Adsorption performance of rice husk towards copper ions from wastewater

This work reports the adsorptive discharge of copper ion (Cu(II)) from wastewater by using rice husk (RH) at ambient temperature. The RH was characterized by using scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. The percentage removal of Cu(II) from wastewater was increased from 33% to 62%, 31% to 67% and 49% to 66% with contact time, mass of RH, and temperature respectively whereas decreased from 68% to 52% with increasing initial concentration of solution. Adsorption isotherm study demonstrated that experimental data fitted well to non-linear Freundlich isotherm. Kinetics study showed that experimental data fitted well to non-linear pseudo-second-order model. Adsorption thermodynamic investigations represented that adsorption of Cu(II) was an endothermic process because the value of enthalpy (Delta H = 9.453 kJ/mol) was positive. Contrary, the negative value of Gibb's free energy represented that adsorption of Cu(II) was spontaneous process. Moreover, the influence of diverse ions on adsorption Cu(II) was also elucidated.