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

摘要

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 m~2g_(-1)to 3.9 m~2g_(-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.