The invention discloses a tetrathiomolybdate intercalated ternary iron-
magnesium-
zinc layered double
hydroxide catalyst, a preparation method thereof and an application of the tetrathiomolybdate intercalated ternary iron-
magnesium-
zinc layered double
hydroxide catalyst in degrading azo dyes by activating peroxymonosulfate. According to the method, a
carbonate intercalated ternary LDH precursor is synthesized through a
hydrothermal reaction, interlayer anions are replaced with
nitrate and tetrathiomolybdate through
ion exchange, and the target catalyst is obtained. In the catalyst, a unique Fe-Mg-Zn ternary
metal laminate and a MoS < 2-> intercalation structure cooperatively construct a multi-
active center, and MoS < 2-> is used as an
electron donor to promote cyclic regeneration of Fe < 3 + > / Fe < 2 + >. The catalyst keeps ultrahigh activity in a wide range of pH (potential of
hydrogen) of 3-9, can completely degrade 10 mg / L of acid orange 7 within 5 minutes, and is stable in structure and low in
metal dissolution risk. The problems of
low activity, slow Fe < 3 + > reduction,
metal ion dissolution and the like under neutral and alkaline conditions in an advanced oxidation technology based on peroxymonosulfate are solved, and the method has important application value in the field of printing and
dyeing wastewater treatment.