An Eco‐Friendly Polyvinyl Alcohol/Graphene Oxide‐Based Hydrogel as a Methylene Blue Adsorbent

Abstract

Recently, hydrogels have been introduced for wastewater treatments as eco‐friendly and efficient adsorbents. Polyvinyl alcohol (PVA)‐based hydrogel reinforced with graphene oxide (GO) can be used for methylene blue (MB) removal from water. PVA/GO hydrogels (5 wt. % PVA and 0.5–2 wt. % GO) were prepared via the freeze‐thaw method, and the effect of GO weight percentage, freezing time, and cycle numbers were investigated. Regarding the results, the composite containing 1 wt. % GO, prepared by six‐hour freezing, and five cycles of freeze‐thawing, had the highest compressive strength (1.6±0.1 MPa) among the studied samples. Furthermore, by adding aloe vera to the PVA/GO composite containing 2 wt. % GO, the removal efficiency of MB was increased from 96 % to 99 % after 72 h, although the surface area was decreased from 31.6 m2 g−1 to 3.9 m2 g−1. Adsorption investigations were also highlighted PVA/GO and PVA/GO/aloe vera hydrogel composites follow the pseudo‐second‐order kinetics and Langmuir isotherm models.

Influence of graphene oxide on rheology, mechanical, dielectric, and triboelectric properties of poly(vinyl alcohol) nanocomposite hydrogels prepared via a facile one step process

“…The dielectric properties of the PVA/GO nanocomposite hydrogels suggest the ability of the material to store electrical charge, and these properties depend on the atomic, ionic, electronic, interfacial, and dipolar polarization under the influence of an externally applied electric field. [65][66][67] In this regard, nanocomposite hydrogels possessing these properties could be useful for energy storage devices and electronics applications. 54 The dielectric properties of the PVA/GO nanocomposite hydrogels with increased concentration of GO as a function of frequency were measured at room temperature (Table S3, ESI †).…”