Synthesis of platy potassium magnesium titanate and its application in removal of copper ions from aqueous solution

Platy potassium magnesium titanate (K0.8Mg0.4Ti1.6O4, KMTO) was synthesized by a flux method. The potential application of KMTO in removing copper ions from water pollutants was investigated. The crystal phases of specimens were identified by XRD. The morphology and structural information were characterized by SEM and TEM. The adsorption behavior under different conditions was investigated, including different pH values and different initial copper ion concentrations. The results show that the maximum adsorption capacity of Cu(II) ions is 290.697 mg/g, and almost 99.9% of Cu(II) ions can be removed, which is much higher than that of other sorbents reported. The kinetics of KMTO for the adsorption of Cu(II)ions was studied and the best fit can be obtained by the pseudo-second-order model. Adsorption isothermal data can be well interpreted by the Freundlich equation (R2=0.991). In conclusion, this study highlights that KMTO is a potential material for the efficient removal of heavy metal ions in polluted water. It also opens up a new opportunity for the applications of platy KMTO.

Factor analysis on the purity of magnesium titanate directly prepared from seashore titanomagnetite concentrate through direct reduction

Magnesium titanate was prepared directly through external coal reduction of seashore titanomagnetite concentrate and magnesium oxide(MgO).The effects of roasting temperature and the type and dosage of reductants on the purity of generated magnesium titanate particles were systematically investigated.Scanning electron microscopy and energy-dispersive spectroscopy analyses were performed to characterize the magnesium titanate particles and observe their purity under different conditions.Results showed that the roasting temperature remarkably influenced the purity of magnesium titanate.At 1200,1300,and 1400℃,some magnesium ferrite and magnesium aluminate spinel were dissolved in magnesium titanate.However,as the roasting temperature increased to 1500℃,relatively pure magnesium titanate particles were generated because no magnesium ferrite was dissolved in them.The type and dosage of the reductants also remarkably affected the purity of magnesium titanate.The amount of fine metallic iron disseminated in the magnesium titanate particles obviously decreased when lignite was used as a reductant at a dosage of 70wt%.Thus,high-purity magnesium titanate particles formed.At a roasting temperature of 1500℃and with 70wt%lignite,the magnesium titanate product with a yield of 30.63%and an iron content of 3.01wt%was obtained through magnetic separation.

DIELECTRIC PROPERTIES OF ZNTIO_3 MICROWAVE CERAMICS CONSOLIDATED WITH MGTIO_3

Stabilized ZnTiO4 was prepared by doping magnesium oxide through traditional solid state reaction. The experimental results indicate that zinc titanate crystals doped with magnesium oxide grow well and the decomposition into Zn2TiO4 and TiO2 is restrained through traditional solid state reaction, By adjusting molar ratio of MgO, better properties can be obtained The dielectric properties of the ceramics doped with 30% MgO（ molar percentage） sintered at 1060℃ are as follows：the value of quality factor is greater than 20000（6.5 GHz ）, the temperature coefficient of resonance frequency is about 2 ± 10^-6 /℃,the dielectric constant ranges from 180 to 22.Besides,it is proved that heat treatment can optimize microstructure and the value of quality factor, which increases from 23833.93 to 47584.00 after 2h of heat treatment at 1040℃.

Preparation of MgO-Mg_2TiO_4 Composite and Its Corrosion Resistance to Electrolyte

MgO- Mg2TiO4 composite was prepared by adding chemically pure TiO2（0,1%,2%,5% and 10%,in mass,the same hereinafter） to light-burned magnesia（particle size 〈0.045 mm）,ball milling,dry pressing,and reaction sintering at 1 400,1 500 and 1 600 ℃ fo3 h,respectively. Apparent porosity,bulk density and corrosion resistance to AlF3- Na3AlF6- K3AlF6 were in vestigated. Phase composition and microstructure wer analyzed. The results show that：（1） MgO- Mg2TiO4 composite can be synthesized by reaction sintering; with TiO2 addition increasing from 0 to 5%,the specimen i denser obviously accompanying with more Mg2TiO4 form ing and MgO grains growing; the specimen with 10%TiO2obtains a slightly lower density than that with 5%TiO2due to larger volume expansion resulting from th formation of more Mg2TiO4;（2）with TiO2 addition in creasing from 0 to 5%,corrosion resistance to AlF3-Na3AlF6- K3AlF6 of the specimens improves gradually owing to the density increase and the Mg2TiO4 possessing good chemical stability distributing along periclas grains; compared with the specimen with 5% TiO2,tha with 10% TiO2 owns a little worse corrosion resistanc because of the lower density.

Humidity Sensitive Characteristics of Porous Li-Mg-Ti-O-F Ceramic Materials

Ceramic porous MgTiO3 materials have been prepared by classical solid-state route. The sintered pellets of MgTiO3 with different LiF contents were characterized for humidity-sensing application. The sintered disks of these mixtures were subjected to capacitance measurements at 20℃as function of the relative humidity from which revealed that the Mixture MgTiO3 + 2% LiF (w/w) has the better characteristics. The disks were subjected to DC resistance measurements as a function of relative humidity in the range 15% - 95% RH. The selectivity of this material was discussed and compared to commercial sensor results. The response and recovery characteristics were assessed.

Preparation and luminescent properties of MgTiO_3:Eu^(3+) phosphor for white LEDs

A novel red phosphor Eu3＋ doped magnesium titanate （MgTiO3） was synthesized via sol-gel method. The X-ray diffraction patterns （XRD） revealed that a pure MgTiO3 phase was obtained. Its excitation spectrum consisted of a broad band （〈350nm） and a series of narrow bands in the long wavelength, and the strongest excitation peak at 465nm might be exited by GaN-chip to emit red light for white LED. The phosphors showed strong emission at 614nm which could be attributed to the 5D0→7F2 emission of Eu3＋ . The emission intensity of MgTiO3：Eu3＋ phosphor reached the maximum at the Eu3＋ concentration of 3.5mol.%. The luminescent properties （such as emission intensity and decay times） were further improved by introducing Al3＋ as a charge compensator, demonstrating potential applications in white LED.