An abundant porous biochar material derived from wakame (Undaria pinnatifida) with high adsorption performance for three organic dyes.

In this study, an activated wakame biochar material (AWBM) was prepared by a one-step calcination and activation method, whose adsorption performances for methylene blue (MB), Rhodamine B (RB) and malachite green (MG) were also analyzed. The results showed AWBM was a mesoporous fluffy structure material with a higher specific surface (1156.25 m2/g), exhibiting superior adsorption capacities for MB (841.64 mg/g), RB (533.77 mg/g) and MG (4066.96 mg/g), respectively. In addition, FT-IR analysis showed that AWBM possessed abundant active groups (such as -OH, -CO and -CH), further enhancing the adsorption efficiencies. The Langmuir model could better fit the three dyes adsorption isotherms process using AWBM, and the Pseudo-second-order model could better describe the adsorption kinetic experimental data. The thermodynamic analysis showed that the three dyes adsorption using AWBM was spontaneous endothermic reaction. This study suggests AWBM has enormous potential in the application of removing organic dyes from wastewater.

Magnetic activated biochar nanocomposites derived from wakame and its application in methylene blue adsorption.

In this work, magnetic wakame biochar nanocomposites for the first time had been synthesized to investigate their adsorption to methylene blue dye. As-prepared magnetic biochar samples were obtained by the impregnation method to load nickel on wakame biochar via one-step carbonization with activation agent KOH at 800 °C. The prepared samples were characterized by BET, XRD, FTIR, Raman, SEM, TEM and so on. The results exhibited that the maximum adsorption capacity of BW(Ni)0.5 to methylene blue could reach 479.49 mg/g at 20 °C. The adsorption behavior was more suitable for Langmuir isotherm equation and the kinetic data were most consistent with the pseudo second-order model. And also, the adsorption reaction was a spontaneous and endothermic process. After five cycles, it was found that BW(Ni)0.5 had a high adsorption capacity for methylene blue (117.58 mg/g). This study demonstrated that wakame biochar could have great potential in dye wastewater treatment.