Synthesis and Characterization of a Novel Hybrid Material Titanium Amino Tris(methylenephosphonic acid) and Its Application as a Cation Exchanger

Abstract

In the present work, a novel hybrid ion-exchange material was synthesized by a sol−gel route, by treating titanium tetrachloride with claw-type amino tris(methylenephosphonic acid) (ATMP) to give titanium amino tris(methylenephosphonic acid) (Ti-ATMP). Ti-ATMP was characterized by elemental analysis (ICP-AES and C, H, N analysis), spectral analysis (FTIR), thermal analysis (TGA), XRD, SEM, and EDX spectroscopy, including physicochemical and ion-exchange characteristics. The equilibrium exchange of transition-metal ions (viz., Cu 2+ , Ni 2+ , Co 2+ Zn 2+ ) and heavy-metal ions (viz., Pb 2+ ,Cd 2+ , Hg 2+ ) with the H + ions contained in ATMP was studied at constant ionic strength and varying temperatures, and various thermodynamic parameters such as the equilibrium constant (K), standard Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were evaluated. The Nernst−Planck equation was used to study the ion-exchange kinetics, and various kinetic parameters, namely, the self-diffusion coefficient (D 0 ), energy of activation (E a ), and entropy of activation (ΔS*), were evaluated under conditions favoring a particle-diffusion-controlled mechanism. Metal-ion adsorptions with variations in concentration and temperature were studied using the Langmuir and Freundlich adsorption isotherms. The distribution coefficient (K d ) and breakthrough capacity (BTC) values for transition-and heavy-metal ions were determined. Based on K d (mL•g −1 ), the selectivity order for metal ions toward Ti-ATMP was found to be Cu 2+ (19820) > Zn 2+ (3280) > Co 2+ (2630) > Ni 2+ (2390) among transition-metal ions and Pb 2+ (3590) > Cd 2+ (2340) > Hg 2+ (610) among the heavy-metal ions. The elution behavior of these metal ions was studied using different acids and electrolytes. A study on regeneration and reuse of the ion exchanger Ti-ATMP shows that it is effective up to five cycles without much decline in performance, which indicates that Ti-ATMP has good potential for use as a cation exchanger.

Water-free, Proton-Conducting Hybrid Materials for Elevated-Temperature Electrochemical Systems

“…This hypothesis is confirmed by the experimental value of cation exchange capacity of 4 mequiv/g reported for Ti/NTMPA 1:1 dihydrated compound. 27 In fact a theoretical calculation considering one phosphonic OH group for each Ti-NTMPA unit results in a value of 2.8 mequiv/g. Importantly, such free moieties are potential proton sources useful for cation exchange 27 or proton conduction.…”

“…27 In fact a theoretical calculation considering one phosphonic OH group for each Ti-NTMPA unit results in a value of 2.8 mequiv/g. Importantly, such free moieties are potential proton sources useful for cation exchange 27 or proton conduction.…”

Cellulose as a Scaffold for Self-Assembly: From Basic Research to Real Applications

“…The improved performance is attributed to the rough and wrinkled surfaces with a lamellar structure in the cellulose/graphene composite, which provides an advantageous condition for the adsorption process. Inorganic ion exchangers including Ti­(IV)-, Na­(I)-, and Sn­(IV)-based materials are known to be one of the most efficient agents for the removal of heavy metals from water. − Fe­(III) has a strong affinity for arsenic anions. Zhao et al designed and prepared a Fe­(III)-loaded ligand exchange cotton cellulose adsorbent (Fe­(III)­LECCA) .…”

Facile preparation of a silica‐sphere–poly(catechol hexamethylenediamine) composite for the competitive removal of cadmium(II), lead(II), and copper(II) ions

“…Therefore, numerous adsorbents, from natural zeolites to nanomaterials and from biomass to composites, have been prepared. In addition, there has been a growing interest in the development of low‐cost, nontoxic, and environmentally friendly adsorbents that contain donor atoms such as O, N, S, and P …”

“…6 Therefore, numerous adsorbents, from natural zeolites 7 to nanomaterials 8 and from biomass 9 to composites, 10 have been prepared. In addition, there has been a growing interest in the development of low-cost, nontoxic, and environmentally friendly adsorbents that contain donor atoms such as O, N, S, and P. 11,12 Polydopamine, which may attach virtually to all types of material surfaces and create a variety of adlayers on its own surface for its groups of catechol and amine, has received much attention over the past 10 years. 13,14 Polydopamine and its composites have been used to remove heavy-metal ions.…”