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Engelhard Titanosilicate molecular sieve, ETS-10, has unique selectivity and adsorption capacity for gas separation. Microwave heating was found to be a more efficient technique for regeneration of ETS-10 compared to conventional temperature swing regeneration. However, microwave regeneration of ETS-10 can be further improved by modifying its dielectric properties. This research investigated the effect of ion exchange of ETS-10 on its dielectric, adsorption and microwave regeneration properties. Monovalent and divalent cations (Li + , K + , Ca 2+ , Cu 2+ , and Ba 2+ ) were used for ion exchanging ETS-10. The analysis of ion-exchanged samples showed a decrease in their dielectric properties, resulting in decreased microwave absorbance during regeneration. However, increasing the water adsorption capacity and decreasing the dielectric properties of the adsorbent resulted in up to 27% increase of ETS-10 regeneration efficiency, suggesting that adsorbate heating is more effective than adsorbent heating when desorbing polar adsorbates. Among the ion exchanged samples, Li-ETS-10 is the most suitable candidate for microwave regeneration when loaded with polar adsorbate, based on adsorption capacity, desorption efficiency, and energy consumption. [ABSTRACT FROM AUTHOR]

ETS-10 and ETS-4 microporous materials were synthesized in presence of tetralkylammonium (TAA) ions from gels of molar composition w NaO-0.10 TAABr-1 SiO-z TiO-0.6 KF-1.28 w HCl-39.5 HO with TAA = tetramethyl-, tetraethyl-, tetrapropyl- and tetrabutyl-ammonium in hydrothermal conditions at 190 °C. The TAA ions enter the microporous channel of ETS-10, while they cannot penetrate the void spaces of ETS-4. The ETS-10 microcrystals are all cubic, while the ETS-4 crystals are laminar and irregular. The microporous volume of ETS-10 is equal to 0.11-0.13 cm g, the microporous volume of ETS-4 is very small, 0.002-0.008 cm g. The ion exchange of Cs, Cd, Pb and Hg ions using their corresponding nitrates show kinetic effects, i.e. the efficiency of ion exchange is higher at 1 than 2 h, the thermodynamic equilibrium. For ETS-10, partially dehydrated cations intervene in the ion exchange, while for ETS-4 well dehydrated ions can only penetrate the available pores. [ABSTRACT FROM AUTHOR]

Cadmium(II) is a toxic hazardous cation, whose presence in the environment causes great concern because of its bioaccumulation in organisms and bioamplification along food chain. Hence, the removal of cadmium compounds from industrial waters and wastewaters is particularly essential, which requires intensive experimental and modelling studies to deal with the problem. In this work, the ion exchange of Cd ions from aqueous solution using microporous titanosilicates (ETS-4 and ETS-10) has been modelled using adapted Maxwell-Stefan equations for the ions transport inside the sorbent particles. The fundamentals of the Maxwell-Stefan equations along with correlations for the convective mass transfer coefficients have been used with advantage to reduce the number of model parameters. In the whole, the model was able to represent successfully the kinetic behaviour of 11 independent and very distinct curves of both studied systems (Cd/Na/ETS-4 and Cd/Na/ETS-10). The predictive capability of the model has been also shown, since several uptake curves were accurately predicted with parameters fitted previously to different sets of experimental data. [ABSTRACT FROM AUTHOR]

A series of Eu-incorporated ETS-10 samples were successfully prepared based on the traditional ion exchange method. The relationship between photogenerated charge behaviors and luminescent properties has been investigated in detail. It has been demonstrated that as a result of the charge transfer from the titanate quantum wires to Eu crystal field states, the host matrix ETS-10 functions as the sensitizer of Eu to enhance the red luminescence, while Eu cations contribute to the recombination of photogenerated charges. The behavior of photogenerated charges has significant impact on the luminescent properties of Eu-incorporated ETS-10 materials. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the removal of Cd2+ ions from aqueous solution using microporous titanosilicate ETS-10 was investigated in order to assess its potential as decontaminating agent in tertiary treatments. Accordingly, batch stirred tank experiments were carried out to study the ion exchange kinetics and equilibrium. Results show that pH affects considerably the ion exchange capability of ETS-10: at pH 4 it is 1.567×102 eqm−3, at pH 6 it is 3.629×103, and no further increment was observed at pH 8. This is an extremely important observation since pH of industrial effluents and other wastewaters rounds 6. Both Langmuir and Langmuir–Freundlich isotherms were fitted to the experimental data measured. The second model performs slightly better as the calculated absolute average deviations show: AADL =2.94% and AADLF =2.40%. Concerning the kinetic behavior, the ion exchange was successfully represented by a Nernst–Planck based model (AAD=11.9%). [Copyright &y& Elsevier]

Abstract: Nano-sized large pored titanium silicate zeolitic materials, ETS-10 and ETAS-10 with different Al2O3/TiO2 ratio were successfully applied to the removal of heavy metal ions, in particular, Cu2+, Co2+, Mn2+ and Zn2+. The study of equilibrium and adsorption isotherm at 298K and 323K for Cu2+, Co2+, Mn2+ and Zn2+ were conducted using batch mode. The uptake rates for Cu2+, Co2+, Mn2+ and Zn2+ were extremely rapid and fitted to the pseudo-second order equation well. The equilibrium capacities by the pseudo-second order equation on ETS-10 and ETAS-10 synthesized by titanium oxysulfate as the titanium source were determined to be 1.31mmol/g and 1.13mmol/g for Cu2+, 1.05mmol/g and 1.08mmol/g for Zn2+, 0.96mmol/g and 0.99mmol/g for Mn2+, 0.93mmol/g and 1.01mmol/g for Co2+ at 30mmol/l of initial concentration. Adsorption isotherms for Cu2+, Co2+, Mn2+ and Zn2+ were fitted to Langmuir, Freundlich and Langmuir–Freundlich isotherms. The results show that Langmuir–Freundlich isotherm has fitted best to the current system. The selectivity of heavy metal ions both on ETS-10 and ETAS-10 at 298K is in the order of Cu2+ >Zn2+ >Mn2+ >Co2+ while it is in the order of Cu2+ >Mn2+ >Zn2+ >Co2+ at 323K. The monolayer capacities on ETS-10 and ETAS-10 synthesized by titanium oxysulfate as the titanium source at 298K were determined to be 1.55mmol/g and 1.62mmol/g for Cu2+, 1.30mmol/g and 1.32mmol/g for Zn2+, 0.98mmol/g and 1.11mmol/g for Mn2+, 0.91mmol/g and 0.89mmol/g for Co2+, respectively. However, at 323K, the monolayer capacity of Mn2+ ion on ETS-10 and ETAS-10 was determined rather larger than that of Zn2+ ion. Finally, thermodynamic parameters suggest that the adsorption process of Cu2+, Co2+, Mn2+ and Zn2+ on ETS-10 and ETAS-10 is endothermic and spontaneous process, being indicated by positive ΔH 0 and negative ΔG 0. In addition, positive ΔS 0 suggests that heavy metal ions are not stable on the adsorption sites of ETS-10 and ETAS-10 probably due to the increase in translation energy of heavy metal ions displaced from the adsorption sites. [Copyright &y& Elsevier]

A series of batch experiments were conducted to ascertain the ability of titanosilicate ETS-10 to remove ammoniacal nitrogen from synthetic aqueous solutions of ammonium chloride. Ammonium uptake was favoured by neutral medium, higher initial ammonium concentration, low ionic strength of solution (absence of background electrolyte), alkali metal form of ETS-10 and high temperature. From equilibrium data, plotted as ion exchange isotherms in equivalent fractions, the apparent selectivity coefficients and the thermodynamic functions were calculated. The titanosilicate ETS-10 seemed to have good potential for ammonium removal from wastewaters. [ABSTRACT FROM AUTHOR]

Ion exchange experiments were carried out for the removal from aqueous solution of cobalt ions by an Engelhard Titanium Silicates -- 4 and 10 synthesized from alkaline gels. Selectivity factors were estimated by the construction of ion exchange and Langmuir isotherms and determination of thermodynamic values. It is shown that ETS-10 have a better affinity for Co uptake. [ABSTRACT FROM AUTHOR]