DE2316731A1 - REGENERATION PROCESS - Google Patents

Description

United States Atomic Energy Commission, Washington, D.C, USA

Regeneration process.

The invention relates to a method of regeneration for a carbon sorbent and to a method of treating waste organic material that is dissolved or dispersed in an aqueous fluid. In general, the invention relates to a method for reducing environmental pollution, and it is particularly possible
is, the sorption process and the regeneration process of one
carry out carbon-containing sorbent simultaneously.

Carbonaceous materials such as lignin charcoal, bone charcoal, charcoal or coke particles, activated charcoal and the like are used as sorbents for a variety of purposes in many chemical processes to clarify, purify or refine a desired product
to reach. Over time, these materials become

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cleanses saturated or clogged and are then called "Consumed" means because they no longer have their sorption effect exercise in an appropriate manner.

Processes for the regeneration of such spent sorbents are already known. In each. In some cases, these processes require that the spent sorbent be removed from the sorption process so that regeneration can be carried out, which is generally a high temperature oxidation process. This oxidation usually destroys a considerable percentage of the sorbent by converting it to CO and / or CO ₂ , producing a regenerated or rejuvenated product with reduced sorption capacity.

In general, the invention has set itself the goal of specifying a method by means of which organic substances dissolved in wastewater or dispersed substances can be removed. Specifically, the invention aims to provide a method which the organic Removes substances from wastewater by sorption, namely by sorption on a carbon-containing sorbent, whereby the sorbent is regenerated again and again at the same time.

According to the invention, these objects are achieved by a method in which organic matter - dissolved or dispersed containing wastewater with a carbon containing sorbent is irradiated with radiation of high energy. In the context of this invention the term means High energy radiation such a form of radiation that the Has ability to destroy organic compounds with chromophoric groups into colorless or less colored forms or convert. In the examples below, cobalt-60, a gamma-ray emitting isotope, is found to be effective Radiation source used for high energy radiation. Other functionally equivalent radiation sources can be used when performing used in this invention; it is for example

- " 137" 134 _ 192, "152,154 referred to: Cs, Ce, Ir and Eu '

The invention is illustrated by the following examples.

Example I -

Activated charcoal with a grain size of 30 meshes made from coconut shell was mixed with an aqueous solution of a saturated organic dye. The saturation point was defined as where more than 95% of the color of the dye solution was sorbed by the charcoal. The discoloration was determined by the decrease in light absorption at 350, 450 and 550 millimicrons, i.e. the main absorption peaks for this Dye. The absorbance values were summed to give a "color factor" which was used as a basis for the comparator Results was used; was there

Color factor = (X + Y + Z) D,

where X, Y and Z = the sum of the optical wavelengths at the three selected wavelengths and

D = a dilution factor that corresponds to the dilution of the samples with corresponds to distilled water in order to bring the sample into the color range of the measuring spectrophotometer.

An additional volume of the color solution was then added to the saturated Charcoal mixed and irradiated with a cobalt-60 source. After the irradiation, the aqueous phase was removed from the Separated charcoal and examined for absorption at the specified wavelengths. The irradiations were carried out in air Ambient pressure and temperature, i.e. 25 C. Table I below shows the results of this experiment .

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TABLE I.

Color
solution Color solution
irradiated
without wood
money Color solution +
saturated charcoal
irradiated Radiation dose in wheel • 10 ⁶ "" . 10 ⁶ Color factor 1, 325 0.685 0.189 % Color removed 50 86

Radiation exposure time in min.

% Color reduction is AB χ TÖO, where A = color units of

A.
untreated sample and B = color units of the treated

Sample.

It is concluded from the results in Table I that the presence of of the used charcoal increased the color removal by 36% compared to the color removal that is achieved with irradiation alone receives. It is believed that this effect on reactivation the charcoal is reduced by the gamma radiation. The process obviously includes the destruction of the organic Material, which is held at the sorption sites of the spent charcoal, so that the observed increase in the color removal is due to the availability of new or regenerated sorptive sites.

Example II

10 grams of activated coconut charcoal (30 mesh grain size) saturated with a dye solution were repeatedly irradiated, namely in contact with successive 100-cc volumes of the

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Dye solution. The results are summarized in Table II.

TABLE II

Rehearse-

Descriptive dose running exercise in wheel

1 saturated _c charcoal 5x1 CT

2 charcoal
used in run 1 1x10

3 charcoal
used in Run 2 1 x10

4 charcoal
used in run 3 2x10

Radiation exposure
time in min.

36

72

72

149

Coloring factor

0.44 8.0

0.488 8.4

0.454 7.9

0.204 8.3

Color distance in%

83

81

83

92

Based on a color factor of 2.615 of the non-irradiated Staining solution.

Based on the constant percentage of color removal at Runs 1-3 clearly show that the irradiation created or regenerated the sorption sites in the charcoal, which were initially were already saturated with the dye. The increased increase in paint removal in Run 4 indicates that the extent of the Color removal is a function of dosage or exposure time or both.

Example III

A preferred mode of operation of this invention is to add high pressure oxygen to the feed will. It has been found that a high oxygen pressure is the equivalent purpose of radiation serves to a limited extent, or, in other words, a high oxygen pressure increases at at a given dosage the regenerative effect of radiation on charcoal. Generally there is a minimum oxygen pressure of at least 50 psi (pounds per square inch) is required to

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obtain a measurable efficiency.

In this example, the effect of oxygen pressure was on the reactivation of charcoal is determined by gamma radiation.

10 grams of charcoal saturated with a coloring solution of the one described above Art was irradiated in 100 cm of distilled water, at a pressure of 1000 psi oxygen for a period of 72 minutes with a gamma dose of 10 R. These Treatment was carried out to determine whether the saturated charcoal would be reactivated for adsorption of the dye from a standard dye solution. '

The results are shown in Table III.

TABLE III

Saturated charcoal before irradiation under 1000 psi O ₂ , exposed to a 100 ecm standard color solution

Saturated charcoal after irradiation at 1000 psi O ₂ with 100 ecm units of H ^ O, exposed to a standard barrel

Weight of the charcoal in g

Radiation exposure time in min.

Radiation dose in rad

Color reduction of the dye solution after mixing with charcoal in%

none none

The results show that the reactivation of the char "occurred. In other words, the restoration of the Käpä'zi- ^ '" tat the charcoal is practically equal to the capacity of the xvaÜSa- ~ ^J ' radiated charcoal as received from the manufacturer .

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Example IV ■

Further experiments were carried out on the effect of gamma radiation in the presence of oxygen to determine the reactivation of the dye-saturated charcoal. In these attempts 10 g of charcoal saturated with an organic dye solution were irradiated in 100 ecm of distilled water at 1000 psi oxygen pressure for 72 minutes and up to a total gamma radiation dose of 10 R. The charcoal was then added to a new amount of 100 ecm for 16 hours Exposure to the standard dye solution to determine whether the sorption capacity for the dye is restored to the standard dye solution was or not. The results of this experiment are given in Table IV.

TABLE IV

Saturated charcoal before irradiation after irradiation at 1000 psi 0.1000 psi O ₂ with exposed to a 100ccm distilled 100 ecm standard H ₃ O (then exposed to a color solution 1u0ccm color solution I)

Charcoal weight in g 10 10

Radiation exposure time in minutes none 72

Radiation dose in R none .10

Color reduction of the aqueous

Color solution after 16 hours

Shake with charcoal

in% 5 91

The results show that either the charcoal's capacity has been restored or that new sorption sites have been created Charcoal were produced so that it could reduce the dye solution by 91%.

Example V
An aqueous solution of benzyl cyanine dye was through a

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Pumped charcoal column / under three conditions:

1) At atmospheric pressure without irradiation;

2) at atmospheric pressure with an irradiation of the charcoal in the amount of 10 R from a Köbält-60 source; and finally

3) with the one under an oxygen pressure of 1500 psi

7 solution and irradiation of the charcoal on 10 R as under 2),

The results are summarized in Table V below.

TABEL

Analytical data for the radioactive oxidation of benzyl cyanine 6B dye

No irradiation; 1Ö ⁷ R field 10 ⁷ R field; atmos- atmospheric 1500 psi spherical pressure pressure ■: '.

Flow velocity

in liters per hour 0.50 2.00 2 * OO

Breakthrough capacity of the _r

Charcoal "..,

in liters 14 25 108

Original through- '

coolness at 550 m ^ * -

in% 2.5 2.5 2.5

Flow rate through 95 91 nonchalance at 550 ny *. 65 82 in accordance 13 liters 16 liters 24 liters 27 liters 108 liters

96.5

The experiment was completed after 108 liters.

The results show that the charcoal capacity was increased from 14 liters to 25 liters, when the charcoal was placed in a radiation source, but an increase to about 108 1

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occurred when the solution was additionally subjected to oxygen pressure of 1500 psi. It should be noted that the permeability of the aqueous fluid after passage through the charcoal was 96.5% after more than 108 liters of the dye solution had passed through the charcoal column. Indeed show the data describes a process for the continuous sorption of the organic content of a feed flow on the carbon layer to cause discoloration and simultaneous regeneration of the spent carbon. It is indeed one clear indication that the capacity of the carbon layer is actually increased when the dosage and the oxygen content increase in the infeed.

The importance of this invention as a method of controlling contaminants can be clearly seen particularly when considering that prior to this invention it was known that water-based dye wastewater continued through Exposure to radiation can be decolorized. Since over 99 percent by weight of most wastewater is water, detects one readily that it is desirable to reduce the irradiation of the aqueous phase and the radiation dose to the concentrate organic color. By arranging the charcoal in an irradiation vessel, the charcoal can be sorbable Fraction removed from the wastewater stream and concentrated on the charcoal. In this way it is possible to have the irradiation to maximize the organic material and to minimize the irradiation of the water. By adjusting the sewage flow the radiation dose can be adjusted so that a constant in situ regeneration of the charcoal occurs, assisted by an oxygen pressure in the range of 50 to 20OO psi, so as to support the oxidation of the sorbed organic matter and to ensure constant reactivation of the sorbent while continuously producing a decolored aqueous product.

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The invention has been described with reference to the treatment of organic dye solutions; it is "however clear / that the invention can also be used to treat such organic substances that produce liquid or gaseous waste products, such as they at paper mills and textile mills and also at food processing plants occur in order to win a product which is released into the atmosphere or without damage public waters can be released.

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Claims (7)

1. A method for regenerating an inert particulate carbonaceous sorbent which contains organic compounds sorbed therein , characterized in that the sorbent is irradiated with high energy radiation, at an oxygen pressure between ambient pressure up to 2000 psi, for as long as until the sorption quality of the sorbent is regenerated. 2. The method according to claim 1, characterized in that the Sorbent is mixed with an aqueous phase. 3. Process for the treatment of organic waste material, which is dissolved or distributed in an aqueous wastewater, characterized in that the wastewater with an inert contacting particulate carbonaceous sorbents at oxygen pressures up to 2000 psi, wherein the resulting mixture is irradiated with high energy radiation until a discolored liquid is produced which is then separated. 4. The method according to claim 3, characterized in that the sorbent-waste water mixture at an oxygen pressure irradiated in the range of 50 to 2000 psi. 5. The method according to claim 3, characterized in that one of the following materials is used as the sorbent: Finely divided activated charcoal made from wood, activated charcoal made from bone, charcoal and Activated carbon made from coke. 6. The method according to claim 3, characterized in that the radiation is gamma radiation. 7. The method according to one or more of the preceding claims, characterized in that the aqueous phase is passed through a porous column of an inert particulate carbonaceous Sorbent is passed, under an oxygen pressure up to 2000 psi, with the column 309842/093 * '■ irradiated with high energy radiation? becomes a discolored to produce aqueous product which leaves this column. 309842/0934