CTAB-assisted synthesis of Bi2MoO6 hierarchical microsphere and its application as a novel efficient and recyclable adsorbent in removing organic pollutants

Herein we have synthesized Bi2MoO6 (BMO) hierarchical microspheres via a solvothermal method using hexadecyl trimethyl ammonium bromide (CTAB) as surfactant, and demonstrated that the synthesized BMO can be used as an efficient and recyclable adsorbent for removing organic pollutants. By using methylene blue (MB) as the target pollutant, the adsorption kinetics, adsorption isotherms and adsorption thermodynamics of MB onto the BMO adsorbent were systematically investigated. The effects of pH, temperature and adsorbent dosage on the MB adsorption by BMO were predicted by response surface methodology (RSM) with Box-Behnken design (BBD). It is interestingly demonstrated that the BMO adsorbent can be easily regenerated via a simple calcination process in air and exhibits excellent reusability. To promote the practical application of the BMO adsorbent in water purification, we have further compared its adsorption capability in removing 18 kinds of organic pollutants (including various organic dyes, antibiotics and other serious organic pollutants) at different acidic-alkaline environments. In the normal and alkaline (pH 12) environments, the highest adsorption is observed for Congo red (CR) with qe = 216.331 and 232.723 mg g−1, respectively; whereas in the acidic environment (pH 2), the highest adsorption is observed for eriochrome black T (EBT) with qe = 64.362 mg g−1. Based on the experimental results, the involved adsorption mechanism was analyzed.