▎ 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(2) g(-1) to 3.9 m(2) 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.