title: Removal of arsenite(As(III)) and arsenate(As(V)) by synthetic pyrite (FeS2): synthesis, effect of contact time, and sorption/desorption envelopes.
abstract: Reliable techniques for synthesizing pyrite are necessary in order to develop effective treatment methods that use pyrite to remove arsenic from water and to stabilize arsenic in wastes. The Fe(3+)/HS(-) values of 0.500 and 0.571 at 60°C and pH values ranging from 3.6 through 5.6 were found to produce pyrite most efficiently. Removal of As(V) was faster than removal of As(III) and the extent of removal of both As(III) and As(V) were more accurately described by the Langmuir adsorption model. Removal of As(III) was observed to increase as pH increased across the range investigated (pH 7-10). However, an optimum pH in the range between pH 8 and pH 9 was observed for removal of As(V). Sorption envelopes for As(III) showed low removal at low pH, increasing removal as pH was increased and moderate irreversibility as pH was titrated backward. Sorption envelopes for As(V) showed similar behavior except low removals were observed initially at high pH, removals increased as pH decreased and moderate to high levels of irreversibility were observed as pH was raised back to the initial values.
authors.affiliation: Chemical Engineering Program, Texas A&M University at Qatar, Education City, PO Box 23874, Doha, Qatar. Electronic address: dong_suk.han@qatar.tamu.edu.
authors.forename: Dong Suk
authors.initials: DS
authors.lastname: Han
authors.affiliation: Chemolee Lab Corporation, Irving, TX 75061, USA.
authors.forename: Jin Kun
authors.initials: JK
authors.lastname: Song
authors.affiliation: Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA.
authors.forename: Bill
authors.initials: B
authors.lastname: Batchelor
authors.affiliation: Chemical Engineering Program, Texas A&M University at Qatar, Education City, PO Box 23874, Doha, Qatar.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Abdel-Wahab
mesh_terms: D000327:Adsorption; D001149:Arsenates / Q000302:isolation & purification*; D018053:Arsenites / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D013440:Sulfides / Q000138:chemical synthesis / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors
chemical_list: D001149:Arsenates; D018053:Arsenites; D013440:Sulfides; C011342:pyrite; D007501:Iron; C015001:arsenite; C025657:arsenic acid