Design of hybrid PVA–CA–Jania rubens biomatrix for removal of lead

ABSTRACT

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 R_L values are in the range of 0.1–0.38. The sorption capacity (q_e) 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 (q_e) and maximum biosorption (q_m) 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
• kinetics
• pretreatment
• PVA–SA–J. rubens matrix
• SEM
• thermodynamics

Funding

The author is thankful to the Department of Science and Technology (SERB) for research grant financial support (Letter No. SERB/F/4631/2013-2014).