Hierarchical porous activated biochar derived from marine macroalgae wastes (): facile synthesis and its application on Methylene Blue removal.

Biochar is one of the most promising candidates of the cost-effective adsorbent for wastewater treatment. Herein, a novel hierarchical porous activated biochar derived from (EPAC) was synthesized an oily sludge-assisted "one-step" carbonization and activation approach. The results proved that the oily sludge additive acts as a natural structure directing agent during the EPAC preparation. The resultant EPAC possesses favorable properties such as high surface area and hierarchical pore distribution, which bring about its outstanding adsorption capability (910 mg g) for Methylene Blue dyes from wastewater. The adsorption kinetics, isotherms, thermodynamics and the effect of pH and the background ionic species on the adsorption process were investigated. The adsorption data could be well illustrated by Langmuir models and pseudo-second-order models. Furthermore, thermodynamic parameters revealed that the adsorption reaction was an endothermic and spontaneous process. The adsorption process was influenced by the solution pH and background ionic species because of the competitive adsorption. Moreover, the regeneration analysis demonstrates a presentable recyclability of the EPAC. In view of its good adsorption performance, the EPAC prepared in this study has the potential of treating dye wastewater in practical applications.