Surface Modification of Starch by Isopropoxytris(ethylenediamino‐N‐ethoxy)Titanate with a Chelating Claw for Heavy Metal Removal

Abstract Isopropoxy tris(ethylenediamino‐N‐ethoxy) titanate‐modified starch (TIS) was prepared and characterized by XPS, FTIR, SEM, and TGA. It has been used for the removal of Cu 2+ , Co 2+ , Ni 2+ , and Mn 2+ from aqueous solutions. At an optimal pH of 7, fast adsorption was observed within 10 min of contact, and 80% of the maximum capacity was achieved. Adsorption reached equilibrium after 30 min. This course followed a pseudo‐second‐order equation with the sequence Cu 2+ > Mn 2+ > Co 2+ > Ni 2+ , which is related to the substitution rates of the hydrated metal ions. A linear relationship between the pseudo‐second‐order equation constant (log k 2 ) and substitution rate constants (log k hs ) of the hydrated metal ions was established. For the isotherm, the Langmuir equation fitted well with the adsorption data, suggesting monolayer coverage of the TIS surface. The maximum adsorption capacity for metal ions followed the order of Cu 2+ > Co 2+ > Ni 2+ > Mn 2+ . FTIR and thermal studies indicated the chelation of metal ions with ethylenediamino groups, in agreement with the adsorption investigations.