Competitive removal of cationic dye (BR 46) and heavy metal (copper II) from synthetic textile effluent using adsorbent of Melia azedarach sawdust

Sawdust of Melia azedarach wood was investigated for removal of BR46 dye and Cu2+ from a binary-solute system. A central composite design was used to determine the effect of various variables including the initial concentration of dye (x(1)) and Cu2+ (x(2)), solution pH (x(3)), contact time (x(4)), and adsorbent dose (x(5)) in the process. Fourier transform infrared spectroscopy (FTIR) was utilized to characterize the surface chemistry of pristine-and solute-loaded sawdust. The results of FTIR showed that the functional groups, especially OH groups, on the sorbent surface are capable of adsorbing cationic dye and heavy metal. The mean removal efficiency of BR46 and Cu2+ was obtained as 92.07% and 92.72%, respectively. The experiments indicated the antagonistic adsorption of the cationic dye and heavy metal in a binary system. Adsorbent dose and contact time had the highest and lowest impacts on the decolorization efficiency, respectively, while solution pH and adsorbent dose were the most and the least influential variables on the copper removal, respectively. Adsorption isotherm studies revealed that the experimental data were better fitted to the Langmuir isotherm model. According to the study, adsorption process onto sawdust of M. azedarach can be considered as a choice for economical treatment of polluted effluents of the textile industry.