Influence of chitosan characteristics on polymer properties: II. Platinum sorption properties

Abstract

The sorption of platinum on glutaraldehyde cross-linked chitosan was investigated at pH 2, using several chitosan samples prepared from different origins and characterized by different mol fractions of N-acetylation (F A ). The influence of material conditioning was also tested: chitosan was dissolved and then re-precipitated and/or dried (using either oven-drying or freeze-drying). The influence of the different characteristics and treatments on both sorption isotherms and uptake kinetics was checked. Part I has studied the effect of preparation and source on sample crystallinity. Shrimp chitosan has a greater sorption affinity for platinum than fungal chitosan and squid chitosan respectively. Sorption kinetics were found comparable for fungal chitosan and shrimp chitosan, while diffusion was more restricted in squid chitosan due to the higher crystallinity. Decreasing the F A increased sorption capacity for shrimp chitosan but decreased sorption levels for squid material. While F A did not influence sorption kinetics for shrimp material it strongly decreased kinetics for squid chitosan. The type of drying procedure hardly affected sorption kinetics and isotherms but when a reprecipitation step was included in the preparation procedure, the material had to be freeze-dried to maintain high sorption properties. The freeze-drying did not control sorption performance, except in the case of re-precipitated material.

Metal anion sorption on chitosan and derivative materials: a strategy for polymer modification and optimum use

“…They explained that the aldehyde reaction with amine groups with low cross-linking prevents the formation of closely packed chain arrangements without any significant loss of swelling ability. This crystallinity may be also controlled by (a) the origin (fungal biomass, shrimp shell or squid pen) [37,38] and (b) the extraction procedures of chitin and chitosan from original material. Molybdate sorption properties have been compared for different materials derived from shrimp chitin and a direct correlation was found between the less efficient chitosan samples and those that were characterized by the presence of a peak at 2h ¼ 22°on the X-ray diffraction patterns [17] (Fig.…”

Dispersion of chitosan on perlite for enhancement of copper(II) adsorption capacity

“…Several attempts have been made to chemically modify the structure of chitosan, and its performance has been evaluated through adsorption of heavy metal ions from aqueous solutions. The amine and hydroxyl groups in chitosan allow a variety of chemical modifications [21].…”

Recovery of Metal Ions by Chitosan: Sorption Mechanisms and Influence of Metal Speciation

“…insufficient information on chitosan characteristics (degree of deacetylation), [15] experimental data (particle size for example), or by the selection of inappropriate experimental conditions (sorbent dosage, contact time, pH). Hence, some investigations have been conducted without pH control and led to conclude on high sorption efficiencies while the decrease in metal concentration should be attributed to metal precipitation.…”