Synthesis of acidified palygorskite/BiOI with exceptional performances of adsorption and visible-light photoactivity for efficient treatment of aniline wastewater

The acidified palygorskite/BiOI composites with different amounts of acidified palygorskite were synthesized using an ethylene glycol-assisted solvothermal method. The morphology, structure, surface area and pore-size distribution of the composites were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N-2 adsorption-desorption isotherms. The BiOI microspheres consisting of numerous nanosheets were uniformly dispersed on the surface of acidified palygorskite. The composite with doping amount of 50 wt.% acidified palygorskite manifested a large BET area of 118.5 m(2)/g with mesoporous structure of 10.8 nm. The surface chemistry was obtained by the determination of the point of zero charge. The introduction of acidified palygorskite made the composites have more acidic character. The adsorption of aniline onto acidified palygorskite/BiOI followed the pseudo-second-order model and the Freundlich equation. As pH increased, equilibrium adsorption concentration showed an upward trend, and reached a maximum at pH = 7. The 50 wt.%-acidified palygorskite/BiOI exhibited the optimal adsorption performance and visible-light photoactivity for 50 mg L-1 of aniline solution. About 90 wt.% of aniline was removed through combination of high adsorption and efficient photodegradation processes. (C) 2015 Elsevier B.V. All rights reserved.