Preparation of new chelating fiber with waste PET as adsorbent for fast removal of Cu2+ and Ni2+ from water: Kinetic and equilibrium adsorption studies

A new chelating fiber (WJN-1) was prepared with waste PET for fast removal of Cu2+ and Ni2+ from water. Elemental analysis, SEM, contact angle, BET surface area and 13CNMR were used to characterize WJN-1. The higher uptake capacity of Cu2+ and Ni2+ by WJN-1 was achieved at higher pH values, and the lower uptake capacity was observed in an acidic medium. Kinetic study indicated that the adsorption of Cu2+ and Ni2+ could be well fitted by the pseudo-second-order equation, suggesting intra-particle diffusion process as the rate-limiting step of the adsorption process. When the temperature was raised within the range of 278–308 K, the adsorption enthalpy changes of WJN-1 were about from 6.69 to 16.05 kJ mol−1, and the free energy changes were about from −2.03 to −9.28 kJ mol−1. Although the presence of Ca2+ in solution had negligible effect on the removal of Cu2+ and Ni2+, WJN-1 could remain over 90% of its adsorption capacity even if the Ca2+ concentration was up to 75 mg L−1. 1 M HCl or 0.1 M EDTA could be used as effective eluant to desorb the Cu2+ and Ni2+ adsorbed by WJN-1, and the adsorption capacity of WJN-1 for two heavy metal ions could still be maintained at 93% level at the 5th cycle. Taken together, it was expected that WJN-1 could be used as a promising adsorbent for fast removal of Cu2+ and Ni2+ from water, and the present work also might provide a simple and effective method to reuse the waste PET fibers.

► A new chelating fiber was prepared with waste PET and characterized.
► This new chelating fiber could fast remove Cu2+ and Ni2+ from water.
► The sorption mechanism, thermodynamics and dynamic were illustrated.
► The influence of Ca2+ on removal of Cu2+ and Ni2+ was illustrated.
► This new chelating fiber had high sorption capacity and reuse potential.