Effect of Thermal Regeneration on the Breakthrough Performance of Ceramsite Saturated with Methylene Blue

The regeneration of a spent packing is crucial with respect to the development of circular economy and abstemious society.Thus,the effects of regeneration temperature,resistant time,heating rate,and regeneration cycle on the breakthrough performance of methylene blue(MB)dye⁃exhausted ceramsite in a two⁃stage fixed⁃bed column were studied in this work.Results illustrate that the ceramsite exhibited excellent potential regeneration properties under the following optimal regeneration conditions:treatment temperature was 600°C,resistant time was 15 min,heating rate was 20℃/min,regeneration cycle was over 9 cycles,and the breakthrough time,saturation time,regeneration efficiency(RE),and regeneration loss rate(RLR)were 540 min,1020 min,64.61%,and 17.73%,respectively.The RE declined by 35.14%in over 1 cycle,while the RLR increased by 3.15 times in over 9 cycles.Besides,Thomas model was suitable to describe the two⁃stage fixed⁃bed column adsorption and thermal regeneration process with R2=0.978.In conclusion,a thorough understanding of the regeneration behavior of the two⁃stage fixed⁃bed column packed with ceramsite provides reference to obtain an effective and feasible regeneration approach,and it is beneficial for further application in water treatment.

Magnetic core-shell microparticles for oil removing with thermal driving regeneration property

Here, we report the construction of magnetic core-shell microparticles for oil removal with thermal driving regeneration property. Water-in-oil-in water (W/O/W) emulsions from microfluidics are used as templates to prepare core-shell microparticles with magnetic holed poly (ethoxylated trimethylolpropane triacrylate) (PETPTA) shells each containing a thermal-sensitive poly (N-Isopropylacrylamide) (PNIPAM) core. The microparticles could adsorb oil from water due to the special structure and be collected with a magnetic field. Then, the oil-filled microparticles would be regenerated by thermal stimulus, in which the inner PNIPAM microgels work as thermal-sensitive pistons to force out the adsorbed oil. At the same time, the adsorbed oil would be recycled by distillation. Furthermore, the adsorption capacity of the microparticles for oil keeps very stable after 1st cycle. The adsorption and regeneration performances of the microparticles are greatly affected by the size of the holes on the outer PETPTA shells, which could be precisely controlled by regulating the interfacial forces in W/O/W emulsion templates. The optimized core-shell microparticles show excellent oil adsorption and thermal driving regeneration performances nearly without secondary pollution, and would be a reliable green adsorption material for kinds of oil.

Puerarin ameliorates allodynia and hyperalgesia in rats with peripheral nerve injury

Puerarin is a major active ingredient of the traditional Chinese plant medicine,Radix Puerariae,and commonly used in the treatment of myocardial and cerebral ischemia.However,the effects of puerarin on neuropathic pain are still unclear.In this study,a neuropathic pain animal model was created by partial sciatic nerve ligation.Puerarin（30 or 60 mg/kg） was intraperitoneally injected once a day for 7 days.Mechanical allodynia and thermal hyperalgesia were examined at 1 day after model establishment.Mechanical threshold and paw withdrawal latency markedly increased in a dose-dependent manner in puerarin-treated rats,especially at 7 days after model establishment.At 7 days after model establishment,quantitative real-time reverse transcriptase-polymerase chain reaction results showed that puerarin administration reversed m RNA expression of transient receptor potential vanilloid 1（Trpv1） and transient receptor potential ankyrin 1（Trpa1） in a dose-dependent manner in dorsal root ganglion neurons after peripheral nerve injury.These results suggest that puerarin dose-dependently ameliorates neuropathic pain by suppressing Trpv1 and Trpa1 up-regulation in dorsal root ganglion of neuropathic pain rats.

Sulfur poisoning and regeneration of MnO_x-CeO_2-Al_2O_3 catalyst for soot oxidation

MnOx-CeO2-Al2O3 mixed oxides were prepared by impregnating manganese and cerium precursors on alumina powders via a sol- gel deposition method. The oxide catalyst exhibited a poor resistance to sulfur dioxide after the treatment in 100 ppm SO2/air at 350 °C for 50 h. The formation of manganese sulfate and especially cerium sulfate reduced the availability of surface active metal oxides, blocked the pore structure and decreased the surface area of the catalyst. These changes in chemical and structural and textural properties resulted in a severe loss in the activities of the sulfated catalyst for NO and soot oxidation. The decomposition of sulfates was almost complete during the calcina-tion in air at 800 °C for 30 min, which partially recovered the surface active sites and the catalyst surface area despite the significant sintering of metal oxides. Consequently, the NOx-assisted soot oxidation activity of the catalyst was regenerated to some extent by the oxidation treatment.

Physicochemical regeneration of high silica zeolite Y used to clean-up water polluted with sulfonamide antibiotics

High silica zeolite Y has been positively evaluated to clean-up water polluted with sulfonamides, an antibiotic family which is known to be involved in the antibiotic resistance evolution. To define possible strategies for the exhausted zeolite regeneration,the efficacy of some chemico-physical treatments on the zeolite loaded with four different sulfonamides was evaluated. The evolution of photolysis, Fenton-like reaction, thermal treatments, and solvent extractions and the occurrence in the zeolite pores of organic residues eventually entrapped was elucidated by a combined thermogravimetric（TGA–DTA）, diffractometric（XRPD）, and spectroscopic（FT-IR） approach. The chemical processes were not able to remove the organic guest from zeolite pores and a limited transformation on embedded molecules was observed. On the contrary, both thermal treatment and solvent extraction succeeded in the regeneration of the zeolite loaded from deionized and natural fresh water. The recyclability of regenerated zeolite was evaluated over several adsorption/regeneration cycles, due to the treatment efficacy and its stability as well as the ability to regain the structural features of the unloaded material.

Elemental mercury removal from coal gas by CeMnTi sorbents and their regeneration performance

Ce and Mn modified TiO_(2) sorbents(CeMnTi) were prepared by a co-precipitation method,and their ability to remove elemental mercury from coal gas in a fixed bed reactor was studied.Based on results of Brunauer-Emmett-Teller(BET),X-ray diffraction(XRD),scanning electron microscope(SEM),and X-ray photoelectron spectroscopy(XPS) studies,the modification mechanisms of the CeMnTi sorbents are discussed.Mn doping improved the specific surface area and dispersion of cerium oxides on the sorbent surface,while Ce doping increased the proportion of Mn^(4+)in manganese oxides by a synergetic effect between manganese oxides and cerium oxides.The effects of the active component,temperature,and coal gas components on the mercury removal performance of the sorbents were investigated.The results showed that the CeMnTi sorbents exhibited high mercury removal efficiency.Ce_(0.2)Mn_(0.1)Ti adsorbed 91.55% elemental mercury from coal gas at 160℃.H2 S and O2 significantly improved the ability of sorbents to remove mercury.Part of the H2_(S) formed stable sulfates or sulfites through a series of oxidation reaction chains on the sorbent surface.HCl also improved the mercury removal performance,but reduced the promotion effect of H2_(S) for mercury removal when coexisting with H2_(S).CO and H2 had a minor inhibitory effect on mercury adsorption.The recycling performance of the sorbents was investigated by thermal regeneration.The thermal decomposition of the used sorbents indicated that mercury compounds were present mainly in the form of HgO and HgS,and higher temperature was beneficial for regeneration.The formation of sulfates and sulfites in the presence of H2_(S) led to a decrease in mercury removal efficiency.

Effects of SO2 and H2O on low-temperature NO conversion over F-V2O5-WO3/TiO2 catalysts

F-V2 O5-WO3/Ti02 catalysts were prepared by the impregnation method.As the content of F ions increased from 0.00 to 0.35 wt.%,the NO conversion of F-V2 O5-WO3/TiO2 catalysts initially increased and then decreased.The 0.2 F-V2 O5-WO3/TiO2 catalyst(0.2 wt.%F ion)exhibited the best denitration(De-NOx)performance,with more than 95%NO conversion in the temperature range 160-360℃,and 99.0%N2 selectivity between 110 and 280℃.The addition of an appropriate amount of F ions eroded the surface morphology of the catalyst and reduced its grain size,thus enhancing the NO conversion at low temperature as well as the sulfur and water resistance of the V2 O5-WO3/Ti02 catalyst.After selective catalytic reduction(SCR)reaction in a gas flow containing SO2 and H2 O,the number of NH3 adsorption sites,active component content,specific surface area and pore volume decreased to different degrees.Ammonium sulfate species deposited on the catalyst surface,which blocked part of the active sites and reduced the NO conversion performance of the catalyst.On-line thermal regeneration could not completely recover the catalyst activity,although it prolonged the cumulative life of the catalyst.In addition,a mechanism for the effects of S02 and H2 O on catalyst NO conversion was proposed.