Few studies have used biochar mixtures to remove potentially toxic elements from industrial wastewater. The present batch studies compare the adsorption of Cu 2 + , Cd 2 + , and Pb 2 + by single and mixed sorbents using rice husk feedstock (RH), rice husk biochar (RHB), ethylene-diamine-tetra-acetic acid-modified biochar (EDTA-RHB), and a mixture (MB) of these biosorbents. Metal sorption studies were carried out by varying the adsorbents, metal ion concentrations, contact time, and solution pH in a synthetic industrial wastewater. In all experiments, RHB, EDTA-RHB, and MB removed up to 98% of the metal ions within 60 min at pH 4. Kinetic studies showed that first- and second-order models gave the best fit for MB; whereas, the Freundlich model gave the best fit for the isotherm data. Results indicate that MB and EDTA-RHB treatments were more effective for adsorbing the studied heavy metals than RH or RHB. Such biosorbents could be useful in the treatment of co-existing potentially toxic elements from wastewater. • Individual and mixed biosorbents efficiently removed the heavy metals. • Double Gompertz model best fitted to the metal removal, vs. logistic, 2x logistic, or Gompertz. • Adsorption by mixed adsorbents best fitted with Freundlich compared to Langmuir model. • Mixed adsorbents had higher adsorption of Cu 2+ , Cd 2+ , and Pb 2+ in a mixture solution.