Preparation of Co/S co-doped carbon catalysts for excellent methylene blue degradation

S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB)degradation.The effects of two different mixing routes were identified on the MB degradation performance.Particularly,the catalyst obtained by the alcohol solvent evaporation(MOF-AEP)mixing route could degrade 95.60%MB(50 mg/L)within 4 min(degradation rate:K=0.78 min^(-1)),which was faster than that derived from the direct grinding method(MOF-DGP,80.97%,K=0.39 min^(-1)).X-ray photoelectron spectroscopy revealed that the Co-S content of MOF-AEP(43.39at%)was less than that of MOF-DGP(54.73at%),and the proportion of C-S-C in MOF-AEP(13.56at%)was higher than that of MOF-DGP(10.67at%).Density functional theory calculations revealed that the adsorption energy of Co for PMS was -2.94 eV when sulfur was doped as C-S-C on the carbon skeleton,which was higher than that when sulfur was doped next to cobalt in the form of Co-S bond(-2.86 eV).Thus,the C-S-C sites might provide more contributions to activate PMS compared with Co-S.Furthermore,the degradation parameters,including pH and MOF-AEP dosage,were investigated.Finally,radical quenching experiments and electron paramagnetic resonance(EPR)measurements revealed that ^(1)O_(2)might be the primary catalytic species,whereas·O~(2-)might be the secondary one in degrading MB.

Application and Hydration Resistance of SiC Refractories for Water-cooled Wall of Waste Incinerators

According to the dual needs of heat transfer and thermal insulation in incinerators,different parts of the incinerators are designed with refractories of different SiC contents.Water vapor is mainly concentrated in the zones of feeding,drying and combustion,and the main damage factors of SiC refractories include high temperature and hydration.The results of hydration resistance of typical SiC-containing refractories show that the higher the SiC content,the worse the hydration resistance.Si_(3)N_(4)-SiC refractories after oxidation treatment have good hydration corrosion resistance,which are appropriate for water-cooled wall of waste incinerators.

Typical Refractories Design of Rotary Kiln Hazardous Waste Incineration System

This paper summarizes the current situation of China’s industrial hazardous waste treatment,the disposal technology and the characteristics of rotary kiln incineration system,analyzes the refractory lining design of rotary kiln incineration system in China,and puts forward optimization suggestions according to the process characteristics.

Influence of Flotation Magnesia Particles and Al_(2)O_(3) Fines on Properties of Periclase-spinel Bricks

Periclase-spinel bricks were prepared using sintered magnesia,flotation magnesia,fused magnesium aluminate spinel and calcined Al_(2)O_(3)fines as the starting materials and calcium lignosulfonate as the binder,mixing,shaping and firing at 1650℃.Flotation magnesia particles were used to replace ordinary sintered magnesia particles and different amounts of calcined Al_(2)O_(3)fines were extra-added(0%,3%and 5%,by mass)to investigate their effects on the properties of periclase-spinel bricks.The results show that:the periclase-spinel bricks prepared with flotation magnesia particles have reduced apparent porosity and cold compressive strength,and enhanced bulk density,thermal shock resistance,hot strength and hot toughness.As the calcined Al_(2)O_(3)fines addition increases,the apparent porosity and the cold compressive strength decrease,and the bulk density,the thermal shock resistance,the hot strength and the hot toughness are improved.

Research and Application Progress of Bauxite Based Homogenized Grogs in China

The progress of research and production of bauxite based homogenized grogs in China was summarized and the achievements of their application and modification in recent years were epitomized.In combination with the shortcomings existing in the research,production and application,the suggestions of bauxite based homogenized grogs for future development were put forward.

Strength Acquisition Mechanism of High Temperature Resistant Materials Prepared by Waste Architectural Ceramics

In order to realize the large-scale and high-value utilization of waste architectural ceramics,high-temperature resistant materials based on waste architectural ceramics were prepared with sodium silicate as the binder,clay/bauxite and metakaolin/bauxite as coating materials,and the cold strength obtaining mechanism was explored.The phase composition,the microstructure and the mechanical properties of the high temperature resistant materials based on waste architectural ceramics were tested and analyzed.The results showed that when the heat treatment temperature was between 110-1000℃,the strength of the samples mainly came from the physical adhesion of sodium silicate and fine powder.When the temperature rose to 1100℃,the strength of the sample was improved since the internal low-melting-point components melted and promoted sintering.The addition of clay and bauxite can effectively enhance the flexural strength of the samples when the heat treatment temperature is 1000℃.When the heat treatment temperature rises from 900 to 1000℃,the flexural strength of the samples will be enhanced owing to the formation of silica alumina spinel and mullite from metakaolin.