Application of nanochitosan and chitosan particles for adsorption of Zn(II) ions pollutant from aqueous solution to protect environment

Developing nano-micro size chitosan beads using imidazolium-based ionic liquid: A perspective

The aggressive search for unique materials in recent years has put forward chitosan and modified-chitosan as materials with unique structural and morphological characteristics for various important applications. Just as imidazolium-based ionic liquids are the commonly applied ionic liquids (ILs) type for chitosan modifications for various applications, their further modifications into beads for enhancing their properties is now gaining most attention. However, most of the currently prepared imidazolium ILs modified-chitosan beads are not in nano size due to preparation difficulties. In response to this and referencing the research works in the literature, the possible breakthrough directions including synthesis routes, and physical and mechanical transformation processes are proposed. These procedures are expected to provide certain theoretical and empirical basis, as well as technical guide for developing nano-micro size chitosan beads using imidazolium based ILs.

Development of a New Eco-Friendly Copolymer Based on Chitosan for Enhanced Removal of Pb and Cd from Water

Worldwide, concerns about heavy metal contamination from manmade and natural sources have increased in recent decades. Metals released into the environment threaten human health, mostly due to their integration into the food chain and persistence. Nature offers a large range of materials with different functionalities, providing also a source of inspiration for scientists working in the field of material synthesis. In the current study, a new type of copolymer is introduced, which was synthesized for the first time by combining chitosan and poly(benzofurane-co-arylacetic acid), for use in the adsorption of toxic heavy metals. Such naturally derived materials can be easily and inexpensively synthesized and separated by simple filtration, thus becoming an attractive alternative solution for wastewater treatment. The new copolymer was investigated by solid-state nuclear magnetic resonance, thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photon electron microscopy. Flame atomic absorption spectrometry was utilized to measure heavy metal concentrations in the investigated samples. Equilibrium isotherms, kinetic 3D models, and artificial neural networks were applied to the experimental data to characterize the adsorption process. Additional adsorption experiments were performed using metal-contaminated water samples collected in two seasons (summer and winter) from two former mining areas in Romania (Roșia Montană and Novăț-Borșa). The results demonstrated high (51–97%) adsorption efficiency for Pb and excellent (95–100%) for Cd, afttr testing on stock solutions and contaminated water samples. The recyclability study of the copolymer indicated that the removal efficiency decreased to 89% for Pb and 58% for Cd after seven adsorption–desorption cycles.

Research progress of adsorption and removal of heavy metals by chitosan and its derivatives: A review

Chitosan has received widespread attention as an adsorbent for pollutants because of its low cost and great adsorption potentials. Chitosan has abundant hydroxyl and amino groups that can bind heavy metal ions. However, it has defects such as sensitivity to pH, low thermal stability, and low mechanical strength, which limit the application of chitosan in wastewater treatment. The functional groups of chitosan can be modified to improve its performance via crosslinking and graft modification. The porosity and specific surface area of chitosan in powder form are not ideal, therefore, physical modification has been attempted to generate chitosan nanoparticles and hydrogel. Chitosan has also been integrated with other materials (e.g. graphene, zeolite) resulting in composite materials with improved adsorption performance. This review mainly focuses on reports about the application of chitosan and its derivatives to remove different heavy metals. The preparation strategy, adsorption mechanism, and factors affecting the adsorption performance of adsorbents for each type of heavy metal are discussed in detail. Recent reports on important organic pollutants (dyes and phenol) removal by chitosan and its derivatives are also briefly discussed.

Uptake of Pb(II) onto nanochitosan/sodium alginate hybrid beads: Mechanism and kinetics study

Nanochitosan/sodium alginate (NCS/SA) beads were prepared using nanochitosan and alginate as a high-performance absorbent for Pb(II) removal from aqueous solution. The morphology, structure, thermal stability, surface area, and elements present in the NCS/SA beads before and after adsorption were characterized using instrumental techniques like SEM, FTIR, TGA, BET, and EDX analysis, respectively. Various adsorption parameters were studied. The results indicated that the equilibrium adsorption data were fitted to Langmuir isotherms and the maximum Langmuir monolayer capacity of Pb(II) was 178.57 mg/g at 45°C. The adsorption process was in good agreement with pseudo-first-order kinetic model. Mechanism studies showed that electrostatic interaction and ion exchange were the major mechanisms for lead (II) removal by the NCS/SA beads. The results of this study indicate that NCS/SA beads could be used as an effective adsorbent for the elimination of lead (II) present in aqueous solution. PRACTITIONER POINTS: Nanochitosan/sodium alginate beads were synthesized using Ca²⁺ as a crosslinking agent. NCS/SA beads were used to remove Pb(II) for the first time and working parameters were optimized. Adsorption monolayer capacity of NCS/SA adsorbent towards Pb (II) was found to be 178.57 mg/g.

Extraction and characterization of chitin and chitosan: applications of chitosan nanoparticles in the adsorption of copper in an aqueous environment

The main objective of the present work is to develop and characterize a new generation of adsorptive gelled porous bead supports made from nanoparticles of chitosan, bentonite and alginate. There were subsequently used in the purification of water synthetically polluted with cupric ions. The multiple experiments carried out on the adsorption of copper resulted in an equilibrium time reached after 10 min with an elimination percentage of 86%. Adsorption kinetics is better described by the expression of the second-order model whereas the adsorption isotherm is satisfactorily described by the Freundlich model. The different results showed the high affinity of the nanoparticle composite beads of chitosan/bentonite/alginate to cupric ions in an aqueous solution which is probably due to the presence of various chelating agents such as “NH, OH, COO−, and O” in their structure.