1. Full name:     Nguyen Van Huong                   2. Sex: Male

3. Date of birth: 07/06/1985                                4. Place of birth: Hung Yen

5. Admission decision number: 2875/QĐ-ĐHKHTN dated 07-8-2015 of the University of Science, Viet Nam National University.

6. Changes in academic process: Decisions No. 1191/QĐ-ĐHKHTN, dated on 04/05/2019 and 569/QĐ-ĐHKHTN, dated on 14/02/2020 by Rector of VNU University of Science on the extension of training and thesis defense for PhD students.

7. Official thesis title: Utilizing red mud generated by Bayer’s process in the Central Highlands to treat some nitrophenol’s compounds in military industrial wastewater.

8. Major: Environmental Science                                    9. Code: 9440301.01

10. Supervisors: Assoc.Prof.Dr. Nguyen Manh Khai; Assoc.Prof.Dr. Vu Duc Loi

11. Summary of the new findings of the thesis

- Red mud from the Central Highlands (Lam Dong Aluminum factory) has the basic compositions of Fe2O3 (54%), Al2O3 (16,4%), SiO2 (5,14%), TiO2 (6,88%) and some other ingredients such as: Zn, Ba, Hg, Sn, Be…. Crude red mud and denatured red mud have sinificant differences in chemical composition, in which Fe2O3 increases significantly from 54,0% to 63,23% when denatured at 800⁰C and from 63,23% to 66,91% when continued denatured with acid HCl. Also, the composition of TiO2 and Al2O3 increased slightly. The weight loss when heating decreased significantly when denatured at 800oC (from 11,68% to 3,83%), continued denaturing with 2M HCl, the weight loss on calcination decreased (from 3,83% to 1,63%). The average particle size of denatured red mud is 44,27 µm, pH ~ 12.5 and their radiation intensity is lower than the permitted limit. Denatured red mud at 800⁰C and 2M hydrochloric acid has uniform particle size; specific surface area was 6,2 times as large as when denatured at 800⁰C without using acids and 3,8 times more compared with that at 800⁰C and using 1M HCl acid.

- At pH = 3 - 4, 1 g/100mL of denatured red mud RM 800-2M and treatment time of 40 minutes is the best condition to treat TNP with concentration of 35,1 mg/L and TNR with concentration of 148.73 mg/L in 100 mL waste water. At pH = 7, 10g/L of denatured red mud and treatment time of 40 minutes is a good condition to treat DDNP with a concentration of 50 mg/L in 1 liter waste water. The adsorption of TNP and TNR by the denatured red mud from Central Highlands under isothermal conditions obeys the Langmuir and Freundlich adsorption law. For TNP, according to Langmuir's adsorption rule, the parameters qmax = 12,42 mg/g, R2 = 0,9921, KL = 0,40 L/mg and according to Freundlich isotherm with KF = 2,64 mg/g, R2 = 0,9646, n = 1,65. For TNR, according to Langmuir's adsorption rule, parameters qmax = 16,95 mg/g, R2 = 0,9877, KL = 0,415 L/mg and according to Frenundich isotherm with parameters KF = 4.69 mg / g, R2= 0,9949, n = 2,23. For DDNP, according to Langmuir's adsorption rule with parameters qmax = 13,14 mg/g, R2 = 0,9977, KL = 0,61 L/mg. The required amount of adsorption material to treat TNP (58 mg /L) and TNR (150 mg / L) in 1m3 waste water at the Chemical Company 21/General Department of Defense Industry are 6,06 kg and  15,02 kg respectively.

- The UV-Fenton system with the ratio of H2O2 / Fe2+ = 20, pH = 3, UV = 185 nm, I=130 µA/m, treatment time of 90 minutes has the highest efficiency by treating DDNP at the concentration of 400 mg/L. Based on the research results, the thesis developed a new wastewater treatment technology process to handle the wastewater generated from the DDNP production line, calculated the technical parameters, constructed and manufactured a pilot system for testing.

- Establish a technological process for treating the waste water genereted from DDNP production line by combining UV-Fenton and denatured red mud. Calculating, designing and manufacturing a pilot-scale treatment system for waste water generated from DDNP production line with capacity of 1 m3 /batch, installed and tested at the Factory 2/the Chemical Company 21/General Department of Defense Industry; testing system operation, technology transfer training and assessment of water quality after treatment. The water quality after treating achieves Vietnam National Technical Regulation on industrial wastewater QCVN 40: 2011/BTNMT, column B and the standard of weapons production wastewater (for explosives - GB 14470.2 -2002)

12. Practical applicability, if any:

- Research on denatured red mud and evaluation of their adsorption capacity for TNP, TNR, DDNP in wastewater is the scientific basis to utilize red mud generated by Bayer’s process in the Central Highlands to treat some nitrophenol-containing compounds in military industrial wastewater.

- Study on combination of physicochemical method and advanced oxidation process (AOPs) to treat persistent organic pollutants in wastewater in the military industry. Developing a new wastewater treatment technology based on the results of this study and testing their efficiency for treating wastewater generated by DDNP production line at a pilot scale at the Chemical Company 21/General Department of Defense Industry. The study results showed that the persistent structure of DDNP was destroyed by AOPs with the contribution of red mud. In addition, the eficiency of treating intermediate products improves because of the adsorption by red mud. This approach is effective and highly feasible.

- Based on the research of kinetics and process theory in the laboratory, the thesis calculated the construction and tested the operation of a wastewater treatment system to handle the wastewater generated from the DDNP production line with capacity of 1 m3 per batch at the Chemical Company 21/General Department of Defense Industry. The water quality after treating achieves Vietnam National Technical Regulation on industrial wastewater QCVN 40: 2011/BTNMT, column B.

- The research results of the thesis can be applied practically in the military production factories, which generate wastewater containing nitrophenol’s compounds.

13. Further research directions, if any:

- Research a method to recycling of adsorbent materials after use.

- Research on using red mud as a catalyst for advanced oxidation process (AOPs) to treat nitrophenol compounds.

- Continue to research and apply technology to treat other substances such as dioxins, CS, TNT, RDX, DNP...

14. Thesis-related publications:

[1] Nguyen Van Huong, Vu Duc Loi, Nguyen Thanh Hai, Nguyen Manh Khai (2017), "Research on treatment of picric acid in water using denatured red mud", Journal of Science, Vietnam National University Hanoi  33 (IS), pp. 28-37.

[2] Nguyen Van Huong, Nguyen Manh Khai, Nguyen Ngoc Son, Nguyen Van Hoang (2018), "Research on treatment of Diazodinitrophenol in water by using UV-Fenton method", Journal of Military Science and Technology  54, pp. 210-218.

[3] Nguyen Manh Khai, Nguyen Van Huong, Nguyen Thi Ngoc Anh, Vu Duc Loi (2018), "Research on treatment of styphnic acid in water by using UV-H2O2/ nano TiO2", Journal of Science, Vietnam National University Hanoi  34 (4), pp. 98-103.

[4] Nguyen Van Huong, Luu Quang Minh, Nguyen Manh Khai (2019), “Study on 2-Diazo-4,6-dinitrophenol in waste water using UV- H2O2 / TiO2”, Journal of Military science and technology, Special Issue - No.60A, pp. 52-60.

[5] Nguyen Van Huong, Vu Duc Loi, Nguyen Dinh Hung, Tran Thi To Uyen, Nguyen Manh Khai (2019), “Study on treatment of styphnic acid in water by UV/H2O2/ red mud from Central Highland”, Journal of Military science and technology 61, pp. 150-157.

[6] Nguyen Van Huong, Nguyen Van Hoang, To Van Thiep, Nguyen Manh Khai, The process of treating wastewater from the diazodinitrophenol explosive production line, Patent granting Utility solution No. 2327 according to Decision No. 5618w/QĐ-SHTT dated 20-5- 2020.

[7] Nguyen Van Huong, Doan Cong Danh, Tran Thi Trang, Vu Duc Loi, Nguyen Manh Khai (2019), “Study on treating picric acid in water using UV- H2O2/ TiO2”, Journal of Military science and technology Special Issue, pp. 308-315.