title: Novel cross-linked polymers having pH-responsive amino acid residues for the removal of Cu2+ from aqueous solution at low concentrations.
abstract: Two novel cross-linked anionic polyelectrolytes (CAPE) I and II containing pH-responsive amino acid residues have been synthesized via cycloco- and ter-polymerization of a monomer having diallylammonioethanoate motif (90mol%) and a cross-linker 1,1,4,4-tetraallylpiperazinium dichloride (10mol%) in the absence and presence of SO2 (100mol%), respectively. The experimental data for the adsorption of Cu(2+) on the CAPES fitted Lagergren second-order kinetic model thereby indicating the chemical nature of the adsorption process. The fitness order of Freundlich>Langmuir>Temkin for the isotherm models for CAPE I showed the favorability of adsorption on a heterogeneous surface, whereas for CAPE II the fitness order of Langmuir>Freundlich>Temkin certified the favorability toward monolayer adsorption. The adsorption process was spontaneous and endothermic in nature with negative and positive values for ΔG and ΔH, respectively. For the sorbents CAPE I and CAPE II, the efficiency of Cu(2+) removal at an initial metal concentration of 200ppb was found to be 77.5 and 99.4%, respectively. Desorption efficiencies were found to be 88 and 93% for CAPE I and CAPE II, respectively. Treatment of real wastewater samples spiked with Cu(2+) ions showed the excellent ability of the resins to adsorb metal ions.
authors: Chemistry Department, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia. shaikh@kfupm.edu.sa
authors: Shaikh A
authors: SA
authors: Ali
authors: Othman Charles S
authors: OC
authors: Al Hamouz
authors: Nouri M
authors: NM
authors: Hassan
mesh_terms: D000327:Adsorption; D000596:Amino Acids / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D011108:Polymers; D014874:Water Pollutants, Chemical; D003300:Copper