5 to 0.8. Clearly, the carbon coating will greatly enhance the surface area, which can be the main reason of significant enhanced dye removal performance of hollow SnO2@C nanoparticles. The large number and array of different functional groups on the carbon layers (e.g., carboxylic, hydroxyl, carbonyl) implied the existence of many types of adsorbent-solute interaction [22]. Additionally, carbon coating has made the covalent bond interaction with hexagonal structure, which has a -π structure properties of aromatic ring, easy to interact

with conjugated double bonds. And some of the dye structure have conjugated double bonds and easy to be adsorbed by the coating NSC23766 price carbon [23]. As shown in Figure 8, the hollow SnO2@C nanoparticles can capture more dye molecules due to the introduced carbon layer. Indeed, relatively larger amount of water and Tofacitinib mouse hydroxyl groups can be adsorbed on the surface by hydrothermal process [24]. The surface chemistry of the adsorbents plays a major role in the adsorption. The adsorption of the reactive dye Selleck PU-H71 on carbon is favored, mainly due to the dispersive interactions between the delocalized π electrons of the carbon materials and the free electrons of the dye molecules [20]. The functional groups on the hollow

SnO2@C nanoparticles’ surface acted as a negative potential that provides a weak electrostatic interaction between the organic dyes and the hollow SnO2@C nanoparticles. Figure 7 Nitrogen adsorption-desorption isotherms

and pore size distribution. (a) Nitrogen adsorption-desorption isotherms of the as-synthesized SnO2 and hollow SnO2@C nanoparticles. (b) The pore size distribution of the hollow SnO2@C nanoparticles. Figure 8 Schematic illustration Methamphetamine of synthesis and dye removal processes. Conclusions In summary, hollow SnO2@C nanoparticles have been synthesized on a large scale through a facile hydrothermal method. The as-prepared hollow SnO2@C nanoparticles show excellent adsorption capacity toward RhB, MB, and Rh6G dyes in aqueous solutions. Compared with the naked hollow SnO2 and commercial SnO2 nanoparticles, the adsorption capacity showed about an 89% improvement for RhB organic dye. The porous carbonaceous shells coated on the surface of hollow SnO2 nanoparticles greatly enhanced the specific area, which provides more active sites for dye adsorption. Owing to their unique hollow structures, high surface areas and low cost, the as-obtained hollow SnO2@C nanoparticles are potentially applicable in wastewater treatment. Accordingly, it may be concluded that the developed SnO2@C is an efficient method for the decolorization of RhB, MB, and Rh6G dyes.