Arsenic remediation of drinking water using iron-oxide coated coal bottom ash

Journal Article · Tue Jun 01 04:00:00 EDT 2010 · Environmental Science and Health

DOI:https://doi.org/10.1080/10934529.2010.500940· OSTI ID:985737

MATHIEU, JOHANNA L; GADGIL, ASHOK J; ADDY, SUSAN E.A.; KOWOLIK, KRISTIN

We describe laboratory and field results of a novel arsenic removal adsorbent called 'Arsenic Removal Using Bottom Ash' (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (~;;$0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community-scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R2 = 0.77) ARUBA's adsorption capacity in treating real groundwater is 2.6x10-6 mol/g (0.20 mg/g). Time-to-90percent (defined as the time interval for ARUBA to remove 90percent of the total amount of arsenic that is removed at equilibrium) is less than one hour. Reaction rates (pseudo-second-order kinetic model, R2>_ 0.99) increase from 2.4x105 to 7.2x105 g mol-1 min-1 as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA's arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA's AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to be less expensive than filtration of micron-scale particles, further contributing to the affordability of a community-scale water treatment center.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Environmental Energy Technologies Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 985737
• Report Number(s): LBNL-3681E
• Journal Information: Environmental Science and Health, Journal Name: Environmental Science and Health Journal Issue: 11 Vol. 45; ISSN 1093-4529
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ADSORBENTS
ADSORPTION
ARSENIC
ATMOSPHERIC PRESSURE
BANGLADESH
CAPACITY
COAL
COATINGS
DRINKING WATER
FILTRATION
GROUND WATER
IRON
ISOTHERMS
KINETICS
POWER PLANTS
REACTION KINETICS
REMOVAL
WASTES
WATER
WATER TREATMENT
arsenic
Bangladesh
coal bottom ash
drinking water
water contaminants
water treatment