Novel tyrosine-containing inorganic–organic hybrid adsorbent in removal of heavy metal ions

Abstract

In this study, tyrosine-containing inorganic–organic hybrid bioadsorbent was synthesized, characterized, and used in the removal of heavy metal ions from aqueous solution. The preparation of adsorbent was conducted by hydrolysis of mixture between Ti-tyrosinate and poly-3-glycidyloxypropyltrimethoxysilane (poly-GPTS). This new hybrid adsorbent (hydrolyzed-[poly-GPTS/Ti-Tyr]) was characterized by several techniques. Adsorptions of Pb2+, Ni2+, Cu2+ and Zn2+ metal ions by new adsorbent have been performed with batch method. As a result of the large number of highly electronegative oxygen and nitrogen atoms, the maximum capacity for adsorbed metal ions was high in hydrolyzed-[poly-GPTS/Ti-Tyr]. Different parameters such as solution pH, contact time, adsorbent amount, initial metal ion concentration and adsorption isotherms were studied. The adsorption thermodynamics and kinetics also were determined with equilibrium data. The maximum adsorption capacities of Pb2+, Ni2+, Cu2+, and Zn2+ were found 240.5, 196.7, 182.4, 126.3 mg g−1, respectively. The adsorption equilibrium data were fitted well with Langmuir isotherm. The thermodynamic studies indicated that the adsorption was spontaneous and exothermic. The adsorption kinetic parameters were best suited to pseudo-second-order model. The synthesized adsorbent promises to be an effective adsorbent for the removal of heavy metal ions from aqueous solutions.