Macroscopic and spectroscopic investigation of interactions of arsenic with synthesized pyrite

Show simple item record

dc.contributor.advisor Batchelor , Bill en_US
dc.contributor.committeeMember Autenrieth , Robin en_US
dc.creator Kim , Eun Jung en_US 2010 -01 -15T00 :05 :02Z 2014 -02 -19T19 :34 :30Z 2010 -01 -15T00 :05 :02Z 2014 -02 -19T19 :34 :30Z 2008 -12 en_US 2009 -05 -15 en_US
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /ETD -TAMU -3138
dc.description.abstract Sulfide minerals have been suggested to play an important role in regulating dissolved metal concentrations in anoxic environments . Pyrite is the most common sulfide mineral and it has shown an affinity for arsenic , but little is known about the arsenic retention mechanisms of pyrite . In this study , interactions of arsenic with pyrite were investigated in an anoxic environment to understand geochemical cycling of arsenic better and to predict arsenic fate and transport in the environment better . A procedure using microwaves was studied to develop a fast and reliable method for synthesizing pyrite . Arsenic -pyrite interactions were investigated using macroscopic (solution phase experiments ) and microscopic (X -ray photoelectron spectroscopic investigation ) approaches . Pyrite was successfully synthesized within a few minutes via reaction of ferric iron and hydrogen sulfide under the influence of irradiation by a conventional microwave oven . The SEM -EDX study revealed that the nucleation and growth of pyrite occurred on the surface of elemental sulfur , where polysulfides are available . Compared to conventional heating , microwave energy results in rapid ( < 1 minute ) formation of smaller particulates of pyrite . Higher levels of microwave power can form pyrite even faster , but faster reaction can lead to the formation of pyrite with defects . Arsenic removal by pyrite was strongly dependent on pH and arsenic species . Both arsenite (As (III ) ) and arsenate (As (V ) ) had a strong affinity for the pyrite surface under acidic conditions , but As (III ) was removed more effectively than As (V ) . Under acidic conditions , arsenic removal continued to occur almost linearly with time until complete removal was achieved . However , under neutral to alkaline conditions , fast removal was followed by slow removal and complete removal was not achieved in our experimental conditions . A BET isotherm equation provided the best fit to arsenic removal data , suggesting that surface precipitation occurred at high arsenic /pyrite ratio . The addition of competing ions did not substantially affect the ultimate distribution of arsenic between the pyrite surface and the solution , but changing pH affected arsenic stability on pyrite . X -ray photoelectron spectroscopy revealed that under acidic conditions , arsenic was removed and formed solid phases similar to As2S3 and As4S4 by reaction with pyrite . However , under neutral to alkaline conditions , arsenic was removed and formed As (III ) -O and As (V ) -O surface complexes , as well as As2S3 /As4S4 -like precipitates . As pH increases , the amount of arsenic that formed As2S3 /As4S4 -like precipitates decreased , while the amount that formed As (III ) -O and As (V ) -O surface complexes increased . Under alkaline conditions , a FeAsS -like phase was also detected . en_US
dc.format.medium electronic en_US
dc.format.mimetype application /pdf en_US
dc.language.iso en _US en_US
dc.subject arsenic en_US
dc.title Macroscopic and spectroscopic investigation of interactions of arsenic with synthesized pyrite en_US
dc.type Book en
dc.type.genre Electronic Dissertation en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US


Macroscopic and spectroscopic investigation of interactions of arsenic with synthesized pyrite. Available electronically from http : / /hdl .handle .net /1969 .1 /ETD -TAMU -3138 .

Files in this item

Files Size Format View

There are no files associated with this item.

This item appears in the following Collection(s)

Show simple item record

Search DSpace

Advanced Search