Removal of ammonium nitrogen (NH4+-N) by Cu-loaded amino-functionalized adsorbents

Biplab K. Mahata, Kun Lin Chung, Sue-Min Chang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Cu-loaded amino-functionalized SiO2 and weak-base-anion-exchange resin were prepared as advanced adsorbents for NH4+ removal and their adsorption ability and mechanisms were insightfully studied. Ammonium adsorption went through endothermic deprotonation followed by exothermic complexation (ΔH = −68.03 kJ/mol) to the Cu2+ ions. Such chemisorption followed a second-order kinetics and the Langmuir isotherm. The adsorption quickly reached an equilibrium within 1.0–60 min with an extraordinarily high rate constant of 0.01–2.86 g/mg-min. Besides, a high adsorption capacity of 9.30–21.37 mg/g was obtained. The adsorption ability effectively increased with increasing initial pH values, and the final pH was maintained at 5.3–5.8 due to the buffering effect in the –NH/CuCl2/NH3 system. Coexistence of 1.0–5.0 mM chloride-based salts (NaCl, KCl, CaCl2, MgCl2) promoted the NH4+ adsorption by 1.5–1.9 times. However, over amounts of salts inhibited the adsorption. The used adsorbent was successfully recovered by soaking with 0.15 M NaCl solution and 94.37–99.97% adsorption ability was preserved within four recovery cycles.

Original languageEnglish
Article number128589
Pages (from-to)1-11
Number of pages11
JournalChemical Engineering Journal
StatePublished - 1 May 2021


  • Amino groups
  • Ammonium-N (NH4+-N)
  • Complexation
  • Cuion
  • Weak-base-anion-exchange resin


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