<p>Environmental pollution with heavy metals has caused serious concerns due to their carcinogenic properties, no degradable and biological accumulation. Therefore, it is necessary to remove them to allowable levels before discharging into the environment. One of the effective technologies for heavy metal removal is the ion flotation method due to economy, availability, and high removal power for ions at low concentrations. The purpose of the present study was to investigate nickel ion removal through green ion flotation process using tea waste, as a natural collector, after preparing an infusion. This experimental study was conducted as a pilot on a laboratory scale. The effective factors on the ion flotation process including the initial nickel concentration, solution pH, frother agent percentage, air flow rates, flotation times, and solution ionic strength were optimized for the nickel removal efficiency. To minimize the study cost, various experiments were designed using Design Expert software with the response surface methodology (RSM). The obtained results were analyzed using an ANOVA test with a confidence level of 95%. The experimental results indicated that increasing the aeration flow rate from 50 to 150&#xa0;mL/min increased the nickel removal efficiency to achieve the maximum value of 94% at pH 6. In conclusion, aeration flow rate and pH were among the most important effective factors on efficiency of green ion flotation process in removing nickel ions from aqueous solutions.</p>