Fabrication of Poly(β-Cyclodextrin-Epichlorohydrin-Thiourea) to Efficient Removal of Heavy Metal Ions from Wastewater

A novel crosslinked water-insoluble β-cyclodextrin polymer was synthesized from reacting thiourea (TU) with β-cyclodextrin (β-CD) and epichlorohydrin (ECH). The structure of fabricated β-cyclodextrin-epichlorohydrin-thiourea (β-CD-ECH-TU) polymer was characterized by fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), scanning electron microscope (SEM), thermal gravimetric analysis (TGA) and elemental analyses. The porous β-CD-ECH-TU polymer was used an attractive and effective adsorbents for the removal of heavy metal ions such as lead(II) (Pb²⁺) and cadmium(II) (Cd²⁺) ions from wastewater. The effect of contact time and initial adsorbent dose on the extent of adsorption was investigated. The equilibrium data obtained by experiments were analyzed by Langmuir, Freundlich and Temkin isotherms. The results were fitted with Langmuir model at ambient temperature. A maximum adsorption capacity of (qₘ) 285.126 and 126.58 (mg/g) was obtained for Pb²⁺ and Cd²⁺ respectively and the selectivity order could be given as Pb²⁺ > Cd²⁺. The adsorption effectiveness of the β-CD-ECH-TU polymer remained constant through five regeneration cycles.