ABSTRACT
Natural polysaccharides form a major class of the most extensively used biopolymers for different applications, one of which includes membrane-based separation. The major advantages offered by these materials for membrane-based separation include the following:
• Hydrophilicity of the polymer owing to the presence of hydroxyl groups present in the glucose units that comprise them
• Presence of large numbers of other functional groups such as carboxyl, amine, and hydroxyl groups
5.1 Introduction .................................................................................................. 161 5.2 Alginic Acid.................................................................................................. 162
5.2.1 Applications of Alginic Acid in Membrane Technology .................. 162 5.2.1.1 Pervaporation ..................................................................... 162 5.2.1.2 Removal of Metal Ions: By Membrane-Based
Separation or by Adsorption .............................................. 164 5.3 Chitosan ........................................................................................................ 165
5.3.1 Application of Chitosan in Membrane Technology .......................... 168 5.3.1.1 Pervaporation ..................................................................... 168 5.3.1.2 Ultraltration and NF Membranes .................................... 170 5.3.1.3 Removal of Metal Ion and Dyes ........................................ 174
5.4 Cellulose ....................................................................................................... 176 5.4.1 Applications of Cellulose in Membrane Technology ....................... 177
5.4.1.1 UF and NF Membrane ...................................................... 177 5.4.1.2 Pervaporation ..................................................................... 179 5.4.1.3 Removal of Metal Ions and Dye from Aqueous
Solutions ......................................................................... 180 5.5 Cyclodextrins ................................................................................................ 181 5.6 Lignins .......................................................................................................... 182 5.7 Conclusions ................................................................................................... 183 References .............................................................................................................. 184
• Flexible structure of the polymer chains and their chemical reactivity • Their abundant occurrence in nature and relatively low cost • Biocompatibility and biodegradability
Over the decades, these environmental-benign materials have been used for the removal of heavy metal ions from industrial wastes, toxic dyes from textile industries, pervaporation, and protein separations. This chapter gives a detailed account of the commonly used biopolymers in membrane technology, including chitosan (CH), alginic acid, and cellulose.
