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INFORMATION ON DOCTORAL THESIS - PHAM THI MINH - PhDSTUDENT Thesis title: "Research characteristic of azo organic compounds mineralization in dye textile wastewater by electro-Fenton met

INFORMATION ON DOCTORAL THESIS - PHAM THI MINH - PhD

STUDENT

Thesis title: "Research characteristic of azo organic compounds mineralization

in dye textile wastewater by electro-Fenton method”

PhD student: Pham Thi Minh

Training establishment: Institute of Tropical Technology - Vietnam Academy of Science and Technology

Major: Theoretical chemistry and Physical chemistry

Supervisors: Assoc Prof Nguyen Thi Le Hien

Assoc Prof Dinh Thi Mai Thanh

1 Objective of the thesis

1.1 Synthesize spinel oxide Cu1,5Mn1,5O4 by co-precipitation method

1.2 Synthesize Ppy and Ppy(Cu1,5Mn1,5O4)/Ppy coatings on carbon substrate 1.3 Determine the optimal conditions for processing treatment of azo organic compounds in dye textile wastewater

1.4 Research dyeing wastewater treatment in some dye textile manufactures by electro-Fenton effects

2 Main results of the thesis

2.1 Successfully synthesize spinel oxide Cu1,5Mn1,5O4 by co-precipitation method with small, fine, uniform with spinel-structured particles

2.2 Successfully synthesize Ppy and Ppy(Cu1,5Mn1,5O4)/Ppy coatings on carbon –substrate by static-current method at current density i = 2 mA/cm2 The Ppy(Cu1,5Mn1,5O4)/Ppy cathode electrode has high stability and best catalytic

electrochemical ability for oxygen reduction process to produce H2O2 in the solution with pH3, better than the C and C/PPY electrodes

2.3 Colored azo compounds such as red methyl, orange methyl, red Congo can

be completely oxidized by electro-Fenton effects using C/ Ppy(Cu1,5Mn1,5O4)/Ppy electrodes, at current density of 1 mA/cm2 , in pH3 solution containing iron (II) of 1 mM concentration, and oxygen speed of 1 liter/minute

By UV-Vis spectra, the decomposition efficiency has been identified for red methyl as 0.35 mM , red Congo as 0.25 mM and orange methyl as 1.0mM attained respective values of 88 %, 75% and 72% after 5 hours treatment

By COD determination method, the result is consistent with the results

of UV - Vis analysis The COD reduction efficiency of 0.35 mM red methyl; 0.25mM red congo and 1.0 mM orange methyl after 20 hours treatment attained respective values 76%, 91% and 74%

2.4 The kinetics of azo compounds mineralization is identified on the basis of experimental results according to the first-class supposed kinetic equation, which is suitable for the studies published in some international journals

2.5 The results of untreated textile wastewater processing from Van Phuc and Duong Noi villages in laboratory in optimal conditions promise application Fenton-Electro effect in treatment azo compound s in dye textile wastewater

For Duong Noi dye textile wastewater, COD value decrease from 450

to 70 mg/l (the COD reduction yield attained 84% respectively), color grade reduces from 1360 to 85 Pt - Co after 10 hours treatment

For Van Phuc dye textile wastewater: COD value decrease from 1000

to 80 mg / l (the COD reduction yield attained 92%, respectively), color grade reduces from 1750 to 95 Pt - Co after 14 hours treatment

3 New findings and contributions of the thesis

3.1 Successfully synthesize spinel oxide Cu1,5Mn1,5O4 by co-precipitation method with small, fine, uniform and spinel-structured particles

3.2 Synthesize two types of electrodes, including C/PPY and C/Ppy(Cu1,5Mn1,5O4)/Ppy by electrochemical method These electrodes have suitable electrocatalytic for the oxygen reduction process to create hydrogen peroxide

3.3 Find out the most suitable condition (the concentration of Fe2+, the imposed current density, cathode electrode material and oxygen rate) to mineralize red methyl, red congo and orange methyl by electro- Fenton method, setting the basis for mineralization of azo compounds in textile wastewater

3.4 Preliminarily use C/Ppy and C/Ppy(Cu1,5Mn1,5O4)/Ppy materials as the cathode electrodes for Van Phuc and Duong Noi textile wastewater mineralization by electro-Fenton method The COD indicator and color grade of wastewater after treatment achieved the standard of industrial wastewater Class

B ISO 2008/BTNMT