TY - JOUR
T1 - Lepidocrocite and its heat-treated forms as effective arsenic adsorbents in aqueous medium
AU - Repo, Eveliina
AU - Mäkinen, Marko
AU - Rengaraj, Selvaraj
AU - Natarajan, Gomathi
AU - Bhatnagar, Amit
AU - Sillanpää, Mika
N1 - Funding Information:
Authors thank the TEKES (Finnish Funding Agency for Technology and Innovation) Moniwater project for financial support.
PY - 2012/1/15
Y1 - 2012/1/15
N2 - The aim of this study was to investigate the adsorption potential of heat treated lepidocrocites (γ-FeOOH) towards As(III) and As(V) ions in aqueous solutions. Initially, mesoporous lepidocrocite was synthesized, treated at different temperatures, and characterized using various analytical techniques. During the heating, transformation of lepidocrocite into hematite was observed. The adsorption of As(III) and As(V) was studied by batch experiments and the effects of different operational parameters e.g., adsorbent dose, solution pH, contact time, and the initial concentration of As(III)/(V) (isotherms) were studied. Lepidocrocite treated at 250°C exhibited >99% and 94% adsorption from 50. mg/L As(V) and As(III) solutions, respectively with an adsorbent dose of 2.5. g/L. The highest uptake capacity was obtained for As(III) (55. mg/g) on lepidocrocite without the heat treatment and for As(V) (38. mg/g) on lepidocrocite treated at 250°C, which was assigned to be a mixture of maghemite and hematite. The adsorption kinetic data fitted well with the pseudo-second-order model and the BiLangmuir isotherm had the best applicability to describe the adsorption equilibrium.
AB - The aim of this study was to investigate the adsorption potential of heat treated lepidocrocites (γ-FeOOH) towards As(III) and As(V) ions in aqueous solutions. Initially, mesoporous lepidocrocite was synthesized, treated at different temperatures, and characterized using various analytical techniques. During the heating, transformation of lepidocrocite into hematite was observed. The adsorption of As(III) and As(V) was studied by batch experiments and the effects of different operational parameters e.g., adsorbent dose, solution pH, contact time, and the initial concentration of As(III)/(V) (isotherms) were studied. Lepidocrocite treated at 250°C exhibited >99% and 94% adsorption from 50. mg/L As(V) and As(III) solutions, respectively with an adsorbent dose of 2.5. g/L. The highest uptake capacity was obtained for As(III) (55. mg/g) on lepidocrocite without the heat treatment and for As(V) (38. mg/g) on lepidocrocite treated at 250°C, which was assigned to be a mixture of maghemite and hematite. The adsorption kinetic data fitted well with the pseudo-second-order model and the BiLangmuir isotherm had the best applicability to describe the adsorption equilibrium.
KW - Adsorption
KW - Arsenic
KW - Lepidocrocite
KW - Metal removal
KW - Water treatment
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U2 - 10.1016/j.cej.2011.11.030
DO - 10.1016/j.cej.2011.11.030
M3 - Article
AN - SCOPUS:84455205492
SN - 1385-8947
VL - 180
SP - 159
EP - 169
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
ER -