Vol.:(0123456789) 1 3 J Polym Environ DOI 10.1007/s10924-017-0958-9 ORIGINAL PAPER Adsorption Efciency of Polyaspartate-Montmorillonite Composite Towards the Removal of Pb(II) and Cd(II) from Aqueous Solution Abeer S. Elsherbiny 1,2  · Mohamed E. El-Hefnawy 1,2  · Ali H. Gemeay 2   © Springer Science+Business Media New York 2017 adsorption process. Also, The thermodynamic parameters were calculated and indicated that the adsorption was spon- taneous and exothermic process. The mechanism of cation exchange and complexation of metal ions was suggested. IPS composite has a considerable potential for the removal of heavy metal ions from aqueous solution and wastewater stream. Keywords Selective modifcation · Montmorillonite · Ionene · Polyaspartate · Adsorption · Heavy metals Introduction The fast developing areas in nanotechnology for waste- water treatment and environmental preservation are based on the synthesis of novel highly adsorbent materials or the modifcation of the traditional adsorbents. Organically modifed layered-silicates have been become an attractive class of organic–inorganic hybrid materials because of their potential use in a wide range of applications such as in pol- ymer nanocomposites, in paints, inks, greases, cosmetics, adsorbent, efuent treatment, catalysis, and drug delivery carrier [1]. Organo-clays have increasingly been used as adsorbents because they are cheaper than other materials. In many cases, organo-clay linings have been used as bar- riers in landflls to prevent contamination of groundwater and subsoil by leachates containing metals [2, 3]. Surface modifcation method of montmorillonite (Mt) by poly- mers was found to be one of the most efective methods, as the surface properties can be commonly changed by a variety of functional polymers. Mt has a lamellar structure with a thickness on the scale of nanometers (~1 nm) and has lateral dimensions ranging from 30 nm to several μm, depending on the silicate used [4]. These silicate layers are Abstract The selective modifcation of sodium mont- morillonite (Na + -Mt) surface with polyionene followed by poly (succinimde-co-aspartate) has been considered. Na + -Mt was allowed to react with well characterized poly- ionene in two fold excess. The resulting polyionene/Mt (IC) was further modifed with poly (succinimide-co-aspartate) through an ion exchange process. The obtained polyaspar- tate/Mt (IPS) composite was characterized by elemental analysis, X-ray difraction, FTIR spectroscopy, thermo- gravimetric analysis (TGA), scanning electron microscopy (SEM), and BET surface analyzer. The adsorption ef- ciency of IPS composite was investigated for the removal of Pb(II) and Cd(II) from aqueous solution under diferent experimental conditions including initial metal ions con- centration, temperature and single and binary mixture sys- tems of metal ions. The experimental data were analyzed by Langmuir, Freundlich, Temkin, and Dubinin-Radushk- evich models. Langmuir model reveals that the monolayer adsorption capacity of IPS was 92.59 and 67.57 mg/g for Pb(II) and Cd(II), respectively. The modifcation of par- ent Na + -Mt enhanced their adsorption capacity by about 87.91 and 29.84% for Pb(II) and Cd(II), respectively, due to inclusion of extra active sites of polyaspartate. The mean sorption energy, E calculated from Dubinin–Radushk- evich isotherm were 2.75 and 1.98 kJ/mol for the adsorp- tion of Pb(II) and Cd(II), respectively, indicating physical * Abeer S. Elsherbiny balsharbeeeni@kau.edu.sa; abeer.elsherbiny@science.tanta. edu.eg 1 Department of Chemistry, Science and Art College, King Abdulaziz University, Rabigh Campus, Rabigh 21911, Kingdom of Saudi Arabia 2 Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt