Nitrate sorption from water on a Surfactant-Modified Zeolite. Fixed-bed column experiments

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• 作者：Joachim Schick^a ; Philippe Caullet^a ; ^{P.Caullet@uha.fr} ; Jean-Louis Paillaud^a ; Joë ; l Patarin^a ; Claire Mangold-Callarec^b
• 关键词：Nitrate removal ; Fixed-bed column ; Surfactant-modified clinoptilolite ; HDTMA ; Regeneration
• 刊名：Microporous and Mesoporous Materials
• 出版年：2011
• 出版时间：July 2011
• 年：2011
• 卷：142
• 期：2-3
• 页码：549-556
• 全文大小：390 K

文摘

This study concerns fixed-bed column experiments performed at a laboratory scale in order to remove nitrate ions from water using a surfactant-modified (HDTMA⁺ = hexadecyltrimethylammonium) clinoptilolite as adsorbent. The influence of the initial nitrate concentration (0.32–2.42 mmol/L), the flow rate or flux (1.6–47.2 cm/min) and the presence of competing anions chloride, sulphate and bicarbonate, is examined. At the beginning of each experiment, removal rates R are very high, larger than about 95 % , and then decrease progressively during filtration. As expected, the higher the initial nitrate concentration and/or the flow rate are, the earlier the column becomes completely inefficient. In comparison to corresponding batch-wise experiments, the performances of the Surfactant-Modified Zeolite are better in the column in particular larger exchange rates values at complete breakthrough (≈60 % ). In the presence of competing anions, the nitrate uptake performances are variously affected, being significantly or slightly reduced in the presence of (exchange behavior similar to the one of ) or of respectively, whereas chloride, with no affinity towards SMZ, has practically no influence. Some leaching of HDTMA⁺ ions occurs continuously upon filtration (concentration ≈ 10⁻⁴–10⁻⁵ mol/L). In relation to the ecotoxicity of these species (concentration limit ≈ 10⁻⁷ mol/L), a treatment of the effluents is necessary and was successfully performed by filtration through an activated carbon bed. Finally, from a 45 mmol/kg -loaded SMZ, a complete regeneration (NaBr 1 mol/L, L/S = 10 mL/g, batch system) is achievable after about 6 h.