The objective of this work was to study the effect of particle size (500–2000, 250–500, and less than 250 µm) and bio-adsorbent (orange, potato, and passion fruit) on the removal of lead and chromium from solution. The size and type of peels affected the capacity to adsorb metal ions (p <0.05). Passion fruit had the highest metal adsorption, followed by orange and potato, since the cation exchange capacity (217.70 ± 39.57 cmol (+) kg-1) was higher in passion fruit. The size of the adsorbent did not affect the organic matter, ash, exchange capacity, surface chemistry, or pH of the peels. However, these properties were different between the bio-adsorbents (p <0.05). Adsorption isotherms of the metals did not fit a single model. The Freundlich equation explained the adsorption of the metallic ions to the orange rind, and of lead to the passion fruit. The linear model was the best fit for the adsorption isotherms of the metals on potato peel. The adsorption of chromium on the passion fruit had a maximum adsorption capacity of 3.3 mg g-1. These results indicate that plant waste materials, especially passion fruit peel, have potential as feasible and low-cost adsorbent.