The contamination of water systems by heavy metals greatly threatens human health and ecological safety. An efficient adsorbent is critical for the removal of these contaminants. In this work, magnetic Ni 3 Si 2 O 5 (OH) 4 nanotubes (NTs) have been synthesized via in situ hydrothermal reduction and further functionalized by grafting poly(4-vinyl pyridine) (P4VP) brushes on its surface via atom transfer radical polymerization. Characterizations by Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, and X-ray photoelectron spectroscopy proved that P4VP was successfully grafted on the surface of magnetic Ni 3 Si 2 O 5 (OH) 4 NTs. The resultant Ni 3 Si 2 O 5 (OH) 4 - g -P4VP NTs are efficient nanosorbents for removing Cr(VI) anions from water. The Cr(VI) adsorption capacity of Ni 3 Si 2 O 5 (OH) 4 - g -P4VP NTs reaches 1.49 mmol/g at a pH of 3. The pseudo-second-order kinetic model and the Freundlich isothermal model are suitable to describe the adsorption process. The analysis using Weber–Morris and Boyd models indicates that both intraparticle diffusion and external film diffusion affect the Cr(VI) adsorption process. The adsorption enthalpy is estimated to be 18.37 kJ/mol. More than 90% of the Cr(VI) adsorption capacity of the Ni 3 Si 2 O 5 (OH) 4 - g -P4VP NTs remains after eight adsorption and desorption cycles.

PAMPS-g-Ni3Si2O5(OH)4 NTs for the effective removal of Pb(ii).

Superhydrophobic ZnO micro/nanocrystals were fabricated on a large scale using a facile one-pot hydrothermal process successfully. The morphologies and chemical composition of as-synthesized ZnO were investigated by the scanning electron microscope (SEM) and X-ray powder diffraction (XRD). The morphology of ZnO products changed from uniform size microrods to flower-like micronanostructures, when the temperature changed from 120°C to 180°C. The morphology of ZnO was strongly affected by the pH. The wettability of the as-synthesized ZnO micro/nanocrystals was studied by measuring water contact angle (CA). The largest static CA for water is 167°, which is closely related to both the ZnO micro/nanostructure and chemical modification. Furthermore, the as-prepared ZnO surface showed superhydrophobicity for some corrosive liquids such as basic and acidic aqueous solutions. The CAs of the surface modified with ZnO prepared at 160°C were over 155° in the range of pH = 1–13.