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

摘要: Abstract This study concerns fixed-bed column experiments performed at a laboratory scale in order to remove nitrate ions from water using surfactant-modified (HDTMA+ = hexadecyltrimethylammonium) clinoptilolite as adsorbent. The influence of the initial concentration (0.32–2.42 mmol/L), flow rate or flux (1.6–47.2 cm/min) and presence competing anions chloride, sulphate bicarbonate, is examined. At beginning each experiment, removal rates R are very high, larger than about 95%, then decrease progressively during filtration. As expected, higher and/or are, earlier becomes completely inefficient. In comparison corresponding batch-wise experiments, performances Surfactant-Modified Zeolite better particular exchange values complete breakthrough (≈60%). anions, uptake variously affected, being significantly slightly reduced SO 4 2 - (exchange behavior similar one NO 3 ) HCO respectively, whereas with no affinity towards SMZ, has practically influence. Some leaching HDTMA+ occurs continuously upon filtration (concentration ≈ 10−4–10−5 mol/L). relation ecotoxicity these species (concentration limit ≈ 10−7 mol/L), treatment effluents necessary was successfully by through an activated carbon bed. Finally, 45 mmol/kg -loaded regeneration (NaBr 1 mol/L, L/S = 10 mL/g, batch system) achievable after 6 h.