0.2 L / m 3 of water, the dosage of the medicament B is 0.1-0.3 kg / m 3 , and the concentration of the medicament C is 5-10%, the dosage is 0.05-0.1 L / m 3 of water.

[0041] The technical solutions of the present application will be further described through specific examples.

[0042] Example 1

[0043] Preparation of the medicament A: 4 g of potassium permanganate was dissolved in 100 mL of boiling water, 0.2 g of metal chelator pyrophosphoric acid was added and dissolved, 0.2 g of catalyst was added to the solution when used, and the medicament A was prepared;

[0044] Preparation of the medicament B:

[0045] a. 5.6 g of nano zero-valent iron was dissolved in 100 mL of water to obtain a first solution, 10 mL of 10% mercaptoethanol solution (second solution, mass ratio of nano zero-valent iron to mercaptoethanol was 1:0.2) was added to the first solution, the pH of the solution was adjusted to 3, and the solution was oscillated and ultrasonicated for 15 min to obtain a primary modified substance;

[0046] b. 0.28 g of iron porphyrin was dissolved in 100 mL of N,N'-dimethylformamide to obtain a third solution, 5.6 g of the primary modified substance (mass ratio of the primary modified substance to iron porphyrin was 0.05:1) was added to the third solution, the pH was adjusted to 4-5 under the protection of pyridine, and the reaction was carried out at 80°C for 2 h to obtain a secondary modified substance;

[0047] c. The secondary modified substance was taken out, washed with deionized water and ethanol for several times, and freeze-dried to obtain the medicament B;

[0048] Preparation of the medicament C: 5 g of polyferric sulfate and 0.25 g of anionic polyacrylamide were dissolved in 100 mL of water to obtain the medicament C.

[0049] Example 2

[0050] Preparation of the medicament A: 4.5 g of potassium permanganate was dissolved in 100 mL of boiling water, 0.5 g of metal chelator pyrophosphoric acid was added and dissolved, 0.5 g of catalyst was added to the solution when used, and the medicament A was prepared;

[0051] Preparation of the medicament B:

[0052] a. 5.6 g of nano zero-valent iron was dissolved in 100 mL of water to obtain a first solution, 25 mL of 10% mercaptoethanol solution (second solution, mass ratio of nano zero-valent iron to mercaptoethanol was 1:0.5) was added to the first solution, the pH of the solution was adjusted to 4-5, and the solution was oscillated and ultrasonicated for 15 min to obtain a primary modified substance;

[0053] b. 0.56 g of iron porphyrin was dissolved in 100 mL of N,N'-dimethylformamide to obtain a third solution, 5.6 g of the primary modified substance (mass ratio of the primary modified substance to iron porphyrin was 0.2:1) was added to the third solution, the pH was adjusted to 4-5 under the protection of pyridine, and the reaction was carried out at 80°C for 2 h to obtain a secondary modified substance;

[0054] c. Take out the secondary modified material, rinse with deionized water and ethanol several times, and freeze-dry to obtain the medicament B;

[0055] Preparation of medicament C: 10 g of polyferric sulfate and 1 g of anionic polyacrylamide were dissolved in 100 mL of water to prepare the medicament C.

[0056] Example 3

[0057] Preparation of medicament A: 4 g of potassium ferrate was dissolved in 100 mL of boiling water, 0.2 g of metal chelator pyrophosphate was added and dissolved, and 0.2 g of catalyst was added to the solution when used to prepare the medicament A;

[0058] Preparation of medicament B:

[0059] a. 5.6 g of nano zero-valent iron was dissolved in 100 mL of water to obtain a first solution, 10 mL of 10% mercaptoethanol solution (second solution, mass ratio of nano zero-valent iron to mercaptoethanol was 1:0.2) was added to the first solution, the pH of the solution was adjusted to 3, and the solution was oscillated and ultrasonicated for 15 min to obtain a primary modified material;

[0060] b. 0.28 g of iron porphyrin was dissolved in 100 mL of N,N'-dimethylformamide to obtain a third solution, 5.6 g of the primary modified material (mass ratio of the primary modified material to iron porphyrin was 0.05:1) was added to the third solution, the pH was adjusted to 4-5 under the protection of pyridine, and the reaction was carried out at 80°C for 2 h to obtain a secondary modified material;

[0061] c. The secondary modified material was taken out, rinsed with deionized water and ethanol several times, and freeze-dried to obtain the medicament B;

[0062] Preparation of medicament C: 5 g of polyferric sulfate and 0.25 g of anionic polyacrylamide were dissolved in 100 mL of water to prepare the medicament C.

[0063] Comparative Example 1

[0064] The difference from the example is that the medicament A is not used for oxidation of organic matter in wastewater, and only the medicaments B and C are used to remove pollutants in wastewater.

[0065] Comparative Example 2

[0066] The difference from Example 1 is that the medicament B uses unmodified nano zero-valent iron.

[0067] Comparative Example 3

[0068] The difference from Example 1 is that for the preparation of medicament B, only mercaptoethanol is used to modify according to step b to obtain a primary modified material, and no secondary modification is performed.

[0069] Example 1 for verifying effect

[0070] The wastewater to be treated is mining wastewater, and the main pollutants include COD (phenols, sulfur ions), lead, arsenic, cadmium and other heavy metal compounds, and the average concentrations are COD 230 mg / L, lead 5.5 mg / L, arsenic 15.6 mg / L, and cadmium 0.4 mg / L, and the pH value of the wastewater is less than 5.

[0071] According to the aforementioned medicament application method and dosage, the medicaments prepared in Examples 1, 2, 3 and Comparative Examples 1, 2 and 3 are added to the wastewater respectively, and the reaction is carried out at room temperature, the concentrations of heavy metals in the effluent are measured according to the national standard method, and the removal rates of heavy metal pollutants are calculated, and the results are shown in Table 1.

[0072] Table 1 Removal rate of heavy metals (%)

[0073]

[0074] As can be seen from Table 1, the removal rates of heavy metal compounds in the mining wastewater of Examples 1-3 are all above 90%, which are obviously improved compared with Comparative Examples 1-3.

[0075] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A heavy metal wastewater treatment agent, characterized in that, It includes three components: drug A, drug B, and drug C; Among them, reagent A is a liquid reagent, which includes a strong oxidant, a chelating agent and a catalyst; Reagent B is a solid reagent, mainly a heavy metal adsorbent; Agent C is a liquid agent, including flocculants and coagulants.

2. The wastewater treatment agent according to claim 1, characterized in that, In the reagent A, the strong oxidant is potassium ferrate or potassium permanganate; the catalyst is sodium humate; and the chelating agent is inorganic sodium pyrophosphate. The mass ratio of the strong oxidant, the catalyst and the chelating agent is (40-45):(2-5):(2-5).

3. The wastewater treatment agent according to claim 1, characterized in that, The heavy metal adsorbent in reagent B is modified nano-zero valent iron, and its preparation method is as follows: A first solution containing nano-zero-valent iron powder and a second solution containing mercapto-modified material are mixed and reacted to obtain a primary modified material; The first modified compound and a third solution containing porphyrin compounds are mixed and reacted to obtain the second modified compound; The modified material was freeze-dried to obtain a black powder, namely modified nano-zero valent iron.

4. The wastewater treatment agent according to claim 3, characterized in that, The mass ratio of the mercapto-modified compound to nano-zero-valent iron is (0.2-0.5):1; the mass ratio of the allyl porphyrin compound to nano-zero-valent iron is (0.05-0.2):

1.

5. The wastewater treatment agent according to claim 1, characterized in that, The flocculant in reagent C is polyferric sulfate or polyaluminum ferric silicate; the coagulant aid is anionic polyacrylamide.

6. The application of the wastewater treatment agent according to any one of claims 1-5 in the treatment of wastewater containing heavy metals, characterized in that, The heavy metal wastewater is an acidic wastewater containing one or more of the following heavy metals: lead, zinc, arsenic, cadmium, copper, nickel, and magnesium, or organic compounds such as phenols, lipids, and sulfates, with a pH < 5.

7. The application according to claim 6, characterized in that, The specific application method of the wastewater treatment agent is as follows: Add reagent A to the wastewater, stir and react until the solution ORP ≥ 300mV, then allow for one precipitation. Adjust the pH of the supernatant after the first precipitation to 10-11, add reagent B, stir and react, and then precipitate a second time. Add reagent C to the supernatant after secondary sedimentation. After reaction and sedimentation, the supernatant meets the wastewater discharge standards.

8. The application according to claim 9, characterized in that, The concentration of agent A is 3-5%, and the dosage is 0.1-0.2 L / m³. 3 The dosage of water and reagent B is 0.1-0.3 kg / m³. 3 The concentration of reagent C is prepared at 5-10%, and the dosage is 0.05-0.1 L / m³. 3 water.

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