JPS5855542A - Treatment of photographic waste liquid - Google Patents

Abstract

PURPOSE:To easily recover silver from photographic waste liquid and to enable to reuse said waste liquid, by treating the photographic waste liquid with anion exchange resin supporting a certain kind of a sulfur-contg. chelating agent. CONSTITUTION:Silver is wrested and recovered from the extremely stable complex salt of silver thiosulfate contained in photographic waste liquid, by treating the waste liquid with anion exchange resin supporting a sulfur-contg. chelating agent represented by the general formula (in the formula, each of X and Y independently means a sulfonic, carboxylic or hydroxylic group, or one of them is hydrogen atom while the other means a sulfonic, carboxylic or hydroxylic group). Silver adsorbed on the carrier of the sulfur-contg. chelating agent is easily eluted by an eluate such as thiourea, and the carrier can be repeatedly reused. The use amount of the carrier as the sulfur-contg. chelating agent is the same mol as or more than an amount of silver in the photographic waste liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating photographic waste liquid using an anion exchange resin supporting a sulfur-containing chelating agent (hereinafter referred to as "support"). That is, waste liquids such as tired photographic fixers, bleach-fixers, or washing water after bleaching and bleach-fixing operations are treated with the present carrier.

As is well known, a huge amount of silver is used in the photographic industry, as is well known regarding the processing method of photographic waste liquid for the purpose of recovering the silver in the waste liquid and furthermore, reusing the waste liquid. However, due to the depletion of silver resources and the rising price of silver, there is a strong demand for the recovery and reuse of silver in photographic waste liquids. In addition, the circulation and reuse of waste liquids is also considered important from the viewpoint of preventing water pollution, making effective use of chemicals used in photographic processing, and securing water resources.Currently, there are no methods for recovering silver from photographic waste liquids. , hydrogen sulfide method, electrolytic method, ion exchange resin method, or substitution method (a method that utilizes ionization tendency).

Aluminum and iron are used. ) etc. are known. However, these methods have problems in terms of hygiene, equipment, recovery rate, and quality of recovered silver, and there is a current demand in the photographic industry for the development of new recovery methods.

Silver in photographic waste liquid is mostly present in the form of tetraosulfate complex ions, as shown by the 9th order reaction formula.

Therefore, the biggest reason why recovery of silver from photographic waste liquid has not been carried out smoothly in the past is that in addition to the existence of highly concentrated silver in the form of the above-mentioned extremely stable complex ions, it also coexists with high concentrations of hypo, etc. It is said.

Therefore, the present inventors developed a stable silver thiosulfate complex (ion) that has the ability to remove silver from extremely stable silver thiosulfate complexes (ions) and is not affected by other highly concentrated components other than silver (ions) present in photographic waste liquid. As a result of intensive investigation into a wastewater treatment method using a carrier having a functional group, we found that an anion exchange resin, that is, a carrier carrying a certain kind of sulfur-containing chelating agent, is effective against silver ions and silver in silver thiosulfate complex ions. The present invention was completed based on the discovery that the waste liquid exhibits excellent selective adsorption performance through the above-mentioned carrier treatment, and that the waste liquid from which only silver is efficiently recovered and removed through the above-mentioned support treatment can be reused. The sulfur-containing chelating agent, which is a component of the related carrier, has the following general formulas (A) and (B).

In the formula, X and Y each independently represent a sulfonic acid group, a carboxyl group, or a hydroxyl group, or one of them is a hydrogen atom and the other is a sulfonic acid group, a carboxyl group, or a hydroxyl group. means.

The compounds of formulas (A) and (B) are easily synthesized from dithizone or azothiovirine, in which X and Y in formula (A) or (B) are both hydrogen atoms, which are well known as analytical reagents. Typical examples thereof include dithizone sulfone 111 (X and Y in formula (A) represent a sulfonic acid group) (hereinafter referred to as "DzS" 05), azothiopyrine sulfonic acid [X in formula (B)] and Y represents a sulfonic acid group.] (hereinafter referred to as "ATPS").

The anion exchange resin for the other component is not particularly limited, and any commercially available basic type can be used, but it is used in accordance with the types of X and Y in the above formula (A) or (B). is preferable. For example, when X is a sulfonic acid group, a strongly basic anion exchange resin is suitable for increasing the amount of the chelating agent (A) or chelating agent (A) supported.

Supporting the chelating agent (A) or (B) on the anion exchange resin can be achieved in an aqueous solution by the following simple operation. For example, chelate, curing agent 0.2 to 2 per 11 resin.
When mmol is dissolved in water and mixed with resin, the adsorption and loading is completed when the color of the reagent disappears. At this point, the carrier used in the present invention can be prepared by filtering it.

The phase support prepared in this way has excellent stability and adsorption capacity due to the fact that a large amount of the chelating agent is supported on the resin through ion exchange reaction and physical adsorption. .

Regarding the silver adsorption performance of the support prepared in this manner in photographic waste liquid, we conducted a silver adsorption experiment in a silver thiosulfate complex ion solution using representative Amberlite 00400 supported on ZS and ATPS. It was confirmed that it exhibited excellent silver scavenging and adsorption performance for thiosulfate complex ions.

To carry out the present invention, photographic waste liquids with advanced fatigue, such as waste liquids of fixers, bleach-fixers, and washing water after fixing and bleach-fixing operations, can be treated with a -i-ne carrier. , batch method, and column method. In the case of a batch method, it is preferable to carry out the mixing while stirring or shaking).

The amount of this carrier used is just enough to support it. - Although it depends on the type of chelating agent, it is necessary to use the same molar amount of chelating agent as the amount of silver contained in the treatment waste liquid or more.

The amount of support loaded with that amount is required. Also 1g&
No particular consideration is required regarding the temperature or pH during the application, and it can be applied over a wide range.

The photographic waste liquid treated with the carrier in this manner can be reused as a photographic processing liquid since only the silver contained therein is adsorbed and removed at a high adsorption rate.

Furthermore, in addition to treating exhausted photographic waste liquid, it is also possible to incorporate a treatment method using a single carrier into the photographic processing process by devising equipment, etc., and to continuously circulate and regenerate the processing liquid.

On the other hand, silver adsorbed on one carrier is considered to exist in the form of resin-chelating agent-silver.

If treated with a suitable eluent, the resin and chelating agent can be eluted without affecting their binding, and the 9-piece carrier can be repeatedly reused. Examples of the eluent include reagents 9 that form soluble compounds with silver, such as thiourea. As for the elution method, collect the silver adsorbent and add 0.1 to 5 ml of the eluent.
It can be treated with a molar aqueous solution.

The present invention will be explained below with reference to Examples.

These are merely examples to illustrate the invention.

It is also possible to use an anion exchange resin carrying a chelate north side other than ATPS or DzS, and to apply the present carrier to recovery of silver from sources other than photographic waste liquid.

Example 1 Sodium thiosulfate pentahydrate 49.69. A silver thiosulfate complex ion solution was prepared by diluting sodium sulfite LO to 1 liter (pH 7,0) with water and adding 10s9 of silver nitrate as silver to this solution.For each of this silver complex ion solution 50- Q, 2 mrrrol/9 resin DzS
Or add each &100sI9 and 5001119 of Amberlite CG400 carrying ATPS, and heat at 25°C with N
After shaking for 0 minutes, the silver concentration in the supernatant was measured by atomic absorption spectrometry to determine the adsorption rate, and the results are shown in Table 1.

Table 1 Silver adsorption rate Example 2 DzS (0,2s+uaoVg) where silver 1)9 was adsorbed
Resin) Support 7 members 5a) Oct400. ff to 0
．． The sample was treated with 8 to 1.2 molar thiourea solution at a concentration of 500 ml, and an elution experiment of the deposited silver was carried out. As the results are shown in Table 1, a good silver desorption rate was exhibited.

Table Ⅲ Desorption of silver using thiourea Example 8 Thiosulfate 13um pentahydrate 248F and anhydrous sodium sulfite 15F are dissolved in water. Dissolve 12 Qs9 (1,11 mmaoz) of silver nitrate in this solution, and then add water to make a total volume of 1 mm.
Divide into equal parts and perform the next adsorption/desorption experiment eight times.

That is, this model fixing waste solution +l was passed through a DzS resin-packed column (DzS (Q, 2 mmol/9 resin)-supported Amberlite CG400, 8.59, 0.8 cm diameter column) at a flow rate of 8171/hour. .

Further, L2 mole thiourea was used to elute silver adsorbed on the resin.

The model fixing waste solution +l was again passed through the resin from which silver had been eluted, and adsorption and desorption experiments were conducted in the same manner a total of 8 times.

The results of this experiment are shown in Table 1 below.

Table 1 Recovery of silver from model fixing waste solution [Silver analysis was carried out by atomic absorption method] Example 4 Ammonium thiosulfate 100 g, disodium ethylenediaminetetraacetate 49. Iron ethylenediaminetetraacetate II)
4θg of the complex salt, 29g of sodium sulfite, 1g of potassium chloride, 10g of sodium thiocyanate and 10ajj of 20% aqueous ammonia are diluted with water.The developed film is repeatedly treated with this bleach-fix solution. When the silver concentration of the fatigued bleach-fix solution was measured by atomic absorption method, it was 11.697.
It was 1. This fatigue bleach-fix solution.

DzS resin packed column (D z 8 (0,8 mmol
/g Resin) Supported Amberlite CG400,189.
The solution was passed through a column with a diameter of 2 CII at a flow rate of 1 i/$.

As a result, the leakage point was 75-, and the silver concentration in the treatment liquid up to the leakage point was 0.24/l or less.

On the other hand, when the bleach-fixing power of the nine treatment solutions was evaluated using test films, it was found that the original bleach-fixing power was recovered as shown in Table N.

Table N Bleach-fix regeneration test film: After constant exposure to 7-di fine grain film, Kodak D-7! Developed with (1:4 liquid) (2
0° C., 7 minutes), washed with water, and dried degraded In-L78±0.
02's 74 MU cut into 0.5 tan squares.

Evaluation of bleach-fixing power: Swell the test film with water for 10 minutes, drain the water with a filter paper, then soak it in a bleach-fix solution kept at 25°C, and measure the time it takes to become colorless and transparent (7) using a stopwatch. do.

Claims (1)

[Scope of Claims] Photographic waste liquid is prepared by the general formula (wherein, 1. A method for recovering silver from photographic waste, the method comprising treating it with an anion exchange resin carrying a sulfur-containing chelating agent (meaning an acid group, a carboxyl group or a hydroxyl group).