Removal of lead (II) from wastewater using active carbon of Caryota urens seeds and its embedded calcium alginate beads as adsorbents

Nitric acid activated carbon prepared from the seeds of Caryota urens plant (ACSCU) and the calcium alginate beads doped with the active carbon (CABCU) are investigated as adsorbents for the removal of lead (II) ions from polluted water using batch methods of extraction. By varying various physicochemical parameters such as pH, initial concentration of Pb (II), sorbent dosage, temperature, equilibration time and presence of co-ions, the extraction conditions are optimized for the maximum (89.0% for ACSCU and 96.0% for CABCU) removal of Pb (II). The adsorption capacities for ACSCU and CABCU are found to be 42.9 mg/g and 86.9 mg/g respectively. Even after five regenerations of adsorbents substantial amount (not less than 80%) of Pb (II) is removed. The active carbon is characterized using XRD, FESEM, and FT-IR and the sorption mechanism is investigated using various isotherms and noted that the Freundlich model describes well the adsorption process. Thermodynamic parameters are analyzed and inferred that the adsorption is endothermic and spontaneous in nature. 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.