Abstract: N/O-rich porous carbon adsorbent was synthesized from coffee powder residue collected from the nearby cafeteria using pyrolysis at 200°C. The adsorbents were used for Ni adsorption using synthetic Ni-incorporated water. The structural, morphological, surface chemistry information of the sample was extracted using various characterization techniques. The two peaks at 23.3° and 41.1° in the X-ray diffraction pattern confirm the graphitic nature of carbon, whereas the third peak at 12.1° reveals the co-existence of certain graphitic oxide in the sample. The IR spectrum indicates the presence of N-containing (NH) functional groups on the virgin sample. A shift of band positions corresponding to NH and OH vibrations indicates adsorbed Ni(II) interaction with the sample. Experiment optimization of input variables by one factor at a time model was used to optimize three experimental parameters: solution pH, initial Ni(II) concentration (IC), and adsorbent dosage for higher Ni(II) removal and optimum time using Response surface methodology. The adsorption studies of the adsorbent toward Ni(II) removal from aqueous solution were performed using response surface methodology by optimizing adsorption parameters. According to the analysis of variance, a lack of fit of 1.38 is estimated, which validates the model very well. Analysis of variance techniques was used for experimental validation. The maximum removal efficiency of 97.6% is achieved at pH 7 for initial concentration 5.5 mg/L and adsorbent weight 0.2 g in 50 mL solution for 52 min. pHzpcof the sample was determined as 7 in agreement with the experiment confirming thereby the optimum pH for Ni(II) adsorption. Adsorption data were well fitted to Langmuir adsorption isotherm indicating a homogeneous monolayer adsorption of Ni(II) on the sample. The hydroxyl and amine functional groups on the sorbent form Ni complex via coordinate bonding with Ni(II). For Ni(II) content <9 mg/L, the adsorbent dosage and contact time can be optimized for a removal efficiency of 90–100%.