Graphene Oxide Reinforced Alginate/PVA Double Network Hydrogels for Efficient Dye Removal

Abstract

Dually crosslinked graphene oxide reinforced alginate/polyvinyl alcohol (PVA) double network (DN) hydrogels were prepared via a facile freeze/thaw method followed by soaking in a Ca2+ solution. The morphology and structure of the hydrogels were systematically examined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The effects of pH, dosage of hydrogel, adsorption time, and temperature on the adsorptive property of DN hydrogels towards methylene blue (MB) were also studied. Results indicated that the hydrogels exhibited typical 3D porous structures and had an efficient adsorption effect towards MB due to strong interactions between DN hydrogels and MB molecules. The adsorption isotherm was found to coincide with the Langmuir model with a monolayer adsorption. The highest adsorption capacity of DN hydrogels for MB was examined as 480.76 mg·g−1.

Influence of Magnetic Nanoparticles on Modified Polypyrrole/m-Phenylediamine for Adsorption of Cr(VI) from Aqueous Solution

“…Table S3 shows adsorption kinetic parameters obtained from the linear and nonlinear fitting of the data to the PFO and PSO models. The R 2 values obtained for the linear and nonlinear fittings of the data to the PFO model are lower than those obtained for the PSO kinetic model, suggesting that the adsorption of Cr(VI) onto PPy-mPD/Fe3O4 nanocomposite followed PSO kinetics [25]. Additionally, the obtained qe values for the PSO model were comparable to the qe values obtained experimentally.…”

“…The pH of the solution is the most vital parameter to be considered for the adsorption of heavy metal ions, because it affects the surface charge of the adsorbent, as well as the speciation of the metal ions in solution [25]. Figure 5a shows the effect of pH on the removal efficiency of Cr(VI) by the PPy-mPD/Fe 3 O 4 nanocomposite.…”

“…Furthermore, the larger values of k i suggest that film diffusion is faster, and has a more significant role as the RLS [34,[36][37][38]. In addition, temperature-dependent kinetics data were used to calculate the activation energy (E a ) for Cr(VI) adsorption by the PPy-mPD/Fe 3 O 4 nanocomposite obtained at 15,25,35 and 45 • C, and the results are provided in Table S2. The E a of the adsorption process can be related to the PSOR constant, k 2 (g/mg/min) by the linearised Arrhenius (lnk2 = lnA − E a RT ), T is the temperature T (K), A (g/mg/min) is the frequency factor, R denotes the general gas constant (J/mol/K), and E a (kJ/mol) is the activation energy.…”

Controlled Release of 5‐Fluorouracil from Alginate Hydrogels by Cold HMDSO−Plasma Surface Engineering

“…On the other hand, polyvinyl alcohol (PVA) (Figure c) is a synthetic polymer that has been widely employed in biomedical applications . Integration of PVA and alginate have resulted in the design of smart hydrogel systems for a broad spectrum of applications ranging from agriculture to dye removal, pervaporation, wound dressings, tissue engineering and drug delivery …”

Influence of Process Parameters in Graphene Oxide Obtention on the Properties of Mechanically Strong Alginate Nanocomposites

“…Currently, much effort has been made to improve the performance of alginates. In this sense, the addition of inorganic nanoreinforcements has been demonstrated to be an effective strategy to overcome the disadvantages of alginate [11][12][13], as well as to provide new functionalities. Gholizadeh et al [14] incorporated different contents of hydroxyapatite nanoparticles to alginate and obtained an improvement in physical and mechanical properties, as well as antimicrobial activity, compared to alginate [14].…”