The analysis result of HPLC diagrams revealed phenol, pnitrophenol, p-crezol and some kinds of organic pollutants in the landfill leachate were totally decomposed after 12 h of treatment. Moreover, the re-usability of Mn-TiO2-bentonite catalysts was also studied with good efficiency. It was concluded that the Mn-TiO2-bentonite photocatalyst could be a cost-effective method for the pre-treatment of non-biodegradable organic pollutants in the landfill leachate. | Vietnam Journal of Science and Technology 55 (4C) (2017) 304-310 PHOTODEGRADATION OF NON-BIODEGRADABLE ORGANIC COMPOUNDS IN LANDFILL LEACHATE BY Mn-TiO2-BENTONITE Tran Minh Duc1, 2, *, Dang Xuan Hien1 1 School of Environmental Science and Technology, Ha Noi University of Science and Technology, No. 1, Dai Co Viet, Hai Ba Trung, Ha Noi, Viet Nam 2 Faculty of Chemistry, Ha Noi National University of Education, 136 Xuan Thuy, Ha Noi, Viet Nam * Email: ductran162hnue@ Received: June 2017; Accepted for publication: 18 October 2017 ABSTRACT The photocatalytic process helps to enhance biodegradability of landfill leachate. TiO 2bentonite nanocrystalline powders with various Mn-doping levels were synthesized by the sol– gel process using TiCl4 and manganese nitrate as precursors. The synthesized nanomaterials were characterized by X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray analysis (EDX). The experimental results indicated that the removal of chemical oxygen demand (COD), biological oxygen demand (BOD5), total organic carbon (TOC) and color by 2%Mn-TiO2-bentonite photocatalyst could be reached more than 81%, 83%, 65% and 96%, respectively. Under optimal conditions, the BOD5/COD ratio was elevated from to . The organic compounds in landfill leachate before and after treatment using Mn-TiO2-bentonite photocatalyst were analyzed by means of high performance liquid chromatography (HPLC). The analysis result of HPLC diagrams revealed phenol, pnitrophenol, p-crezol and some kinds of organic pollutants in the landfill leachate were totally decomposed after 12 h of treatment. Moreover, the re-usability of Mn-TiO2-bentonite catalysts was also studied with good efficiency. It was concluded that the Mn-TiO2-bentonite photocatalyst could be a cost-effective method for the pre-treatment of non-biodegradable organic pollutants in the landfill leachate. Keywords: treatment of landfill leachate, .