Biochar/MnAl-LDH composites for Cu (ΙΙ) removal from aqueous solution

Biochar/MnAl-layered double hydroxides (LDH) composites were prepared to remove Cu (ΙΙ) from aqueous solution. The affecting factors including sorbent dosage, initial pH and coexistence cations were investigated by batch experiments. The data of X-ray diffraction (XRD), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) showed that biochar/MnAl-LDH composites was successfully synthesized. The characterizations also indicated the adsorption process involved surface precipitation Cu2.5(OH)3SO4 and isomorphic substitution of Mn (ΙΙ) with Cu (ΙΙ). Kinetics and isotherms studies showed that Cu (ΙΙ) adsorption onto biochar/MnAl-LDH followed pseudo second order model and Langmuir model. The rate constant k2 increased with solution pH. The maximum adsorption capacity of Cu (ΙΙ) on biochar/MnAl-LDH was 74.07mg/g. Compare to other modified biochar and activated carbon, biochar/MnAl-LDH showed higher sorption performance and potential applicability for heavy metal removal from waste water.