Preparation and characterization of bifunctional BiOClxIy solid solutions with excellent adsorption and photocatalytic abilities for removal of organic dyes

A series of BiOClxIy solid solutions with bifunctional properties was prepared by a hydrolysis method. When used as potential adsorbents for removal of dyes in wastewater, the as prepared samples exhibited the excellent adsorption and photocatalytic abilities, which indicated that the removal ability had been restored completely without centrifugal separating or other chemical desorption methods. Especially to the sample 301 prepared with a 3:1 M ratio of Cl to I, its adsorption capacity could reach nearly 5.0 mg g−1 within 5 min, which was at least 3 times larger than that of the individual BiOX (ca. 1.3 mg g−1), and its degradation efficiency of high concentration (20 mg L−1) methyl orange (MO) was up to 100% after 50 min of visible light irradiation. The relevant characterization results revealed that not only high specific surface area but also the electron structure of interlayer could be the key factors for the high adsorption ability. The possible mechanism was also discussed.