Élimination des ions ammonium de solutions aqueuses par la silice mésoporeuse (SBA-15) fonctionnalisée avec des groupements organiques acides

Authors: Babou Kammoe, Romuald Brice
Advisor: Hamoudi, SafiaBelkacemi, Khaled
Abstract: Water pollution resulting from the excessive presence of nitrogen nutrients arising from agricultural practices and human activities such as the discharge of domestic and industrial wastewater has become a major environmental problem. The main objective of this study is to optimize the formulation of new adsorbents for the removal of ammonium ions contained in agricultural runoff. For this purpose, two mesoporous materials functionalized with arene and propyl sulfonic acid groups by cocondensation and post-synthesis grafting on the one hand and a novel adsorbent containing a bridged benzene moiety on the other hand were synthesized. They have been characterized and tested in batch and continuous modes. Arene and propylsulfonic acid adsorbents with an organosilane/silica molar ratio of 20% show a maximum adsorption capacity of about 25 mg NH4+/g at the lowest temperature studied (5° C). For a given initial ammonium concentration, the removal efficiency (W) increased with increasing adsorbent loading. The adsorption capacity was improved by increasing the molar organosilane silica ratio to reach 42 mg NH4+/g with a ratio of 40% at 25 ° C. The equilibrium data of both adsorbents followed the Langmuir model and the kinetic pseudo second order model is the one that best describes their kinetic behavior. Negative values of the enthalpy (ΔH0) and entropy (ΔS0) obtained indicate that the reaction is exothermic and that there is downward of the random arrangement of the adsorbate at the solid/liquid interface, respectively. Finally, the adsorbents are regenerated easily and maintained their adsorption capacity after five consecutive cycles of adsorption-desorption. The continuous study was conducted with the arene sulfonic acid adsorbent synthesized by grafting. The results obtained show that the time of occurrence of breakthrough curves decreases with increasing flow rate and initial ammonium concentration, but increases with increased bed height. Thomas and Yoon-Nelson models allowed a good prediction of experimental breakthrough curves. Finally, the breakthrough curves were not changed significantly after three consecutive cycles of adsorption-desorption. With the adsorbent containing the bridged benzene group, adsorption capacities between 34 and 40 mg NH4+/g were obtained.
Document Type: Thèse de doctorat
Issue Date: 2014
Open Access Date: 20 April 2018
Permalink: http://hdl.handle.net/20.500.11794/25183
Grantor: Université Laval
Collection:Thèses et mémoires

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