Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/196632
Type: Artigo de periódico
Title: Evaluation Of Boron Removal From Water By Hydrotalcite-like Compounds.
Author: Ferreira, Odair Pastor
de Moraes, Sandra Gomes
Durán, Nelson
Cornejo, Lorena
Alves, Oswaldo Luiz
Abstract: Layered double hydroxides (LDHs) or hydrotalcite (HT)-like compounds with different kinds of metal ions (Mg-Al and Mg-Fe) in the brucite-like sheets were prepared and their adsorption properties were studied in the boron removal from aqueous solution under laboratory conditions. The hydrotalcites were synthesized by the coprecipitation method and were characterized by chemical analyses, X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR) and specific surface area measurements (BET). The affinity of these materials with a mixture of B(OH)(3) and B(OH)(4)(-) was studied as a function of contact time, initial pH of the solutions, HT quantity and B concentration (adsorption isotherms). It was found that 120 min is enough time for the equilibrium state to be reached in boron adsorption. Boron removal was independent of the initial pH of the solutions because of the high buffering capacity of the LDHs. On the other hand, the adsorption capacity increases with increasing the adsorbent quantity. The adsorption isotherms, described by the Langmuir model, are of L-type, suggesting that B(OH)(4)(-) is adsorbed preferentially on HT-like materials. Besides, Mg-Al hydrotalcites showed higher adsorption capacity than Mg-Fe. We proposed that in Mg-Al hydrotalcites, the boron removal occurs by both adsorption on external surface and ion exchange, whereas for Mg-Fe it occurs only by surface adsorption. After treatment of a solution containing 5.2 mgBl(-1) with Mg-Al hydrotalcites the final boron concentration reached the recommended limit by WHO for drinking water (0.5 mgl(-1)).
Subject: Adsorption
Aluminum Hydroxide
Boron Compounds
Hydrogen-ion Concentration
Kinetics
Magnesium Hydroxide
Water Pollutants, Chemical
Water Purification
Water Supply
Rights: fechado
Identifier DOI: 10.1016/j.chemosphere.2005.04.009
Address: http://www.ncbi.nlm.nih.gov/pubmed/15936056
Date Issue: 2006
Appears in Collections:Unicamp - Artigos e Outros Documentos

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