Continuous flow photocatalytic reactor using ZnO–bentonite nanocomposite for degradation of phenol

Removal of phenol employing ZnO–bentonite nanocomposite as photocatalyst with UV irradiations is evaluated under Continuous Stirred Tank Reactor (CSTR). XRD patterns of nanocomposites indicated modifications in the lattice structure of bentonite due to intercalation of ZnO nanospheres in the matrix with particles size of 20–30 nm as revealed from TEM. Thin film of composites coated on SS plate surface exhibited ∼70% removal of phenol from the simulated effluent under at lower flow rate (10 ml min−1) and higher pH (12) at a fixed nanocomposite loading. The effluent obtained after CSTR treatment is analyzed by LC–MS which suggested that photocatalytic degradation of phenol results in the formation of adipic acid and 2,4,6-triphenoxy phenol through radical mechanism.

► Continuous process using nano ZnO bentonite on the removal of phenol is developed.
► In situ ion exchange method was used to synthesize ZnO-bentonite nanocomposite.
► LC–MS analysis indicates that the degradation of phenol takes place through radical mechanism.
► Results show the formation of adipic acid and 2,4,6-triphenoxy phenol.