Burcu İLERİ, Ömer APAYDIN, Önder AYYILDIZ

DENITRIFICATION OF NITRATE BY COMBINED ULTRASOUND AND ZERO VALENT MAGNESIUM AT pH CONTROLLED CONDITIONS

In this study, ultrasound (US), zero-valent magnesium (Mg0) and their simultaneous combination were tested at different Mg0 doses (0.5, 1, 1.5, 2 ve 2.5 g/L), pH values (2, 4, 7 ve 9) and ultrasonic powers (30, 60 ve 90 W) for nitrate reduction. Ultrasound alone was found to be ineffective for nitrate removal at different pH values. Effect of ultrasonic power for pH controlled operation, nitrate reduction was increased with increasing dose of magnesium powder. Ultrasound induced profound effects on denitrification capacity of magnesium particles. For example, with controlling pH at 4, 95% of initial nitrate was reduced by 2.5 g/L of magnesium powder within 60 min, while keeping the applying combined US/Mg0 for 30, 60, and 90 W ultrasonic powers at the same dose, required durations to achieve at the same nitrate removal efficiencies were determined to be approximately 30, 20 and 20 min, respectively. When pH was controlled at 7 and 9, up to 70% of nitrate was removed by 2.5 g Mg0/L dose after 60 min , but in the same conditions with 90 W ultrasonic power a complete nitrate reduction was attained only within 30 min. Effect of ultrasonic on magnesium surface activation and nitrate removal was arised more clearly at alkaline conditions, when particle surface passivation was increased at increased pH . Nitrogen gas (N2), nitrite (NO2-) and ammonium/ammonia (NH4+/NH3) were detected as the major denitrification by-products following US/Mg0 treatment. As more ultrasonic power and magnesium dose were applied, the rate of conversion of nitrate to nitrogen gas increased significantly.

Keywords:

Ultrasound zero valent magnesium, nitrate reduction, passive film,

PDF

___

[1] Harter T., (2009). Agricultural Impacts on Groundwater Nitrate, Nitrates in Groundwater, Southwest Hydrology Magazine, 8 (4), 1–38.
[2] Almasri M.N., (2007). Nitrate Contamination of Groundwater: A conceptual Management Framework, Environmental Impact Assessment Review, 27 (3), 220–242.
[3] Almasri M.N., Kaluarachchi J.J., (2004). Assessment and Management of Long-term Nitrate Pollution of Groundwater in Agriculture-dominated Watersheds, Journal of Hydrology, 295 (1-4), 225–245.
[4] Doğanlar D.U., (2006). Effects of Wastewater Irrigation on Groundwater Quality, Yüksek Lisans Tezi, Fen Bilimleri Enstitüsü, Dokuz Eylül Üniversitesi.
[5] Grawal G.D., Lunkad S.K., Malkhed T., (1999). Diffuse Agricultural Nitrate Pollution of Groundwaters in India, Water Science and Technology, 39 (3), 67–75.
[6] Keeney D., Olson R.A., (1986). Sources of Nitrate to Groundwater, Critical Reviews in Environmental Control,16 (3), 257−304.
[7] İnsani Tüketim Amaçlı Sular Hakkında Yönetmelik (İTASHK), Ankara, (2005).
[8] Samatya S., (2006). Removal of Toxic Species (NO3-, F-) From Water By Ion Exchange, Electrodialysis and Sorption Methods, (Ph.D.), Ege Üniversitesi, Fen Bilimleri Enstitüsü.
[9] Kapoor A., Viraraghavan T., (1997). Nitrate Removal from Drinking Water-Review, Journal of Environmental Engineering, 123 (4), 371−380.
[10] Luk G. K., Au-Yeung W.C., (2002). Experimental Investigation on the Chemical Reduction of Nitrate from Groundwater, Advances Environmental Research, 6 (4), 441−453.
[11] Crane R.A., Scott T.B., (2012). Nanoscale Zero-valent Iron: Future Prospects for an Emerging Water Treatment Technology, Journal of Hazardous Materials, 211−212, 112−125.
[12] Hu H.Y., Goto N. ve Fujie K., (2001). Effect of pH on the Reduction of Nitrite in Water by Metallic Iron, Water Research, 35 (11), 2789–2793.
[13] Zhang J., Hao Z., Zhang Z., Yang Y., Xu X., (2010). Kinetics of Nitrate Reductive Denitrification by Nanoscale Zero-valent Iron, Process Safety and Environmental Protection 8 (8), 439–445.
[14] Tuğrul Z., (2006). Toz Halinde Fe0 ve Al0 ile Nitratın Kimyasal Denitrifikasyonu, Yüksek Lisans Tezi, Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü.
[15] Kumar M., Chakraborty S., (2006). Chemical Denitrification of Water by Zero-valent Magnesium Powder, Journal of Hazardous Materials, 135 (1-3), 112−121.
[16] Lee G., Park J., (2013). Reaction of Zero-valent Magnesium with Water: Potential Applications in Environmental Remediation, Geochimica et Cosmochimica Acta, 102, 162–174.
[17] Bokare A. D., Choi W., (2009). Zero-valent Aluminum for Oxidative Degradation of Aqueous Organic Pollutants, Environmental Science and Technology, 43 (18), 7130–7135.
[18] Choe S., Liljestrand H. M., Khim J., (2004). Nitrate Reduction by Zero-valent Iron under Different pH Regimes, Applied Geochemistry, 19 (3), 335–342.
[19] Huang Y. H., Zhang T. C., (2004). Effects of Low pH on Nitrate Reduction by Iron Powder, Water Research, 38 (11), 2631–2642.
[20] Ramavandi B., Mortazavi S.B., Moussavi G., Khoshgard A., Jahangiri M., (2011). Experimental Investigation of the Chemical Reduction of Nitrate Ion in Aqueous Solution by Mg/Cu Bimetallic Particles, Reaction Kinetics Mechanisms and Catalysis, 102 (2), 313–329.
[21] Mortazavi S.B., Ramavandi B, Moussavi G., (2011). Chemical Reduction Kinetics of Nitrate in Aqueous Solution by Mg/Cu Bimetallic Particles, Environmental Technology, 32(3), 251–260.
[22] Wan D., Liu H., Zhao X., Qu J., Xiao S., Hou Y., (2009). Role of the Mg/Al Atomic Ratio in Hydrotalcite-supported Pd/Sn Catalysts for Nitrate Adsorption and Hydrogenation Reduction, Journal of Colloid and Interface Science, 332 (1), 151–157.
[23] Devor R., Carvalho K.K., Aitken B., et.al., (2008). Dechlorination Comparison of Mono-substituted PCBs with Mg/Pd in Different Solvent Systems, Chemosphere, 73 (6), 896–900.
[24] Patel U, Suresh S., (2006). Dechlorination of Chlorophenol by Magnesium-Silver Bimetallic System, Journal of Colloid and Interface, 299 (1), 249–259.
[25] Mahamuni N.N., Adewuyi Y.G., (2009). Advanced Oxidation Processes (AOPs) Involving Ultrasound for Waste Water Treatment: A Review with Emphasis on Cost Estimation, Ultrasonic Sonochemistry, 17 (6), 990-1003.
[26] Hua I., Hoffmann M.R., (1987). Optimization of Ultrasonic Irradiation as an Advanced Oxidation Technology, Environmental Science Technology, 31 (8), 2237–2243.
[27] Mason T.J., Lorimer J.P., (2002). Applied Sonochemistry,Wiley VCH, pp 303.ISBN 3-527-30205-0.
[28] Mason T.J., Tiehm A., (2001). Advances in Sonochemistry, Volume 6, Ultrasound in Environmental Protection, ed. Elsevier, pp 273, ISBN 0-444-50705-.
[29] Brotchie Adam, Borisova D., Belova V., Möhwald H., Shchukin D., (2012). Ultrasonic Modification of Aluminum Surfaces: Comparison Between Thermal and Ultrasonics Effects, Journal of Physical Chemistry, 116 (14), 7952–7956.
[30] Morais N. L.P.A, Brett C.M.A., (2002). Influence of Ultrasound on the Corrosion of Aluminium, Key Engineering Material, 230–232, 412– 415.
[31] Wang A., Guo W., Hao F., Yue X., Leng Y., (2014). Degradation of Acid Orange 7 in Aqueous Solution by Zero-valent Aluminum Under Ultrasonic Irradiation, Ultrasonic Sonochemistry, 21(2), 572–575.
[32] Liang F., Fan J., Guo Y., Fan M., Wang J., Yang H., (2008). Reduction of Nitrite by Ultrasound Dispersed Nanoscale Zero-valent Iron
Particles, Industrial and Engineering Chemistry Research, 47 (22), 8550–8554. [33] Tsai Y.J., Chou F.C., Cheng T.C., (2009). Coupled Acidification and Ultrasound with Iron Enhances Nitrate Reduction, Journal of Hazardous Materials, 163 (2–3), 743–747.
[34] Geiger C.L., Ruiz N.E., Clausen C.A., Reinhart D.R., Quinn J.W., (2002). Ultrasound Pretreatment of Elemental Iron: Kinetic Studies of Dehalogenation Reaction Enhancement and Surface Effects, Water Research, 36 (5), 1342–1350.
[35] Chand R., Ince N.H., Gogate P.R., Bremner D.H., (2009). Phenol Degradation using 20, 300 and 520 kHz Ultrasonic Reactors with Hydrogen peroxide, Ozone and Zero valent Metals, Separation and Purification Technology, 67 (1), 103−109.
[36] Hung H.M., Ling F.H., Hoffmann M.R., (2000). Kinetics and Mechanism of the Enhanced Degradation of Nitrobenzene by Elemental Iron in the Presence of Ultrasound, Environmental Science and Technology, 34 (9), 1758–1763.
[37] Ileri B., Ayyildiz O., Apaydin O., (2015). Ultrasound-assisted activation of zero-valent magnesium for nitrate denitrification: Identification of reaction by-products and pathways, Journal of Hazardous Materials, 292, 1–8.
[38] APHA, (1995). Standard Methods for the Examination of Water and Wastewater, 20th Ed., Washington, DC.