Removal Of Heavy Metals From Aqueous Solutions By Novel Melamine Formaldehyde Polyaminopolycarboxylic Acid Chelating Adsorbents

Author : Ahmad Baraka
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (141 download)

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Download or read book Removal of Heavy Metals from Aqueous Solutions by Novel Melamine-formaldehyde-polyaminopolycarboxylic Acid Chelating Adsorbents written by Ahmad Baraka and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The contamination of water recourses by heavy metals is a serious worldwide environmental problem. Industrial activities, mining and coal combustion are typical contamination sources. Removal of these metals from wastewater effluents is crucial as this contamination is non-biodegradable and highly toxic. Extensive research has been carried out to introduce new materials which alleviate these metals from wastewater effluents before their discharge into water bodies such as rivers and lakes. Conventional methods to remove heavy metals from wastewater include chemical precipitation, ion-exchange and chelation-adsorption. Adsorption is an important and developing research area because of the new material types available according to the application. Furthermore, it is standard process to place the adsorbent in a column and pump the wastewater through in a continuous system. It is also a cost-effective process. Chelating adsorbents are typically characterised by functional groups containing 0, N, S, and P donor atoms which coordinate to different heavy metal ions. It is necessary that the adsorbent has a high capacity and that the kinetics of adsorption is sufficiently fast. Polyaminepolycarboxylic (PAPC) acids are strong chelating agents and form stable chelates with different types of metals: transition, lanthanides and actinides. In spite of its exceptional chelating power, many of the PAPC compounds - such as DTPA (8-coordinations), CDTA (6-coordinations) and NTA (4-coordinations) - have not been thoroughly studied for use as active sites in adsorbent materials for heavy metal remediation from contaminated water effluents. Furthermore, the effect of the number of coordination groups on the adsorption behaviour has not been investigated. Use of these strong chelating agents (PAPC) for heavy metal removal by a polymeric adsorbent is presented in this study, with discussion of the chelation mechanism and affinity. The PAPC chelating agents were anchored on melamineformaldehyde (MF) gel. Although MF gel has suitable chemical and physical properties allowing the production of an adsorbent for heavy metal removal, it has not been studied. MF gel is porous and its matrix has a suitable platform to functionalize with some chelating compounds. PAPC-modified melamine-formaldehyde matrix is easy to produce compared to conventional chelating resins based on styrene/divinylbenzene. In this work, melamine-formaldehyde-polyaminepolycarboxylic acid (MF-PAPC) chelating adsorbents were synthesised by anchoring polyaminepolycarboxylic acids (PAPC) to melamine by the reaction of the carboxylic group of PAPC with a primary amine group of melamine forming a covalent amide bond during MF matrix formation.