TREATING SULFURIC ACID

Abstract

Provided is a method for treating sulfuric acid comprising the step (I) of bringing said sulfuric acid into contact with a collection of solid particles (B) having BET surface area of 50 m.sup.2/g to 5,000 m.sup.2/g and having volume-average particle diameter of 200 m or less.

Claims

1. A method for treating sulfuric acid comprising the step (I) of bringing said sulfuric acid into contact with a collection of solid particles (B) having BET surface area of 50 m.sup.2/g to 5,000 m.sup.2/g and having volume-average particle diameter of 200 m or less.

2. The method of claim 1, wherein said solid particles (B) are activated carbon particles.

3. The method of claim 2, wherein said sulfuric acid, prior to said step (I), has undergone a reaction with a copolymer.

4. The method of claim 2, wherein said sulfuric acid is in the form of a solution that comprises sulfuric acid and water.

5. The method of claim 2, wherein said activated carbon particles are powdered activated carbon particles.

6. The method of claim 2, wherein said method further comprises the step, after said step (I), of separating said sulfuric acid from said activated carbon particles.

Description

EXAMPLE 1: WITH AND WITHOUT ACTIVATED CARBON

[0039] The sulfuric acid that was treated was spent sulfuric acid produced by treatment of a resin that was a copolymer containing polymerized units of styrene and divinyl benzene. The spent sulfuric acid contained water and other impurities. In each sample, 50 mL of spent sulfuric acid was used. Powdered activated carbon was added and the mixture was shaken by hand. The carbon was allowed to settle, and the liquid on the top of the container was observed visually. Results were as follows:

[0040] Results were as follows:

TABLE-US-00001 Example Activated Carbon (g) Color 1-1-C.sup.(1) 0 dark brown, opaque 1-2 0.33 clear to light yellow, transparent 1-3 0.66 clear to light yellow, transparent 1-4 1.0 clear to light yellow, transparent .sup.(1)Example 1-1-C is a comparative example
The use of activated carbon significantly reduced the color of the sulfuric acid.

COMPARATIVE EXAMPLE 2: WITH AND WITHOUT ADSORBENT RESIN

[0041] An experiment similar to Example 1 was performed twice, each time with a different commercial Optipore resin used in place of activated carbon. Each Optipore resin used was a synthetic resin that is highly porous compared to other synthetic resins and each has volume-average particle diameter larger than 250 m. No significant difference in color was observed among the samples. The Optipore resin had volume-average particle diameter greater than 200 m.

COMPARATIVE EXAMPLE 3: WITH AND WITHOUT DIATOMACEOUS EARTH

[0042] An experiment similar to Example 1 was performed with diatomaceous earth used in place of activated carbon. No significant difference in color was observed among the samples. Diatomaceous earth is known to have BET surface area less than 50 m.sup.2/g.

EXAMPLE 4: SEPARATION OF SULFURIC ACID

[0043] A mixture of spent sulfuric acid and powdered activated carbon (similar to sample 1-2) was mixed with diatomaceous earth. The resulting mixture was placed in a vacuum funnel. Partial vacuum was pulled on the bottom of the vacuum funnel, and clear, light yellow sulfuric acid was pulled through the funnel, while the activated carbon and the diatomaceous earth were retained on the funnel.