Investigation of Ammonium Ion Removal from Aqueous Solutions Using Arene- and Propylsulfonic Acid Functionalized Mesoporous Silica Adsorbents
- Romuald Brice Babou Kammoe and
- Safia Hamoudi *
To counter environmental threats to the water resources polluted by NH4+, which is common in wastewaters and agricultural runoff, adsorption using mesoporous functional materials represents a promising alternative to existing treatment methods. In this study, adsorption of NH4+ ions from aqueous solutions was investigated on arene- and propylsulfonic acid functionalized SBA-15 mesoporous silica materials. The adsorbents were synthesized via co-condensation and post-synthesis grafting procedures. Adsorbents were characterized by means of X-ray diffraction, N2 physisorption, titration, and elemental analyses. The effects of pH, NH4+ initial concentration, temperature, adsorbent loading, organosilane molar ratio, and presence of competitive species on the performance of the adsorbent materials were examined. All the adsorbents having an organosilane/silica molar ratio of 1:5 displayed maximum adsorption capacity around approximately 25 mg g−1 NH4+ at the lowest temperature investigated, 5°C. This capacity decreased with increasing temperature. For a given initial NH4+ concentration, the removal efficiency (W) increased with increasing adsorbent loading. For instance, W increased from 24 to 59% when the adsorbent loading was increased from 2 to 10 g L−1 at 25°C. The adsorption isotherms were well described by a Langmuir model equation. Adsorption capacity improved with increasing organosilane/silica molar ratio, reaching 42 mg g−1 NH4+ with a ratio of 2:5 at 25°C. Arene- and propylsulfonic acid functionalized SBA-15 materials synthesized via co-condensation and post-synthesis grafting proved to be effective high-capacity adsorbents for the removal of NH4+ ions from aqueous solutions.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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