The semiconductor, electroplating, metallurgy, and ceramic industries discharge high concentration fluoride containing wastewater, making fluoride pollution in natural water a global problem.Thus, Zn?Mg?Al LDO is a good adsorbent material. Under different reaction temperatures of n(Zn2+)/n(Mg2+)/n(Al3+), Zn?Mg?Al LDH was synthesized by co?precipitation method, and Zn?Mg?Al?LDH was calcined at different temperatures to obtain Zn?Mg?Al?LDO. X?ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT?IR) and BET specific surface area testing methods were used to study the structure and properties of Zn?Mg?Al LDO. The adsorption experiment was conducted on 50 mL of NaF solution with an mass concentration of 20.0 mg/L to investigate the performance of Zn?Mg?Al LDO in adsorbing and removing fluoride ions. The results showed that the Zn?Mg?Al LDO prepared under the conditions of n(Zn2+)/n(Mg2+)/n(Al3+)=2∶1∶1, reaction temperature of 75 ℃, and calcination temperature of 400 ℃ exhibited the best adsorption and removal performance of fluoride ions, with an adsorption and removal rate of 85.39%. Zn?Mg?Al LDO has characteristic peaks of hydrotalcite, good crystal structure, and a layered structure. Zn?Mg?Al LDO is a mesoporous material with a specific surface area of 103.15 m2/g. In addition, the kinetics and adsorption mechanism of the adsorption process were also studied. The results indicate that the adsorption process follows the Langmuir adsorption isotherm and quasi second?order kinetic equation.
With the rise of electric revolution and the establishment of "carbon dioxide emission and carbon neutrality" strategy, petroleum coke has got great development in value?added applications such as lithium cathode materials and high?grade prebaked anode.However,high value?added applications of petroleum coke all have strict requirements for sulfur content of petroleum coke. The high sulfur content in petroleum coke will have a negative impact on the high value application of petroleum coke.The research status of main desulphurization technologies of petroleum coke,including solvent extraction desulfurization technology,high temperature calcination desulfurization technology,oxidation desulfurization technology, alkali metal compound desulfurization technology,hydrodesulfurization technology,microbial desulfurization technology and process intensification auxiliary desulfurization technology are summarized.It was found that the desulphurisation rate of process?enhanced assisted desulphurisation could reach 93.6%,which could reduce the sulphur mass fraction in petroleum coke from 7.57% to 0.48%. The desulfurization technology of petroleum coke should maintain the principle that the structure of petroleum coke after desulfurization is not destroyed to the greatest extent.Therefore,oxidative desulfurization coupled process enhancement assisted desulfurization should have bright prospect in industrial application of petroleum coke desulphurization.
Industrial wastewater is mainly composed of sewage and waste liquid produced in industrial production process, which has been characterized by its complex composition, wide variety, large difference and difficulty in treatment.The commonly used methods for preparation of hydrotalcite were reviewed, such as chitosan method, plasma method and agricultural waste method. Hydrotalcite materials in the adsorption process are mostly in powder, which is difficult to be recycled, and rarely used in industry applications. In view of the above problems, Fe ions can be introduced in hydrotalcite materials to generate magnetism, which is be beneficial to recovery. By developing cheaper synthetic materials, simple and fast preparation methods, stable physical and chemical properties of hydrotalcite materials, industrial applications could be achieved. The introduction of magnetic materials into hydrotalcite composites can help to recycle. With the in?depth study of hydrotalcite preparation technology, the prospect of dealing with toxic pollutants will be better.
Finite Element Analysis of Sealing Performance of Non Standard Octagonal Gasket on Hydrotreating Reactor
Aiming at non standard octagonal gasket used in hydrotreating reactor. Ansys was used to calculate the contact stress on the sealing surface during the hydrostatic pressure test, and the causes of the different contact stress on each sealing surface were analyzed. The results showed that the contact stress down to the trough when the test pressure was the highest, the maximum stress on the inner side of gasket was away from the center of gasket, and the outer situation was in contrast to it. Variation of gasket sealing surface contact stress provides a reference to the analysis and evaluation of other non standard seal structure.