Study on the Adsorption of CuFe2O4-Loaded Corncob Biochar for Pb(II)

A series of the magnetic CuFe2O4-loaded corncob biochar (CuFe2O4@CCBC) materials was obtained by combining the two-step impregnation of the corncob biochar with the pyrolysis of oxalate. CuFe2O4@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 CuFe2O4@CCBC(5%) demonstrated a specific surface area of 74.98 m(2)center dot g(-1), saturation magnetization of 5.75 emu center dot g(-1)and pH(ZPC)of 7.0. The adsorption dynamics and thermodynamic behavior of Pb(II) on CuFe2O4@CCBC and CCBC were investigated. The findings indicated that the pseudo-second kinetic and Langmuir equations suitably fitted the Pb(II) adsorption by CuFe2O4@CCBC or CCBC. At 30 degrees C and pH = 5.0, CuFe2O4@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 x 10(-3)g center dot mg(-1 center dot)center dot min(-1)and 132.10 mg center dot g(-1)separately, which were obviously higher than those of CCBC (4.38 x 10(-3)g center dot mg(-1)center dot min(-1)and 15.66 mg center dot 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 CuFe2O4-loaded biochar presents a high potential for use as an eco-friendly adsorbent to eliminate the heavy metals from the wastewater streams.