Technology Description

Irradiation of aqueous solutions with high-energy electrons results in the formation of the aqueous electron, eaq

, hydrogen

radical, H·, and the hydroxyl radical, OH·. These reactive transient species initiate chemical reactions capable of destroying

organic compounds in aqueous solution, in most cases oxidizing

them to carbon dioxide, water and salt. No sludge is formed and

no pretreatment is necessary. The reaction by-products are nontoxic and thus this process represents a new technology for the

restoration of contaminated water, soils and sediments.

At one end of the system, an aqueous solution containing the

hazardous organic chemical(s) is directed over a weir where it

falls in a thin sheet (approximately 4 millimeters thick). At the

other end of the system, a 1.5-million volt insulated core transformer (ICT) electron accelerator generates electrons and accelerates them to approximately 97% the speed of light. These

accelerated electrons are propelled in a concentrated beam down

a high-vacuum tube toward a scanner which scans the beam to a

rectangular shape and directs it toward the aqueous solution

which is flowing over the weir. It is at this point, when the

electrons penetrate the waste stream, that treatment occurs. The

studies have been conducted at 120 gal/min, and can be easily

scaled up for larger applications. The process is essentially pH

independent in the range 3-11.

Waste Applicability

Current studies using high energy electron beam irradiation have

demonstrated that the process is efficient for the destruction of

several classes of hazardous organic compounds. These studies

have been extended to the destruction of phenol in aqueous

solution in a large-scale flow-through system. Studies were conducted at solute concentrations of 1, 10 and 50 mg L-1, over the

pH range 5-9, in the presence and absence of 3% w/w kaolin

clay.

Test Results

High energy electron beam irradiation effectively removes phenol

from aqueous solutions at large scale. Removal is affected by

solute concentration, absorbed dose and total alkalinity. Other

water quality parameters such as the presence of suspended

solids and solution pH are not important factors influencing compound removal. At high phenol concentration (3950 μM), recircuEPA/540/F-93/509

August 1993

Emerging Technology Bulletin

Removal of Phenol from Aqueous Solutions Using High Energy

Electron Beam Irradiation

Florida International University and the University of Miami

United States

Environmental Protection

Agency

Figure 1. Removal of phenol in the presence and absence of inert solids ( 3% clay) using the electron beam treatment process.

No Clay 3% Clay

Absorbed Dose (krad) Absorbed Dose (krad)

700

600

500

400

300

200

100

0

700

600

500

400

300

200

100

0

70

60

50

40

30

20

10

0

70

60

50

40

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20

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0

0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700

Phenol (μ

M)

Phenol (μ

M)

mg L

-1

mg L

-1

Influent

Effluent

Influent

Effluent
lation of the waste stream was necessary to destroy all of the

phenol and its reaction by-products.

It was shown that high energy electron beam irradiation leads to

the formation of oxidized reaction by-products. At low doses and

low phenol concentrations, more than 50% of the decomposition

of phenol was attributed to the formation of hydroquinone, catechol and trace amounts of resorcinol. The formation of these dihydroxy phenol derivatives correspond closely to those reported

as reaction by-products of phenol with OH· radicals. In addition,

aldehydes and formic acid were also identified as reaction byproducts.

For Further Information:

Franklin Alvarez, EPA Project Manager

Risk Reduction Engineering Laboratory

USEPA

26 West Martin Luther King Drive

Cincinnati, OH 45268

(513) 569-7631

Fax (513) 569-7620

Technology Developer Contact:

William J. Cooper

Drinking Water Research Center

Florida International University

Miami, FL 33199

(305) 348-3049

FAX (305) 348-3894

Charles N. Kurucz

Department of Management Science and Industrial Engineering

University of Miami

Coral Gables, FL 33134

(305) 284-6595

FAX (305) 284-2321

Thomas D. Waite

High Voltage Environmental Applications, Inc.

9562 Doral Boulevard

Miami, FL 33178

(305) 593-5330

(305) 533-0071 (FAX)

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

Official Business

Penalty for Private Use

$300

EPA/540/F-93/509