EPS được tách bằng phương pháp HCHO-NaOH được sử dụng để xử lý nước thải của một Công ty dệt nhuộm tại Nam Định được thể hiện trên Hình 3.14.
Trước xử lý Sau khi xử lý bằng EPS
Hình 3.14. Hình ảnh thử nghiệm xử lý nước thải thực tế
Hiệu quả xử lý trên 98%. Nước thải của nhà máy trước và sau khi xử lý bằng EPS có độ màu tương ứng 106 mg/L và 1.59 mg/L. Kết quả thí nghiệm cho thấy khả năng xử lý thuốc nhuộm của EPS, khả năng áp dụng để xử lý nước thải ngoài thực tế còn nhiều hạn chế nhưng cũng cho thấy đây là một vật liệu thân thiện và nhiều tiềm năng.
KẾT LUẬN VÀ KHUYẾN NGHỊ
KẾT LUẬN
1. - Kết quả tách chiết EPS bằng 10 phương pháp vật lý và phương pháp hóa học khác nhau đã thu được một lượng EPS nhất định, từ 27 mg/L đến 7039 mg/L. Hiệu quả tách bằng các phương pháp hóa học tốt hơn so với các phương pháp vật lý. Trong đó, NaOH, H2SO4 và HCl là ba phương pháp tốt nhất, đạt tương ứng 5920 mg/L, 6604 mg/L và 7039 mg/L.
- EPS được tách ra bằng phương pháp HCHO kết hợp với NaOH có khả năng xử lý tốt nhiều loại thuốc nhuộm khác nhau như Blue CLBP, Yellow CL2R và Red CL5B với hiệu suất xử lý đạt tới 85 đến 99% .
2. - EPS thể hiện khả năng xử lý thuốc nhuộm tốt ở khoảng pH axit (pH < 6). - Thời gian đạt phản ứng của EPS đối với thuốc nhuộm khá nhanh, cụ thể là 5 phút với thuốc nhuộm Blue CLBP, 60 phút với thuốc nhuộm Yellow CL2R và Red CL5B.
- Al3+ là cation có khả năng kết hợp tốt với EPS để tăng hiệu quả xử lý thuốc nhuộm.
- Nồng độ EPS phù hợp để xử lý thuốc nhuộm dao động từ 200 – 350 mg EPS/L.
- Ở điều kiện tối ưu, hiệu suất xử lý thuốc nhuộm Blue CLP, Yellow CL2R và Red CL5B đạt được là 99%, 94% và 85%, tương ứng.
3. Quá trình hấp phụ của thuốc nhuộm hoạt tính Blue CLBP, Yellow CL2R và Red CL5B bằng EPS có thể được mơ tả theo phương trình đẳng nhiệt của Langmuir và Freundlic. Dung lượng hấp phụ thuốc nhuộm tính theo phương trình đẳng nhiệt Langmuir của thuốc nhuộm Blue CLP, Yellow CL2R và Red CL5B lần lượt là 0,72 g/g, 0,5 g/g và 0,95 g/g.
KHUYẾN NGHỊ
1. Nghiên cứu thử nghiệm trực tiếp khả năng áp dụng của EPS trên nước thải dệt nhuộm lấy từ các nhà máy khác nhau.
2. Tối ưu hóa phương pháp tách trên nhiều yếu tố hơn để thu được EPS chất lượng tốt nhất, đem lại hiệu quả kinh tế cao như nồng độ của NaOH, nồng độ HCHO, nồng độ bùn, nhiệt độ, thời gian tách.
3. Nghiên cứu khả năng tuần hồn, tái sử dụng các hóa chất tách để nâng cao khả năng áp dụng của phương pháp.
TÀI LIỆU THAM KHẢO
Tiếng Việt
1. Nguyễn Mai Dương, Nguyễn Hải Vân, Nguyễn Thị Lan Anh, Phạm Tuấn Linh, Lê Thanh Sơn, Đặng Thị Cẩm Hà (2014), "Đánh giá bước đầu khả năng xử lý thuốc nhuộm bằng EPS sinh ra bởi chủng Bacillus sp.BES19 trên bùn thải", Tạp chí Khoa học ĐHQGHN: Khoa học Tự nhiên và Công nghệ.
30(5S), tr. 84-94.
2. Nguyễn Mai Dương, Nguyễn Văn Huynh, Nguyễn Hải Vân, Đặng Thị Cẩm Hà (2016), "Loại màu thuốc nhuộm bởi tổ hợp chất trợ keo tụ sinh học (EPS) và laccase", Tạp chí hóa học và ứng dụng. 1(33), tr. 14-21.
3. Nguyễn Mai Dương, Lê Thị Hiền, Nguyễn Đăng Thắng, Đinh Thị Thu Hằng, Đặng Thị Cẩm Hà (2015), "Loại màu thuốc nhuộm bởi laccase của chủng nấm Coriolopsis sp. FPT5 phân lập từ Phú Thọ", Tạp chí Cơng nghệ sinh học 13(2), tr. 367-377.
4. Hồng Khánh Nguyễn (2005), "Tăng cường năng lực bảo vệ môi trường cho một số ngành công nghiệp trọng điểm ở Việt Nam", Viện Công nghệ Môi trường - Viện Hàn Lâm khoa học và công nghệ Việt Nam.
Tiếng Anh
5. Aboulhassan, M.A., et al. (2006), "Improvement of paint effluents coagulation using natural and synthetic coagulant aids", Journal of Hazardous Materials. 138(1), pp. 40-45.
6. Adewuyi, Y.G. (2001), "Sonochemistry: Environmental Science and Engineering Applications", Industrial & Engineering Chemistry Research. 40(22), pp.
4681-4715.
7. Arslan-Alaton, I. (2003), "A review of the effects of dye-assisting chemicals on advanced oxidation of reactive dyes in wastewater", Coloration Technology. 119(6), pp. 345-353.
8. Arslan, I. and Balcioglu, I. A. (2001), "Degradation of Remazol Black B dye and its simulated dyebath wastewater by advanced oxidation processes in heterogeneous and homogeneous media", Coloration Technology. 117(1),
pp. 38-42.
9. Barredo-Damas, S., et al. (2006), "Study of the UF process as pretreatment of NF membranes for textile wastewater reuse", Desalination. 200(1–3), pp. 745-
747.
10. Bezawada, J and et al, . ( 2013), "Production of extracellular polymeric substances (EPS) by Serratia sp. 1 using wastewater sludge as raw material and flocculation activity of the EPS produced", Journal of environmental management. 128, pp. 83-91.
11. Bhaskar, P. and Bhosle., N.B. (2006), " Bacterial extracellular polymeric substance (EPS): A carrier of heavy metals in the marine food-chain",
Environment international. 32(2), pp. 191-198.
12. Bhattacharyya, Krishna G. and Sharma, Arunima (2004), "Azadirachta indica leaf powder as an effective biosorbent for dyes: a case study with aqueous Congo Red solutions", Journal of Environmental Management. 71(3), pp.
217-229.
13. Brown, M.J and Lester, J.N. (1980), "Comparison of bacterial extracellular polymer extraction methods", Applied and Environmental Microbiology.
40(2), pp. 179-185.
14. Buthelezi, Simphiwe P. (2008), "Application of Bacterial Bioflocculants for Wastewater and River Water Treatment".
15. Ciabatti, I., Tognotti, F., and Lombardi, L. (2010), "Treatment and reuse of dyeing effluents by potassium ferrate", Desalination. 250(1), pp. 222-228. 16. Coates, John (2000), "Interpretation of infrared spectra, a practical approach",
Encyclopedia of analytical chemistry.
17. Comte, S., G. Guibaud, and M. Baudu (2006), "Relations between extraction protocols for activated sludge extracellular polymeric substances (EPS) and EPS complexation properties: Part I. Comparison of the efficiency of eight EPS extraction methods.", Enzyme and Microbial Technology. 38(1), pp. 237-245.
18. D’Abzac, P and al., et (2010), "Extraction of extracellular polymeric substances (EPS) from anaerobic granular sludges: comparison of chemical and physical extraction protocols", Applied microbiology and biotechnology. 85(5), pp.
1589-1599.
19. Dignac, M-F. and eat (1998), "Chemical description of extracellular polymers: implication on activated sludge floc structure", Water Science and Technology. 38(8-9), pp. 45-53.
20. Esparza-Soto, Mario and Westerhoff, Paul (2003), "Biosorption of humic and fulvic acids to live activated sludge biomass", Water research. 37(10), pp.
2301-2310.
21. Feng, D. L. and Xu, S. H. (2008), "Characterization of bioflocculant MBF3-3 produced by an isolated Bacillus sp", World Journal of Microbiology and Biotechnology. 24(9), p. 1627.
22. Flemming and H.-C. (2009), Why Microorganisms live in biofilms and the
problem of biofouling, Springer, Marine and industrial biofouling.
23. Flemming, H and A. Leis (2003.), "Sorption properties of biofilms. Encyclopedia of environmental microbiology", John Wiley & Sons, Inc., New York, NY. doi, . 10, p. 0471263397.
24. Flemming, H.-C. and etal (2000), " Physico-chemical properties of biofilms. Biofilms: recent advances in their study and control.", Amsterdam: Harwood
Academic Publishers, pp. 19-34.
25. Flemming, H. and Wingender., J. (2001), "Relevance of microbial extracellular polymeric substances (EPSs)--Part I: Structural and ecological aspects.",
Water Science & Technology(43), pp. 1-8.
26. Frølund, Bo, et al. (1996), "Extraction of extracellular polymers from activated sludge using a cation exchange resin", Water research. 30(8), pp. 1749-1758. 27. Fu, Y. and Viraraghavan, T. (2001), "Fungal decolorization of dye wastewaters:
a review", Bioresource Technology. 79(3), pp. 251-262.
28. Gao, B., Yue, Q., and Miao, J. (2003), "Evaluation of polyaluminium ferric chloride (PAFC) as a composite coagulant for water and wastewater treatment", Water Sci Technol. 47(1), pp. 127-32.
29. Gehrke, T. and etal. (1998), " Importance of extracellular polymeric substances from Thiobacillus ferrooxidans for bioleaching", Applied and Environmental
Microbiology. 64(7), pp. 2743-2747.
30. Goodwin, J. and Forster, C. (1985), " A further examination into the composition of activated sludge surfaces in relation to their settlement characteristics.", Water Research. 19(4), pp. 527-533.
31. Guiné, V. and et al (2006), "Zinc sorption to three gram-negative bacteria: Combined titration, modeling, and EXAFS study.", environmental science &
technology. 40(6), pp. 1806-1813.
32. Hai, F.I., Yamamoto, K., and Fukushi, K. (2007), "Hybrid treatment systems for dye wastewater", Critical Reviews in Environmental Science and Technology. 37(4), pp. 315-377.
33. Hao, O.J., Kim, H., and Chiang, P. (2000), "Decolorization of Wastewater",
Critical Reviews in Environmental Science and Technology. 30(4), pp. 449-
505.
34. Ince, N. H. and Tezcanlı, Gửkỗe (2001), "Reactive dyestuff degradation by combined sonolysis and ozonation", Dyes and Pigments. 49(3), pp. 145-153. 35. Jorand, F, etal. (1998), "Hydrophobic/hydrophilic properties of activated sludge
exopolymeric substances", Water Science and Technology. 37(4-5), pp. 307- 315.
36. Kiran, Ismail, etal. (2006), "Biosorption kinetics and isotherm studies of Acid Red 57 by dried Cephalosporium aphidicola cells from aqueous solutions",
Biochemical Engineering Journal. 31(3), pp. 197-203.
37. Laspidou, C.S and Rittmann, B.E. ( 2002), A unified theory for extracellular polymeric substances, soluble microbial products, and active and inert biomass., Water Research, 36(11).
38. Li, W., et al. (2008), "Flocculation behavior and mechanism of an exopolysaccharide from the deep-sea psychrophilic bacterium
Pseudoalteromonas sp. SM9913", Bioresource technology. 99(15), pp. 6893- 6899.
39. Lin, S.H. and Peng, C.F. (1996), "Continuous treatment of textile wastewater by combined coagulation, electrochemical oxidation and activated sludge",
Water Research. 30(3), pp. 587-592.
40. Liu, A and eat (2001), "Phenanthrene desorption from soil in the presence of bacterial extracellular polymer: observations and model predictions of dynamic beheavior", Water research. 35(3), pp. 835-843.
41. Liu, Hong and Fang, Herbert HP (2002), "Extraction of extracellular polymeric substances (EPS) of sludges", Journal of biotechnology. 95(3), pp. 249-256. 42. Liu, W, et al. (2009), "Characterization of bioflocculants from biologically
aerated filter backwashed sludge and its application in dying wastewater treatment", Bioresource technology. 100(9), pp. 2629-2632.
43. Liu, Y, Lam, MC, and Fang, HH (2001), "Adsorption of heavy metals by EPS of activated sludge", Water Science and Technology. 43(6), pp. 59-66.
44. Liu, Y. and H-H, Fang (2003), "Influences of extracellular polymeric substances (EPS) on flocculation, settling, and dewatering of activated sludge".
45. Lowry, O.H. and etal (1951), "Protein measurement with Folin-Phenol reagent",
The Journal of Biological Chemistry. 193, pp. 265-275.
46. M., D and etal (1956), "Colorimetric method for determination of sugars and related substances", Analytical Chemistry. 28, pp. 350-356.
47. Mabinya and L.V., etal. (2012), "Studies on bioflocculant production by Arthrobacter sp. Raats, a freshwater bacteria isolated from Tyume River, South Africa", International journal of molecular sciences. 13(1), pp. 1054- 1065.
48. Marcucci, M., etal. (2001), "Treatment and reuse of textile effluents based on new ultrafiltration and other membrane technologies", Desalination. 138(1–
3), pp. 75-82.
49. Mayer, C. and et al. (1999), "The role of intermolecular interactions: studies on model systems for bacterial biofilms.", International journal of biological
macromolecules,. 26(1), pp. 3-16.
50. McKay, G., Porter, J. F., and Prasad, G. R. (1999), "The Removal of Dye Colours from Aqueous Solutions by Adsorption on Low-cost Materials",
Water, Air, and Soil Pollution. 114(3-4), pp. 423-438.
51. Meriỗ, S., Kaptan, D., and Ölmez, T. (2004), "Color and COD removal from wastewater containing Reactive Black 5 using Fenton’s oxidation process",
Chemosphere. 54(3), pp. 435-441.
52. Merzouk, B., Madani, K., and Sekki, A. (2010), "Using electrocoagulation– electroflotation technology to treat synthetic solution and textile wastewater, two case studies", Desalination. 250(2), pp. 573-577.
53. Mohamed, R.M.S.R., et al. (2014), "Colour removal of reactive dye from textile industrial ưastewater using different types of coagulants", Asian Journal of Applied Sciences 2(5), pp. 650 - 657.
54. More, T. T., et al. (2014), "Extracellular polymeric substances of bacteria and their potential environmental applications", Journal of environmental management. 144, pp. 1-25.
55. More, T.T., et al. (2012), "Surampalli, Bacterial polymer production using pre- treated sludge as raw material and its flocculation and dewatering potential",
Bioresource Technology,. 121, pp. 425-431.
56. Murthy, Sudhir N and Novak, John T (1999), "Factors affecting floc properties during aerobic digestion: implications for dewatering", Water Environment Research. 71(2), pp. 197-202.
57. Ncibi, Mohamed Chaker, Mahjoub, Borhane, and Seffen, Mongi (2007), "Kinetic and equilibrium studies of methylene blue biosorption by Posidonia oceanica (L.) fibres", Journal of Hazardous Materials. 139(2), pp. 280-285. 58. Pan, L. and eatl. (2003), "Porous lanthanide-organic frameworks: synthesis,
characterization, and unprecedented gas adsorption properties", Journal of the American Chemical Society. 125(10), pp. 3062-3067.
59. Pan, X. and et al, . (2010), " A comparison of five extraction methods for extracellular polymeric substances (EPS) from biofilm by using three- dimensional excitation-emission matrix (3DEEM) fluorescence spectroscopy", Water Sa. 36(1), pp. 111-116.
60. Park, C and Novak, J.T. (2007), "Characterization of activated sludge exocellular polymers using several cation-associated extraction methods",
Water research. 41(8), pp. 1679-1688.
61. Patil and S.V, et al. (2011), "Studies on characterization of bioflocculant exopolysaccharide of Azotobacter indicus and its potential for wastewater treatment", Applied biochemistry and biotechnology. 163(4), pp. 463-472. 62. Pere, J, et al. (1993), "Characterization and dewatering of activated sludge from
the pulp and paper industry", Water Science and Technology. 28(1), pp. 193- 201.
63. Phalakornkule, C., et al. (2010), "Electrocoagulation of blue reactive, red disperse and mixed dyes, and application in treating textile effluent", Journal
of Environmental Management. 91(4), pp. 918-926.
64. Robinson, T., et al. (2001), "Remediation of dyes in textile effluent: a critical review on current treatment technologies with a proposed alternative",
Bioresource Technology. 77(3), pp. 247-255.
65. S, Comte., G, Guibaud., and M, Baudu. (2007), "Effect of extraction method on EPS from activated sludge: an HPSEC investigation", Journal of hazardous
66. Sandhya, S. and Swaminathan, K. (2006), "Kinetic analysis of treatment of textile wastewater in hybrid column upflow anaerobic fixed bed reactor",
Chemical Engineering Journal. 122(1–2), pp. 87-92.
67. Sesay, M. L, Özcengiz, G, and Sanin, F. D (2006), "Enzymatic extraction of activated sludge extracellular polymers and implications on bioflocculation",
Water research. 40(7), pp. 1359-1366.
68. Sheng, G-P, Yu, H-Q, and Li, X-Y (2010), "Extracellular polymeric substances (EPS) of microbial aggregates in biological wastewater treatment systems: a review", Biotechnology advances. 28(6), pp. 882-894.
69. Slokar, Y.M. and Marechal, A.M.L. (1998), "Methods of decoloration of textile wastewaters", Dyes and Pigments. 37(4), pp. 335-356.
70. Solís, Myrna, et al. (2012), "Microbial decolouration of azo dyes: A review",
Process Biochemistry. 47(12), pp. 1723-1748.
71. Späth, R., Flemming, H. C., and Wuertz, S. (1998), "Sorption properties of biofilms", Water Science and Technology. 37(4), pp. 207-210.
72. Subramanian, S. Bala and etal (2010), "Extracellular polymeric substances (EPS) producing bacterial strains of municipal wastewater sludge: isolation, molecular identification, EPS characterization and performance for sludge settling and dewatering", Water research. 44(7), pp. 2253-2266.
73. Sutherland, I.W. (1994), " Structure-function relationships in microbial exopolysaccharides", Biotechnology advances. 12(2), pp. 393-448.
74. Tan, I. A. W., Ahmad, A. L., and Hameed, B. H. (2008), "Adsorption of basic dye on high-surface-area activated carbon prepared from coconut husk: Equilibrium, kinetic and thermodynamic studies", Journal of Hazardous Materials. 154(1–3), pp. 337-346.
75. Van, Nguyen Hai, et al. (2015), "Extracellular polymeric substances production in sludge by bacteria isolated from Hanoi brewery", Tap Chi Sinh Hoc.
36(3).
76. Vijayaraghavan, K. and Yun, Yeoung-Sang (2007), "Utilization of fermentation waste (Corynebacterium glutamicum) for biosorption of Reactive Black 5 from aqueous solution", Journal of Hazardous Materials. 141(1), pp. 45-52. 77. Vijayaraghavan, K. and Yun, Yeoung-Sang (2008), "Biosorption of C.I.
Reactive Black 5 from aqueous solution using acid-treated biomass of brown seaweed Laminaria sp", Dyes and Pigments. 76(3), pp. 726-732.
78. Wang, S.-G. and al., et (2007), "Production of a novel bioflocculant by culture of Klebsiella mobilis using dairy wastewater", Biochemical engineering journal. 36(2), pp. 81-86.
79. Wingender, Jost, Neu, Thomas R, and Flemming, Hans-Curt (1999), Microbial
extracellular polymeric substances: characterization, structure and function,
80. Wingender, Jost, Neu, Thomas R., and Flemming, Hans-Curt (1999), "What are bacterial extracellular polymeric substances?", Microbial extracellular polymeric substances, Springer, pp. 1-19.
81. Wong and Y.-S., et al. (2012), " Production of bioflocculant by Staphylococcus cohnii ssp. from palm oil mill effluent (POME)", Water, Air, & Soil Pollution,. 223(7), pp. 3775-3781.
82. Wu, J.-Y. and Ye., H.-F. (2007), "Characterization and flocculating properties of an extracellular biopolymer produced from a Bacillus subtilis DYU1 isolate", Process Biochemistry. 42(7), pp. 1114-1123.
83. Yagub, M.T., et al. (2014), "Dye and its removal from aqueous solution by adsorption: A review", Advances in Colloid and Interface Science. 209, pp.
172-184.
84. Yang, Q. and al., et (2012), "A novel bioflocculant produced by Klebsiella sp. and its application to sludge dewatering", Water and Environment Journal.
26(4), pp. 560-566.
85. Zhang, J., etal (2002), "Characterization of a bioflocculant produced by the marine myxobacterium Nannocystis sp. NU-2", Applied microbiology and biotechnology. 59(4-5), pp. 517-522.
86. Zhang, X and Bishop, P.L. (2003), "Biodegradability of biofilm extracellular polymeric substances", Chemosphere. 50(1), pp. 63-69.
87. Zhang, Z., et al. (2009), "A novel biosorbent for dye removal: extracellular polymeric substance (EPS) of Proteus mirabilis TJ-1", J Hazard Mater.
163(1), pp. 279-284.