ABSTRACT
Growing human population and industrialization throughout the world have been increasing environmental pollution. Of the pollutants, heavy metals are considered the most problematic (Kandile et al. 2015). Currently, chitin and its derivatives are receiving
29.1 Introduction ................................................................................................................................................................... 403 29.2 Chitin and chitosan polymers..................................................................................................................................... 403
29.2.1 Bioadsorbent potential of chitin and chitosan .............................................................................................. 403 29.2.2 Biomedical application of chitin and chitosan ............................................................................................. 404
29.3 Carbohydrates of marine mollusks and their biological applications .................................................................. 405 29.4 Polymers of sea cucumber and their medicinal property ...................................................................................... 406 29.5 Marine microbial polysaccharides and their biological activities ......................................................................... 406 29.6 Seaweed polysaccharides and their applications ..................................................................................................... 407 29.7 Summary ........................................................................................................................................................................ 409 Acknowledgment ................................................................................................................................................................... 409 References ................................................................................................................................................................................ 409
attention as natural bioadsorbents. Studies with chitin as a biosorbent are fewer than with chitosan, and it is believed that the concentration of primary amine groups of chitosan is the main reason for its metal adsorption capacity, which is characterized through different processes such as cationic (chelation), anionic (electrostatic attraction), or polar interactions (ion-dipole, dipoledipole, van der Waals’ interactions, etc.) (Jose et al. 2010). However, chitin also possesses considerable concentration of primary amine groups even at high degrees of acetylation; this makes chitin a competitive absorbent to other materials (Jose et al. 2010). For example, chitin from the marine sponge A. aerophoba efciently adsorbed uranium content up to 288 mg/g compared to many other types of chitinous sorbents (Schleuter et al. 2013). Similarly, Liu et al. (2013b) investigated the heavy metal removing efciency of chitin microparticles and chitin nanobrils. Their results indicated that chitin nanobrils could more efciently remove heavy metals such as Cd(II), Ni(II), Cu(II), Zn(II), Pb(II), and Cr(III) than chitin microparticles, and they have suggested that the higher adsorption was due to the higher specic surface area and widely distributed pores of the nanobrils.
