Enhanced removal of chromium (VI) from wastewater using active carbon derived from Lantana camara plant as adsorbent

Activate carbon prepared from the stems of Lantana camara plant (ACSLC) is investigated as adsorbent for the removal of chromium (Cr) (VI) from polluted water using batch methods of extraction. Various extraction conditions such as pH, initial concentration of Cr (VI), sorbent dosage, temperature, equilibration time and presence of co-ions are optimized. The adsorption capacity is found to be 26.25 mg/g and is more than hitherto reported sorbents in the literature. The spent adsorbent can be regenerated and reused with a marginal reduction in its adsorption capacity. The active carbon is characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) studies. The sorption mechanism is investigated using various isotherm models and found that the Freundlich model describes the adsorption process well. Thermodynamic studies reveal the endothermic and spontaneous nature of physisorption. The kinetics of adsorption is well defined by the pseudo-second-order model. The methodology developed is successfully applied to effluent samples collected at various industries.