Modification of chitosan/calcium alginate/Fe3O4 hydrogel microsphere for enhancement of Cu(II) adsorption

Abstract

Copper in drinking water causes a significant environmental problem. Composite material based on alginate hydrogel has been gaining attention in the field of Cu(II) adsorption. However, alginate-based hydrogel exhibits poor mechanical property and relative low adsorption capacity which limit their application. The present study is devoted to the modification of chitosan/calcium alginate/FeO (CAF) hydrogel microsphere by NaOH solution for enhancement of Cu(II) adsorption. Results reveal that modification of CAF via NaOH solution significantly improves the mechanical strength and Cu adsorption capacity of pristine materials. FTIR and XRD analysis confirms that CAF and newly prepared materials (NACAF) are successfully prepared. SEM and EDX are employed to analyze the surface morphology and elemental composition, respectively, both before and after their loading with Cu. XPS study demonstrates adsorption mechanism is based on chelation and ion-exchange. Compressive stress-strain curves demonstrate NACAF has better mechanical performance than CAF. The adsorption kinetics of the two adsorbents follow a pseudo-second-order model. The equilibrium data were best described by Langmuir isotherm model, and the estimated maximum equilibrium sorption capacity, q ,is 261.31 mg/g for the NACAF, which is larger than that of CAF (145.39 mg/g). Hence, NACAF shows excellent mechanical strength and high sorption capacity for Cu. It has great potential for Cu(II) removal in aqueous solutions.

A Bifunctional Chitosan/Alginate Nanoparticles (CANPs) for Trace Metals Adsorption as well as Antibacterial Polyelectrolyte Complex (PEC) Materials

“…However, after the adsorption process, Zn/CANPs and Cu/CANPs became smoother and less porous. These images demonstrated that metal ions were adsorbed by CANPs through their pores [23]. Furthermore, the ability of CANPs to adsorb metal ions was validated using EDX.…”

Magnetically Recyclable Wool Keratin Modified Magnetite Powders for Efficient Removal of Cu2+ Ions from Aqueous Solutions

“…The effects of the initial Cu 2+ ion concentration on the adsorption capacity of wool keratin modified Fe 3 O 4 powders were determined by adding 0.05 g powders in a series of flasks containing 50 mL Cu 2+ ion solution with various concentrations (5,10,20,30,40, and 50 mg/L) at pH 5. After 90 min adsorption under 293, 303, 313, and 323 K conditions respectively, the supernatants were collected by centrifugation and the residual Cu 2+ ion concentrations were measured.…”

“…The adsorption kinetic behaviors of Cu 2+ ions on the wool keratin modified Fe 3 O 4 powders were determined by using the pseudo-first-order kinetic, pseudo-second-order kinetic, and intra-particle diffusion models, respectively. A total of 0.05 g of powders was placed in a series of flasks containing 50 mL Cu 2+ ion solution at a certain initial concentration (5,10,20,30,40, and 50 mg/L) and a temperature of 293 K. The supernatant in each flask was collected by centrifugation at specific time and the residual Cu 2+ ion concentration was measured. The fitting adsorption models under different initial Cu 2+ ion concentration conditions were shown in Supplementary Materials Figure S4.…”

“…The typical nanomaterial sorbents with magnetic features have been widely studied for the removal of heavy metal species because they have high surface area and are easy to separate from aqueous solutions by applying external magnetic fields [18]. Recently, many magnetite (Fe 3 O 4 ) based adsorbents have been developed by incorporation of chitosan [19], chitosan and calcium alginate [20], chitosan and polyether sulfone [21], polyacrylamidoxime [22], asparagine [23], polyethylenimine [24], ethylenediamine coupled with graphene oxide and chitosan-g-poly(acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid) copolymer [25], TiO 2 and graphene [26], graphene oxide [27], amino acid and graphene oxide [28], carbon [29], polydopamine or polyamidoamine [30], NH 2 -MIL-125 (Ti) [31], organodisulfide [32], curcumin [33], alginate [34], zeolite and cellulose nanofibers [35], and selective adsorbents ethylene diamine tetraacetic acid [36] and N-(trimethoxysilylpropyl) ethylenediamine triacetic acid [37]. For example, the catechol groups of dopamine can integrate with metal ions and increase the hydrophilic ability of asprepared adsorbents [38].…”