Synthesis, characterization, and metal uptake capacity of a new polyaniline and poly(acrylic acid) grafted sodium alginate/gelatin adsorbent

• Published in: Desalination and water treatment 2014, Vol.52 (1-3), p.526-535
• Main Authors: Vani, T.J. Sudha, Reddy, N. Sivagangi, Reddy, P. Ramasubba, Rao, K.S.V. Krishna, Ramkumar, Jayshree, Reddy, A.V.R.
• Format: Article
• Language: English
• Subjects: Adsorbents; Polyaniline; Sodium alginate; Toxic metal ions
• ISSN: 1944-3986; 1944-3986
• DOI: 10.1080/19443994.2013.846460

The present work reports the development of new (sodium alginate-gelatin (SAG))-g-poly(acrylic acid)/polyaniline (SAPAPN) from sodium alginate/gelatin blend by cross-linking with glutaraldehyde, followed by grafting with poly(acrylic acid) and polyaniline by free radical polymerization using ammonium persulfate. The structure, thermal stability, and morphology of SAPAPN adsorbent was characterized by Fourier transform infrared spectroscopy, thermo gravimetric analysis, and scanning electron microscopy, and results were consistent with the expected structures. The influence of various experimental conditions like pH, time, and initial feed concentrations on the uptake of metal ions like Cu2+, Ni2+ by SAPAPN adsorbent was tested. It was seen that the adsorption equilibrium data could be fitted to the Langmuir isotherm. Desorption studies were performed in acid media and EDTA, to examine whether the SAPAPN adsorbent can be recycled for the metal ion removal. The results showed that with SAPAPN adsorbent, the maximum metal ion uptake achieved is 0.8386 mMg−1 for Cu2+ and 2.2026 mMg−1 for Ni2+, respectively. Metal ion sorption studies showed that the adsorbent can be used for the removal of hazardous metal ions from aqueous solutions. The copper and nickel uptake achieved suggests the potential use of the adsorbent to extract divalent toxic metals from industrial aqueous streams.