Environmentally benign modified biodegradable chitosan for cation removal

Abstract

The biodegradable biopolymer chitosan had its linear structure chemically modified in a two-step reaction, first by exploring the amino reactivity with glycidylmethacrylate, whose intermediate product, containing an aldehyde group, was then reacted with 1,2-ethanedithiol. Chitosan and the synthesized biopolymers were characterized by elemental analyses, infrared spectroscopy, nuclear magnetic resonance of the carbon nucleus in the solid state, X-ray diffractometry, thermogravimetry and scanning electron microscopy, to give a degree of immobilization of 3.00 mmol g -1 . The available basic nitrogen, sulfur and oxygen Lewis centers attached to the enlarged pendant chains enriched the ability of the biopolymer for copper, lead and cadmium sorption from aqueous solution, to give maximum capacities of 2.05 ± 0.01; 2.53 ± 0.02 and 1.88 ± 0.01 mmol g -1 , when compared to chitosan with 1.54 ± 0.33; 1.22 ± 0.04 and 1.12 ± 0.08 mmol g -1 , respectively, using the Langmuir sorption isotherms. Based on the present results, the highest amount of these cation sorptions, especially with lead that is associated with sulfur-cation soft interactions, is dependent directly on not only the presence of long pendant chain attached, but also the availability of favorable Lewis base centers. The experimental data adjusted to the Langmuir, the Freundlich and the Temkin sorption isotherms using linear and non-linear regression methods and are in agreement with the best fit for Langmuir model type I.

Chitosan-Based Bio-Composite Modified with Thiocarbamate Moiety for Decontamination of Cations from the Aqueous Media

“…The anchoring of thiocarbamate moiety to the chitosan (CH) pendant chain was confirmed by determining the sulfur, carbon, and nitrogen content of the modified chitosan. The percentage, quantity L o (mmol g −1 ), and C/N of these elements were determined using Equation (1) [31], as shown in Table 1. The presence of sulfur contents (1.24 mmol g −1 ) based on the sulfur elemental analysis in chemically modified chitosan showed the addition of thiocarbamate moiety in the pristine chitosan.…”

Engineering Functionalized Chitosan-Based Sorbent Material: Characterization and Sorption of Toxic Elements

“…The amount of cations on the sorbent increased with time until a dynamic equilibrium was established; this phenomenon is mostly determined from sorption isotherm. In this study, both linear and nonlinear models for Langmuir, Freundlich, and Temkin isotherms were deployed, and the results obtained are summarized in Table 2 [35]. The results showed that the chemically modified chitosan (CH-ANP) has a higher sorption capacity for copper, lead, and cadmium as compared to the pristine chitosan.…”

Novel chitosan/polyurethane/anatase titania porous hybrid composite for removal of metal ions waste

“…Biopolymers, especially polysaccharides, are low cost and non‐toxic adsorbents because they are biodegradable and, generally, have high adsorption efficiency . All these efforts were focused on individual adsorption materials.…”

“…11 -13 However, some of these methods have difficulties with ions recovery, especially from dilute metal solutions, 14 generation of other waste products 15 or high cost processes. Several materials have been studied for heavy metal ion adsorption, obtaining high efficiency at low cost for pollutants removal; 16 like organic-based adsorbents, zeolites, industrial by-products, and polymeric materials. 17 Biopolymers, especially polysaccharides, 16 are low cost and non-toxic adsorbents because they are biodegradable and, generally, have high adsorption efficiency.…”

“…Several materials have been studied for heavy metal ion adsorption, obtaining high efficiency at low cost for pollutants removal; 16 like organic-based adsorbents, zeolites, industrial by-products, and polymeric materials. 17 Biopolymers, especially polysaccharides, 16 are low cost and non-toxic adsorbents because they are biodegradable and, generally, have high adsorption efficiency. 14 All these efforts were focused on individual adsorption materials.…”