Biosortion of Cr(VI) from Aqueous Solutions Using Chemically Modified Okra Powder
Pages 73-79
Joelington do C. Conceição, Victor Hugo S. Ramos, Edilson de Jesus, Antônio Santos Silva and Antônio Wilson M. de C. Costa

DOI: http://dx.doi.org/10.6000/1927-5129.2014.10.11

Published: 27 March 2014

Abstract: The main objective of this work was to use the okra powder modified with citric acid as biosorbent for the removal of Cr(VI) from aqueous solutions. Samples of Cr(VI) solution were prepared by diluting the 100 ppm solution diluted from the 1000 ppm stock solution prepared with K₂Cr₂O₇. The determination of Cr(VI) was performed spectrophotometrically by the method of complexation with 1,5-diphenylcarbazide, measuring the absorbance at a 540 nm wavelength. The experiments were conducted at 25 ± 1 °C; 2, 5, 7 and 8 initial pH; 10-240 minutes contact time and 0.05 g of adsorbent. The Freundlich and Langmuir models were used to fit the experimental data. The Freundlich model provided R²=0.9599, indicating adsorption on heterogeneous conditions. Analysis of fluorescence of X-rays, SEM and FTIR were used to prove the okra powder efficiency in the removal of Cr(VI) from aqueous solutions.