MXene/sodium alginate gel beads for adsorption of methylene blue

To enhance the adsorption performance of 2D graphene-like materials Ti3C2Tx (T = OH, O, F) on methylene blue (MB) and realize its reuse, sodium alginate (SA) was used to immobilize Ti3C2Tx to form Ti3C2Tx/SA beads. The beads were fabricated with Ti3C2Tx powder and SA by ionic crosslinking. Based on the SEM, FTIR and XRD analysis, Ti3C2Tx was bound to SA tightly, which avoided the loss of adsorbent and improved the adsorption effect. The adsorption characteristics of MB were investigated at different material ratios, temperature, pH and initial concentration. The results indicated that Ti3C2Tx/SA-30% was chosen as the appropriate mass ratio, the maximum adsorption capacity of which was 92.17 mg/g at pH 7 and 298 K. The MB adsorption efficiency was maintained 81.36% after three cycles. The adsorption process was conformed to pseudo-second-order kinetics, and fitted well with Langmuir isotherm model. Thermodynamic analysis suggested that the process of MB adsorbed on Ti3C2Tx/SA beads was endothermic and spontaneous. The results showed that Ti3C2Tx/SA beads had potential application in pollutants removal for efficient adsorption and superior reusability.