Characterization and Properties of Chitosan | InTechOpen, Published on: 2011-06-24. Authors: Elson Santiago de Alvarenga

The crosslinked chitosan-Fe(III) (Ch-FeCL) adsorbent was developed using Fe(III) immobilized on chitosan beads. After drying, the beads presented a diameter of approximately 1 mm and are stable in air. The adsorption behavior of As(III) and As(V) on the Ch-FeCL was evaluated at pH 7 by studies conducted in batch and in columns. Maximum adsorption capacities estimated by the Langmuir adsorption model were 21.24 and 27.59 mg g-1 for As(III) and As(V), respectively. Adsorption kinetics is described by the pseudo second order kinetic equation. The results of column adsorption indicated that arsenic was not found in the effluent solution from roughly 60 and 759 bed volumes for As(III) and As(V), respectively. Results were satisfactory when employing the adsorbent for removal of As(III) and As(V) from groundwater, tap water and river water samples.

A comparative study of the chemical composition of essential oils of two very similar species of the Verbenaceae family (Lantana camara and L. radula) revealed that the main components of essential oil of L. camara were germacrene-D (19.8%) and E-caryophyllene (19.7%), while those of L. radula were E-caryophyllene (25.3%), phytol (29.2%) and E-nerolidol (19.0%). We have hypothesized that the observed differences could contribute to the differentiated reaction of the two species of Lantana to the attack of the phytopathogenic fungi Corynespora cassiicola. An experiment, involving C. cassiicola cultivation in culture media containing volatile oils of the two species demonstrated that the oils of L. radula were more fungistatic than the oils of L. camara, in accordance with the in vivo observations. It is likely that E-nerolidol and phytol, only found in the oil of L. radula, play a significant role in the effects of L. radula on C. cassiicola.