%0 Journal Article
%T Comparative Biosorption Studies of Hexavalent Chromium Ion onto Raw and Modified Palm Branches
%A Mona A. Shouman
%A Nady A. Fathy
%A Soheir A. Khedr
%A Amina A. Attia
%J Advances in Physical Chemistry
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/159712
%X The waste of palm branches (PB) was tested for its ability to remove chromium (VI) from aqueous solution by batch and column experiments. Palm branches chemically modified with an oxidizing agent (sulphuric acid) then coated with chitosan and surfactant (hexadecyl trimethyl ammonium bromide surfactant, HDTMA), respectively, were carried out to improve the removal performance of PB. The results of their Cr (VI) removal performances are pH dependent. The adsorption data could be well interpreted by the Langmuir, Freundlich, and Flory-Huggins isotherm models. The maximum adsorption capacity obtained from the Langmuir model for the chitosan coated oxidized palm branches is 55£¿mg/mg. The adsorption process could be described by pseudo-second-order kinetic model. The intraparticle diffusion study revealed that film diffusion might be involved. The biosorbents were successfully regenerated using 1£¿M HCL solution. 1. Introduction Increased industrialization and human activities have created impact on the environment through the disposal of waste containing heavy metals. Heavy metals are toxic even in extremely minute quantities on human health and to the fauna and flora of receiving water [1]. It is known that legal standards on environment control are becoming strict and, as a result, the discharge of heavy metals into aquatic bodies and sources of potable water is being rigorously controlled. Most heavy metals exist in a cationic form, but Cr (VI) combined with oxygen is anionic in natural aquatic system. The maximum permissible limit of chromium in natural water is only 0.05£¿mg/L by the US Environmental Protection Agency [2]. Acute exposure to Cr (VI) causes nausea, diarrhea, liver, and kidney damage, internal hemorrhage, and respiratory problems [3, 4]. Chromium compounds are widely used in electroplating, metal finishing, magnetic tapes, pigments, leather tanning, wood protection, chemical manufacturing, electrical and electronic equipment, and catalysis [5]. Several treatment technologies have been developed to remove chromium from aqueous phase. Common methods include biosorption [6], ion exchange [7], chemical reduction, ultrafiltration [8], and adsorption [9]. The adsorption process is an effective technique for the treatment of anionic metals. Activated carbon, a representative adsorbent, has been widely used to remove diverse pollutants, including organic pollutants, reactive dyes, cationic heavy metals, and anionic metals from the aqueous phase. Although it is a preferred adsorbent, and its widespread use, it is restricted due to its high cost
%U http://www.hindawi.com/journals/apc/2013/159712/