Efficient Methylene Blue Removal From Water via Graphene Oxide‐Based Composite Cryogel Column

Abstract In this study, a composite poly(2‐hydroxyethyl methacrylate)/graphene oxide (PHEMA‐GO) cryogel column was developed for removal of methylene blue (MB) from aqueous solution. The PHEMA‐GO composite cryogel column was synthesized by adding GO into cryogelation mixture and comprehensive characterization studies were conducted via Fourier Transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), mercury porosimetry, and swelling study. The total porosity was determined as 66.72%. The pore size was in the range of 4.31–220.6 µm. The MB adsorption capacity of PHEMA‐GO cryogel column was investigated considering different parameters, including GO amount, pH, contact time, ionic strength, temperature, and initial MB concentration. The maximum MB amount adsorbed amount onto the PHEMA‐GO composite cryogel column was determined as 253 mg/g at 298 K (pH:5.3). The adsorption data were obeyed to Langmuir isotherm model and pseudo‐second‐order kinetic model. The adsorbed amount of MB was not affected from ionic strength, which is important for the dye removal from the textile wastewater. The composite cryogel column was reused 10 times without a decrease in the MB adsorption capacity. The application potential of the PHEMA‐GO composite cryogel column was demonstrated using a real textile wastewater sample.