CN109626486B - Method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater - Google Patents

Abstract

A method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater. Carbon-containing materials are carbonized-activated to prepare porous carbon materials with high specific surface area and rich pore structure, which are used for coupling treatment of high-concentration organic wastewater and heavy metal wastewater and preparing Hydrogen rich gas. The porous carbon materials prepared from carbon-containing waste are used for the adsorption and enrichment of organic matter and heavy metal ions in high-concentration organic wastewater and heavy metal wastewater, respectively, so as to realize the removal of heavy metals and organic matter. The porous carbon material adsorbed with heavy metal ions is calcined at high temperature to prepare a supported carbon-based catalyst, which is used for catalytic reforming of the organic matter desorbed from the porous carbon adsorbed with organic matter to prepare hydrogen-rich gas. The porous carbon that adsorbs and enriches organic matter is completely desorbed and then recycled to the adsorption of high-concentration organic wastewater, and the deactivated carbon-based catalyst is used to recover heavy metals through oxidative calcination. The water source used in the catalytic reforming experiment is the water separated after the adsorption is completed, so as to achieve the purpose of treating waste with waste and regenerating resources.

Description

A method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater

technical field

The invention belongs to the field of wastewater treatment, in particular to a method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater.

Background technique

At present, the problem of water pollution in my country is becoming more and more serious, and it has become a major problem that needs to be solved urgently in the development of the national economy. With the development of society, industrial production continues to increase, and industrial sewage discharge is becoming more and more serious. Many enterprises directly discharge a large amount of industrial wastewater into rivers or bays, which not only affects the water ecosystem, but also seriously threatens human health. Various coking wastewater, pharmaceutical wastewater, textile printing and dyeing wastewater, and petrochemical wastewater are all high-concentration organic wastewater, which are very difficult to process.

The organic matter concentration in high-concentration organic wastewater is high, and the COD is generally above 2000mg/L; the BOD value is low, the biochemical treatment is difficult, and the composition is complex; high-concentration organic wastewater has high chroma and peculiar smell; strong acid and alkali. If it is directly discharged, it will not only cause human sensory discomfort, but also block sunlight from irradiating the water surface after entering the water body, causing the photosynthesis rate of microorganisms and aquatic plants in the water to decrease, resulting in changes in the aquatic ecology, and causing the death of fish and other aquatic animals in the water. Sulfide, nitrogen and other substances in high-concentration organic wastewater seep into the ground through surface water, which will directly endanger human health and even lead to death after being used by humans and animals. In addition, the effluent of high-concentration organic wastewater after ordinary treatment contains high aromatic organic carbon compounds, which will affect the quality of surface water and increase the cost of subsequent drinking water treatment.

Heavy metal wastewater is wastewater containing heavy metals (generally containing heavy metals such as nickel, copper, mercury, chromium, cadmium, arsenic, lead, zinc, etc.) discharged from industrial production processes such as mining, metallurgy, and machinery manufacturing. Degrades in the environment. Heavy metals discharged with heavy metal wastewater, even if the concentration is small, will accumulate in algae and sediments, and be adsorbed by fish and shellfish, resulting in food chain concentration, thus causing pollution. Moreover, heavy metals can interact strongly with proteins and various enzymes in the human body, deactivating them, and may also accumulate in some organs of the human body, exceeding the limit that the human body can tolerate, which will cause acute poisoning in the human body , subacute poisoning or chronic poisoning, causing great harm to the human body. For example, Minamata disease (mercury pollution) and Ititai disease (cadmium pollution) in Japan are caused by heavy metal pollution. At present, the activated carbon adsorption method is used for the treatment of high-concentration organic wastewater and heavy metal wastewater, but the regeneration and elution of activated carbon are difficult. In view of the complexity and recalcitrance of high-concentration organic wastewater and heavy metal wastewater, as well as the limitations of the adsorbents used, it is important to study a method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater, which is important for ecological environmental protection and drinking water safety. significance.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method for coupling treatment of high-concentration organic waste water and heavy metal waste water in view of the problems in the above-mentioned prior art. Porous carbon materials with pore structure are used for the adsorption and enrichment of organic matter and heavy metal ions in high-concentration organic wastewater and heavy metal wastewater, respectively. The hydrogen-rich gas is prepared from the organic matter desorbed from the porous carbon that adsorbs the organic matter in the wastewater, so as to realize waste-to-waste and resource regeneration.

In order to achieve the above object, the method for coupling treatment of high-concentration organic waste water and heavy metal waste water in the present invention comprises the following steps:

Step 1, carbonizing the carbon-containing raw material after pretreatment, mixing the obtained carbonized material with an activator, and heating and activating in an inert atmosphere to prepare a porous carbon material with high specific surface area and rich pore structure;

Step 2: Use porous carbon material to adsorb organic matter in high-concentration organic wastewater, and perform solid-liquid separation on porous carbon and water to obtain porous carbon that adsorbs and enriches organic matter and the first separated water; use porous carbon material to adsorb heavy metals in heavy metal wastewater ions, the porous carbon and water are subjected to solid-liquid separation to obtain porous carbon that adsorbs and enriches heavy metal ions and the second separated water;

Step 3: The porous carbon adsorbed and enriched with organic matter is placed in a desorption chamber for thermal desorption treatment, so that the organic matter adsorbed and enriched on the surface of the porous carbon material and in the pores is desorbed in the form of gaseous volatiles during the heating process to obtain Gaseous volatiles, the porous carbon after desorption is recycled to adsorb organic matter in high-concentration organic wastewater; the porous carbon that adsorbs and enriches heavy metal ions is calcined at high temperature in an inert atmosphere to form a supported carbon-based catalyst for adsorbing heavy metal ions The porous carbon material is equivalent to the catalyst carrier, and the heavy metal ions adsorbed on the surface and pores of the porous carbon are equivalent to the active component;

Step 4. The gaseous volatiles are introduced into the reforming chamber where the supported carbon-based catalyst is placed, and the gaseous volatiles undergo a reforming reaction, and the reaction water source is taken from the first separated water and the second separated water, and converted into hydrogen-rich gas;

Step 5. The carbon-based catalyst deactivated after the reaction is oxidized and calcined to realize the recovery of heavy metals.

The carbon-containing raw material is selected from petroleum coke, biomass, waste rubber or waste plastic, and the biomass includes fruit shells, straws and sawdust.

The pretreatment described in step 1 includes crushing, screening and drying.

The activator in the first step is at least one of KOH, ZnCl ₂ , H ₃ PO ₄ , NaOH, FeCl ₃ , KCl and K ₂ CO ₃ .

The inert atmosphere described in step 1 is provided by nitrogen, argon or helium, and the activation temperature ranges from 400 to 900°C.

The COD of the high-concentration organic wastewater is 2000-30000 mg/L, and the BOD/COD is less than 0.3.

The heavy metal content of the heavy metal wastewater is 0.1-100 g/L.

The heating temperature during the thermal desorption treatment in the third step is 100-300°C.

In the fifth step, oxidative calcination is carried out in an air atmosphere or an oxygen atmosphere, and the calcination temperature is 600-900°C.

The inert atmosphere described in step 3 is provided by nitrogen, argon or helium, and the calcination temperature is 500-1000°C;

Heavy metal wastewater refers to heavy metal wastewater containing at least one of metal ions Ni, Cu, Fe, Co, Cd and Au.

The heavy metal ions adsorbed on the surface of the porous carbon and in the pores of the supported carbon-based catalyst include one or more of metal ions Ni, Cu, Fe, Co, Cd and Au.

Compared with the prior art, the present invention has the following beneficial effects: the raw materials for preparing porous carbon materials are widely sourced, including petroleum coke, biomass (such as husks, straw, wood chips, etc.), waste tires, waste rubber, waste plastics, etc. Carbon material, the prepared adsorbent material has high specific surface area and high stability, good adsorption effect, simple preparation process, and can reduce the pollution of waste to the environment while obtaining an efficient adsorbent. The porous carbon material provided by the present invention can obtain a supported carbon-based catalyst through reduction and calcination after adsorbing and enriching heavy metal ions in heavy metal wastewater. The porous carbon material used for adsorbing heavy metals is equivalent to a catalyst carrier, which is adsorbed on the surface and The heavy metal ions in the pores are equivalent to active components, which alleviates the problem of heavy metal recovery and treatment after traditional activated carbon desorption and the problem of adsorbent regeneration to a certain extent, and also realizes the solidification and effective recycling of heavy metals in wastewater. The coupled treatment method for high-concentration organic waste water and heavy metal waste water provided by the invention does not involve a biological reactor, is flexible in operation, simple in process, low in cost, and does not generate secondary pollution. The present invention adsorbs high-concentration organic waste water and waste water containing heavy metal ions by using the porous carbon material prepared from carbon-containing materials, which can effectively realize the removal of heavy metal ions and organic substances in the waste water, and greatly reduce the cost and cost of subsequent water treatment. The porous carbon material after adsorption of heavy metals can be prepared into a supported carbon-based catalyst after high temperature calcination. The catalyst can prepare hydrogen-rich gas by catalytically reforming the organic matter desorbed from the porous carbon. The coupling treatment of wastes also achieves the purpose of waste treatment and resource regeneration.

Description of drawings

Fig. 1 is the process flow diagram of coupling treatment of high-concentration organic waste water and heavy metal waste water of the present invention;

In the accompanying drawings: 1-carbon-containing raw material; 2-porous carbon material; 3-high-concentration organic waste water; 4-porous carbon enriched with organic matter; 5-first separated water; 6-gaseous volatile matter; 7-desorbed Porous carbon; 8-deactivated carbon-based catalyst; 9-supported carbon-based catalyst; 10-second separation water; 11-porous carbon enriched with heavy metal ions; 12-heavy metal wastewater.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

Referring to Fig. 1, the method for coupling treatment of high-concentration organic waste water and heavy metal waste water according to the present invention comprises the following steps:

Step 1: The carbon-containing raw materials 1 such as petroleum coke, biomass, waste rubber, waste plastics, etc. are subjected to carbonization treatment after pretreatment such as crushing, screening, drying, etc. , Porous carbon material 2 with high specific surface area and rich pore structure was prepared by heating activation; the activator was at least one of KOH, ZnCl ₂ , H ₃ PO ₄ , NaOH, FeCl ₃ , KCl and K ₂ CO ₃ , The activation temperature is in the range of 400 to 900°C.

Step 2: After the porous carbon material 2 prepared in step 1 is used to adsorb the organic matter in the high-concentration organic wastewater 3, the porous carbon and water are subjected to solid-liquid separation to obtain the porous carbon 4 that adsorbs and enriches the organic matter and the first decomposed water. 5. After the porous carbon material 2 prepared in step 1 is used to adsorb heavy metal ions in the heavy metal wastewater 12, the porous carbon and water are subjected to solid-liquid separation to obtain the porous carbon 11 that adsorbs and enriches heavy metal ions and the second decomposed water 10. ; COD in water of high concentration organic wastewater 3 is 2000～30000mg/L, BOD/COD<0.3. The heavy metal content of the heavy metal wastewater 12 is 0.1-100 g/L.

Step 3: The porous carbon 4 obtained after solid-liquid separation in step 2 for adsorbing and enriching organic matter is placed in a desorption chamber for thermal desorption treatment, so that the organic matter enriched on the surface of the porous carbon material and in the pores is heated during the heating process. It is desorbed in the form of gaseous volatiles 6. The heating temperature in the desorption process is generally 100-300°C, and the porous carbon 7 after the desorption is completed can be recycled to adsorb the organic matter in the high-concentration organic wastewater 3; the adsorption and enrichment of heavy metals obtained after the solid-liquid separation in the second step The ionic porous carbon 11 is calcined at high temperature in an inert atmosphere to form a supported carbon-based catalyst 9. The porous carbon material used to adsorb heavy metal ions is equivalent to the catalyst carrier, while the heavy metal ions adsorbed on the surface and pores of the porous carbon are equivalent to the active catalyst. components. The formed carbon-based catalyst can be one or more metal ions containing Ni, Cu, Fe, Co, Cd, Au and the like. The calcination temperature used in the catalyst preparation process is generally 500-1000°C.

In order to prevent the oxidation of the porous carbon during the calcination process, inert gases such as nitrogen, argon, and helium are used as protective gases during the calcination process. At the same time, the heavy metal ions adsorbed on the porous carbon are also solidified on the porous carbon material by calcination;

Step 4: The desorbed and volatilized gaseous volatiles 6 are introduced into the reforming chamber pre-placed with the supported carbon-based catalyst 9, and the gaseous volatiles 6 undergo a reforming reaction during the contact process with the supported carbon-based catalyst 9, and are converted into Hydrogen rich gas. The reaction water source is a part of the first separated water 5 and the second separated water 10, and the other part is directly discharged after subsequent treatment;

Step 5: After the catalytic reforming reaction is completed, the deactivated carbon-based catalyst 8 is oxidized and calcined to realize the recovery of heavy metals. The temperature of oxidative calcination is generally 600 to 900°C, and it is carried out in an air atmosphere or an oxygen atmosphere.

The technical effect of the present invention is explained below by embodiment:

Example 1

The method for coupling treatment of high-concentration organic waste water and heavy metal waste water according to the present invention comprises the following steps:

Step 1. Preparation of carbon-containing raw material 1: Using pine wood chips as raw materials, the pine wood chips are crushed, sieved, and dried, and then carbonized to prepare carbon-containing raw material 1. The carbonization temperature is 700 ° C, and the carbonization treatment time is 2h.

Step 2. Preparation of porous carbon material 2: After mixing the biomass-based carbonized material obtained in step 1 with potassium hydroxide in a ratio of 1:4, react in a fixed-bed reactor, and after the reaction, wash with acid and water After several times of drying, the porous carbon material 2 was obtained. In the process, the activation temperature of the carbon-containing raw material 1 was 700° C. and the reaction time was 2 h.

Step 3: Coupling treatment of high-concentration organic waste water and heavy metal waste water: the porous carbon material 2 prepared in step 2 is used for the adsorption of organic matter and heavy metals in high-concentration organic waste water 3 and heavy metal waste water 12, respectively. Take 100 ml of high-concentration organic waste water with a COD content of 7000 mg/L, add 0.8 g of the porous carbon material 2 prepared in step 2 to the waste water, and after the adsorption is completed, the removal rate of organic matter in the waste water is 95%. Take heavy metal wastewater with nickel ion concentration of 10 g/L, add 0.8 g of porous carbon material 2 prepared in step 2 to the wastewater, and after adsorption is completed, the removal rate of heavy metals in wastewater is 95%.

Step 4. Preparation of supported carbon-based catalyst 9: The supported carbon-based catalyst 9 is prepared by reducing and calcining the porous carbon material 2 adsorbed with Ni ions. The calcination temperature is 600° C. and the calcination time is 6 h.

Step 5. Research on hydrogen production by catalytic reforming: The supported carbon-based catalyst 9 in step 4 is used for catalytic reforming of the organic matter desorbed from the porous carbon material 2 that has adsorbed organic matter in step 3, and the reforming temperature is 600 ° C. The obtained Hydrogen yield 73%.

Example 2

The method for coupling treatment of high-concentration organic waste water and heavy metal waste water according to the present invention comprises the following steps:

Step 1. Preparation of carbon-containing raw material 1: Using petroleum coke as a raw material, the petroleum coke is crushed, sieved, and dried, and then carbonized to prepare carbon-containing raw material 1. The carbonization temperature is 700°C, and the carbonization treatment time is 2h.

Step 2. Preparation of porous carbon material 2: After mixing the petroleum coke carbonized material obtained in step 1 with potassium hydroxide in a ratio of 1:4, react in a fixed-bed reactor, and after the reaction is finished, use acid washing and water washing. The second time, the porous carbon material was obtained by drying, and the activation temperature of the carbonized material in this process was 700 °C, and the reaction time was 2 h.

Step 3: Coupling treatment of high-concentration organic waste water and heavy metal waste water: the porous carbon material 2 prepared in step 2 is used for the adsorption of organic matter and heavy metals in high-concentration organic waste water 3 and heavy metal waste water 12, respectively. Take 100 ml of high-concentration organic waste water with a COD content of 7000 mg/L, add 0.8 g of the porous carbon material 2 prepared in step 2 to the waste water, and after the adsorption is completed, the removal rate of organic matter in the waste water is 98%. Take heavy metal wastewater with nickel ion concentration of 10 g/L, add 0.8 g of porous carbon material 2 prepared in step 2 to the wastewater, and after adsorption is completed, the removal rate of heavy metals in wastewater is 98%.

Step 4. Preparation of supported carbon-based catalyst 9: The supported carbon-based catalyst 9 is prepared by reducing and calcining the porous carbon material 2 adsorbed with Ni ions. The calcination temperature is 700° C. and the calcination time is 3 hours.

Step 5. Research on hydrogen production by catalytic reforming: The supported carbon-based catalyst 9 in step 4 is used for catalytic reforming of the organic matter desorbed from the porous carbon material 2 that has adsorbed organic matter in step 3, and the reforming temperature is 600 ° C. The obtained Hydrogen yield 78%.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solutions of the present invention Several modifications or simple substitutions are also possible, which would also fall within the scope of protection defined by the appended claims.

Claims (10)

1. A method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater is characterized by comprising the following steps:

firstly, pretreating a carbon-containing raw material (1), then carrying out carbonization treatment, mixing the obtained carbonized material with an activating agent, and heating and activating in an inert atmosphere to prepare a porous carbon material (2) with a high specific surface area and a rich pore structure;

step two, adsorbing organic matters in the high-concentration organic wastewater (3) by using a porous carbon material (2), and performing solid-liquid separation to obtain porous carbon (4) adsorbing the enriched organic matters and first separated water (5); adsorbing heavy metal ions in the heavy metal wastewater (12) by using a porous carbon material (2), and performing solid-liquid separation to obtain porous carbon (11) adsorbing and enriching the heavy metal ions and second separated water (10);

placing the porous carbon (4) adsorbing and enriching the organic matters in a desorption chamber for thermal desorption treatment, so that the organic matters adsorbed and enriched on the surface of the porous carbon material and in pore channels are desorbed in a gaseous volatile matter (6) form in the heating process, and the desorbed porous carbon (7) is recycled for adsorbing the organic matters in the high-concentration organic wastewater (3); calcining the porous carbon (11) adsorbing and enriching the heavy metal ions at high temperature in an inert atmosphere to form a supported carbon-based catalyst (9), wherein a porous carbon material (2) for adsorbing the heavy metal ions is a catalyst carrier, and the heavy metal ions adsorbed on the surface and in pore channels of the porous carbon are active components;

the heavy metal wastewater (12) is heavy metal wastewater containing at least one of metal ions Ni, Cu, Fe, Co, Cd and Au, and the heavy metal ions adsorbed on the surface and in the pore channels of the porous carbon by the supported carbon-based catalyst (9) comprise one or more of metal ions Ni, Cu, Fe, Co, Cd and Au;

introducing the gaseous volatile matter (6) into a reforming chamber provided with a supported carbon-based catalyst (9), wherein the gaseous volatile matter (6) is subjected to a reforming reaction, and a reaction water source is obtained from the first separated water (5) and the second separated water (10) and is converted into a hydrogen-rich gas;

and step five, carrying out oxidation and calcination on the carbon-based catalyst (8) inactivated after the reaction to realize the recovery of heavy metals.

2. The method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater according to claim 1, wherein the method comprises the following steps: the carbonaceous raw material (1) is petroleum coke, biomass, waste rubber or waste plastic, and the biomass is any one of fruit shell, straw and wood chip.

3. The method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater according to claim 1, wherein the method comprises the following steps: the pretreatment in the step one comprises crushing, screening and drying treatment.

4. The method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater according to claim 1, wherein the method comprises the following steps: the activating agent in the step one is KOH or ZnCl₂、H₃PO₄、NaOH、FeCl₃KCl and K₂CO₃At least one of (1).

5. The method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater according to claim 1, wherein the method comprises the following steps: the inert atmosphere in the first step is provided by nitrogen, argon or helium, and the activation temperature range is 400-900 ℃.

6. The method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater according to claim 1, wherein COD in the high-concentration organic wastewater (3) is 2000-30000 mg/L/COD < 0.3.

7. The method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater according to claim 1, wherein the heavy metal content of the heavy metal wastewater (12) is 0.1-100 g/L.

8. The method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater according to claim 1, wherein the method comprises the following steps: and the heating temperature of the third step in the thermal desorption treatment process is 100-300 ℃.

9. The method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater according to claim 1, wherein the method comprises the following steps: and fifthly, oxidizing and calcining the mixture in an air atmosphere or an oxygen atmosphere at the calcining temperature of 600-900 ℃.

10. The method for coupling treatment of high-concentration organic wastewater and heavy metal wastewater according to claim 1, wherein the method comprises the following steps: and step three, providing an inert atmosphere by nitrogen, argon or helium, wherein the calcining temperature is 500-1000 ℃.

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