Biotemplated synthesis of hollow nickel silicate fiber for organic dye contaminants and its selective adsorption

Silicate is one kind of the fundamental constituent of minerals with the interesting properties, such as environment-friendliness, easily availability and hydrophilic surface chemistry. In this study, cotton fiber as versatile biotemplate is employed to synthesize hollow nickel silicate fibers through hydrothermal treatment and carbonization removal of the template. The as-prepared hollow nickel silicate fiber is rich in hydroxyl group and mesoporous structure according to the characterization of SEM、FTIR、XRD and N2 adsoprtion-desorption measurement. The adsorption performance of hollow nickel silicate fiber for methylene blue (MB) and congo red (CR) dye from the aqueous solution is systematically investigated. The results show that the dye adsorption of HNiSiFs for MB and CR is in accordance with the pseudo-second-order kinetic model, and Langmuir isotherm model is predominant for the monolayer adsorption process with the maximum adsorption capacity of 195.7 and 414.9 mg g−1 for MB and CR, respectively. Moreover, the as-prepared hollow nickel silicate fiber can selectively adsorb anionic dye containing N group from the mixed anionic pollutant solution. The electrostatic interaction of cationic organic molecular or molecular containing N group with HNiSiFs is the main driving force for the effective and specific adsorption.