NL2031887B1

NL2031887B1 - Preparation method and application of material for removing gaseous iodine

Info

Publication number: NL2031887B1
Application number: NL2031887A
Authority: NL
Inventors: Chen Yishi; Fu Lan; Xie Donghai; Fu Kan
Original assignee: Radiation Env Monitoring Station Of Hainan Province
Priority date: 2022-05-17
Filing date: 2022-05-17
Publication date: 2023-09-20

Abstract

Disclosed is a preparation method and application of a novel radioactive waste gas adsorption material. Through use of a self - made preparation raw material which takes discarded banana peel as activated carbon, an optimal ratio of activated carbon preparation is found. The prepared activated carbon raw material has relatively large specific surface area and total pore volume, thereby improving an adsorption capacity of further improved activated carbon in the present invention. A maximum adsorption capacity of the adsorption material prepared by the present invention to radioactive iodine at room temperature reaches 450 mg/g of an adsorbent; and a removal rate of the radioactive iodine reaches an emission limit. Meanwhile, the present invention saves preparation cost of the activated carbon raw material, has certain environment - friendly performance and provides a potential recycling mode for application of wet waste.

Description

PREPARATION METHOD AND APPLICATION OF MATERIAL FOR REMOVING GASEOUS

IODINE

Technical Field

The present invention relates to the field of environment - friendly materials, in particular to a preparation method and application of an adsorption material for removing gaseous iodine.

Background

Some nuclides such as iodine - 125, iodine - 131, fluorine - 18, technetium - 99m, strontium - 89, carbon - 14 and samarium - 153 are often used in nuclear medicine examination and treatment in hospitals. Among many radionuclides, radioactive iodine is considered to be the most harmful radionuclide because of long half - life, high toxicity and a wide range of radiation effects.

In the process of preparing iodine - 125 and iodine - 131 drugs in a nuclear medicine department, radioactive iodine vapor generated is easy to form radioactive aerosol, causing serious radiation pollution. The radioactive iodine aerosol can produce external radiation by adhering to a human body and internal radiation through inhaling by the human body, thereby endangering human health. Therefore, effective removal of gaseous radioactive iodine plays a vital role in safe utilization of nuclear technologies and environmental protection. At present, a capture method of gaseous iodine is mainly a solid adsorption method; and adsorption materials play a key role in iodine adsorption.

Summary

The purpose of the present invention is to provide a preparation method and application of a gaseous iodine adsorption material.

A technical solution adopted by the present invention: a preparation method of a novel radioactive waste gas adsorption material comprises the following steps: (1) cleaning banana peel; cutting the banana peel and soaking the banana peel in an ethanol solution; putting the solution into liquid nitrogen for freezing for 8 h; crushing the freeze - dried banana peel; soaking the crushed material in a mixed solution made of ammonium dihydrogen phosphate and copper sulphate for 0.5 h, and then irradiating the solution in a microwave oven with a microwave power of 500 - 800 W and 145 kPa for 20 min; and then performing screening to screen out activated carbon with an equivalent diameter of 120 - 140 meshes; (2) weighing 100 g of the activated carbon prepared in step (1), putting the screened activated carbon into a beaker, adding 100 ml of absolute ethanol, performing ultrasonic treatment at 25°C for 30 min, and then washing with purified water for three times for later use; (3) taking 1mol/l nitric acid; mixing the nitric acid with the activated carbon treated in step (2) in a beaker through stirring; performing water bath treatment at 50 - 55°C for 1 h; performing washing with deionized water and suction filtration for many times after standing for 4 h, and drying the activated carbon obtained after suction filtration in an oven at 100°C and a pressure of 140 kpa for 1 h; and mixing 1mol/l NaOH and the activated carbon treated with 1mol/l dilute nitric acid in a beaker, performing magnetic stirring at 50°C for 1 h, performing washing with deionized water and suction filtration for many times after standing for 4 h until the mixture is neutral, drying overnight in a vacuum oven at 100°C and a pressure of 140 kPa, and storing the activated carbon in a dryer for later use; (4) measuring 200 ml of dopamine hydrochloride and putting the dopamine hydrochloride into a beaker; adding 5 g of the activated carbon treated in step (3); performing ultrasonic dispersion at 30°C for 0.5 h; adding a small amount of a dopamine aqueous solution in the ultrasonic process to make the pH of the mixed solution as 8 - 9; sealing a beaker mouth and performing magnetic stirring at room temperature for 30 min; (5) adding a proper amount of tetramethyl ethylenediamine solution into the mixed solution obtained in step (4); adjusting the pH value until the mixture is neutral with a ratio of the tetramethyl ethylenediamine solution to the mixed solution of 1 : 3; and performing ultrasonic dispersion and magnetic stirring and mixing of the obtained mixed solution successively for 25 min to obtain a tetramethyl ethylenediamine mixed solution; (6) dispersing 2g of AgNO:s in 100 ml of ethylene glycol; stirring evenly; then adding the mixed solution obtained in step (5); performing magnetic stirring at a constant temperature of 60°C; vacuumizing during the process of stirring for 1 h; then cooling to the room temperature; performing centrifugal separation at 5000 rpm for 5 min; discarding a supernatant; performing centrifugal washing with absolute ethanol for three times; and drying in the oven at 100°C and 145 kPa to obtain silver - loading activated carbon; (7) putting 5 g of the activated carbon treated in step (8) into a round bottom flask; adding 100 ml of diethanolamine aqueous solution into the flask; performing magnetic stirring at a constant temperature of 50°C; vacuumizing during the process of stirring for 30 min; then sealing the flask in a high - pressure reaction kettle; heating to 100°C; maintaining for 6 h; cooling to the room temperature; performing centrifugal separation; performing centrifugal washing with absolute ethanol for three times; and drying in the oven at 100°C.

Beneficial effects: 1. A maximum adsorption capacity of the adsorption material prepared by the present invention to radioactive iodine at room temperature reaches 450 mg/g of an adsorbent; and a removal rate of the radioactive iodine reaches an emission limit. 2. In the process of preparing the adsorbent of the present invention, through use of a self - made preparation raw material which takes discarded banana peel as activated carbon, an optimal ratio of activated carbon preparation is found. The prepared activated carbon raw material has a relatively large specific surface area and a relatively large total pore volume, thereby improving an adsorption capacity of further improved activated carbon in the present invention.

Meanwhile, the present invention saves the preparation cost of the activated carbon raw material, has certain environment - friendly performance and provides a potential recycling mode for application of wet waste.

Detailed Description

The present invention will be further illustrated in detail below.

Embodiment 1:

A preparation method of a novel radioactive waste gas adsorption material comprises the following steps: (1) cleaning banana peel; cutting the banana peel and soaking the banana peel in an ethanol solution; putting the solution into liquid nitrogen for freezing for 8 h; crushing the freeze - dried banana peel; soaking the crushed material in a mixed solution made of ammonium dihydrogen phosphate and copper sulphate for 0.5 h, and then irradiating in a microwave oven with a microwave power of 500 - 800 W and 145 kPa for 20 min; and then performing screening to screen out activated carbon with an equivalent diameter of 120 - 140 meshes. In the experiment, the most common banana peel is used as a preparation source of activated carbon, which can reduce generation of wet waste and renewable usages thereof to a certain extent. In addition to the banana peel, the peel of jackfruit or durian can also be used as the raw material for preparation of activated carbon, which can realize resource recycling to a certain extent; (2) weighing 100 g of the activated carbon prepared in step (1); putting the screened activated carbon into a beaker; adding 100 ml of absolute ethanol; performing ultrasonic treatment at 25°C for 30 min; and then washing with purified water for three times for later use; (3) taking 1mol/l nitric acid; mixing the nitric acid with the activated carbon treated in step (2) in a beaker through stirring; performing water bath treatment at 50 - 55°C for 1 h; performing washing with deionized water and suction filtration for many times after standing for 4 h; drying the activated carbon obtained after suction filtration in an oven at 100°C and a pressure of 140 kpa for 1 h; mixing 1mol/l NaOH and the activated carbon treated with 1mol dilute nitric acid in a beaker; performing magnetic stirring at 50°C for 1 h; performing washing with deionized water and suction filtration for many times after standing for 4 h until the mixture is neutral, drying overnight in a vacuum oven at 100°C and a pressure of 140 kPa; and storing the activated carbon in a dryer for later use. As found in the experiment, under the pressure condition, a specific surface area of the activated carbon reaches an optimal value; (4) measuring 200 ml of dopamine hydrochloride and putting the dopamine hydrochloride into a beaker; adding 5 g of the activated carbon treated in step (3); performing ultrasonic dispersion at 30°C for 0.5 h; adding a small amount of a dopamine aqueous solution in the ultrasonic process to make the pH of the mixed solution as 8 - 9; sealing a beaker mouth and then performing magnetic stirring at room temperature for 30 min;

(5) adding a proper amount of tetramethyl ethylenediamine solution into the mixed solution obtained in step (4); adjusting the pH value until the mixture is neutral with a ratio of the tetramethyl ethylenediamine solution to the mixed solution being 1 : 3; and performing ultrasonic dispersion and magnetic stirring and mixing of the obtained mixed solution successively for 25 min to obtain a tetramethyl ethylenediamine mixed solution; (6) dispersing 2g of AgNO: in 100 ml of ethylene glycol; stirring evenly; then adding the mixed solution obtained in step (5); performing magnetic stirring at a constant temperature of 60°C; vacuumizing during the process of stirring for 1 h; then cooling to the room temperature; performing centrifugal separation at 5000 rpm for 5 min; discarding a supernatant; performing centrifugal washing with absolute ethanol for three times; and drying in the oven at 100°C and 145 kPa to obtain silver - loading activated carbon; (7) putting 5 g of the activated carbon treated in step (6) into a round bottom flask; adding 100 ml of diethanolamine aqueous solution into the flask; performing magnetic stirring at a constant temperature of 50°C; vacuumizing during the process of stirring for 30 min; then sealing the flask in a high - pressure reaction kettle; heating to 100°C, maintaining for 6 h; cooling to the room temperature, performing centrifugal separation; performing centrifugal washing with absolute ethanol for three times; and drying in the oven at 100°C.

According to the adsorption material prepared by the above method, the inventor performed an adsorption test in a laboratory.

Embodiment 1 and reference examples 1 - 3 were set. The difference between reference example 1 and embodiment 1 is that reference example 1 lacks the treatment of steps (4) to (7).

The difference between reference example 2 and embodiment 1 is that reference example 3 lacks the treatment of steps (6) and (7). The difference between reference example 2 and embodiment 1 is that reference example 3 lacks the treatment of step (7).

In the experiment, aiming at adsorption of gaseous elementary iodine by the adsorption materials prepared in different reference examples, adsorption results are evaluated. 5 g of the above samples are weighed respectively. The above samples are put in a test device. The test device uses nitrogen as a carrier gas; and gaseous elementary iodine is injected into the test device. The injection duration of gaseous elementary iodine is 5 - 8 h. Then, the content of iodine adsorbed by the adsorbent is measured by a weighing method after adsorption saturation. The whole experiment process is carried out at a room temperature. Experimental results are shown in Table 1 below:

Table 1 Adsorption Capacity and Adsorption Rate of Adsorption Material oon capt ae

As shown by the experimental results in the above table, the adsorption capacity of the adsorption material prepared by the method according to the present invention to iodine reaches 450 mglz/g of the adsorbent. The adsorption capacity is 59.9%, 27.5% and 16.2% higher than 5 those of reference example 1, reference example 2 and reference example 3, respectively. That is, a maximum value of the adsorption capacity of the adsorption material prepared by the method according to the present invention to elementary iodine is superior to those of untreated activated carbon. The adsorption efficiency is significantly increased.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit the protection scope of the present invention.

Although the present invention is described in detail with reference to the preferred embodiments, those ordinary skilled in the art shall understand that the technical solution of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solution of the present invention.

Claims

CONCLUSIESCONCLUSIONS

1. Een werkwijze voor het bereiden van een nieuw adsorptiemateriaal voor radioactief afvalgas, welke werkwijze de volgende stappen omvat: (1) het schoonmaken van bananenschillen; het snijden van de bananenschil en het weken van de bananenschil in een ethanoloplossing; het overbrengen van de oplossing in vloeibare stikstof voor bevriezing gedurende 8 h, het malen van de gevriesdroogde bananenschil; het weken van het gemalen materiaal in een gemengde oplossing bestaande uit ammoniumdiwaterstoffosfaat en kopersulfaat gedurende 0,5 uur, en volgens het bestralen van de oplossing gedurende 20 minuten in een microgolfoven met een microgolfvermogen van 500 - 800 W en 145 kPa; vervolgens het zeven van de actieve kool met een diameter die equivalent is aan 120-140 mesh; (2) het afwegen van 100 g van de in stap 1) bereide actieve kool, het overbrengen van de gezeefde actieve kool in een bekerglas, het toevoegen van 100 ml absolute ethanol, het uitvoeren van een ultrasone behandeling bij 25°C gedurende 30 min, en vervolgens het wassen met gezuiverd water gedurende driemaal voor later gebruik; (3) het nemen van 1mol/ salpeterzuur, het al roerend mengen van het salpeterzuur met de in stap 2) behandelde actieve kool in een bekerglas, het uitvoeren van een behandeling in een waterbad bij 50 - 55 °C gedurende 1 uur, het wassen met gedeioniseerd water en na 4 uur te hebben stilgestaan een aantal keren af te zuigen, en het drogen van de na het afzuigen verkregen actieve kool gedurende 1 uur in een oven bij 100 °C en een druk van 140 kpa; en het in een bekerglas mengen van 1 mol/l NaOH met de met 1mol/l verdunde salpeterzuur behandelde actieve kool, het uitvoeren van magnetisch roeren bij 50°C gedurende 1 uur, het uitvoeren van wassen met gedeioniseerd water en afzuigfiltratie gedurende een aantal keren na 4 uur te hebben gestaan totdat het mengsel neutraal is, het drogen gedurende 1 nacht in een vacuümoven bij 100°C en een druk van 140 kPa, en het opslaan van het mengsel in een droger voor later gebruik; (4) het afmeten van 200 ml dopaminehydrochloride en het plaatsen van de dopaminehydrochloride in een bekerglas, het toevoegen van 5 g van de in stap (3) behandelde actieve kool, het gedurende 0,5 uur ultrasoon dispergeren bij 30 °C, het toevoegen van een geringe hoeveelheid dopamineoplossing in water tijdens het ultrasone proces om de pH van de gemengde oplossing op 8 - 9 te brengen, het afsluiten van het bekerglas en 30 minuten lang magnetisch roeren bij kamertemperatuur; (5) het toevoegen van een juiste hoeveelheid tetramethylethyleendiamine oplossing in de gemengde oplossing die is verkregen in stap (4), het aanpassen van de pH-waarde totdat het mengsel neutraal is waarbij de verhouding van de tetramethyl ethyleendiamine oplossing aan de gemengde oplossing 1 : 3 bedraagt, en het achtereenvolgens gedurende 25 min uitvoeren van ultrasoon dispergeren en magnetisch roeren en mengen van de verkregen gemengde oplossing om een tetramethyl ethyleendiamine gemengde oplossing te verkrijgen; (8) het dispergeren van 2 g AgNO: in 100 ml ethyleenglycol; het gelijkmatig roeren; vervolgens het toevoegen van de in stap (5) verkregen gemengde oplossing; het magnetisch roeren bij een constante temperatuur van 60 °C; het tijdens het roeren gedurende 1 uur op vacuüm houden; het vervolgens afkoelen tot kamertemperatuur; het centrifugeren bij 5000 omwentelingen per minuut gedurende 5 minuten; het afgieten van de bovenstaande vloeistof, het driemaal centrifugeren met absolute ethanol; en het drogen in de oven bij 100 °C en 145 kPa om met zilver geladen actieve kool te verkrijgen; (7) het brengen van 5 g van de in stap 5 behandelde actieve kool in een rondbodemkolf; het in de kof brengen van 100 ml waterige oplossing van diëthanolamine; het magnetisch roeren bij een constante temperatuur van 50 °C; het gedurende 30 minuten onder vacuüm roeren; het vervolgens afsluiten van de kolf in een hogedrukreactieketel; het verhitten tot 100 °C; het gedurende 6 uur handhaven; het afkoelen tot kamertemperatuur; het centrifugeren; het driemaal centrifugeren met absolute ethanol; en het drogen in de oven bij 100 °C.A method for preparing a new adsorption material for radioactive waste gas, which method comprises the following steps: (1) cleaning banana peels; cutting the banana peel and soaking the banana peel in an ethanol solution; transferring the solution into liquid nitrogen for freezing for 8 h, grinding the freeze-dried banana peel; soaking the ground material in a mixed solution consisting of ammonium dihydrogen phosphate and copper sulfate for 0.5 hour, and then irradiating the solution for 20 minutes in a microwave oven with a microwave power of 500 - 800 W and 145 kPa; then sieving the activated carbon with a diameter equivalent to 120-140 mesh; (2) weighing 100 g of the activated carbon prepared in step 1), transferring the sieved activated carbon into a beaker, adding 100 ml of absolute ethanol, performing an ultrasonic treatment at 25°C for 30 min , and then washing it with purified water for three times for later use; (3) taking 1mol/nitric acid, mixing the nitric acid with the activated carbon treated in step 2) in a beaker while stirring, carrying out a treatment in a water bath at 50 - 55 °C for 1 hour, washing with deionized water and after standing still for 4 hours, extracting it several times, and drying the activated carbon obtained after extraction for 1 hour in an oven at 100 °C and a pressure of 140 kPa; and mixing 1 mol/l NaOH with the activated carbon treated with 1 mol/l diluted nitric acid in a beaker, carrying out magnetic stirring at 50°C for 1 hour, washing with deionized water and suction filtration for a number of times after standing for 4 hours until the mixture is neutral, drying it overnight in a vacuum oven at 100°C and a pressure of 140 kPa, and storing the mixture in a dryer for later use; (4) measuring 200 ml of dopamine hydrochloride and placing the dopamine hydrochloride in a beaker, adding 5 g of the activated carbon treated in step (3), ultrasonically dispersing at 30°C for 0.5 hour, adding of a small amount of dopamine solution in water during the ultrasonic process to adjust the pH of the mixed solution to 8 - 9, closing the beaker and magnetic stirring at room temperature for 30 minutes; (5) adding an appropriate amount of tetramethylethylenediamine solution into the mixed solution obtained in step (4), adjusting the pH value until the mixture is neutral where the ratio of the tetramethylethylenediamine solution to the mixed solution is 1: 3, and successively carrying out ultrasonic dispersion and magnetic stirring and mixing of the resulting mixed solution for 25 minutes to obtain a tetramethyl ethylenediamine mixed solution; (8) dispersing 2 g of AgNO: in 100 ml of ethylene glycol; stirring it evenly; then adding the mixed solution obtained in step (5); magnetic stirring at a constant temperature of 60 °C; keeping it under vacuum for 1 hour while stirring; then cool it to room temperature; centrifugation at 5000 revolutions per minute for 5 minutes; pouring off the supernatant liquid, centrifuging three times with absolute ethanol; and oven drying at 100°C and 145 kPa to obtain silver-loaded activated carbon; (7) placing 5 g of the activated carbon treated in step 5 into a round bottom flask; introducing 100 ml of an aqueous solution of diethanolamine into the flask; magnetic stirring at a constant temperature of 50 °C; stirring under vacuum for 30 minutes; subsequently sealing the flask in a high-pressure reaction vessel; heating to 100 °C; maintain it for 6 hours; cooling to room temperature; centrifuging; centrifuging three times with absolute ethanol; and drying in the oven at 100 °C.

2. Een toepassing van het adsorptiemateriaal voor het verwijderen van gasvormig jodium, waarbij de maximale adsorptiecapaciteit van het materiaal, verkregen door de bereidingswijze van conclusie 1 voor het adsorberen van gasvormig jodium, bij kamertemperatuur 450 mg/g bereikt.An application of the adsorption material for removing gaseous iodine, wherein the maximum adsorption capacity of the material obtained by the preparation method of claim 1 for adsorbing gaseous iodine reaches 450 mg/g at room temperature.

3. De toepassing van het adsorptiemateriaal voor het verwijderen van gasvormig jodium volgens conclusie 2, waarbij het jodium gasvormig radioactief jodium is.The use of the adsorption material for removing gaseous iodine according to claim 2, wherein the iodine is gaseous radioactive iodine.