TWI446960B - A Method for Making Precious Metal Adsorbents - Google Patents

Description

Method for preparing precious metal adsorbent

The invention discloses a method for preparing a precious metal adsorbent, in particular to a raw material used for an adsorbent, a coating, an emulsion resin, a binder, a polymer concrete and a textile slurry.

The lack of known metal mineral raw materials, the continuous shortening of the product life cycle and the rapid replacement of global information and consumer electronic products, resulting in a large amount of electronic waste, many of which contain a variety of basic metals and precious metals Heavy metal waste comes from a wide range of industries, including mining, metallurgy, machinery manufacturing, chemicals, electronics and instrumentation. Heavy metals often have acute or chronic toxicity, sometimes poisoning organisms in more complex ways, affecting the entire food chain. With the in-depth study of heavy metal toxicology and the development of detection technology, the treatment and disposal standards for heavy metal waste tend to be strict. Except for some parts that can be recycled, most of them need to be stabilized to achieve harmlessness. purpose.

In recent decades, polymer composite microspheres with special synthetic properties have attracted much attention. It is a novel polymer material in which polymethyl methacrylate (PMMA) is polymerized from methyl methacrylate (MMA) monomer. Polymer microspheres are an important organic transparent structural material, which has the advantages of high transparency, good weather resistance, uniform physical and mechanical properties, and excellent processing performance. However, it has the disadvantages of low heat resistance, low metal adsorption rate, insufficient mechanical strength and lack of functional groups. When polymer microspheres are copolymerized or surface modified, different functional groups can be introduced on the surface. Groups (such as -COOH, -NH ₂ , -OH, -SO ₃ H, -CH ₃ Cl, etc.), so that the material obtains new properties, hydrophilic polymers with functional groups, easy to distribute in microspheres Surface, thereby functionalizing its surface, wherein the carboxyl group-containing polymer microspheres have the widest application range, and since the carboxylic acid molecules are easily reacted with various molecules, the polymer microspheres having a carboxylic acid functional group on the surface are Synthesis has received much attention. Many scholars at home and abroad have used different polymerization methods to synthesize polymer microspheres with carboxylic acid groups on the surface. They can be applied to adsorbed proteins as vaccines, bone bonding applications, water treatment and industrial wastewater treatment. Application prospects. Therefore, the main advantage of the polymer microspheres as the adsorbent is that the production process is simple and the cost is low, but the metal adsorption rate, adsorption speed and metal selectivity still need to be improved.

In 2005, Cox et al. used activated carbon to study the rate of adsorption of noble metals by Au(III)>Pd(II)>Ag(I)>Pt(II). Pt(IV). Studies have shown that activated carbon has a large specific surface area, which is favorable for the adsorption of precious metals, but the selectivity is poor, and the difficulty of regeneration is its main disadvantage. In 2002, Say et al. modified the particle system with poly(HEMA-EGDMA) and 2-methacrylamidohistidine (MAH) chelating agent, which has a good adsorption effect on noble metal ions. US Patent No. 5,115,036 and US Patent No. 5,064,879 are copolymers of ethylene and an aminoalkyl acrylate, the functional group of which is electrically anionic for the treatment of metal ions. The reaction time of this method is quite long (ranging from 3 to 16 hours), and the metal ions must be desorbed after the reaction, which is a big test for the cost of the equipment.

Therefore, the present invention discloses a method for preparing a novel precious metal adsorbent, which can solve the above problems by simplifying the process, shortening the reaction time, reducing the cost and high economic benefit.

In view of the above disadvantages of the prior art, the main object of the present invention is to provide a method for preparing a precious metal adsorbent, and the precious metal adsorbent prepared by the method can achieve selective adsorption, short reaction time and high economic efficiency.

In order to achieve the above object, the present invention provides a method for producing a precious metal adsorbent, which comprises the steps of: (A) providing the composition of the monomer 1 and the composition of the monomer 2; (B) adding the composition of the monomer 2 to the monomer 1. Composition; (C) performing a microwave reaction to obtain precious metal adsorbent particles.

The composition of the monomer 1 in the step (A) includes the monomer 1 and the solvent, and the composition of the monomer 2 includes the monomer 2, the initiator and the cationic dispersant (MTC), wherein the monomer 1 and the monomer 2 are Polymerizable organic monomer such as methyl methacrylate, styrene, vinyl acetate, acrylic acid, methacrylic acid, trifluoromethyl methacrylate, methylene succinic acid, ethylene benzoic acid, and monomer 1 and single The bulk 2 may be the same compound. In the preferred embodiment of the invention, monomer 1 is methyl methacrylate and monomer 2 is acrylic acid. The solvent is an aqueous solution containing a trace amount of a salt, and the salt is one of sodium chloride (NaCl) and ammonium chloride (NH ₄ Cl), and the aqueous solution is pure water. The initiator is azobisisobutyronitrile (AIBN), lauroyl peroxide (LPO), ammonium persulfate (APS), potassium persulphate (KPS). )Wait. The cationic dispersant is 2-(methacryloyloxymethyl)methyl-trimethylammonium chloride or 2-propenyloxyethyltrimethylammonium chloride (2-(methacryloyloxy)ethyl) -trimethylammonium chloride), 3-methacryloxy-propyl-trimethoxysilane, and a mixture of hydrochloric acid or sulfuric acid, methacryloyloxymethyltrimethylammonium chloride, and A mixture of methacrylic acid oxiranyl trimethylammonium chloride or the like. Wherein, the reactor used in the microwave reaction in the step (C) comprises a cooling device which can be used to confirm that the microwave heating reaction is carried out during the reaction.

In order to obtain the precious metal adsorbent particles, another embodiment of the present invention provides a method for preparing a precious metal adsorbent, the steps of which include (A) providing the composition of the monomer 1 and the composition of the monomer 2; B) adding the composition of the monomer 2 to the composition of the monomer 1; (C) performing a microwave reaction to obtain the precious metal adsorbent particles; (D) performing the centrifugation procedure of the solution in the step (C); (E) the particle The filtration and washing procedures are carried out; (F) the filtered particles are subjected to a drying procedure. Thereby, the invention achieves high efficiency and simplifies the process, and the precious metal adsorbent prepared in the embodiment of the invention has the advantages of narrow particle size distribution, good selectivity and high adsorption amount.

The above summary, the following detailed description and the accompanying drawings are intended to further illustrate the manner, the Other objects and advantages of the present invention will be described in the following description and illustration. Explain it.

The embodiments of the present invention are described below by way of specific examples, and those skilled in the art can readily appreciate the other advantages and advantages of the present invention.

Referring to Figure 1, the present invention is to synthesize a precious metal adsorbent, the steps of which include: step (A): providing the composition of monomer 1 and the composition of monomer 2 (11), wherein monomer 1 The composition includes the monomer 1 and the solvent, and the composition of the monomer 2 includes the monomer 2, the initiator and the cationic dispersant (MTC). In the present embodiment, the monomer 1 and the monomer 2 are methyl methacrylate. , styrene, vinyl acetate, acrylic acid, methacrylic acid, trifluoromethacrylic acid, methylene succinic acid, vinyl benzoic acid, etc., and monomer 1 and monomer 2 can be the same compound; B): adding the composition of the monomer 2 to the composition (12) of the monomer 1, the monomer 2 is added to the monomer 1 under a certain ratio and uniform stirring; and the step (C): performing the microwave reaction to obtain the precious metal adsorbent particles ( 13) The conditions of the microwave reaction are as follows: the reaction time may be 5 to 120 minutes, the power may be 30 W to 300 W, and the reaction temperature may be 60 to 85 °C.

Please refer to FIG. 2, which is a schematic diagram of another process of a precious metal adsorbent according to the present invention. The steps include the steps of: (A) providing the composition of the monomer 1 and the composition of the monomer 2 (21); and the step (B) The composition of the monomer 2 is added to the composition of the monomer 1 (22); the step (C) is subjected to microwave reaction to obtain the precious metal adsorbent particles (23); and the step (D) is the centrifugation of the solution in the step (C). (24); Step (E) The particles are subjected to a filtration and washing procedure (25); and the particles (F) filtered are subjected to a drying procedure (26). The particles have a large specific surface area and a fast adsorption speed. The characteristics of selective adsorption, excellent fluidity, and the like are described in the following examples in order to further illustrate the present invention.

Embodiment 1:

First, 5 g of methyl methacrylate monomer (MMA monomer) was mixed with 0.1 g of the initiator azobisisobutyronitrile (AIBN) to form an organic phase. The medium composition was 40 g of methanol, 10 g of pure water and 0.1 g of cationic dispersant (MTC) were added to the medium, then a certain amount of acrylic acid (AA) was added, and the mixture was stirred for 20 minutes to mix the solution into a homogeneous phase. The microwave reaction conditions and parameters are as follows: The model is a Discover microwave reactor produced by CEM. The methyl methacrylate solution before the reaction was a clear and transparent aqueous solution, and the solution was poured into a 100 mL round bottom flask and placed in a microwave reactor for microwave reaction. The reaction mode of the microwave reactor was set to the standard mode, the microwave wattage was 150 W, the reaction temperature was 75 ° C, and the amount of acrylic acid added for each sample was 0.1, 0.2, 0.3, 0.4, 0.5 gram, respectively, and the air cooling was started ( Power MAX), after the reaction is completed, the microwave reactor will cool the reactants to 50 ° C by the air of the air pump to obtain a polymethyl methacrylate crosslinked acrylic acid dispersion solution. Please refer to Table 1 for particle size analysis. The instrument analyzed the effect of different amounts of acrylic acid on the particle size of polymethyl methacrylate crosslinked acrylic acid. A small amount of sample was measured by a particle size analyzer and SEM. The function of air cooling (Power MAX) was to continuously cool the reaction vessel by cooling gas and simultaneously irradiate the microwave. Since the conventional microwave reactor automatically reduces or completely shuts down the microwave power when the temperature reaches the set temperature, the conventional thermochemical action will replace the microwave heating chemistry, but if the air cooling system is used, In the reaction, high-pressure air was continuously introduced to cool the reactants, and it was confirmed that the microwave heating reaction was performed during the reaction. The microwave reaction time may be 5 to 120 minutes, the microwave power may be 30W to 300W, and the microwave reaction temperature may be 60 to 85 °C.

When the microwave reaction system is further added with 0.1 g of acrylic acid (AA), the intermediate particle diameter of the microspheres is 3.67 μm, and when the amount of acrylic acid (AA) is 0.5 g, the particle diameter is increased to 6.01 μm, and the polymerization with no prior acrylic acid (AA) is added. Comparing, it was found that the addition of acrylic acid (AA) can greatly increase the particle size.

In this embodiment, in order to verify the shape of the particles after the microwave reaction, the obtained polymethyl methacrylate crosslinked acrylic acid (Poly (MMA-MTC-AA)) further proposes the following steps: the polymethyl group Methyl acrylate cross-linked acrylic acid solution for centrifugal washing; and removing the polymethyl methacrylate cross-linked acrylic acid solution One of the solute in the liquid and drying the solute to obtain the polymethyl methacrylate crosslinked acrylic acid (Poly (MMA-MTC-AA)) particles, wherein the drying temperature can be 50 to 90 ° C, the drying time can be Dry polymethyl methacrylate crosslinked acrylic acid (Poly (MMA-MTC-AA)) particles were formed for 2 to 24 hours. Figure 3 is a scanning electron microscope (SEM) analysis of a Poly(MMA-MTC-AA) particle prepared by adding 0.1 g of acrylic acid (AA). The polymethyl methacrylate nanometer. The particle formation particle size can range from 3 microns to 7 microns (31).

Embodiment 2:

A method for preparing a precious metal adsorbent, a polymethyl methacrylate crosslinked acrylic acid (Poly(MMA-MTC-AA)) particle, a noble ion solution adsorption method, and a heavy metal ion solution and a polymethyl group The methyl acrylate crosslinked acrylic particles are adsorbed. One of the treatment methods containing a precious metal solution, comprising a polymethyl methacrylate crosslinked acrylic particle (Poly(MMA-MTC-AA)) having a carboxyl functional group bonded to the surface thereof and a solution containing a precious metal ion having a temperature in the chamber At a temperature of 95 ° C, the precious metal ions are reduced to an elemental state and attached to the surface of the particles. The noble metal ion adsorbing elements may be Au (III), Pd (II), Ag (I), Pt (II), Pt (IV), copper (II), and indium (II).

First, use polymethyl methacrylate (PMMA) as a precious metal adsorption application, and select three kinds of samples, such as traditional PMMA, PMMA-MTC (using MTC as dispersant), and Poly (MMA-MTC-AA) (using MTC as dispersant). Object, a series of palladium adsorption comparisons, and the traditional method of polyvinylpyrrolidone (PVP) is a polymethyl methacrylate (PMMA) obtained as a dispersant. Take 10ml of the solution containing Poly (MMA-MTC-AA), add 500ppm palladium ion solution, stir at room temperature for 30 minutes, the solution will change from white to black, and the polymer microsphere solution with adsorbed palladium will be pumped. Gas filtration was carried out to obtain a clear filtrate, and the palladium ion concentration in the filtrate was further analyzed by ICP. It can be seen from Table 2 that after the adsorption of palladium by three polymer microspheres such as PMMA, Poly (MMA-MTC), and Poly (MMA-MTC-AA), the residual palladium ion concentration in the filtrate is 257 ppm, 66-75 ppm, and less than 6 ppm.

It can be seen from the above that Poly (MMA-MTC-AA) polymer microspheres have the best adsorption effect. Studies have shown that the microwave reaction system is added with acrylic acid (AA), and the surface of the polymer microspheres contains carboxyl functional groups which will adsorb with palladium and carboxyl groups. When the functional group is at a higher temperature, the noble metal ions can be accelerated and adsorbed on the surface of the microspheres, so that the adsorption amount of the precious metal is increased.

In summary, the present invention provides a method for preparing a precious metal adsorbent, which comprises a polymethyl methacrylate crosslinked acrylic acid (Poly (MMA-MTC-AA)) particle, which has a narrow particle size distribution and a reaction. Fast, low cost, easy process, good selectivity and high adsorption capacity.

The above-described embodiments are merely illustrative of the features and functions of the present invention, and are not intended to limit the scope of the technical scope of the present invention. Modifications and variations of the above-described embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be as set forth in the scope of the claims described below.

11~13‧‧‧Steps

21~26‧‧‧Steps

31‧‧‧ adsorbent particles

Figure 1 is a schematic view showing the process of the precious metal adsorbent of the present invention.

Figure 2 is a schematic view of another process of the precious metal adsorbent of the present invention.

Fig. 3 is a scanning electron microscope analysis diagram of the first embodiment of the present invention.

11~13‧‧‧Steps

Claims (12)

A method for preparing a precious metal adsorbent, the steps comprising: (A) providing the composition of the monomer 1 and the composition of the monomer 2; (B) adding the composition of the monomer 2 to the composition of the monomer 1; (C) performing microwave The precious metal adsorbent particles are reacted. A method for producing a precious metal adsorbent according to claim 1, wherein the monomer 1 comprises a monomer 1 and a solvent. The method for producing a precious metal adsorbent according to claim 1, wherein the composition of the monomer 2 comprises a monomer 2, an initiator, and a cationic dispersant. The method for preparing a precious metal adsorbent according to claim 1, wherein the monomer 1 and the monomer 2 are methyl methacrylate, styrene, vinyl acetate, acrylic acid, methacrylic acid, and the like. A polymerizable organic monomer such as fluoromethacrylic acid, methylene succinic acid or vinyl benzoic acid, and the monomer 1 and the monomer 2 may be the same compound. The method for producing a precious metal adsorbent according to claim 2, wherein the solvent is an aqueous solution containing a trace amount of a salt, and the salt is sodium chloride (NaCl) and ammonium chloride (NH ₄ Cl). And one of them; the aqueous solution of the aqueous solution is pure water. The method for producing a precious metal adsorbent according to claim 5, wherein the concentration of the salt in the solvent to the pure water is 0.01% to 1% by weight. The method for preparing a precious metal adsorbent according to claim 3, wherein the initiator is azobisisobutyronitrile (AIBN) and lauroyl peroxide (LPO). , one of ammonium persulfate (APS) and potassium persulphate (KPS). The method for producing a precious metal adsorbent according to claim 3, wherein the cationic dispersant is 2-(methacryloyloxymethyl)methyl-trimethylammonium chloride. , 2-(methacryloyloxy)ethyl-trimethylammonium chloride, 3-methacryloxy-propyl-trimethoxysilane And one of a mixture of hydrochloric acid or sulfuric acid, a mixture of methacryloyloxymethyltrimethylammonium chloride, and a mixture of methacryloyloxyethyltrimethylammonium chloride. The method for preparing a precious metal adsorbent according to claim 1, wherein the microwave reaction conditions are as follows: the reaction time may be 5 to 120 minutes, the power may be 30 W to 300 W, and the reaction temperature may be 60 to 85 ° C. The method for producing a precious metal adsorbent according to claim 9, wherein the reactor used for the microwave reaction comprises a cooling device. The method for preparing a precious metal adsorbent according to claim 1, wherein the third step is further carried out in order to take out the precious metal adsorbent particles, wherein: step (D) is to centrifuge the solution in the step (C). Procedure; step (E) the particle is subjected to a filtration and washing procedure; and the step (F) is filtered to remove the particles for a drying procedure. The method for preparing a precious metal adsorbent according to claim 4, wherein the monomer 1 type methyl methacrylate and the monomer 2 type acrylic acid form a polymer microsphere, and the particle size is From 3 microns to 7 microns.