Insights into lead removal in water using a novel carbonized material derived from the by‐product of oil refining: action mechanism and performance optimization

Abstract BACKGROUND Pollution control by the treatment of waste is a hot issue currently being studied that continues to attract more and more attention. In this work, by using the solid by‐products of oil refining (i.e., spent bleaching earth, SBE) as the raw materials, an environmentally‐friendly adsorbent (i.e., spent bleaching earth carbon, SBE@C) was prepared by the pyrolysis of SBE to adsorb Pb(II) from water. RESULTS Herein, Pb(II) maximum adsorption capacity of SBE@C (63.30 mg g –1 ) from the Langmuir model is about twice that of SBE (33.13 mg g –1 ). This is mainly attributed to the increased surface area and surface hydrophobicity of SBE@C after pyrolysis. The adsorption kinetics indicated that the pseudo‐second‐order kinetic model and the Elovich model can better fit the kinetic process of SBE and SBE@C for Pb(II) adsorption, respectively. Coexisting cations cause the decrease of Pb(II) adsorption capacity by SBE@C to varying degrees, and the order of their inhibition is: Na + < K + < Mg 2+ < Cu 2+ < Al 3+ < Fe 3+ . Increasing the initial pH of the solution (2.20–5.75) can promote Pb(II) adsorption capacity of SBE@C. CONCLUSION Based on the results of characterization, Pb(II) adsorption mechanism by SBE@C is proposed, including the surface adsorption, electrostatic attraction, ion exchange, and surface complexation. Meanwhile, SBE@C has an excellent re‐utilization ability, and the adsorption ability of SBE@C was speculated to be lost after nine cycles. Overall, SBE@C is considered an economical and efficient adsorbent with broad application prospects.