CN100434547C - Poly-o-phenylenediamine is used as an adsorbent to recover silver from silver-containing solution - Google Patents

Abstract

The invention discloses a method to reclaim silver from solution with silver, which comprises the following steps: adopting static absorption method; using poly o-phenylenediamine as silver ion sorbent; adding silver ion solution with initial density at 1.2-100mmol/L; stirring; absorbing at 30min-24h; filtering. This invention possesses cheap cost, convenient operation and high adsorption efficiency, which can be used to image fusing waste liquid, plating waste liquid, chemical analysis waste liquid and test waste liquid.

Description

Poly-o-phenylenediamine is used as an adsorbent to recover silver from silver-containing solution

technical field

The invention relates to a method for recovering silver from a silver-containing solution using poly-o-phenylenediamine as a silver ion adsorbent.

Background technique

The traditional methods for recovering silver from silver-containing waste liquid mainly include precipitation method, electrolysis method, reduction substitution method and ion exchange method. These traditional methods generally have the disadvantages of high energy consumption, secondary pollution, and little effect on trace silver. The adsorption method can overcome the shortcomings of the above four methods to a certain extent, so it has great development potential. The adsorption effect of the adsorption method mainly depends on the performance of the adsorbent used. As the most commonly used adsorbent in the adsorption method, activated carbon is mainly used in the recovery of trace or ultra-trace silver in silver-containing waste liquid. Using activated carbon to adsorb and enrich ultra-trace silver in natural water, the adsorption rate is as high as 95.8%, and the minimum detected mass concentration is only 0.025 μg/L (Luo Yongyi, Zhang Kerong, Zhang Yao, etc. Research on the adsorption behavior and mechanism of silver on activated carbon [J]. Environmental Chemistry, 1995, 14(1): 75-79). Use activated carbon for water purification of fruit shells and activated carbon for coal water purification to treat film industrial wastewater containing trace silver (171μg/L), which can reduce the concentration of silver in wastewater to less than 50μg/L National drinking water sanitation Standard, the adsorption capacity can reach 3~5mg/g (Jiang Ting, Shi Yinyue, Hua Jinai. Study on the adsorption of trace silver by activated carbon [J]. Forest Products Chemistry and Industry, 1996, 16(2): 49-53). Although activated carbon can make up for the shortcomings of traditional methods to some extent, it is powerless to high-concentration silver waste liquid due to the limitation of its own adsorption capacity. In addition to activated carbon, activated carbon fibers, chelating resins, poly(1,8-naphthalene diamine) can also be used as silver ion adsorbents due to containing a large number of functional groups, especially poly(1,8-naphthalene diamine) It has the largest silver ion adsorption capacity of 1920mg/g (Li X G, HuangM R, Li S X. Facile synthesis of poly(1,8-diaminonaphthalene) microparticles with a very high silver-ion adsorption by a chemical oxidative polymerization[J]. Acta Materialia, 2004, 52:5363-5374.), but using these three kinds of materials as silver ion adsorbents all have higher usage costs, thus limiting their wide application.

Contents of the invention

The purpose of the present invention is to provide a method for recovering silver from silver-containing solution with low cost, convenient operation and high adsorption efficiency.

The method for recovering silver from a silver-containing solution proposed by the present invention adopts a static adsorption method, wherein the silver ion adsorbent adopts poly-o-phenylenediamine. Poly-o-phenylenediamine can be synthesized by chemical oxidative polymerization, and it contains NH-, NH ₂ -groups capable of complexing or redoxing with silver ions. The structural formula of poly-o-phenylenediamine is as follows:

The static adsorption method that the present invention adopts, concrete steps are as follows:

Add poly-o-phenylenediamine into the solution containing silver ions, stir and adsorb for 30 minutes to 24 hours, wherein, the initial concentration of the solution containing silver ions is 1.24-100mmol/L, and the ratio of poly-o-phenylenediamine to the solution containing silver ions is 1-3mg/mL.

The residual silver ion concentration in the filtrate adopts Volhard method titration or measures with plasma absorption spectrometry, then calculates the adsorption capacity of the adsorbent according to (1) formula, and calculates the adsorption rate of silver ions according to (2) formula.

$\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; VM</span>}}{\mathrm{<span\; class="notranslate">\; W</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; q</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Q: adsorption capacity of silver ions (mg/g); q: adsorption percentage of silver ions; C _o : initial silver ion concentration (mol/L);

C: concentration of residual silver ions after adsorption (mol/L); V: volume of solution containing silver ions (mL); M: molecular weight of silver (g/mol);

W: weight (g) of polymer charged.

According to the change of adsorption capacity with adsorption time when poly-o-phenylenediamine adsorbs a certain concentration of silver ions, the curve of adsorption capacity with time can be drawn, and the adsorption equilibrium time and maximum adsorption at a certain concentration of silver ions can be obtained from this curve. Capacity, and the pseudo-second-order kinetic equation can be used to simulate the adsorption kinetics, so as to obtain the initial adsorption rate constant h.

Because the adsorption performance of adsorbent is affected by adsorption time, initial silver ion concentration, and adsorbent dosage, in the present invention, the initial silver ion concentration range is 1.24～100mmol/L, and the consumption of poly-o-phenylenediamine is equal to the silver ion-containing solution. The ratio is 1-3 mg/mL, and the adsorption time is 30 minutes to 24 hours.

In the present invention, the silver ion-containing solution may be a silver nitrate solution, or other silver ion-containing solutions.

Beneficial effects of the present invention: relative to the disclosed silver ion adsorbent poly(1,8 naphthalene diamine), the raw material price of poly-o-phenylenediamine is cheap, therefore, its raw material cost is far lower than poly(1,8 naphthalene diamine). Moreover, it is easy to operate, coupled with its fast and efficient silver ion adsorption capacity, it can be used in the silver recovery treatment of fixing waste liquid, electroplating waste liquid, chemical analysis waste liquid and test waste liquid, as well as through chemical precipitation, electrolysis, ion exchange, etc. The field of retreatment of silver-containing wastewater treated by traditional methods such as metal reduction method, metal reduction method and microbial method has a good application prospect.

Description of drawings

Fig. 1 is the wide-angle X-ray diffraction spectrum of doped poly-o-phenylenediamine synthesized under the condition that the oxygen ratio is 1/1 after being adsorbed on 100 mmol/L silver ions for 24 hours.

Fig. 2 is the XPS diagram of the doped poly-o-phenylenediamine synthesized under the condition that the oxygen ratio is 1/1 after adsorption and 100mmol/L silver ion for 24 hours.

Fig. 3 is the XPS diagram of the de-doped poly-o-phenylenediamine synthesized under the condition that the oxygen ratio is 1/1 after adsorption and 100 mmol/L silver ions for 24 hours.

Detailed ways

Example 1

Take 50 mg of doped poly-o-phenylenediamine synthesized under the condition of oxygen single ratio 1/1, put it into 25 mL of silver ion solution with an initial concentration of 100 mmol/L at 30°C and stir for 24 hours; after filtering, use Volhard Analysis of the remaining silver ion content in the filtrate by the method showed that the poly-o-phenylenediamine had an adsorption capacity of 533 mg/g for the silver ion, and the adsorption rate was 9.9%. The wide-angle X-ray diffraction pattern of poly-o-phenylenediamine after silver adsorption is shown in Figure 1, and the XPS surface element analysis is shown in Figure 2. It can be seen that the adsorbed silver is mainly in the elemental state and also in the ionic state, and the weight ratio of the two is 74/26. Under the same adsorption operation conditions, the doped poly-o-phenylenediamine synthesized under the conditions of oxygen single ratio of 2/1 and 3/1 was used instead, and the obtained adsorption capacities were 447mg/g and 375mg/g respectively, and the adsorption rates were respectively 8.3%, 6.9%.

Example 2

Take 50 mg of de-doped poly-o-phenylenediamine synthesized under the condition of oxygen single ratio 1/1, put it into 25 mL of silver ion solution with an initial concentration of 100 mmol/L mmol/L at 30 ° C, stir and react for 24 h; after filtering, use The content of residual silver ions in the filtrate was analyzed by the Volhard method, and the adsorption capacity of the poly-o-phenylenediamine to silver ions was 444 mg/g, and the adsorption rate was 8.2%. The XPS analysis of poly-o-phenylenediamine after silver adsorption is shown in Figure 3. It can be seen that the adsorbed silver coexists in elemental state and ion state, and the weight ratio of the two is 44/56. Under the same adsorption operation conditions, the de-doped polym-phenylenediamine synthesized under the conditions of oxygen single ratio of 2/1 and 3/1 was used instead, and the obtained adsorption capacities were 408 mg/g and 371 mg/g respectively, and the adsorption rates were respectively 7.6%, 6.9%.

Example 3

Take 50 mg of doped poly-o-phenylenediamine synthesized under the condition of oxygen single ratio 1/1, put it into 25 mL of silver ion solution with an initial concentration of 43.1 mmol/L at 30 ° C, stir and react for 0.5 hour, filter, and use Foer The residual silver ion content in the filtrate was analyzed by the Harder method, and the adsorption capacity of poly-o-phenylenediamine to silver ion was 316 mg/g, and the adsorption rate was 13.6%. XPS analysis showed that the adsorbed silver coexisted in elemental state and ionic state , the weight ratio of the two is 51/49. Under the same conditions, changing the adsorption time to 1 hour, 3 hours, 6 hours, 12 hours, and 24 hours, the obtained adsorption capacities were 324mg/g, 332mg/g, 342mg/g, 370mg/g, and 415mg/g. The ratios were 13.9%, 14.3%, 14.7%, 15.9%, and 17.8%, respectively. The XPS analysis of the doped poly-o-phenylenediamine after 24 hours of silver adsorption showed that the adsorbed ones were mainly in the elemental state and also in the ionic state. The weight ratio of the two is 61/39.

Thus, it can be obtained that the equilibrium adsorption time is 24 hours during the adsorption treatment of silver ions with an initial concentration of 43.1mmol//L, and the adsorption kinetics simulation is carried out with the pseudo-second-order kinetic equation. The correlation coefficient of the simulation is 0.9999, and the standard deviation is 1.149× ^10-4 . The initial adsorption rate constant h obtained by simulation is 5107 mg/(gh).

Example 4

Take 50 mg of doped poly-o-phenylenediamine synthesized under the condition of oxygen single ratio 1/1, put it into 25 mL of silver ion solution with an initial concentration of 1.24 mmol/L at 30 ° C, stir and react for 10 hours, filter, and use Foer Harder method analyzes remaining silver ion content in the filtrate, and available polym-phenylenediamine is 65.7mg/g to the silver ion adsorption capacity, and adsorption rate is 99.1%. Under the same condition, change initial silver ion concentration to be 2.50mmol/ L, 5.00mmol/L, 10.8mmol/L, 21.6mmol/L, 43.1mmol/L, 100mmol/L, the resulting adsorption capacities are 109mg/g, 169mg/g, 276mg/g, 342mg/g, 415mg/g , 533mg/g, and the adsorption rates were 81.2%, 63.1%, 47.5%, 29.4%, 17.8%, and 9.9%, respectively.

Claims (3)

1, a kind of method that reclaims silver from Ag-containing solution is characterized in that adopting static adsorptive method, and silver ion adsorbant uses poly-o-phenylenediamine.

2, the method that from Ag-containing solution, reclaims silver according to claim 1, the concrete steps that it is characterized in that described static adsorptive method are as follows: the poly-o-phenylenediamine adding is contained in the silver ion solution, whip attachment 30 minutes-24 hours, wherein, containing the initial concentration of silver ions of silver ion solution is 1.24-100mmol/L, and poly-o-phenylenediamine is 1-3mg/mL with the proportioning that contains silver ion solution.

3, the method that reclaims silver from Ag-containing solution according to claim 1 is characterized in that described poly-o-phenylenediamine is the doping attitude or the attitude poly-o-phenylenediamine that goes to mix.

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