Feasibility of extracting toxic metals from soil using anhydrous ammonia

Journal Article · Fri Jan 01 00:00:00 EST 1993 · Waste Management; (United States)

DOI:https://doi.org/10.1016/0956-053X(93)90045-X· OSTI ID:5956775

Clifford, D A; Yang, Ming; Nedwed, T ^[1]

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1. Univ. of Houston, TX (United States). Dept. of Civil and Environmental Engineering

It was the purpose of this research to establish the feasibility of using anhydrous ammonia alone and with enhancing ligands to extract lead, cadmium, mercury, copper, and zinc from soil. To evaluate its effectiveness for soil extraction, three devices were used: a pressurized Soxhlet extractor, a plug flow extractor, and a pressurized stirred batch reactor. They all gave essentially the same performance, which suggests that the metal removed was readily extractable. Sixty to seventy percent removal of cadmium, copper, and zinc could be obtained from soils spiked and aged for four months to two years with 50,000 mg/kg of the metal nitrate. Lead and mercury removals were low with pure ammonia. Lead removal increased dramatically, however, when ethylenediaminetetraacetate (EDTA) was added to the ammonia and when aqueous EDTA alone was used as an extractant. When the metal-nitrate spiking concentrations was lowered to 5000 mg/kg, the percent removals for all the metals were generally less than 30%. The presence of water in the soil at the start of extraction significantly reduced the removals of all the metals except cadmium. Overall, ammonia extract of toxic metals does not appear promising for complete site cleanup. However, to determine the practical effectiveness of ammonia extraction as a pretreatment for soil remediation, additional tests need to be performed, and the criterion for success should be a Toxicity Characteristic Leachate Procedure test on the extracted soil.

• OSTI ID: 5956775
• Journal Information: Waste Management; (United States), Vol. 13:3; ISSN 0956-053X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AMMONIA
EXTRACTION
CADMIUM
MATERIALS RECOVERY
COPPER
LEAD
MERCURY
SOILS
DECONTAMINATION
ZINC
EDTA
FEASIBILITY STUDIES
MATERIALS HANDLING EQUIPMENT
REMEDIAL ACTION
AMINO ACIDS
CARBOXYLIC ACIDS
CHELATING AGENTS
CLEANING
ELEMENTS
EQUIPMENT
HYDRIDES
HYDROGEN COMPOUNDS
MANAGEMENT
METALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PROCESSING
SEPARATION PROCESSES
TRANSITION ELEMENTS
WASTE MANAGEMENT
WASTE PROCESSING
540220* - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)