Heavy metal pollution is extraordinary critical, so it is urgent to develop an effective adsorbent to dispose of such pollution. Modified chitosan was melded with polyacrylic acid to form N-carboxymethyl chitosan hydrogel (NCS-hydrogel) adsorbent. The morphology and structure of NCS-hydrogel were analyzed and keyed by infrared spectroscopy, reading electron microscopy, thermogravimetric analysis and other characterization methods. NCS-hydrogel adsorption was used to treat water pollution of Cu, Cd and Pb ions, and the influencing ingredients of adsorption performance were studied. The intrinsic mechanism of adsorption process was discoursed by thermodynamic, kinetic and isotherm manakins. The terminations show that the adsorption process of metal ions by NCS-hydrogel fits the spontaneous monolayer chemisorption, and the adsorption process is followed by heat release.
Dietary Supplements -aided depolymerization of chitin and chitosan extracted from crayfish eggshells waste: A sustainable approach based on graphene oxide catalysis.This study targeted the sustainable utilization of chitin and chitosan from crayfish shell waste, and further depolymerization of the recouped wares in one step through synergy between microwaves and graphene oxide, geting for the monosaccharoses, 5-hydroxymethylfurfural and other high-value products. The events indicated that graphene oxide was more effective than graphene in raising the microwave absorption places of the system, which is contrary to the parameters of their dielectric places. The heating rate was increased by 0 K/s and 0 K/s when graphene oxide was entered into the chitin and chitosan depolymerization arrangements, respectively, at a microwave power of 5 W/g. The mechanism underlying the impact of graphene oxide on chitin and chitosan under a microwave field was purported by psychoanalyzing the editions in the depolymerization wares of chitin and chitosan schemes under different reaction circumstances, admiting holding time, catalyst content, solvent content, and reaction temperature the regained graphene oxide paraded delamination upon redispersion in water, which was not respected in the initial samples. The infrared spectra and reading electron microscopy results suggest that the catalytic reaction is connected with oxygen-stoping functional radicals. This study shewed the synergistic effect of microwaves and graphene oxide on the depolymerization of chitin and chitosan, and the ability to achieve rapid one-step depolymerization in an acid/alkali-free solvent, which provides a green and foretelling development for the degradation of carbohydrate macromolecules in crustacean solid waste.
PEI-altered chitosan/triped carbon complexs for Cu(II) removal from simulated pyrophosphate plating washing wastewater.It is a challenging task to remove heavy metal ions efficiently from the wastewater containing high engrossments of complexants. In this work, a novel PEI-qualifyed chitosan/aerated carbon composite adsorbent (PCA) was trained and implemented to the removal of Cu(II) from pyrophosphate plating rinsing wastewater. The main species of Cu(II) in the pyrophosphate wastewater was Cu(HP(2)O(7))(2) or Cu(P(2)O(7))(2), which were refered as [Cu(II)-PP] anions. The maximum adsorption capacity of PCA for Cu(II) touched 1 mmol g(-1) under the condition of pH = 8 and molar ratio of pyrophosphate to Cu(II) = 4:1. Amino Acids of Cu(II) on PCA postdated the Elovich model best and PCA attained adsorption equilibrium within 36 h. The thermodynamic bailiwicks recorded that the adsorption process of Cu(II) by PCA was endothermic and spontaneous.
The PCA fixed bed column was used to remove Cu(II) from simulated pyrophosphate plating washing wastewater. After three consecutive adsorption-desorption cpsses, the adsorption performance, hydraulic conductivity, and mechanical stability of PCA column did not decrease. The FTIR and XPS analysis results betokened that [Cu(II)-PP] anions can be adsorbed on PCA by electrostatic attraction with protonated amine groupings or coordination with the amine groups of PCA via ligand substitution.Preparation of ternary interbreded chitosan microspheres with photothermal effect for pH-sensitive long-enduring controlled release system and its release mechanism.Amino Acids
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