Removal of Copper from Water and Wastewater Using Dolochar

Since dolochar is a sponge iron industry waste with limited reuse options, it is important to develop useful applications for this waste stream. Here, the adsorption efficiency of dolochar for copper (Cu) was evaluated under a varying parameters including adsorbent dose, contact time, initial concentration, pH, stirring rate and temperature, via batch analysis. Complete Cu removal (100%) with a maximum uptake capacity of 30 mg g−1 was observed under optimised conditions of 60 mg L−1 initial concentration, pH 5, 15 min contact time, 2 g L−1 adsorbent dose and 120-rpm agitation. The adsorption of Cu by dolochar best fitted the Langmuir adsorption model indicating monolayer adsorption of Cu. Kinetics data obeyed a pseudo-second-order reaction with a moderate fit to the intraparticle diffusion model. Thermodynamic studies indicated that the adsorption of Cu by dolochar was an exothermic and spontaneous reaction. The feasibility of using dolochar for Cu-contaminated wastewater remediation was also assessed by treating a Cu industry wastewater sample with dolochar. Cu removal efficiency of 99.4% was observed from wastewater under optimised conditions, highlighting a new useful application for the use of dolochar.