Study on the Adsorption of CuFe(2)O(4)-Loaded Corncob Biochar for Pb(II)

A series of the magnetic CuFe(2)O(4)-loaded corncob biochar (CuFe(2)O(4)@CCBC) materials was obtained by combining the two-step impregnation of the corncob biochar with the pyrolysis of oxalate. CuFe(2)O(4)@CCBC and the pristine corncob biochar (CCBC) were characterized using XRD, SEM, VSM, BET, as well as pH(ZPC) measurements. The results revealed that CuFe(2)O(4) had a face-centered cubic crystalline phase and was homogeneously coated on the surface of CCBC. The as-prepared CuFe(2)O(4)@CCBC(5%) demonstrated a specific surface area of 74.98 m(2)·g(−1), saturation magnetization of 5.75 emu·g(−1) and pH(ZPC) of 7.0. The adsorption dynamics and thermodynamic behavior of Pb(II) on CuFe(2)O(4)@CCBC and CCBC were investigated. The findings indicated that the pseudo-second kinetic and Langmuir equations suitably fitted the Pb(II) adsorption by CuFe(2)O(4)@CCBC or CCBC. At 30 °C and pH = 5.0, CuFe(2)O(4)@CCBC(5%) displayed an excellent performance in terms of the process rate and adsorption capacity towards Pb(II), for which the theoretical rate constant (k(2)) and maximum adsorption capacity (q(m)) were 7.68 × 10(−3) g·mg(−1·)·min(−1) and 132.10 mg·g(−1) separately, which were obviously higher than those of CCBC (4.38 × 10(−3) g·mg(−1)·min(−1) and 15.66 mg·g(−1)). The thermodynamic analyses exhibited that the adsorption reaction of the materials was endothermic and entropy-driven. The XPS and FTIR results revealed that the removal mechanism could be mainly attributed to the replacement of Pb(2+) for H(+) in Fe/Cu–OH and –COOH to form the inner surface complexes. Overall, the magnetic CuFe(2)O(4)-loaded biochar presents a high potential for use as an eco-friendly adsorbent to eliminate the heavy metals from the wastewater streams.