By utilizing the synergistic effect of chitosan (CS), magnetite (Fe3O4) particles, and graphene oxide (GO), a series of efficient and eco-friendly chitosan/magnetite-graphene oxide (CS/MGO) composites were fabricated through a facile chemical route. First, Fe3O4 particles were chemically deposited on the surface of GO to fabricate MGO hybrid. Then, chitosan was attached on MGO sheets, assembling to CS/MGO composites. According to the results of characterization, the covalent Fe-O-C bonds, electrostatic attraction, and hydrogen bonding between GO, Fe3O4, and chitosan ensure excellent structural stability and physico-chemical properties. The adsorption of Cr(VI) onto CS/MGO composites was also carried out under various conditions (content of CS, pH, initial concentration, contact time, and temperature). The CS/MGO composites possess high removal capacity for Cr(VI) from aqueous solution. Moreover, results also suggested that the CS/MGO composites had a strong reducing action for Cr(VI). When adsorption occurred, Cr(VI) and Cr(III) were simultaneously removed by CS/MGO composites. In addition, CS/MGO composites could retain good Cr(VI) removal efficiency after reuse over five cycles. CS/MGO composites are expected to have potential applications as easily regenerative bioadsorbents for Cr(VI) polluted water cleanup.

The oil contamination caused by surfactant-stabilized oil-in-water (O/W) emulsions are of increasing concern because of their persistent stability and high transportability. In this study, magnetic three-dimensional composites, which contain magnetite (Fe3O4) particles, grapheme oxide (GO), and MgAl-layered double hydroxides (MgAl-LDHs), were fabricated and applied as adsorbents to remove emulsified oils from various oil-in-water (O/W) emulsions. Transmission and electron scanning microscopies, X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy, vibrating sample magnetometer, and ζ-potential analysis techniques were utilized to characterize MGO/MgAl-LDH composites. The particle–interface interaction was characterized by interfacial rheometer. Oil removal study results showed that the maximum removal efficiency for the crude oil was a mass ratio of LDHs/MGO = 1:1, while the maximum removal efficiencies for decane and white oil were a mass ratio of LDHs/MGO = 1:3. Under a suitable mass ratio of LDHs to MGO, 98–99% of emulsified oils could be removed by MGO/MgAl-LDH composites. Experimental data were best fitted to the Langmuir isotherm model. Thermodynamic analysis indicated that the adsorption process was both exothermic and spontaneous. The emulsified oil removal efficiencies were increased with increasing ionic strength. In addition, MGO/MgAl-LDH composites could maintain good oil removal efficiency after reusing over five cycles, indicating their great potential for use in an oily wastewater treatment.

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The gelation behavior of diethylenetriamine (DETA) and oleic acid (OLA) with different molar ratios in water was investigated. The gels, which were composed of lamellar phase and vesicles, were characterized using small‐angle X‐ray scattering (SAXS) and freeze‐fracture transmission electron microscopy (FF‐TEM). The responsive rheological properties were also investigated. Our results show that lamellar gels and rodlike micelles were formed successively with the increase of the DETA/OLA molar ratio. The lamellar gels exhibiting high thermal stability can be obtained in a wide range of polyamine/unsaturated fatty acid molar ratios. The mechanism of lamellar gel formation was explained by the packing parameter and the noncovalent interactions between the building blocks. Moreover, gel–sol transition can be triggered by tuning pH and ionic strength. This system has a good emulsification property, and no obvious nanoemulsion droplet coarsening is observed upon dilution after 30 days.