Graphite as a potential adsorbent for ammonium ions removal / Haszalina Abdul Halim, Nur Alwani Ali Bashah and Norhusna Mohamad Nor

The main focus of this work is to evaluate the potential of graphite powder as an adsorbent for ammonium ions (NH4+ ions) removal. Surface functional groups and thermal analysis of graphite adsorbent were conducted by using FTIR and TGA analyses, respectively. The experimental work covered batch adsorptions of NH4+ ions under various adsorption process parameters, which are adsorption contact time, adsorption temperature, initial concentration of NH4+ ions, and graphite adsorbent dosage. Detailed adsorption characteristics of NH4+ ions using graphite adsorbent were evaluated via adsorption isotherms study, implementing Langmuir and Freundlich isotherms. By adopting a one-factor-at-a-time (OFAT) approach, the best adsorption process parameters identified were 50 min of adsorption contact time, 25 °C of adsorption temperature, 100 mg/L NH4+ ions initial concentration, and 0.5 g graphite adsorbent dosage with up to 75 % removal of NH4+ ions. Freundlich adsorption isotherm was the best fitted for NH4+adsorption using graphite with R2 value of 0.9580. The findings of this work could be a benchmark to further develop the characteristics of graphite as a potential adsorbent for NH4+ removal.