CN110038519A - A kind of processing method of acid waste water containing heavy metal - Google Patents

Abstract

The present invention relates to a kind of processing methods of acid waste water containing heavy metal, the pH value of acid waste water is 1.0-3.5, the modified tree peony shell adsorbent material of iminodiacetic acid is added in acid waste water containing heavy metal, it is stirred under room temperature, carry out standing filtering after stir process, after separation of solid and liquid, supernatant reaches discharge standard, solid content nitric acid solution is eluted and is washed with deionized to neutrality, is reused after dry.Processing method of the invention has many advantages, such as at low cost, high-efficient, simple process, possesses preferable industrial applications prospect.

Description

A kind of treatment method of heavy metal acid wastewater

technical field

The invention relates to the technical field of wastewater treatment, in particular to a treatment method for heavy metal-containing acidic wastewater.

Background technique

The non-ferrous metal industry produces a large amount of acidic wastewater with low pH and heavy metals in the process of metal mining, beneficiation and smelting. If it is directly discharged without proper treatment, it will not only corrode infrastructure such as sewer pipes and hydraulic structures, but also seriously pollute surface water, groundwater or soil, and affect the growth and reproduction of animals and plants. A great harm to health. At present, the main methods for treating heavy metal-containing acidic wastewater include chemical precipitation, ion exchange, membrane separation, adsorption and constructed wetlands. Among them, the adsorption method has received extensive attention due to its wide adaptability, simple operation, and large processing capacity. pH value is one of the important factors affecting the adsorption performance. Under the condition of low pH value, H ₃ O ^{+ competes} with heavy metal ions for adsorption sites, and at the same time hinders the dissociation of active groups, resulting in a decrease in adsorption capacity. Therefore, the adsorption method is usually combined with the neutralization and precipitation method, so as to achieve the discharge standard of the heavy metal-containing acid wastewater treatment. However, this will undoubtedly increase the treatment cost, and the large amount of waste residues produced at the same time is likely to cause secondary pollution to the environment.

SUMMARY OF THE INVENTION

The purpose of this invention is to solve the deficiency of the above-mentioned technical problem, and provide a kind of treatment method of heavy metal acid waste water. The method has the advantages of low cost, high efficiency, simple process and the like, and has a good prospect of industrial application.

In order to solve the deficiencies of the above-mentioned technical problems, the present invention adopts the technical scheme as follows: a method for treating acid wastewater containing heavy metals, the pH value of the acid wastewater is 1.0-3.5, and the iminodiacetic acid modified peony shell adsorption material is added to The heavy metal-containing acidic wastewater is subjected to stirring treatment at room temperature. After stirring treatment, it is left to stand for filtration. After solid-liquid separation, the supernatant liquid reaches the discharge standard. The solids are eluted with nitric acid solution and washed with deionized water until neutral, and dried. reuse later.

As a further optimization of the method for treating acid wastewater containing heavy metals in the present invention, the amount of the adsorbent material added is 0.2-2 g/L.

As a further optimization of the method for treating acid wastewater containing heavy metals in the present invention, the stirring speed during the stirring treatment is 100-160 rpm, and the stirring time is 1-3 h.

As a further optimization of the method for treating acid wastewater containing heavy metals in the present invention, the concentration of the nitric acid solution is 0.1-1.0 mol/L.

As a further optimization of the treatment method of heavy metal-containing acidic wastewater in the present invention: the preparation method of the iminodiacetic acid modified peony shell adsorption material is as follows: the peony shell is pulverized and mixed with sodium hydroxide, epichlorohydrin, ethanol and deionized After mixing with water, heating and stirring the reaction, the solid obtained by the reaction is washed and dried, and then added to the mixed solution of iminodiacetic acid and sodium carbonate with heating and stirring. After the reaction is completed, the solid product is collected, washed and dried to obtain an adsorbent material.

As a further optimization of the treatment method of the heavy metal-containing acid wastewater of the present invention: the preparation method of the iminodiacetic acid modified peony shell adsorption material is as follows:

a. After soaking, washing and drying the peony shells with deionized water, crush and sieve them with a pulverizer, and sieve to get 35-24 mesh powder;

b, take the peony shell powder sieved in step a, mix with sodium hydroxide, epichlorohydrin, ethanol and deionized water, heat to 35 ° C to carry out stirring reaction, and the solid obtained after the reaction is washed and dried for subsequent use;

c, take the solid after drying in step b and add it to the mixed solution of iminodiacetic acid and sodium carbonate, heat to 65 ° C to carry out stirring reaction, after the reaction finishes, collect the solid product, wash and dry to obtain iminodiacetic acid modification Peony shell adsorption material.

As a further optimization of a method for treating heavy metal-containing acidic wastewater of the present invention: in step b: add 2-10g peony shell powder, 12-50g sodium hydroxide, 30-100mL epoxy per 100-300mL deionized water Chloropropane and 20-80 mL of ethanol.

As a further optimization of the method for treating heavy metal-containing acidic wastewater of the present invention: the concentration of iminodiacetic acid in the mixed solution of step c is 20-80 g/L, and the concentration of sodium carbonate is 20-60 g/L.

As a further optimization of the method for treating heavy metal-containing acidic wastewater in the present invention, the peony shell is the seed shell of phoenix peony.

beneficial effect

1. The present invention utilizes iminodiacetic acid modified peony shell adsorption material to treat acidic wastewater containing heavy metals such as Cu ²⁺ , Pb ²⁺ and Cd ²⁺ . After the treatment, the pH value of the wastewater can increase from the original 1.0-3.5 From 6.0 to 7.0, the removal rates of heavy metals Cu ²⁺ , Pb ²⁺ and Cd ²⁺ all reached more than 90.0%;

2. The iminodiacetic acid-modified peony shell adsorption material used in the present invention uses waste peony shells as raw materials, utilizes abundant hydroxyl active groups on the surface, and passes through etherification and aminoacetic acid reaction in turn to prepare a kind of chelating group containing chelating group. Group-N(CH ₂ COO ^- ) ₂ , a heavy metal adsorption material with large specific surface area and developed pore structure, the adsorption material has a good treatment effect on acid wastewater containing heavy metals;

3. In the preparation process of the adsorption material, the present invention adopts a lower epoxidation reaction temperature (35°C), which better retains the rich aromatic structure in the raw material of peony shell. Under strong acid conditions, complexes were formed between the delocalized π electrons protonated on the surface of the adsorbent and heavy metal ions. Moreover, with the increase of the pH value of the wastewater, a chelate complex was further formed between the surface active group -N(CH ₂ COO ^- ) ₂ and the heavy metal ions. Therefore, the adsorption material prepared by the present invention can still maintain a good adsorption effect under strong acid conditions;

4. The adsorption material used in the present invention is modified with peony shells as raw materials, and the surface isoelectric point of the modified peony shells rises from 5.8 to 8.9, has strong alkalinity, and can neutralize the acid in part of the waste water. In addition, there is also ion exchange between the sodium ions existing on the surface of the peony shell and the hydrogen ions in the acidic waste water, so after using the modified adsorbent material of the present invention to treat the waste water, the pH value of the waste water is greatly improved, Basically close to neutral.

Description of drawings

Fig. 1 is the scanning electron microscope picture of peony shell raw material among the embodiment 1;

Fig. 2 is the scanning electron microscope image of the adsorbent material obtained in Example 1;

Fig. 3 is the infrared spectrogram of the peony shell raw material and the obtained adsorbent material in Example 1.

Detailed ways

The technical solutions of the present invention are further described below in conjunction with specific embodiments.

Example 1

A method for treating acid wastewater containing heavy metals. The concentrations of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ in the treated acid wastewater are respectively 20g/L, 15g/L and 10g/L, the pH value of the acid wastewater is 2.0, and the acidity of the acid wastewater is 2.0. The amount of waste water was 50L. During treatment, 10g of adsorbent material was added to the waste water, and the mixture was stirred at room temperature for 1 hour, and the stirring speed was 100 rpm. After standing for filtration, a solid matter and a filtrate were obtained, respectively. The solid is eluted with 0.1mol/L nitric acid solution and washed with deionized water until neutral, and can be reused after drying. The concentration of heavy metal ions in the filtrate was measured by ICP-MS, and the removal rates of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ were calculated to be 97.3%, 95.8% and 93.9%, respectively.

The preparation method of the iminodiacetic acid modified peony shell adsorption material is as follows: add 50 g of peony shell (the seed shell of Fengdan peony) into a three-necked bottle, then add 300 g of sodium hydroxide, 750 mL of epichlorohydrin, 500 mL of anhydrous Ethanol and 2500 mL of deionized water were heated to 35 °C and mechanically stirred for 6 h. The product was washed with deionized water to neutrality, dried in vacuum at 60 °C for 12 h, and added to a mixed solution of 20.0 g/L iminodiacetic acid and 20.0 g/L sodium carbonate. After heating to 65°C, the reaction was stirred for 8h. After cooling, the solid product was collected, washed with deionized water until neutral, and vacuum-dried at 60 °C for 12 h to obtain an adsorbent material.

The peony shell raw materials and the prepared adsorbents were processed by scanning electron microscopy. As can be seen from Figure 1, the surface of the peony shell (PSC) presented a densely stacked layered structure with only a few pores. In contrast, a large number of deep pores appear on the surface of the adsorption material (IDA-PSC) in Figure 2, and the raised folds on the inner wall are clearly visible, which provides favorable conditions for the occurrence of adsorption.

Infrared spectroscopy analysis of the raw material of peony shell and the obtained adsorbent material, it can be seen from Figure 3 that the 1619cm ^{- 1} in peony shell (PSC) is a C=O asymmetric stretching vibration peak in -COO-, after modification The blue-shifted 16cm ^-1 and the intensity of the absorption peak increased significantly, as well as the appearance of the C=O symmetric stretching vibration peak in the carboxyl group at 1412cm ^-1 , indicating the formation of carboxylate on the surface of the adsorbent (IDA-PSC). 1117cm ^-1 is the stretching vibration peak of COC in aromatic esters, and the vibration is strengthened after modification, which is related to the introduction of tertiary amine groups, which fully indicates that iminodiacetic acid was successfully connected to the surface of peony shell.

Example 2

A method for treating acid wastewater containing heavy metals. The concentrations of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ in the treated acid wastewater are respectively 50g/L, 40g/L and 30g/L, the pH value of the acid wastewater is 2.5, and the acidity of the acid wastewater is 2.5. The amount of waste water was 20L. During treatment, 20g of adsorbent material was added to the waste water, and the mixture was stirred at room temperature for 1.5h, and the stirring speed was 120rpm. After standing for filtration, a solid matter and a filtrate were obtained, respectively. The solid is eluted with 0.5mol/L nitric acid solution and washed with deionized water until neutral, and can be reused after drying. The concentration of heavy metal ions in the filtrate was determined by ICP-MS, and the removal rates of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ were calculated to be 95.3%, 93.8% and 92.9%, respectively.

The preparation method of the iminodiacetic acid modified peony shell adsorption material is as follows: add 50g peony shell (the seed shell of Fengdan peony) into a three-necked bottle, then add 400g sodium hydroxide, 800mL epichlorohydrin, 600mL anhydrous Ethanol and 2000 mL of deionized water were heated to 35 °C and mechanically stirred for 6 h. The product was washed with deionized water until neutral, dried at 60°C under vacuum for 12 hours, and then added to a mixed solution of 40.0 g/L iminodiacetic acid and 30.0 g/L sodium carbonate. After heating to 65°C, the reaction was stirred for 16h. After cooling, the solid product was collected, washed with deionized water until neutral, and vacuum-dried at 60 °C for 12 h to obtain an adsorbent material.

Example 3:

A method for treating acid wastewater containing heavy metals. The concentrations of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ in the treated acid wastewater are respectively 100g/L, 80g/L and 60g/L, the pH value of the acid wastewater is 3.5, and the acidity of the acid wastewater is 3.5. The amount of waste water was 10L. During treatment, 20g of adsorbent material was added to the waste water, and the mixture was stirred at room temperature for 3h, and the stirring speed was 160rpm. After standing for filtration, a solid matter and a filtrate were obtained, respectively. The solid is eluted with 1.0mol/L nitric acid solution and washed with deionized water until neutral, and can be reused after drying. The concentration of heavy metal ions in the filtrate was measured by ICP-MS, and the removal rates of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ were calculated to be 91.3%, 90.8% and 90.1%, respectively.

The preparation method of the iminodiacetic acid modified peony shell adsorption material is as follows: add 100g peony shell (the seed shell of Fengdan peony) into a three-necked bottle, then add 500g sodium hydroxide, 1000mL epichlorohydrin, 800mL anhydrous Ethanol and 3000 mL of deionized water were heated to 35 °C and mechanically stirred for 6 h. The product was washed with deionized water to neutrality, dried in vacuum at 60°C for 12 h, and added to a mixed solution of 80.0 g/L iminodiacetic acid and 60.0 g/L sodium carbonate. After heating to 65°C, the reaction was stirred for 24h. After cooling, the solid product was collected, washed with deionized water until neutral, and vacuum-dried at 60 °C for 12 h to obtain an adsorbent material.

Example 4:

A method for treating acid wastewater containing heavy metals. The concentrations of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ in the treated acid wastewater are respectively 100g/L, 80g/L and 60g/L, the pH value of the acid wastewater is 1.0, and the acidity of the acid wastewater is 1.0. The amount of waste water was 10 L. During treatment, 20 g of adsorbent material (the adsorbent material prepared in Example 1) was added to the waste water, and stirred at room temperature for 3 hours at a stirring speed of 160 rpm. After standing for filtration, a solid matter and a filtrate were obtained, respectively. The solid is eluted with 1.0mol/L nitric acid solution and washed with deionized water until neutral, and can be reused after drying. The concentration of heavy metal ions in the filtrate was determined by ICP-MS, and the removal rates of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ were calculated to be 90.9%, 90.3% and 90.0%, respectively.

Example 5:

A method for treating acid wastewater containing heavy metals. The concentrations of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ in the treated acid wastewater are respectively 20g/L, 15g/L and 10g/L, the pH value of the acid wastewater is 2.0, and the acidity of the acid wastewater is 2.0. The amount of waste water was 50L. During treatment, 10g of adsorbent material was added to the waste water, and the mixture was stirred at room temperature for 1 hour, and the stirring speed was 100 rpm. After standing for filtration, a solid matter and a filtrate were obtained, respectively. The solid is eluted with 0.1mol/L nitric acid solution and washed with deionized water until neutral, and can be reused after drying. The concentration of heavy metal ions in the filtrate was measured by ICP-MS, and the removal rates of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ were calculated to be 76.3%, 70.8% and 66.9%, respectively.

The preparation method of the iminodiacetic acid modified peony shell adsorption material is as follows: add 50 g of peony shell into a three-necked flask, then add 300 g of sodium hydroxide, 750 mL of epichlorohydrin, 500 mL of absolute ethanol and 2500 mL of deionized water, and heat After reaching 75°C, mechanically stirred for 6h. The product was washed with deionized water to neutrality, dried in vacuum at 60 °C for 12 h, and added to a mixed solution of 20.0 g/L iminodiacetic acid and 20.0 g/L sodium carbonate. After heating to 65°C, the reaction was stirred for 8h. After cooling, the solid product was collected, washed with deionized water until neutral, and vacuum-dried at 60 °C for 12 h to obtain an adsorbent material.

Example 6:

A method for treating acid wastewater containing heavy metals. The concentrations of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ in the treated acid wastewater are respectively 20g/L, 15g/L and 10g/L, the pH value of the acid wastewater is 2.0, and the acidity of the acid wastewater is 2.0. The amount of waste water was 50L. During treatment, 10g of adsorbent material was added to the waste water, and the mixture was stirred at room temperature for 1 hour, and the stirring speed was 100 rpm. After standing for filtration, a solid matter and a filtrate were obtained, respectively. The solid is eluted with 0.1mol/L nitric acid solution and washed with deionized water until neutral, and can be reused after drying. The concentration of heavy metal ions in the filtrate was measured by ICP-MS, and the calculation showed that the removal rates of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ were 58.2%, 40.1% and 39.6%, respectively.

The preparation method of the iminodiacetic acid modified peony shell adsorption material is as follows: add 50 g of peony shell into a three-necked flask, then add 300 g of sodium hydroxide, 750 mL of epichlorohydrin, 500 mL of absolute ethanol and 2500 mL of deionized water, and heat After reaching 100 °C, mechanical stirring was performed for 6 h. The product was washed with deionized water to neutrality, dried in vacuum at 60 °C for 12 h, and added to a mixed solution of 20.0 g/L iminodiacetic acid and 20.0 g/L sodium carbonate. After heating to 65°C, the reaction was stirred for 8h. After cooling, the solid product was collected, washed with deionized water until neutral, and vacuum-dried at 60 °C for 12 h to obtain an adsorbent material.

Example 7

A method for treating acid wastewater containing heavy metals. The concentrations of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ in the treated acid wastewater are respectively 20g/L, 15g/L and 10g/L, the pH value of the acid wastewater is 2.0, and the acidity of the acid wastewater is 2.0. The amount of waste water was 50L. During treatment, 10g of adsorbent material was added to the waste water, and the mixture was stirred at room temperature for 1 hour, and the stirring speed was 100 rpm. After standing for filtration, a solid matter and a filtrate were obtained, respectively. The solid is eluted with 0.1mol/L nitric acid solution and washed with deionized water until neutral, and can be reused after drying. The concentration of heavy metal ions in the filtrate was measured by ICP-MS, and the removal rates of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ were calculated to be 94.5%, 92.9% and 91.8%, respectively.

The preparation method of the iminodiacetic acid modified peony shell adsorption material is as follows: add 50 g of peony shell (the seed shell of Lufen peony) into a three-necked bottle, then add 300 g of sodium hydroxide, 750 mL of epichlorohydrin, 500 mL of anhydrous Ethanol and 2500 mL of deionized water were heated to 35 °C and mechanically stirred for 6 h. The product was washed with deionized water to neutrality, dried in vacuum at 60°C for 12 hours, and added to a mixed solution of 20.0 g/L iminodiacetic acid and 20.0 g/L sodium carbonate. After heating to 65°C, the reaction was stirred for 8h. After cooling, the solid product was collected, washed with deionized water until neutral, and dried under vacuum at 60 °C for 12 h to obtain the adsorbent material.

Example 8

A method for treating acid wastewater containing heavy metals. The concentrations of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ in the treated acid wastewater are respectively 20g/L, 15g/L and 10g/L, the pH value of the acid wastewater is 2.0, and the acidity of the acid wastewater is 2.0. The amount of waste water was 50L. During treatment, 10g of adsorbent material was added to the waste water, and the mixture was stirred at room temperature for 1 hour, and the stirring speed was 100 rpm. After standing for filtration, a solid matter and a filtrate were obtained, respectively. The solid is eluted with 0.1mol/L nitric acid solution and washed with deionized water until neutral, and can be reused after drying. The concentration of heavy metal ions in the filtrate was determined by ICP-MS, and the removal rates of Cu ²⁺ , Pb ²⁺ and Cd ²⁺ were calculated to be 94.2%, 92.1% and 91.3%, respectively.

The preparation method of the iminodiacetic acid-modified peony shell adsorption material is as follows: add 50 g of peony shell (the seed shell of peony) into a three-necked bottle, then add 300 g of sodium hydroxide, 750 mL of epichlorohydrin, 500 mL of anhydrous Ethanol and 2500 mL of deionized water were heated to 35 °C and mechanically stirred for 6 h. The product was washed with deionized water to neutrality, dried in vacuum at 60°C for 12 hours, and added to a mixed solution of 20.0 g/L iminodiacetic acid and 20.0 g/L sodium carbonate. After heating to 65°C, the reaction was stirred for 8h. After cooling, the solid product was collected, washed with deionized water until neutral, and dried under vacuum at 60 °C for 12 h to obtain the adsorbent material.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Technical personnel, within the scope of the technical solution of the present invention, can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above, provided that they do not depart from the technical solution content of the present invention, according to this The technical essence of the invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

Claims (9)

1. a treatment method for heavy metal-containing acid waste water, the pH value of acid waste water is 1.0-3.5, it is characterized in that: iminodiacetic acid modified peony shell adsorption material is added in heavy metal acid waste water, stirs at normal temperature After stirring, it is left to stand for filtration. After solid-liquid separation, the supernatant liquid reaches the discharge standard, and the solid is eluted with nitric acid solution and washed with deionized water until neutral, and reused after drying. 2 . The method for treating heavy metal-containing acidic wastewater according to claim 1 , wherein the addition amount of the adsorbent material is 0.2-2 g/L. 3 . 3. The treatment method of heavy metal-containing acidic wastewater according to claim 1, wherein the stirring speed during the stirring treatment is 100-160rpm, and the stirring time is 1-3h. 4. a kind of treatment method of heavy metal-containing acidic wastewater as claimed in claim 1, is characterized in that: the concentration of described nitric acid solution is 0.1-1.0 mol/L. 5. a kind of treatment method of heavy metal-containing acidic wastewater as claimed in claim 1, is characterized in that: the preparation method of iminodiacetic acid modified peony shell adsorption material is as follows: after peony shell is pulverized, mix with sodium hydroxide, epoxy chlorine Propane, ethanol and deionized water are mixed, heated and stirred for reaction. After the solid obtained by the reaction is washed and dried, it is added to the mixed solution of iminodiacetic acid and sodium carbonate and heated and stirred. After the reaction is completed, the solid product is collected, washed and dried. Then the adsorbent material is obtained. 6. a kind of treatment method of heavy metal-containing acid waste water as claimed in claim 5, is characterized in that: preparation method is as follows: a. After soaking, washing and drying the peony shells with deionized water, crush and sieve them with a pulverizer, and sieve to get 35-24 mesh powder; b, take the peony shell powder sieved in step a, mix with sodium hydroxide, epichlorohydrin, ethanol and deionized water, heat to 35 ° C to carry out stirring reaction, and the solid obtained after the reaction is washed and dried for subsequent use; c, take the solid after drying in step b and add it to the mixed solution of iminodiacetic acid and sodium carbonate, heat to 65 ° C to carry out stirring reaction, after the reaction finishes, collect the solid product, wash and dry to obtain iminodiacetic acid modification Peony shell adsorption material. 7. a kind of treatment method of heavy metal-containing acidic wastewater as claimed in claim 6, is characterized in that: in described step b: every 100-300mL deionized water adds 2-10g peony shell powder, 12-50g sodium hydroxide , 30-100mL epichlorohydrin and 20-80mL ethanol. 8. a kind of treatment method of heavy metal-containing acidic wastewater as claimed in claim 6, is characterized in that: in the mixed solution of described step c, the concentration of iminodiacetic acid is 20-80g/L, and the concentration of sodium carbonate is 20-80g/L 60g/L. 9. The treatment method of heavy metal-containing acidic wastewater according to any one of claims 5-8, wherein the peony shell is the seed shell of phoenix peony.