Application of plant-based coagulant with a novel MnO2.MoS2 nanocatalyst in coagulation/photocatalytic ozonation process for wastewater treatment

Abstract

ABSTRACT In this work, Lallemantia royleana seed mucilage (LRSM) was applied as a plant based coagulant in the initial stage of an integrated method for dye degradation. Photocatalytic ozonation (PCO) process was used under visible-light irradiation in the post-treatment stage. MnO2.MoS2 heterostructure nanocomposite was fabricated by hydrothermal synthesis and applied for the first time in PCO to mineralize Acid Blue 113 dye. The synthesized nanocatalyst was characterized by FT-IR, XRD, FE-SEM, TEM, DRS and BET. Characterization of the nanocatalyst showed that the composite consisted MoS2 with a sheet-like structure and MnO2 in the form of nanoparticles with different sizes in the range of 15–30 nm. By using the response surface methodology (RSM) approach, the best operational condition in the coagulation-flocculation (CF) stage has been acquired at pH 5.0, LRSM dose of 220 mg/L within 27 min. By applying the PCO process, complete decolorization has been attained using 11 mg of the catalyst and 0.2 g/L.h ozone dosage within 9 min. The use of LRSM along with MnO2.MoS2 nanocatalyst in the CF/PCO combined process for treating real wastewater samples indicates that the proposed technique is highly efficient and can be effectively employed to treat dye-containing industrial effluents.