CN103623772B - A kind of adsorbent for removing and reclaim liquid phase mercury and preparation method thereof and using method - Google Patents

Abstract

The invention relates to an adsorbent for removing and recovering liquid-phase mercury and its preparation method and application method. A material with a high specific surface area and a large pore volume is used as a carrier, and a sulfide or selenide nano-adsorbent is loaded thereon. An ion-exchange nanometer mercury-removing adsorbent with high adsorption capacity is prepared. The nano-mercury removal adsorbent is made into a filter layer to filter the waste liquid containing mercury ions, and the mercury ions in the liquid phase are adsorbed on the adsorbent by using the exchange of metal ions on the material with mercury ions to achieve liquid phase removal. purpose of mercury. The adsorbent has the characteristics of large adsorption capacity and fast adsorption rate, and is suitable for mercury removal treatment of coal-fired flue gas, non-ferrous metal smelting flue gas, and other mercury-related industries.

Description

A kind of adsorbent for removing and recovering liquid phase mercury and its preparation method and use method

technical field

The invention belongs to a waste water mercury removal technology in the field of environmental protection. The mercury ions in the liquid phase are adsorbed on the adsorbent mainly through the exchange of metal ions on the adsorbent with mercury ions, so as to achieve the purpose of removing mercury in the liquid phase.

Background technique

Due to its characteristics of persistence, easy migration, bioaccumulation and high toxicity, mercury pollution has attracted widespread attention from the international community. In January 2013, the United Nations Intergovernmental Negotiating Committee adopted a legally binding "International Convention on the Prevention and Control of Mercury Pollution", which will control and reduce mercury emissions on a global scale. Due to the large amount of mercury emissions in my country, it is bound to face severe pressure on compliance. Coal combustion flue gas and non-ferrous metal smelting flue gas are considered to be the two most important anthropogenic sources of mercury. Therefore, mercury emission control technologies in these two industries have attracted much attention. In the process of mercury emission control of coal-fired flue gas, the technology of converting zero-valent mercury in flue gas into divalent mercury by means of oxidation, and then absorbing divalent mercury through wet desulfurization process is the most popular technology in current research. Although this technology can effectively reduce the concentration of mercury in the coal-fired flue gas discharged into the atmosphere, it will inevitably increase the concentration of mercury in the desulfurization liquid and transfer mercury pollution from the atmosphere to water bodies. In the flue gas purification process of non-ferrous metal smelting, there is generally a wet spraying process to reduce the flue gas temperature. During the wet spraying process, the divalent mercury in the flue gas will inevitably be transferred to the washing liquid, resulting in an increase in the mercury concentration in the washing waste liquid. There are other mercury-related industries that more or less produce some mercury-containing waste liquid. These mercury-containing waste liquids generally go through some necessary treatment procedures before discharge to remove the heavy metal mercury, and there are many related studies for this. For example, patent CN201110042926.3 discloses a method for adding vulcanizing agent and composite additives to convert Hg2 ⁺ into HgS particles in wastewater; Method for mercury and its compounds in liquid hydrocarbons. However, most of the current mercury removal methods in waste liquid are to use activated carbon to remove mercury, or to use the reaction of sulfide and mercury to form HgS precipitation to remove mercury in the liquid phase. However, the adsorption capacity of the adsorbent is generally small, and if it is used in large quantities, the operating cost will be high; and the method of using sulfide to generate HgS is difficult to make mercury and sulfur recycle; and if not disposed of properly, these methods may cause secondary pollution.

Contents of the invention

The object of the present invention is to provide an adsorbent for removing and recovering liquid phase mercury and its preparation method and use method in order to overcome the above-mentioned defects in the prior art.

The purpose of the present invention can be achieved through the following technical solutions: a kind of adsorbent for removing and reclaiming liquid phase mercury is characterized in that, the adsorbent is a nano-adsorbent loaded on the adsorbent carrier, and the nano-adsorbent The loading amount of the agent on the adsorbent carrier is 1-50wt%.

The nano-adsorbent is a metal sulfide or metal selenide nano-adsorbent.

The adsorbent carrier is a material with large specific surface area and pore volume, including alumina, diatomaceous earth, molecular sieve, attapulgite, zeolite or activated carbon.

A method for preparing an adsorbent for removing and recovering liquid phase mercury, characterized in that it comprises the following steps:

The first step, select the adsorbent carrier;

The second step is to configure a high-concentration nano-adsorbent solution;

The third step is to immerse the adsorbent carrier in a high-concentration nano-adsorbent solution, and stir the nano-adsorbent solution to make it fully contact with the adsorbent carrier, and use electrostatic attraction or chemical attachment to attract a large number of nano-adsorbents into the adsorbent carrier in the channel and loaded on its surface;

Step 4: After the adsorbent carrier and the nano-adsorbent solution are mixed for 1-3 hours, the adsorbent carrier is separated from the nano-adsorbent solution by filtration, and dried at room temperature to obtain the adsorbent.

The high-concentration nano-adsorbent solution refers to a nano-adsorbent solution configured by one or more metal sulfides or selenides in zinc, iron, aluminum, titanium, manganese, calcium, and its concentration range is 0.1-10.0mol/L.

The stirring speed described in the third step is 60 rpm-300 rpm.

The drying temperature in step (4) is 15-30° C., and the dried adsorbent carrier is calcined at 100-250° C. for 0.1-2.0 hours to form a stable nano-mercury removal adsorbent.

A method for using an adsorbent for removing and recovering liquid-phase mercury, characterized in that it comprises the following steps: a. making the prepared nanometer mercury-removing adsorbent into a filter layer to filter waste liquid containing mercury ions , using the exchange of metal ions and mercury ions on the material, the mercury ions in the liquid phase are adsorbed on the adsorbent to achieve the purpose of removing mercury in the liquid phase; b. When the mercury content in the filtered waste liquid reaches a certain value, that is The filter layer of the nanometer mercury removal adsorbent is replaced, and the mercury adsorbed on the adsorbent is desorbed and recovered through special treatment means.

The waste liquid containing mercury ions passes through the filter layer made of nano-mercury removal adsorbent at a flow rate of 0.05-0.5m/s, and the residence time of the waste liquid in the filter layer is 10-120s; when the filtered waste When the mercury content in the liquid reaches 80-95% of the limit value of the relevant emission standards, the filter layer of the nano-mercury removal adsorbent needs to be replaced, and the replaced nano-mercury removal adsorbent enriched with a large amount of mercury is calcined at a temperature of 500-800°C. The generated mercury sulfide is desorbed, and the desorbed mercury vapor is condensed and recovered at minus 20-50°C.

In the method of the invention, the material with high specific surface area and large pore volume is used as a carrier, and the sulfide or selenide nano-adsorbent is loaded on it to prepare the ion-exchange nano-mercury removal adsorbent with high adsorption capacity. When in use, the adsorbent is directly immersed in a solution rich in mercury ions, and the mercury ions in the liquid phase are adsorbed on the adsorbent by using the exchange of metal ions on the adsorbent with mercury ions, so as to achieve the purpose of removing mercury in the liquid phase. The adsorbent has the characteristics of large adsorption capacity and fast adsorption rate, and is suitable for mercury removal treatment of coal-fired flue gas, non-ferrous metal smelting flue gas, and other mercury-related industries.

Compared with prior art, the present invention has following advantages:

1. The present invention utilizes abundant and cheap materials such as alumina as a carrier, loads metal sulfide nano-adsorbents to prepare adsorbents with high adsorption capacity and speed, and the price is very low;

2. The adsorbent enriched with high-concentration mercury can be concentrated, and the recovery and resource utilization of mercury can be realized through high-temperature desorption and low-temperature condensation.

3. The metal ions that enter the liquid phase through ion exchange during the use of the present invention are non-toxic and harmless, and will not cause secondary pollution;

4. The use method of the present invention is very convenient. It only needs to make the nanometer mercury removal adsorbent into a filter layer to filter the mercury-containing waste liquid, so that the ionic mercury in the liquid phase can be efficiently adsorbed.

5. The present invention is applicable to the removal and recycling of mercury-containing waste liquid in coal-fired flue gas, non-ferrous metal smelting flue gas and other mercury-related industries.

detailed description

The present invention will be described in detail below in conjunction with specific embodiments.

The following embodiments of the present invention are described in detail: the present embodiment is implemented under the premise of the technical solution of the present invention, and detailed implementation and specific operation process are provided, but the protection scope of the present invention is not limited to the following embodiments. In the implementation process of the scheme of the present invention, the focus is on realizing the efficient adsorption of divalent mercury as the goal.

Example 1

Weigh 10 g of activated alumina with a particle size of 0.25 mm as the adsorbent carrier for standby, and prepare 100 ml of zinc sulfide nano-adsorbent reaction precursor solution (zinc chloride 0.5 mol/L, thiourea 2 mol/L, mercaptopropionic acid 1.5 mol/L ). Immerse 10 g of activated alumina in the nano-adsorbent reaction precursor solution, and react with stirring at a speed of 100 rpm at a temperature of 95° C. for 1 hour. The activated alumina loaded with zinc sulfide is separated by filtration, and dried at room temperature of 25 degrees for 5 hours to prepare the zinc sulfide nano-mercury removal adsorbent. After testing, the loading capacity of the nano-adsorbent on the activated alumina is about 32%. The specific surface area of the mercury removal adsorbent is about 367m ² /g.

Example 2

Weigh 10 g of molecular sieves with a particle size of 0.25 mm as the adsorbent carrier for standby, and configure 100 ml of ferrous sulfide nano-adsorbent precursor solution (ferrous chloride 1 mol/L, oleic acid 3 mol/L, sulfur element 3 mol/L, eighteen Alkene 100ml). 10 g of molecular sieves were impregnated in 100 ml of ferrous sulfide nano-adsorbent precursor solution, and reacted with stirring at a speed of 500 rpm for 1 hour at a temperature of 250° C. The molecular sieve loaded with iron sulfide is separated by filtration and washing, and dried at room temperature of 25° C. for 5 hours to prepare an adsorbent for removing mercury from ferrous sulfide. After testing, the loading capacity of the nano-adsorbent on the molecular sieve is about 45%. The specific surface area of the mercury removal adsorbent is 483m ² /g.

Example 3

0.1 g of the zinc sulfide nano-adsorbent prepared in Example 1 was placed in 50 mL of mercuric chloride solution with a concentration of 200 mg/L, and stirred at a speed of 400 rpm. After 5 minutes, the solution was treated by filtration, and the filtrate was detected. The results showed that the removal efficiency of mercury in the solution was greater than 99.9%, and the residual mercury ion concentration was less than 1 μg/L.

Example 4

A method for preparing and using an adsorbent for removing and recovering liquid-phase mercury, comprising the following steps:

The first step is to select diatomite with large specific surface area and pore volume as the adsorbent carrier;

The second step is to configure a high-concentration nano-adsorbent solution: the concentration is 0.1mol/L aluminum selenide solution.

The third step is to immerse the adsorbent carrier in the reaction precursor solution of the metal selenide nano-adsorbent, and stir the nano-adsorbent solution to make it fully contact with the adsorbent carrier at a stirring speed of 60 rpm, using electrostatic attraction or Chemical attachment attracts a large number of nano-adsorbents into the pores of the adsorbent carrier and loaded on its surface;

In the fourth step, the adsorbent carrier is separated from the reaction precursor solution by filtration, and placed at a room temperature of 15° C. to dry to obtain a nanometer mercury-removing adsorbent. The loading of the nano-adsorbent on the adsorbent carrier is 1wt%;

The fifth step is to calcinate the dried adsorbent carrier at 100°C for 2.0 hours to form a stable nano-mercury removal adsorbent;

The sixth step is to make the prepared nano-mercury removal adsorbent into a filter layer to filter the waste liquid containing mercury ions. The waste liquid containing mercury ions passes through the nano-mercury removal adsorbent at a flow rate of 0.1m/s. The filter layer, the residence time of the waste liquid in the filter layer is 30s; use the exchange of metal ions and mercury ions on the material to adsorb the mercury ions in the liquid phase to the adsorbent, so as to achieve the purpose of removing mercury in the liquid phase;

Step 7: When the mercury content in the filtered waste liquid reaches 80-95% of the limit value of the relevant emission standards, it is necessary to replace the filter layer of the nano-mercury removal adsorbent, and replace the adsorbent enriched with a large amount of mercury at 500- Calcined at 800°C to desorb the generated mercury sulfide, and condense the desorbed mercury vapor at minus 20-50°C for recovery.

Example 5

A method for preparing and using an adsorbent for removing and recovering liquid-phase mercury, comprising the following steps:

The first step is to select diatomite with large specific surface area and pore volume as the adsorbent carrier;

The second step is to configure a high-concentration nano-adsorbent solution: a calcium selenide solution with a concentration of 10.0 mol/L.

The third step is to immerse the adsorbent carrier in the reaction precursor solution of the metal selenide nano-adsorbent, and make it fully contact with the adsorbent carrier by stirring the nano-adsorbent solution at a stirring speed of 300 rpm, using electrostatic attraction or Chemical attachment attracts a large number of nano-adsorbents into the pores of the adsorbent carrier and loaded on its surface;

In the fourth step, the adsorbent carrier is separated from the reaction precursor solution by filtration, and dried at room temperature of 30° C. to obtain a nano-mercury removal adsorbent. The loading of the nano-adsorbent on the adsorbent carrier is 50wt%;

The fifth step is to calcinate the dried adsorbent carrier at 250°C for 0.1h to form a stable nano-mercury removal adsorbent;

The sixth step is to make the prepared nano-mercury removal adsorbent into a filter layer to filter the waste liquid containing mercury ions. The waste liquid containing mercury ions passes through the nano-mercury removal adsorbent at a flow rate of 0.05m/s. The filter layer, the residence time of the waste liquid in the filter layer is 120s; use the exchange of metal ions and mercury ions on the material to adsorb the mercury ions in the liquid phase to the adsorbent, so as to achieve the purpose of removing mercury in the liquid phase;

Step 7: When the mercury content in the filtered waste liquid reaches 80-95% of the limit value of the relevant emission standards, it is necessary to replace the filter layer of the nano-mercury removal adsorbent, and replace the adsorbent enriched with a large amount of mercury at 500- Calcined at 800°C to desorb the generated mercury sulfide, and condense the desorbed mercury vapor at minus 20-50°C for recovery.

Claims (3)

1. for removing and reclaim a preparation method for the adsorbent of liquid phase mercury, it is characterized in that, comprise the following steps:

The first step, choose adsorbing agent carrier;

The nano adsorption agent solution of second step, configuration high concentration;

3rd step, adsorbing agent carrier be impregnated in the nano adsorption agent solution of high concentration, and make it fully contact with adsorbing agent carrier by stirring nano adsorption agent solution, be carried on that it is surperficial in the duct utilizing electrostatic attraction or chemical attachment to attract a large amount of nano adsorber to enter adsorbing agent carrier;

Adsorbing agent carrier, until adsorbing agent carrier is with after nano adsorption agent solution mixing 1-3h, is separated by filtering by the 4th step from nano adsorption agent solution, and dry under room temperature, obtains adsorbent;

The nano adsorption agent solution of described high concentration refers to the nano adsorption agent solution be configured to by one or more metal sulfides in zinc, iron, aluminium, titanium, manganese, calcium or selenides, and its concentration range is 0.1-10.0mol/L;

Described adsorbing agent carrier comprises aluminium oxide, diatomite, molecular sieve, attapulgite, zeolite or active carbon.

2. the preparation method of a kind of adsorbent for removing and reclaim liquid phase mercury according to claim 1, is characterized in that, the speed of the stirring described in the 3rd step is 60 revs/min-300 revs/min.

3. the preparation method of a kind of adsorbent for removing and reclaim liquid phase mercury according to claim 1, it is characterized in that, the temperature of the drying described in the 4th step is 15 ~ 30 DEG C, calcines 0.1-2.0h, form stable nanometer mercury-removing adsorbent by dried adsorbing agent carrier 100-250 DEG C.