The annual rise in global coffee consumption has resulted in large amounts of discarded spent coffee ground following the brewing process. Spent coffee ground is a biomass waste that can be utilized in various applications. The present study aimed to assess the possibility of using spent coffee grounds as an alternative adsorbent to remove nitrate from aqueous solutions. Batch adsorption experiments were performed at 298 K and the spent coffee ground underwent a chemical pre-treatment using hydrochloric acid (HCl) at different concentrations. The results showed that the most suitable pre-treatment concentration was 0.4 M of HCl. Experiments were also conducted to study the effects of the solution pH (pH 3–9) and adsorbent dosage (0.2–1.0 g) in terms of nitrate removal efficiency. The experimental data showed that the highest nitrate removal efficiency occurred at pH 4 with 58 ± 0.69% removal efficiency. The adsorption performance was improved from 34% to 68 ± 0.58% as the adsorbent increased from 0.2 g to 1.0 g. These results showed that spent coffee ground could potentially be utilized as the adsorbent for removing nitrate from aqueous solutions.
