Chitosan Resin Research Articles

Preparation of chitosan resin by two-step crosslinking method and its adsorption for palladium in wastewater

To preserve the activity of amine groups on chitosan, chitosan resin (CR) was synthesized using the reversed-phase suspension two-step crosslinking method for the adsorption of palladium from wastewater. The effects of varying the amounts of chitosan, liquid paraffin, ethyl acetate, formaldehyde solution, and epichlorohydrin on the adsorption capacity of CR were investigated using both single-factor experiments and response surface methodology. The preparation conditions for the chitosan resin were optimized, and its adsorption properties were systematically evaluated. The results indicated that CR exhibited a high saturated adsorption capacity for palladium, reaching 195.22 mg·g−1. The adsorption kinetics followed the pseudo-second-order model, while the adsorption isotherms were well described by the Sips model. Thermodynamic analysis demonstrated that the adsorption process was spontaneous and endothermic. Furthermore, CR maintained exceptional stability, with a palladium removal efficiency exceeding 99.8 % even after eight adsorption-desorption cycles. The primary adsorption mechanism is attributed to the interaction between palladium ions and the protonated amino groups of the chitosan resin.

Revisiting the Determination of the Degree of Deacetylation Using Potentiometric Titration: A New Equation for Modified Chitosan.

Chitosan is a biopolymer that can be subjected to a variety of chemical modifications to generate new materials. The properties of modified chitosan are affected by its degree of deacetylation (DDA), which corresponds to the percentage of D-glucosamine monomers in its polymeric structure. Potentiometric titration is amongst the simplest, most readily available, and most cost-effective methods of determining the DDA. However, this method often suffers from a lack of precision, especially for modified chitosan resins. This is in large part because the equation used to calculate the DDA does not consider the molecular weight of the chemically modified monomeric units. In this paper, we introduce a new equation that is especially suited for modified chitosan bearing three different types of monomers. To test this equation, we prepared naphthalene-chitosan resins and subjected them to potentiometric titration. Our results show that our new equation, which is truer to the real structure of the polymeric chains, gives higher DDA values than those of the routinely used equations. These results show that the traditional equations underestimate the DDA of modified chitosan resins.

A New and Rapid HPLC Method to Determine the Degree of Deacetylation of Glutaraldehyde-Cross-Linked Chitosan.

Chitosan is a linear biopolymer composed of D-glucosamine and N-acetylglucosamine units. The percentage of D-glucosamine in the polymeric chain can vary from one sample to another and is expressed as the degree of deacetylation (DDA). Since this parameter has an impact on many properties, its determination is often critical, and potentiometric titration is a common analytical technique to measure the DDA. Cross-linking with glutaraldehyde is one of the most explored modifications of chitosan; however, the determination of the DDA for the resulting reticulated chitosan resins can be challenging. In this paper, we report a new, rapid, and efficient method to determine the DDA of glutaraldehyde-cross-linked chitosan resins via HPLC. This method relies on the use of 2,4-dinitrophenylhydrazine (DNPH) as a derivatizing agent to measure the level of reticulation of the polymer (LR) after the reticulation step. In this study, we prepare three calibration curves (with an R2 value over 0.92) for three series of reticulated polymers covering a large range of reticulation levels to demonstrate that a correlation can be established between the LR established via HPLC and the DDA obtained via titration. The polymers are derived from three different chitosan starting materials. These standard calibration curves are now used on a routine basis in our lab, and the HPLC method has allowed us to change our DDA analysis time from 20 h to 5 min.

Highly effective removal of multi-heavy metals from simulated industrial effluent through an adsorption process employing carboxymethyl-chitosan composites

Monochloroacetic acid precursor-based carboxymethyl chitosan resins were prepared using the chitosan with variant molecular weight. The carboxymethylation assured enhanced active sites on the resin surface, acidic media stability, and henceforth its appropriate constitution to facilitate enhanced multi-heavy metal adsorption-desorption and subsequent regeneration potential. Zn, Pb, and Fe multimetal adsorption properties were investigated. Thereby, kinetic and equilibrium models were sought for their fitness to represent heavy metal sorption data with the preferred complex adsorbate system. The adsorbate system complexity and its constituent co-existing cations significantly influence the sorption characteristics of the mentioned multi-heavy metal ions. The optimal adsorption capabilities for Zn, Pb, and Fe were 238.10 mg g−1, 4.78 mg g−1, and 147.06 mg g−1, respectively. Low-cost acid-base solutions were also considered for the effective regeneration of the resin even after three adsorption-desorption cycles. Prominent findings of the work assured excellent functionality of the carboxymethyl-chitosan resin for the simultaneous lead, iron, and zinc ion elimination from mimicking real-world effluent systems.

Synthesis of carbon disulfide modified chitosan resin and its adsorption properties for palladium(Ⅱ) in wastewater

A novel chitosan resin microsphere (CDCR) adsorbent, which was synthesized by secondary crosslinking and carbon disulfide modification, and was evaluated for its efficacy in recovering palladium from wastewater. The physicochemical properties and adsorption mechanism of CDCR were determined using scanning electron microscope energy dispersive system (SEM-EDS), fourier-transform infrared spectroscopy (FTIR), simultaneous thermal analyzer (TG-DSC), X-ray photoelectron spectroscopy (XPS), etc. The experimental results showed that its saturated adsorption capacity was about 204.34 mg/g. And the adsorption process of Pd(Ⅱ) was found to be in accordance with the pseudo-second-order kinetic model and the Freundlich model. Thermodynamic analysis indicated that the reaction between CDCR and Pd(Ⅱ) was a spontaneous endothermic process. CDCR showed good reusability, maintaining a Pd(Ⅱ) removal efficiency of 99.99% after eight adsorption–desorption cycles. In the multi-ion coexistence solution, CDCR also exhibited excellent selectivity towards Pd(Ⅱ) adsorption. Furthermore, the adsorption of Pd(Ⅱ) by CDCR was primarily attributed to electrostatic interaction with protonated amine groups and complexation with sulfur groups.

Selective purification of quercetin using covalently crosslinked chitosan

AbstractQuercetin is known for potent biomedical applications and selective purification of quercetin is the need of the hour. To achieve selective adsorption of quercetin, we have prepared chitosan resin grafted with quercetin. Chitosan is a polysaccharide that is derived from chitin. The shells of shrimp, crabs, and lobster are crucial for the extraction of chitin. After cellulose, chitin was the second most abundant polysaccharide and chitosan was derived by deacetylation of chitin. Chitosan was justified to be a better bio‐adsorbent because of its low cost and outstanding chelating efficiency. Chitosan was covalently cross‐linked to improve its mechanical stability. Herein, Quercetin grafted chitosan resin (QICR) was prepared, where adsorption occurs by hydrophobic interaction between 2‐phenyl‐chromones structure in resin and quercetin in bulk solution. Prepared QICR was characterized using Fourier Transform Infrared Spectroscopy (FTIR) for confirmation of quercetin grafted in chitosan. The porosity of the prepared resin was confirmed by Brunauer‐Emmett‐Teller (BET) and Scanning Electron Microscopy (SEM) analysis. The adsorption capacity of QICR was calculated for both static and dynamic modes and it was found to be approximately equal. The equilibrium data obtained from the adsorption studies were analyzed for isotherm models. Prepared QICR fits better with Langmuir adsorption isotherm with an R2 value of 0.98. Quercetin adsorption was analyzed for kinetic studies, in which pseudo‐second order describes the adsorption. The desorption capacity of quercetin was also calculated in dynamic mode. The present study reveals that prepared QICR would be a better choice for the selective adsorption of quercetin.

A natural composite and nanocomposite of luffa fibers and chitosan resin under mechanical tests

This article introduces natural composite and nanocomposite panels of Luffa fibers–chitosan resin; and they are subjected to quasi-static penetration tests and compression experiments to discuss their penetration resistance and compression strength. Natural fibers of Luffa cylindrical sponge were used as the reinforcement and natural chitosan resin was produced from shrimp shells. Specimens with various characteristics were produced through hand layup method and they were subjected to penetration test of a blunt-nose punch. Results demonstrated that there is an optimum mass fraction for chitosan and magnetite nanoparticles to achieve the highest penetration strength; and the best layer configuration is as 0 and 90°, alternately. Furthermore, some glass-chitosan composite panels were produced and comparison of their penetration tests and the corresponding Luffa-chitosan composite experiments demonstrated that in a certain condition, the maximum loads of penetrating the punch into the both composite panels are the same. In second type experiments, quasi–static compression tests were performed on some cubic Luffa–chitosan specimens and results showed that the natural composite cube has significant specific absorbed energy; and by selecting its suitable dimensions, a natural energy absorber can be achieved. Development of the natural Luffa–chitosan composite is suggested, based on sustainability considerations; and using it in the bulletproof vests and armors is presented as a creative idea; due to its natural structure, compatibility with human skin, acceptable resistance against the penetration, its biodegradable ability and simple and low cost production process.

Synthesis and characterization of cross linked N-methylene phosphonic chitosan resin chelated with Al(III) for use as adsorbent for fluoride removal from aqueous solutions

Synthesis and characterization of cross linked N-methylene phosphonic chitosan resin chelated with Al(III) for use as adsorbent for fluoride removal from aqueous solutions

Mechanism of selective gold adsorption on ion-imprinted chitosan resin modified by thiourea

Thiourea-modified chitosan-imprinted resin (IM-TUCS) and a corresponding nonimprinted resin (NIM-TUCS) were synthesized and characterized using adsorption experiments. The adsorption results showed that adsorption reached equilibrium within 4 h. The adsorption data were better fitted using the Langmuir model (R2>0.99), and the gold adsorption capacities of IM-TUCS and NIM-TUCS were 933.2 and 373.7 mg·g−1, respectively. The IM-TUCS adsorbent was more suitable for gold than other coexisting anions and cations. The possible mechanism underlying Au(Ⅲ) adsorption on IM-TUCS was further investigated using X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction analyses. The protonation of the amino group on the resin under low pH conditions promoted Au(Ⅲ) adsorption; O, N and S in the C‒OH, C˭S and C-NH2 groups contained in the IM-TUCS coordinated with Au(III) ions. The cross-linking of the imprinted resin provided holes that could hold Au(III), thus the imprinted resin supported more Au(III). The adsorption capacity of the IM-TUCS for Au(III) was significantly higher than that of the NIM-TUCS, which is attributed to the cross-linking of the imprinted resin. Moreover, the IM-TUCS showed specific recognition capabilities for Au(III). After elution with the eluent, IM-TUCS was reused for four cycles with a gold recovery rate of approximately 93%, revealing its high potential economic value.

Removal of cadmium from aqueous solution using modified magnetic glycine modified cross-linked chitosan resin

In the present study, the adsorption of Cd(II) ions onto magnetic glycine modified crosslinked chitosan (MGMCR) resin has been investigated. Batch experiments were performed to study the effect of some parameters such as the initial Cd(II) concentration, pH value of the solution, adsorbent dose and the contact time on the adsorption process. The optimal pH for the adsorption of Cd(II) was found to be at 5 and the equilibrium was accomplished within 120 minutes. The result obtained from equilibrium adsorption studies are fitted in Langmuir and Freundlich adsorption models and the data was found to agree well with the Langmuir model. The maximum uptake was found to be 172 mg g-1 at 25 0C at pH 5.

Adsorption of Bovine Serum Albumin onto Tannic Acid-Immobilized Chitosan Resin

A novel tannic acid-immobilized chitosan resin (TICR) was prepared by Mannich reaction for the adsorption of proteins. The physical properties of TICR were characterized and the effects of contact time, pH, and initial concentration of (bovine serum albumin) BSA on its adsorption by TICR were investigated. The Langmuir isotherm model was applied to describe the adsorption isotherm. The equilibrium data are fitted to the Langmuir isotherm model. The maximum monolayer BSA adsorption capacities of TICR were found to be 1.094, 1.487, and 1.694 mg/g at 298, 308, and 318 K, respectively. Furthermore, the data were analyzed on the basis of pseudo-first order, pseudo-second order, and intraparticle diffusion models. The correlation results suggested that the pseudo-second order model fitted the experimental data very well. The thermodynamic study indicated that the adsorption process of BSA onto TICR was endothermic, and the Gibbs free energy (ΔGo), enthalpy (ΔHo), and entropy (ΔSo) of the adsorption process were calculated according adsorption isotherm data. TICR could be reused for 10 times with only 19 % loss of adsorption capacity for BSA.

Synthesis of triethylene tetramine-modified water-insoluble corn flour caged in magnetic chitosan resin and its adsorption application for removal of patulin from apple juice.

In this study, triethylene tetramine-modified water-insoluble corn flour caged in magnetic chitosan resin (TETA-WICF/MCR) was firstly prepared, which indicates novel aspects for immobilization and chemically modification of mycotoxin adsorbents. The TETA-WICF/MCR was characterized using zoom stereo microscope, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometer (XRD), and magnetic separation performance analysis. Experimental results confirmed successful layer by layer modification of chitosan, biosorbent water-insoluble corn flour (WICF), TETA onto the surface of magnetic beads. The mean diameter of the TETA-WICF/MCR was 2.63mm with good magnetic-responsive ability. Subsequently, the adsorption performance of the TETA-WICF/MCR obtained toward patulin was assessed in batch adsorption system and the results demonstrated that the adsorption process was strongly depended on adsorbent dosage, contact time, temperature, and initial patulin concentration. The results of SEM images and FTIR analysis showed obvious changes in the porous structure of TETA-WICF/MCR after adsorbing patulin, and -NH2 and -OH groups were predominantly involved in the adsorption of patulin. Furthermore, the adsorption kinetics followed the mechanism of pseudo-second-order model, and equilibrium data were well fitted in the Freundlich isotherm model. It was also found that the TETA-WICF/MCR had good reusability without any adverse changes in apple juice. PRACTICAL APPLICATION: Patulin is a regulated toxin biosynthesized by certain fungi that contaminate agricultural commodities, such as fruits, juices, and other beverages. Several approaches have been studied to reduce patulin levels in apple juice and other aqueous systems. There is need for more low-cost and eco-friendly adsorbent capable of detoxifying patulin contaminated. In this sense, triethylene tetramine-modified water-insoluble corn flour caged in magnetic chitosan resin (TETA-WICF/MCR) was first prepared and exhibits easy solid-liquid separation and high adsorption capacity for removing patulin from contaminated apple juice.

Effect of aliphatic diamine spacer length on enzymatic performance of myrosinase immobilized on chitosan microsphere and its application for sulforaphene production

Glucosinolates can be hydrolyzed by the enzyme commonly known as myrosinase (E.C. 3.2.1.147) to a variety of biological compounds. Myrosinase (MYR) has been immobilized through the flexible spacers of different length on cross-linked chitosan resin (CCR). Ethylene diamine, hexamethylenediamine and decamethylene-diamine have been separately used as spacers. The influence of the flexible spacer length on the immobilized MYR (IMYR) properties were evaluated. The optimum pH and Vmax of IMYR linearly increase with the flexible spacer length, and the optimum temperature and Km of IMYR show an opposite trend. The recyclability of IMYR was good, with 90% recovery of activity after 10 cycles and 80% recovery after 30 cycles. IMYR was highly stable under storage conditions, with 95% recovery of activity after one year storage at 4 °C. The IMYR with the longest flexible spacer, decamethylene-diamine, was used as a biocatalyst for sulforaphene production. The overall hydrolysis ratio of glucoraphenin was 93.25 ± 0.91% and the activity of DDMCCR-IMYR remained 95% after 10 days of continuous use.

Adsorption of chromium(VI) from aqueous solution by glycine modified cross-linked chitosan resin

The adsorption of Cr(VI) onto glycine-modified crosslinked chitosan (GMCCR) resin has been investigated. Batch experiments were performed to examine kinetics, adsorption isotherm, pH effect, and thermodynamic parameters. The effect of pH for the adsorption of Cr(VI) was studied at range from 2 to 6 and the equilibrium was accomplished within 150 minutes and maximum removal was achieved under the optimum conditions at pH 3 . The result obtained from equilibrium adsorption studies are fitted Langmuir and Freundlich adsorption models and the data was found that the equilibrium data agreed very well with the Langmuir model . The maximum uptake was found to be 1.5 mmol/g (calc 1.75 mmol/g) at 250C. Thermodynamic parameters for the adsorption system were determined at 298 K, 308 K and 318 K (ΔH° =22.85 kJ•mol−1；ΔG° = −33.17 to −36.93 kJ•mol−1 and ΔS° = 188 J•K−1•mol−1). The positive values of ΔH° and ΔS° suggest an endothermic reaction and increase in randomness at the solid-liquid interface during the adsorption. The negative values of ΔG° indicating a spontaneous adsorption process. The kinetic process was described very well by a pseudo-second-order rate equation.

A novel route for the removal of Cu(II) and Ni(II) ions via homogeneous adsorption by chitosan solution

Abstract An easy and efficient homogeneous adsorption of chitosan for metal ions in a single and binary metal ion systems was investigated. The chitosan solution was firstly mixed into the metal ion solution to quickly chelate metal ions. Then chitosan-metal ion nanoparticles were formed when sodium phytate was added into mixed solution and finally separated by centrifugation. The homogeneous adsorption properties of chitosan for Cu(II) and Ni(II) ions under different adsorption conditions were investigated in detail. The adsorption of Cu(II) and Ni(II) followed the Langmuir model and the pseudo-second order kinetic model. The maximum adsorption capacities for Cu(II) and Ni(II) ions, were 405 and 315 mg/g, respectively, initial concentration 1000 mg/L of Cu(II) or Ni(II) ions, pH 5.2, and temperature 30 °C. These values were five and eight times as much as pure chitosan resin reported, showing a high performance/price ratio although no regeneration. Phosphorus atoms were not determined in the liquid supernatant by ICP though addition of sodium phytate, suggesting no secondary pollution occurred after addition of sodium phytate. These results demonstrated that the homogeneous adsorption of chitosan solution for metal ions was a promising clear production process.

Effects of hydrophilic/hydrophobic surfaces on polymer‐complexation kinetics

ABSTRACTTo establish hydrophilic/hydrophobic effects on polymer‐complexation kinetics, chitosan resins were prepared by radical copolymerization of methacryloyl‐modified chitosans with 2‐hydroxyethyl methacrylate and/or styrene monomers. The primary particles of the gelled copolymers in the suspensions were nicely solidified by basic coagulation bath to form globular beads. Degree of the hydrophilic/hydrophobic properties was controlled by the copolymerization ratio, and each ion‐adsorption kinetics was evaluated by batch method. The initial rate of adsorption in hydrophilic chitosans was higher than that in hydrophobic chitosans, which was attributed to less thickness of the boundary film. We quantitatively evaluated the rate‐determining steps by the initial‐rate analysis, in which the viscosity of the suspension contributes to the film‐diffusion kinetic resistance. The role of hydrophilic/hydrophobic properties of the resins is reasonably rationalized to the length of the boundary films by considering long‐range interactions between the ion and surface. Our results are robust evidence for the ion‐surface interactions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46493.

Biosorption of beryllium from aqueous solutions onto modified chitosan resin: Equilibrium, kinetic and thermodynamic study

ABSTRACTThe goal of the present work is the recovery of beryllium ion from their solution by modified chitosan hydrogel. Chitosan was chemically cross-linked with glutaraldehyde to prevent its dissolution in aqueous acidic solutions. The obtained chitosan/glutaraldehyde adsorbent was reacted with chloroacetic acid to produce carboxymethyl chitosan (CMC), which was converted into sodium form by reaction with sodium hydroxide solution to increase its hydrophilic properties. The chemically synthesized chitosan adsorbent contains carboxylate group that expected to have a strong affinity to beryllium ions according to the hard-soft acid-base concept by Pearson because that beryllium ion is a hard acid and has smaller ionic radii. The synthesized adsorbent was characterized and its affinity towards beryllium ions was tested. The different experimental parameters including pH, beryllium concentration, agitation period and temperature were studied to optimize the biosorption process. The maximum biosorption values of beryllium species on the investigated biosorbent are 44.96 and 36.72 mg/g at pH 1 and 5, respectively. Kinetics and thermodynamic parameters of the biosorption process were evaluated from kinetic and biosorption experiments. The adsorbed beryllium species were eluted with a 3 M H2SO4 solution.

Hierarchical porous nitrogen-doped carbon beads derived from biosourced chitosan polymer

Carbon microbeads with diameters of a few hundreds of microns are produced by dropping chitosan acetate (CA) solution in liquid nitrogen, freeze drying and thermal treatment in inert atmosphere at 700 °C. The structure of the beads is characterized by hierarchical porosity at the three length scales: (i) macropores originating from the phase separation during the water ice crystal grow inside the droplets, immersed in liquid nitrogen, (ii) mesoporores arising in course of the beads thermal treatment, leading to the removal of the porogen molecules (Pluronic F127) added to the CA solution and (iii) micropores induced by the carbonization of chitosan resin. The carbon beads have a rigid skin which present wrinkles with well-defined structure.The carbon bead pore size and volume could be tuned with glyoxal and glyoxylic acid which are able to cross-link in a different manner with chitosan as showed by 13C NMR. The beads are produced by a green process employing entirely biosourced and renewable materials that make them attractive for the large scale applications requiring nanoporous carbons.

Coagulation of Chitosan Solution in Commercial Detergent as Adsorbent for Sorption Methylene Blue Dye

The chitosan resin forming with commercial detergent solution was used as adsorbent for removal of the methylene blue. The effect of the amount of adsorbent was thoroughly investigated through batch adsorption system. The percent adsorption of methylene blue increased in the same direction as the amount of chitosan resin. The experimental result showed that adsorption capacity onto 0.4 g of chitosan resin was 9.1 mg/g. The Langmuir and the Freundlich adsorption isotherms were applied to describe the methylene blue uptake, which could be explained by Freundlich adsorption isotherm onto chitosan resin. Single-state batch adsorption design of methylene blue onto chitosan resin has been studied, using on the Freundlich isotherm equation.

Adsorption of Nitrates Using Quaternized Chitosan Resin

Preparation of a terpolymer of melamine-gluteraldehyde cross linked chitosan was attempted. The resin was quaternized with Tetramethyl ammonium chloride (TMAC) to form Quaternized Melamine-Gluteraldehyde- Chitosan Resin (QMGCR), which was used for the selective adsorption of nitrate from contaminated water. Prepared resin was characterized using FTIR and optimization adsorption conditions were done by batch method. Adsorption of nitrate to the resin was confirmed by FTIR analysis of the adsorbed resin and UV-Vis analysis of the left solution. Resin showed an adsorption capacity of 117.6 mg/g from 1000 mg/mL solution of nitrate. Adsorption capacity was also tested with water samples collected from four nearby rivers and the resins adsorption capacity was not much affected. Resin was regenerated and tested adsorption capacity up to 5 cycle. The Cl¯ ions of quaternized resin was replaced by nitrate ions through selective adsorption and exchange mechanism