A series of expanded vermiculites with a high expansion ratio were prepared with a vermiculite from Xinjiang, China as raw material by an intercalation microwave method and an intercalation calcination method, respectively. The phase composition and morphology of the products were characterized by X-ray diffraction and scanning electron microscopy, and the cation exchange capacity and methylene blue (MB) adsorption capacity of the expanded vermiculite prepared by the two different methods were analyzed. The results show that there is a significant difference in the expansion ratios of expanded vermiculite prepared by the two methods, and the expansion ratio of calcined expanded vermiculite (BCV) is 0.4 times greater than that of microwave expanded vermiculite (WCV). For adsorption in a methylene blue solution with a concentration of 300 mg/L, the calcined expanded vermiculite has a poor adsorption capacity for MB, while the microwave expanded vermiculite has a good adsorption performance for MB due to its higher cation exchange capacity with an adsorption capacity of 391.26 mg/g.

Granular Y molecular sieve loaded with iron nanoparticles with cation exchange performance was synthesized for simultaneous removal of Cu(Ⅱ) and Cr(Ⅵ) from aqueous solution. The results show that the adsorption capacity of Cu(Ⅱ) increases from 46.6 mg/g to 67.6 mg/g, and the adsorption capacity of Cr(Ⅵ) is 13.2 mg/g when using granular Y molecular sieve loaded with iron nanoparticles. The removal of Cr(Ⅵ) by the loaded material is improved due to the coexistence of Cu(Ⅱ). The removal mechanism of Cu(Ⅱ) by the loaded material involves the cation exchange of Y molecular sieve and the reduction of Fe(0). The removal of Cr(Ⅵ) is mainly attributed to the reduction of Fe(0), and the reductive products of Cu(Ⅱ) can promote the removal of Cr(Ⅵ) by the loaded material.

Platinum (Pt) was encapsulated in ZSM-5 by an one-step hydrothermal method for dehydrogenation of propane to prepare propylene (PDH). The catalysts were characterized by X-ray diffraction, specific surface area measurement, H₂-pluse, scanning electron microscopy and transmission electron microscopy. Under the optimal reaction conditions, the propane conversion and propylene selectivity are 48% and 57%. In addition, the catalytic system can also resist the toxic effect of DBT, and the propane conversion and propylene selectivity are not reduced with DBT containing a catalytic system.

Graphene oxide (GO) composite nanofiltration membranes (GO-EDA/Al₂O₃ membrane) cross-linked by ethylenediamine (EDA) were fabricated on dopamine (PDA) modified alumina ceramic membranes. The covalent bonds enhance the interlayer and interface stability of the as-prepared membranes. A method that can simply adjust the layer spacing of GO composite membranes was proposed. The number of hydroxyl groups inside the GO composite membranes can be changed through varying the drying temperature, thus affecting the pure water permeation and salt rejection of the GO composite membranes. The results show that the thickness of the GO composite membranes fabricated at the drying temperature of 40 ℃ is 50-120 nm. The pure water permeance and the rejection towards Na₂SO₄ solution are 34 L/(m²·h·MPa) and 87.8%, respectively. The GO composite membranes still remain an excellent stability and a high rejection rate after being immersed in pure water for 680 h.

To improve the low-temperature oxidation resistance of MoSi₂, a core-shell structured MoSi₂@SiO₂ was prepared by a direct preoxidation method, and the preoxidation conditions, as well as the structure and the low-temperature oxidation resistance of MoSi₂@SiO₂ composite, were investigated. Results show that the core-shell structured MoSi₂@SiO₂ can be obtained under preoxidation at 800 ℃ for 1 h. The obtained SiO₂ shell is amorphous which is formed due to the non-selective oxidation of MoSi₂ and the evaporation of the oxidation product MoO₃. The oxidation mass gain rate of MoSi₂@SiO₂ is <1.6% after isothermal cyclic oxidation at 400-700 ℃ for 12 h.

High h-BN ceramics were prepared by an oscillatory pressure sintering technique (OPS), and the effect of oscillatory pressure on the sintering densification and grain growth of h-BN ceramics was investigated. Boron nitride ceramics were also prepared by a hot pressing sintering process (HP). The density, microstructure, fracture reliability, degree of grain orientation, mechanical and thermal properties of boron nitride ceramics at different sintering processes were analyzed. The results show that the fracture surface of OPS specimens is denser, and the grain orientation becomes clear, compared with those of HP specimens. A high proportion of parallel-arranged BN grains can effectively improve the densification of BN ceramics. The maximum hardness, fracture toughness and flexural strength of OPS specimens are 0.31GPa, 1.09MPa·m^1/2 and 74.4MPa, respectively, which are greatly improved, compared with HP specimens at the same sintering parameters. According to the data of grain orientation determined by X-ray diffraction patterns, the application of oscillatory pressure obviously promotes the densification and sintering of boron nitride ceramics, thus improving the fracture reliability and thermal conductivity.

Si₃N₄ ceramics were prepared via gas pressure sintering under nitrogen pressure of 1.0 MPa at 1 850℃ for 3 h with Y₂O₃ and MgSiN₂ as sintering aids. The effects of MgSiN₂/Y₂O₃ mole ratio and their total amount on the porosity, microstructure, mechanical properties and thermal conductivity of Si₃N₄ ceramics were investigated. The results show that the growth of rod-like β-Si₃N₄ grains was more sufficient and the growth of abnormal grain decreased with the increase of Y₂O₃ content at the constant total content of MgSiN₂ and Y₂O₃. Si₃N₄ ceramics with the optimal properties were prepared at a molar ratio of MgSiN₂:Y₂O₃ of 5∶2 and the total amount of sintering aids of 10.5%, having the bending strength and thermal conductivity of 510 MPa and 67.01 W·m^-1·K^-1, respectively.

Aluminium-based ceramics are widely used in aerospace, rail transit and national defense due to their advantages like light mass, high specific strength, small thermal expansion coefficient, high dimensional stability, high temperature resistance, remarkable fatigue resistance and excellent wear resistant. In this paper, SiC_p-B₄C_p(m(SiC_p)∶m(B₄C_p)=1∶1) reinforced Al matrix (i.e., (SiC_p-B₄C_p)/Al) composites were prepared by a selective laser melting (SLM) method with SiC and B₄C as reinforcing phases and pure Al powder as a matrix material under certain conditions (i.e., powder layer thickness and hatch distance of 0.05 mm, scanning speed of 300 mm/s and laser power of 350 W). The effect of SiC_p-B₄C_p content on the microstructure, porosity, microhardness, friction and wear properties and flexural strength of (SiC_p-B₄C_p)/Al composites were investigated. The results show that the (SiC_p-B₄C_p)/Al composites reinforced with 10% SiC_p-B₄C_p exhibit the minimum apparent porosity (i.e., 4.5%) and flexural strength (i.e., 177 MPa), and the composites reinforced with 20% SiC_p-B₄C_p have the maximum hardness, lowest friction coefficient and wear rate (i.e., 172.6 HV_0.1, 0.4 and 3.4×10^-5 mm³N^-1m^-1).

An efficient and eco-friendly oil-water separation strategy is urgently needed to solve the problem of oily sewage due to the frequent occurrence of oil leakage accidents. Diatomite porous ceramics were firstly prepared by a foaming-gelcasting method, and then superhydrophilic-oleophobic diatomite porous ceramics were prepared by a simple vacuum impregnation method with the diatomite porous ceramics as a matrix and fluorine-containing polymer (Capstone FS-50) as a modifier. The effect of sintering temperature on the phase composition, microscopic morphology and physical properties of porous diatomite ceramics was investigated and the influence of CS-50 concentration on the oil contact angle and chemical stability of the surface of modified diatomite porous ceramics was also analyzed. The mesopore structure of disk-like diatomite becomes more and more blocked, the porosity of the porous samples decreases from 84.3% to 81.6% and the compressive strength increases from 0.93 MPa to 2.01 MPa as the sintering temperature increases from 1 100 to 1 200℃. The oil contact angle of the prepared modified diatomite porous ceramics firstly increases and then becomes stable with increasing Capstone FS-50 concentration. At the concentration of Capstone FS-50 of 5%, the oil contact angle of the porous ceramic is high up to 138°, and whose water contact angle is about 0°. In addition, the modified diatomite porous ceramics still maintain hydrophilic and oleophobic after soaking in acid, alkali and salt solutions, thus exhibiting superior chemical corrosion resistance.

Porous mullite lightweight materials were prepared by a microemulsion template method and subsequent sintering with fly ash and calcined bauxite as raw materials, Isobam 104 as a dispersant, carboxymethyl cellulose as a suspending agent, polyoxyethylene sorbitan monooleate (Tween 80) as a surfactant, isooctane as an oil phase, ethylene glycol glycidyl ether as a binder and tetraethylenepentamine as a curing agent. The influences of fly ash content and Tween 80 content on the phase composition, linear shrinkage, bulk density, porosity, microstructure and mechanical properties of porous mullite lightweight materials were investigated. The results show that the linear shrinkage rate, bulk density and mechanical strength of porous materials prepared with 55% fly ash decrease, but the porosity increases as the volume ratio of Tween 80 to water increases from 2∶100 to 5∶∶100. When the volume ratio of Tween 80 to water is 5∶100, the compressive strength and flexural strength of porous mullite lightweight materials with a porosity of 65.5%, a spherical pore diameter of 162 μm, and a linear shrinkage rate of only 14.5% can reach 42.5 MPa and 26.0 MPa, respectively.