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The high dispersion and stability of a nanocomposites suspension are required as a crucial factor in many of their applications. In this study, ZnO nanosheets covered with polyaniline (PANI) thin layer (ZnO@PANI) were synthesized by a simple in‐situ polymerization. The as‐prepared ZnO@PANI powders were well characterized by XRD, Raman, FTIR, XPS and photoluminescence spectra, as well as SEM and TEM techniques. The effect of PANI incorporation on the chemical dissolution and dispersing stability of ZnO aqueous suspension was investigated. Dissolution experiments showed that the dissolution of ZnO was effectively restrained by the surface‐hybridized PANI layer. ZnO@PANI suspension can be more stable in a wider pH range. Dynamic Light Scattering (DLS) analysis indicated that ZnO@PANI particles were thoroughly dispersed in the neutral and alkaline solution as proven by the emergence of a single distribution with a high diffused intensity. Sedimentation experiments suggested that ZnO@PANI suspension was a more stable dispersion taking into account the effect of pH and ionic strength.

BACKGROUND Uniform and well‐dispersed hollow microspheres of oligoaniline were synthesized by a facile and template‐free method in alkaline medium. The morphology of oligoanilines was controlled from hollow to hard microspheres, by simply changing the volumes of alkaline medium. SEM, TEM, XRD, FTIR and physical adsorption of nitrogen were used to characterize the products. Hexavalent chromium ion uptake experiments were run with these aniline oligomers. RESULTS Adsorption experiments showed that the removal of chromium ions was strongly dependent on the initial pH of the solution. The pseudo‐second‐order kinetic and Langmuir isotherm models were well correlated with the experimental data. The adsorption of Cr(VI) and synergistic reduction to Cr(III) were confirmed by analyzing remnant chromium in the liquid and XPS detection of the exhausted adsorbent. A redox/pseudo‐protonation process was suggested as the mechanism to explain the Cr(VI) removal. The adsorbed chromium ions could be desorbed by NaOH solution. The higher desorption efficiency of 96.2% was achieved by using 1.0 mol L‐1 NaOH as the desorption agent. CONCLUSIONS It was observed that the hollow microsphere were the most effective adsorbent of the three adsorbents and its removal efficiency reached 99% to remove 60 mg L‐1 Cr(VI). The facile fabrication, efficient removal of Cr(VI) and simple regeneration offered an option to remove Cr(VI) contamination from natural water and industrial wastewater. © 2017 Society of Chemical Industry