Functionalization of polyvinyl alcohol hydrogels with graphene oxide for potential dye removal

Abstract

Because of highly frozen macromolecule chains, polyvinyl alcohol (PVA) hydrogels have never been used for dye removal. This work focuses on improving the adsorption capacity of the PVA hydrogel by using amphiphilic graphene oxide to improve its macromolecular chain mobility in crystal domain and introduce new functional groups. To evaluate its effectiveness, crystal structure, swelling kinetics, and model dye methylene blue (MB) adsorption of the as-prepared PVA hybrid hydrogels were systematically investigated. The results indicate that the hybrid PVA hydrogels have lower crystallinity and less crystal stability, demonstrating the improved macromolecular chain mobility. Moreover, improved swelling ratios of PVA/GO hydrogels also illustrate the enhanced macromolecular chain mobility. MB adsorption experiment indicates that GO introduced can result in great improvement in MB adsorption. And the adsorption process follows the second-order kinetic model and Morris-Weber model, which is determined by the intraparticle diffusion. Furthermore, MB adsorption isotherm follows Freundlich model and the adsorption is heterogeneous. Desorption studies indicate that the interaction between PVA hydrogels and MB consists of both physisorption and chemisorption.

Influence of natural and synthetic crosslinking reagents on the structural and mechanical properties of chitosan-based hybrid hydrogels

“…Ogawa et al (1992) reported that the first two peaks correspond to a hydrated form of CS. The diffraction pattern of PVA presented peaks at 2θ values of 12 • , 20 • , 23.4 • and 41 • ; these peaks corresponded to 350 diffraction planes of (100), (101), (200) and (111), respectively, according to Hyon et al (1975) and Li et al (2014). From the X-ray diffraction pattern located in the middle of Fig.2c), it can be observed that the peak associated with CS (at 10 • ) disappeared; in addition, the full width at half maximum (FWHM) of the peaks close to 20 • increased.…”

“…Nevertheless, PVA is soluble in water. This property could be disadvantageous for some 10 applications; however, PVA has been widely used in applications such as articular cartilage and pancreas regeneration (Baker et al (2011);Paradossi (2013)), drug-eluting contact lenses (Carreira et al (2014)), sensors for biological variables (Tou et al (2014); Carmona et al (2015)) and even for capturing organic dyes and metallic ions (Li et al (2014); Hui et al (2015)). 15 Natural hydrogels such as collagen, gelatin, alginate, agarose and chitosan (CS) are very attractive and are commonly used for biological applications.…”

A Cu–m-phenylenediamine complex induced route to fabricate poly(m-phenylenediamine)/reduced graphene oxide hydrogel and its adsorption application

“…Despite the excellent prospects, G-gel still lacks superior chemical activity due to the deficiency of functional sites, which is not beneficial for its versatile application, typically the water purification [6][7][8][9][10][11]. It has been reported that the crosslinking of polymer with graphene produced functionalized G-gel, which is superior for water purification, such as poly(vinyl alcohol)/G-gel and poly(dopamine)/G-gel [12][13][14][15][16]. Aminecontaining conjugated polymers have been widely investigated as water purification agents during the last two decades [17].…”

Polyethylene glycol and poly(vinyl alcohol) hydrogels treated with photo-initiated chemical vapor deposition

“…11,12 Polyethylene glycol (PEG) and Poly(vinyl alcohol) (PVA) are biocompatible and biodegradable polymers widely used for the preparation of functional hydrogels in pharmaceutical industry. [13][14][15] PEG-based hydrogels can be prepared by ring-opening polymerization of ethylene oxide cyclic monomers, radiation crosslinking of PEG or free radical polymerization of PEG macromers, whereas PVA hydrogels can be prepared by the common freezing/thawing cycle without chemical crosslinking. 14,16,17 The functionalization of PEG and PVA hydrogels has been explored via a plethora of methods such as the Passerini three-component reaction, polyelectrolyte multilayer microencapsulation and microwave-assisted functionalization.…”

“…[13][14][15] PEG-based hydrogels can be prepared by ring-opening polymerization of ethylene oxide cyclic monomers, radiation crosslinking of PEG or free radical polymerization of PEG macromers, whereas PVA hydrogels can be prepared by the common freezing/thawing cycle without chemical crosslinking. 14,16,17 The functionalization of PEG and PVA hydrogels has been explored via a plethora of methods such as the Passerini three-component reaction, polyelectrolyte multilayer microencapsulation and microwave-assisted functionalization. [18][19][20] The heterogeneous network structures containing dense crosslinking regions are produced by chain polymerization of hydrogels.…”