Polyvinyl alcohol-sodium alginate (PVA-SA) matrix was fabricated and red algae Jania rubens was embedded for removal of lead from aqueous solutions. The Pb(II) uptake rate was rapid primarily at 1 h and equilibrium was achieved within 2 h. The optimum pH was 5, the data were well fitted by Langmuir and Freundlich models, and RL values are in the range of 0.1-0.38. The sorption capacity (qe) of PVA-calcium alginate (CA)-J. rubens matrix increased from 10.77 to 37.195 mg g-1 with increasing Pb(II) concentration from 24.86 to 98.75 mg L-1 at the temperature of 30°C and pH 5. The sorption capacity (qe) and maximum biosorption (qm) were noted as 37.179 ± 0.32 and 71.43 mg/g, respectively. The adsorption process was well described by pseudo-second-order model. The reaction is endothermic, is spontaneous, and increases in randomness. The functional groups present on matrix, i.e., -OH, -C-N, -C-O,-CO-NH, -NH2, -SH, and -C-OH, were intensely involved in the process. Scanning electron microscopy results revealed the morphological changes due to adsorption of Pb(II) on and inside of PVA-CA-J. rubens matrix. Desorption study indicates the efficient regeneration of PVA-CA-J. rubens biomass matrix for three cycles and is a promising matrix for removal of Pb(II) and can be used in continuous systems.
Keywords: FTIR; PVA–SA–J. rubens matrix; SEM; kinetics; pretreatment; thermodynamics.