Removal of Ni (II), Co (II) and Pb (II) ions from aqueous media using Starch Stabilized Magnetic Nanoparticles as adsorbents

Abstract

Varying percentages (0, 0.005, 0.010, 0.015, 0.020 and 0.025) of ecofriendly Starch Stabilized Magnetic Nanoparticles (SSMNPs) were used in the removal of M²⁺ (Ni²⁺, Co²⁺ and Pb²⁺) ions from aqueous media by the batch adsorption technique. The λmax determined and used for Ni²⁺, Co²⁺ and Pb²⁺ were 400, 380 and 320 nm respectively. The influence of pH, adsorbent starch concentration, initial metal concentration and contact time on the removal processes was investigated. The results showed that 0.025 % loaded SSMNPs gave the optimal sorption efficiencies of 91.3 (pH = 6.8 & 11.1), 90.91 and 96.97 % (at pH < 3) respectively for all three ions. The contact times required to reach the equilibrium concentrations were 15, 75 and 105 mins for Pb²⁺, Co²⁺ and Ni²⁺ ions respectively. The kinetic rate constants (Lagergren and Pseudo-2^nd-order) for Ni²⁺ and Co²⁺ adsorption were all greater than those from Pb2+ions. Langmuir correlation coefficients showed a better fit for the adsorption isotherms. Ni sorption capacity of 60.61 mg g^-1 obtained from Langmuir was the highest of the three at constant [SSMNPs] while 109.89 mg g^-1 for Pb with was the highest at constant [M²⁺].