8 research outputs found
Study on heavy metal adsorption by chitosan biopolymer
Heavy metal pollution is a serious problem to aquatic ecosystems because some of
these metals are potentially toxic even at very low concentrations. Chitosan, a
biopolymer produced from crustacean shells, has applications in various areas,
particularly in drinking water and wastewater treatment due to its ability to remove
metallic ions from solutions. The purpose of this research work was to study the
adsorption of cadmium and lead ions into chitosan, produced from shrimp shells at
the laboratory level. Shrimp type “penaeus monodon” (giant tiger prawn) was used
to synthesis the chitosan. The main characteristic properties such as degree of
deacetylation (DD); the amount of amine groups in chitosan, viscosity, crystallinity
and thermal analysis were done by using Fourier transform infrared spectroscopy,
Brookfield viscometer, X-ray spectroscopy, thermo gravimetric analysis (TGA) and
differential thermal analysis (DTA). Chitosan, with a degree of deacetylation
between 80%- 95% was used in the experimental part and the flake sizes were
smaller than 0.25mm. Experimental work involved the determination of the
adsorption isotherms and kinetic studies for each metallic ion in a batch system.
Effect of Degree of deacetylation (DD) of the chitosan, effect of initial pH of the
metal ion solution, effect of particle size, effect of initial heavy metal concentration,
and effect of chitosan dosage were studied. The results showed that the adsorption
capacity depends strongly on pH of the solution, DD of chitosan and slightly
depends on the particle size. According to the results, pH values at 6.5 for cadmium
and pH values at 4.5 for lead show higher adsorption capacity. High DD chitosan
showed higher adsorption capacity mainly due to the higher number of active amino
groups in high DD sample.
Simplified kinetic models such as pseudo-first-order, pseudo-second-order, Elovich
model and intra-particle diffusion model were used to determine the rate limiting
step. Both linear and non-linear According to the kinetic models pseudo second
order model best described the adsorption process. Both linear and non-linear models
and Elovich model best described the adsorption process. Multilinearity in the
intraparticle diffusion model suggested that the adsorption of heavy metal consists of
two major steps, due to the different pore sizes of chitosan.
Equilibrium experimental data were analyzed by using two different isotherm
models namely, Langmuir and Freundlich. According to the results, adsorption
process of cadmium and lead heavy metals is heterogeneous and multilayer
adsorption as it best fit with the Freundlich isotherm model. According to the
thermodynamic experiments, adsorption process is favorable and physical adsorption
was predominant in the adsorption process. Desorption of the heavy metals was
possible by using different regeneration solutions
Study of Adsorption Characteristics of Cadmium into Chitosan biopolymer to be used for waste water treatments
Pollution by heavy metals is a serious threat to aquatic ecosystems because some of
these metals are potentially toxic even at very low concentrations. Chitosan, a biopolymer produced from crustacean shells, has applications in various areas, particularly in drinking water and wastewater treatment due to its ability to remove metallic ions from solutions. The purpose of this research work was to study the adsorption of cadmium on chitosan produced from shrimp shells at a laboratory level. Chitosan, with a degree of deacetylation of approximately 70%, was used in the experimental part and the flake sizes were smaller than 0.25mm. Experimental work involved the determination of the adsorption isotherms for each metallic ion in a batch system. The resulting isotherms were fitted using Langmuir model and the parameters of the equation were determined. Kinetic studies of adsorption for metallic ions at different concentrations and with different particle sizes were performed in batch system. Simplified models such as pseudo-first-order, pseudo-secondorder, and intra-particle diffusion equations were used to determine the rate controlling step. The results showed that the adsorption capacity depends strongly on pH and on the species of metallic ions in the solution. Batch adsorption experiments were performed at two differentdegrees of deacetylation (DD) values, time period ranging from 15 minutes to 3 hours and pH of solutions ranging from 3 to 7. The study showed that the solution pH strongly affects the adsorption capacity of chitosan
Adsorption of cadmium and lead heavy metals by Chitosan Biopolymer : a study on equilibrium Isotherms and kinetics
Since heavy metal pollution is a significant aspect to aquatic ecosystems, the objective of this research work was to investigate adsorption characteristics of chitosan as an
alternative adsorbent material. In this study, chitosan, synthesized from locally available shrimp type “penaeus monodon” was used to observe adsorption characteristics of
cadmium (Cd) and lead (Pb) heavy metals from aqueous solution. Batch kinetic experiment studies were conducted for changing initial pH, initial concentration of metal ions, particle size and degree of deacetylation (DD) of chitosan. Simplified models such
as, pseudo first order, pseudo second order and intra-particle diffusion models were used to analyze the experimental data. The result showed that the adsorption capacity strongly depends on pH and DD. It was clearly seen that higher adsorption of heavy metals occur at comparatively high pH and high DD. Equilibrium experimental data were analyzed by using two different isotherm models namely, Langmuir and Freundlich. The characteristic parameters for each isotherm and related correlation coefficients were determined by using mathematical modeling software. Isotherms show that adsorption process of Cd
and Pb is a heterogeneous process
Effect of deacetylation conditions on synthesis of chitosan using shrimp type "penaeus monodon"
In this study synthesis of chitosan from shrimp type penaeus monodon and effect of degree of deacetylation
conditions were studied. Chitin was extracted from shrimp shells and deacetylation process was done to
synthesize chitosan under different conditions. Characterization of the synthesized chitosan was done using
Fourier Transmission Infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. The effect of
NaOH concentration, reaction temperature, and reflux time on the deacetylation process was investigated.
Degree of deacetylation of chitosan was determined using infrared spectroscopy technique. Mainly, the
increasing of NaOH concentration, temperature, number of deacetylation time and reflux time can enhance the
degree of deacetylation (DD) of chitosan
Alginate: Pharmaceutical and Medical Applications
Due to their outstanding properties in terms of mild gelation conditions
and simple functionalization, biocompatibility, low toxicity, biodegradability,
non-antigenicity and chelating ability, as well as relatively low cost, alginates have
been widely used in a variety of biomedical applications including tissue engineering
and drug delivery systems. Smart alginate hydrogels for on-demand drug release in
response to environmental stimuli and 3D bioprinting will play an important role in
the future. These and the introduction of appropriate cell interactive features will be
crucial for many tissue engineering applications. The focus of the present chapter is
to highlight the great potential of the alginates as biomaterial for biomedical applications
and to discuss the role that alginate-based materials are likely to play in
biomedical applications in the future.info:eu-repo/semantics/publishedVersio