XANES | An-Najah Staff

Determination of Adsorption and Speciation of Chromium Species by Saltbush (Atriplex ‎Canescens) Biomass using a Combination of Xas and Icp–Oes

Tue, 2015-02-10 15:13 — Maather Sawalha

Journal Title, Volume, Page:

Microchemical Journal Volume 81, Issue 1, Pages 122–132

Year of Publication:

2005

Link:

http://www.sciencedirect.com/science/article/pii/S0026265X05000196

Authors:

Maather F. Sawalha

Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968-0513, USA

Current Affiliation:

Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine

[email protected]

J.L. Gardea-Torresdey

Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968-0513, USA

J.G. Parsons

Department of Chemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968-0513, USA

Geoffrey Saupe

Department of Chemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968-0513, USA

J.R. Peralta-Videa

Department of Chemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968-0513, USA

Preferred Abstract (Original):

Studies were performed to determine the effect of pH on chromium (Cr) binding by native, esterified, and hydrolyzed saltbush (Atriplex canescens) biomass. In addition, X-ray absorption spectroscopy studies were performed to determine the oxidation state of Cr atoms bound to the biomass. The amounts of Cr adsorbed by saltbush biomass were determined by inductively coupled plasma–optical emission spectroscopy (ICP–OES). For Cr(III), the results showed that the percentages bound by native stems, leaves, and flowers at pH 4.0 were 98%, 97%, and 91%, respectively. On the other hand, the Cr(VI) binding by the three tissues of the native and hydrolyzed saltbush biomass decreased as pH increased. At pH 2.0 the stems, leaves, and flowers of native biomass bound 31%, 49%, and 46%, of Cr(VI), respectively. The results of the XAS experiments showed that Cr(VI) was reduced in some extend to Cr(III) by saltbush biomass at both pH 2.0 and pH 5.0. The XANES analysis of the Cr(III) reaction with the saltbush biomass parts showed an octahedral arrangement of oxygen atoms around the central Cr(III) atom. The EXAFS studies of saltbush plant samples confirmed these results.

Removal of Cadmium from Contaminated Waters Using Saltbush (Atriplex Canescens) Biomass: Identification of Cd Binding Sites

Tue, 2015-02-10 10:55 — Maather Sawalha

Journal Title, Volume, Page:

International Journal of Environment and Pollution, Volume 34, Pages 28-42

Year of Publication:

2008

Link:

http://inderscience.metapress.com/content/8381j038543013qk

Authors:

Maather F. Sawalha

Environmental Science and Engineering PhD Program, University of Texas at El Paso, El Paso, 79968 TX, USA

Current Affiliation:

Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine

[email protected]

Jose R. Peralta-Videa

Chemistry Department, University of Texas at El Paso, El Paso, 79968 TX, USA

Jason G. Parsons

Chemistry Department, University of Texas at El Paso, El Paso, 79968 TX, USA

Jorge H. Gonzalez

Chemistry Department, University of Texas at El Paso, El Paso, 79968 TX, USA

Jorge L. Gardea-Torresdey

Environmental Science and Engineering PhD Program, and Chemistry Department, University of Texas at El Paso, El Paso, 79968 TX, USA

Preferred Abstract (Original):

The effect of pH on Cd(II) binding capacity of saltbush biomass was determined. Metal quantification performed using ICP/OES showed that Cd binding increased as pH increased from 2.0 to 5.0. The highest percentage of Cd bound ranged from 74-81%, 22-40%, and 70-80% for the native, esterified, and hydrolysed biomass. XAS studies showed that cadmium was present as Cd(II) and oxygen was the nearest neighbouring atom with bond lengths of approximately 2.3 Å and coordination numbers ranging between 4 and 5. Results indicated that carboxyl groups may be the primary ligand involved in the Cd binding by saltbush biomass.