- Research article
- Open Access
Adsorption performance of packed bed column for nitrate removal using PAN-oxime-nano Fe2O3
© Jahangiri-rad et al.; licensee BioMed Central Ltd. 2014
- Received: 18 January 2014
- Accepted: 28 May 2014
- Published: 4 June 2014
The Erratum to this article has been published in Journal of Environmental Health Science and Engineering 2014 12:120
A continuous fixed bed study was carried out by using PAN-oxime-nano Fe2O3 as a sorbent for the removal of nitrate from aqueous solution. The effect of factors, such as flow rate (2, 5 and 7 mL/min) and bed depth (5, 10 and 15 cm) were studied. Data confirmed that the breakthrough curves were dependent on flow rate and bed depth. The adsoption capacities observed in diffent conditions of flow rates (2,5 and 7 mL/min) were 11.65, 24.38 and 25.89, respectively. Thomas model was applied to experimental data to predict the breakthrough curves using linear regression and to determine the characteristic parameters of the packed bed column. Bed depth/service time analysis (BDST) model was used to investigate the effect of bed depth on breakthrough curves. The results showed that Thomas model was suitable for the normal description of breakthrough curve at the experimental condition. The data were in good agreement with BDST model with R2 > 0.98. Statistical analyses were performed on fluoride removal obtained from different flow rates using SPSS16 software by applying Kruskal- Wallis test. These findings suggested that PAN-oxime-nano Fe2O3 in the column structure presents a great potential in removal of nitrate from aqueous solutions.
- PAN-oxime-nano Fe2O3
- Packed bed column
- Breakthrough curve
The principal sources of nitrogen are from nitrogeneous compounds produced by plant and animals or the mining of sodium nitrate for use in fertilizers, and the atmosphere. The most oxidized form of nitrogen is nitrate[1, 2]. World wide, the average intake of nitrate is about 75 to 100 mg/d, of which approximately 80 to 90 percent comes from vegetables. people on a vegetarian diet may consume as much as 250 mg/d of nitrate. Accordingly, drinking water accounts for only 5 to 10 percent of nitrates consumed. However, if the nitrate levels in the water are five times the MCL (10 mg/L), water may supply a person about half the daily diet requirements3. Nitrate is of primary concern for infants younger than 6 months of age. Infants are very susceptible to methemoglobinemia, a condition known as “blue baby syndrome.” High nitrate levels that are reduced in the stomach and/or the saliva of an infant to nitrite cause blue baby syndrome. Nitrite in the blood combines with hemoglobin to form methemoglobin, which reduces the capability of the blood to transport oxygen throughout the body. This results in the skin of a baby turning blue and can be fatal. The present MCL in the United States is 10 mg/L as nitrate and Canada has established a maximum acceptable concentration (MAC) of 10 mg NO3 (N/L). Due to the fact that nitrate is a stable, highly soluble ion, it is difficult to remove by conventional processes. Present technologies for nitrate removal from water supplies include chemical and biological denitrification, reverse osmosis, electrodialysis, ion exchange and adsoprtion. The process of adsorption of the material through of a fluid mixture flowing in to a packed column has gained great interest in recent years. There is a need to carry out the column studies to assess the required contact time for the adsorbate to achieve equilibrium as the results obtained from the batch studies for the contaminants adsorption studies may not be directly applied for field application in the treatment of polluted water. In the present study, PAN-oxime-nano Fe2O3 were used for nitrate removal. Continuous adsorption experiments were conducted to understand and quantify the effect of influencing parameters such as, initial floe rates and bed heights on breakthrough curve. BDST model, which offers a simple approach and rapid prediction of adsorber performance, is applied for modelling adsorption of nitrate in PAN-oxime-nano Fe2O3 column.
Preparation and characterization of PAN-oxime-nano Fe2O3
Hydroxilamine hydrochloride (16 g), sodium carbonate (12 g), and 0.4 g of PAN powder were added to a 250 mL bottle to which 100 mL of deionized water was added and shaken. The reaction was carried out at 70°C for 120 min. After reaction, the resultant was filtered and let to dry. Fe2O3 was coated on PAN functionalized by adding 0.2 g of selected Fe2O3 and 100 mL deionized water in a sealed bottle. The solution was shaken at 70°C for 120 min. The resultant was filtered and dried in a vacuum oven at 60°C. PAN functionalized-Fe2O3 was used as an adsorbent. The characteristics of PAN-oxime-nano Fe2O3 was studied by XRD, FTIR and SEM in our earlier study.
Where qe is the nitrate adsorbed (mg/g), C0 is the influent nitrate concentration (mg/L) Ce is effluent nitrate concentration (mg/L), Ve is the volume of solution required to reach the exhaustion point (L) and m is the mass of adsorbent (g).
Modeling of column operation
Full-scale column operation was designed according to the data collected in laboratory level. Many mathematical models have been used for the evaluation of efficiency and applicability of the column models for full scale operations. To design a column sorption process it was necessary to predict the breakthrough curve or concentration time profile and sorption capacity of the sorbent for the selected sorbate. Many models have been developed to predict the sorption breakthrough behaviour with high degree of accuracy. In this study the Thomas model was used to evaluate the behaviour of the selected adsorbent-adsorbate system.
Adsorption capacity of the column
Descriptive statistical analysis of various flow rates on fluoride removal at time of 9 h
Results of Kruskal Wallis test statistics
Effect of flow rate
Effect of bed height
The Thomas and BDST model parametres for adsorption of nitrate on PAN-oxime-nano Fe 2 O 3
Thomas model parameters
Flow rate (mL/min)
BDST model parameters
K a (L/mg h)
A good removal of nitrate was observed by fixed-bed by PAN-oxime-nano Fe2O. The adsorption studied showed that at longer bed depth better removal of nitrate would be achieved. The calculated adsorption capacity (N0) and the rate constant (Ka) were 1433 Mg/L and 0.0112 L/mg h, respectively. Thomas and BDST models were successfully used for predicting breakthrough curves for nitrate removal using different flow rates and depth. The application of the BDST model at 10% of breakthrough point gave satisfactory results with an R2 = 0.999.
The authors would like to thank the staff of medical sciences research center, Islamic Azad University, Tehran, Iran for their collaboration in this research.
- Nixon N: English water utility tackles nitrate removal. Water Eng Manage 1992, 139(3):27–28.Google Scholar
- Bailey-Watts AE, Gunn IMD, Kirika A: 'Loch Leven: Past and Current Water Quality and Options for Change'. Edinburgh: Report to the Fourth River Purification Board, Institute of Freshwater Ecology; 1993.Google Scholar
- Manahan Stanley E: Fundamentals of Environmental Chemistry. Boca Raton: CRC PressLLC; 2001.Google Scholar
- Vladimir NB: Environmental Chemistry: Asian Lessons. New York, Boston, Dordrecht, London, Moscow: Kluwer Academic Publishers; 2003.Google Scholar
- Huang YH, Zhang TC: Effects of low pH on nitrate reduction by iron powder. Water Res 2004, 38: 2631–2642. 10.1016/j.watres.2004.03.015View ArticleGoogle Scholar
- Schoeman JJ, Steyn A: Nitrate removal with reverse osmosis in a rural area in South Africa. Desalination 2003, 155: 15–26. 10.1016/S0011-9164(03)00235-2View ArticleGoogle Scholar
- Hell F, Lahnsteiner J, Frischherz H, Baumgartner G: Experience with full-scale electrodialysis for nitrate and hardness removal. Desalination 1998, 117: 173–180. 10.1016/S0011-9164(98)00088-5View ArticleGoogle Scholar
- Samatya S, Kabay N, Yuksel U, Arda M, Yuksel M: Removal of nitrate from aqueous solution by nitrate selective ion exchange resins. Reac Funct Polym 2006, 66: 1206–1214. 10.1016/j.reactfunctpolym.2006.03.009View ArticleGoogle Scholar
- Baba Y, Ohguma K, Kawano K: Highly selective adsorption resins, Synthesis of chitosan derivatives and their adsorption properties for nitrate anion. Chem 1999, J1999(7):471–472.Google Scholar
- Bao ML, Griffini O, Santianni D, Barbieri K, Burrini Dand Pantani F: Removal of bromate ion from water using granular activated carbon. Water Res 1999, 33: 2959–2970. 10.1016/S0043-1354(99)00015-9View ArticleGoogle Scholar
- Nabizadeh R, Jahangiri-Rad M, Yunesian M, Nouri J, Moattar F, Sadjadi F: Synthesis and characterization of functionalized polyacrylonitrile coated with iron oxide nanoparticles and its applicability in nitrate removal from aqueous Solution. Des awter treatment 2013. doi:10.1080/19443994.2013.867816Google Scholar
- Gupta VK: Equilibrium uptake, sorption dynamics, process development, and column operations for the removal of copper and nickel fromaqueous solution andwastewater using activated slag, a low-cost adsorbent. Ind Eng Chem Res 1998, 37: 192–202. 10.1021/ie9703898View ArticleGoogle Scholar
- Baek K, Song S, Kang S, Rhee Y, Lee C, Lee B, Hudson S, Hwang T: Adsorption kinetics of boron by anion exchange resin in packed column bed. J Ind Eng Chem 2007, 13(3):452–456.Google Scholar
- Chang H, Yuan X, Tian H, Zeng A-W: Experiment and prediction of breakthrough curves for packed bed adsorption of water vapor on cornmeal. Chem Eng Process 2006, 45: 747–754. 10.1016/j.cep.2006.03.001View ArticleGoogle Scholar
- Goud VV, Mohanty K, Rao MS, Jayakumar NS: Prediction of mass transfer coefficients in packed bed using tamarind nut shell activated carbon to remove phenol. Chem Eng Technol 2005, 28(9):991–997. 10.1002/ceat.200500099View ArticleGoogle Scholar
- Khraisheh MA, Al-Degs YS, Allen S, Ahmad M: Elucidation of the controlling steps of reactive dyes adsorption on activated carbon. Ind Eng Chem Res 2002, 41: 1651–1657. 10.1021/ie000942cView ArticleGoogle Scholar
- Faust SD, Aly OM: Adsorption Processes for Water Treatment. Guidford, Butterworth Scientific Ltd: Butterworth Publishers; 1987. ISBN 0–409–90000–1Google Scholar
- Kavak D, Öztürk N: Adsorption of boron from aqueous solution by sepirolite: II Column studies. II Illuslrararasi Bor Sempozyumu 2004, 23–25: 495–500.Google Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.