Enhanced As(V) Adsorption Properties in Sn-Substituted Goethites - Changes in Chemical Reactivity and Surface Characteristics

ANA L. LARRALDE; ANA E. TUFO ; PEDRO J. MORANDO; ELSA E. SILEO

International Journal of Innovative Research in Engineering & Management

International Journal of Innovative Research in Engineering & Management

Lugar: India; Año: 2015 vol. 2 p. 63 - 70

2350-0557

In this work, the adsorption of arsenic (V) onto crystallinesubstituted goethites was studied for samples with different Sncontents.The highest Sn-content of the prepared samples was 5.5(expressed as 100[Sn]/[Sn]+[Fe]) as all attempts to preparegoethites with higher tin content only rendered amorphousmaterials. The Sn-for-Fe substitution caused changes on thephysico-chemical properties of the obtained samples, and thethermal analysis indicated that the formed Sn-goethites weremetal-deficient goethites with increased thermal stabilizationtowards decomposition to hematite. BET surface analysisevidenced the presence of large mesoporous or macroporous in allsamples and the following trend in SSA values: GSn5.5(54.90±0.08) > GSn0 (25.75±0.09) > GSn2.1 (17.19±0.05 m2g-1).The As(V) adsorption presented a maximum at pH = 5.50 ± 0.05for all samples and the data showed that GSn5.5 nearly duplicatesthe amount of As adsorbed per gram of pure goethite. To evaluatethe chemical stability of the samples, dissolution kineticsmeasurements in acidic conditions were also performed.Dissolution rate followed the trend GSn2.1 > GSn0 > GSn5.5.The facts that GSn5.5 dissolves slower than the pure sample andthat adsorbs twice as much as pure goethite indicate that GSn5.5is a promising agent for As(V) removal technologies.