Effect of oxidation treatment on the adsorption and the stability of mercury on activated carbon

Oxidation treatment on the adsorption and the stability of Hg on activated carbon （AC） was inrestigated. Both MnO2-AC and FeCl3-AC were produced during oxidation treatment. The measurement of modified AC＇s mercury adsorption capacity was conducted in a simulated coal-fired flue gas by adsorbing test apparatus. TCLP and column leaching methods were used to test the stability of mercury adsorbed on ACs. The results indicate that the oxidation treatment changed the pore structure of the AC and modified the carbon surface by creating chemical components such as MnO4^-, Mn^4＋, O, NO^3-, Fe^3＋, Cl^-, etc. The Hg sorption capacity on MnO2-AC or FeCl3-AC was about three times higher than that of untreated carbon. In addition, the mercury control cost of each of the formers was about the half cost of the untreated carbon. The stability of Hg absorption was studied, it found that mercury adsorbed on the oxidation treated AC was not better than that of untreated carbon. It could concluded that the insoluble form of Hg is very important to the stability of mercury adsorbed on AC. This study suggests that the FeCl3-AC is the best absorbent for Hg with high adsorption capacity, better Hg adsorption stability in leaching environment, and lower cost among the three ACs tested.

pH-activatable oxidative stress amplifying dissolving microneedles for combined chemo-photodynamic therapy of melanoma

Photodynamic therapy(PDT)-mediated oxidation treatment is extremely attractive for skin melanoma ablation,but the strong hydrophobicity and poor tumor selectivity of photosensitizers,as well as the oxygen-consuming properties of PDT,leading to unsatisfactory therapeutic outcomes.Herein,a tumor acidic microenvironment activatable dissolving microneedle(DHA@HPFe-MN)was developed to realize controlled drug release and excellent chemo-photodynamic therapy of melanoma via oxidative stress amplification.The versatile DHA@HPFe-MN was fabricated by crosslinking a self-synthesized protoporphyrin(PpIX)-ADH-hyaluronic acid(HA)conjugate HA-ADH-PpIX with“iron reservoir”PA-Fe 3+complex in the needle tip via acylhydrazone bond formation,and dihydroartemisinin(DHA)was concurrently loaded in the hydrogel network.HA-ADH-PpIX with improved water solubility averted undesired aggregation of PpIX to ensure enhanced PDT effect.DHA@HPFe-MN with sharp needle tip,efficient drug loading and excellent mechanical strength could efficiently inserted into skin and reach the melanoma sites,where the acidic pH triggered the degradation of microneedles,enabling Fe-activated and DHA-mediated oxidation treatment,as evidenced by abundant reactive oxygen species(ROS)generation.Moreover,under light irradiation,a combined chemo-photodynamic therapeutic effect was achieved with amplified ROS generation.Importantly,the Fe-catalyzed ROS production of DHA was oxygen-independent,which work in synergy with the oxygen-dependent PDT to effectively destroy tumor cells.This versatile microneedles with excellent biosafety and biodegradability can be customized as a promising localized drug delivery system for combined chemo-photodynamic therapy of melanoma.

Quick Surface Treatment of AZ31B by AC Micro-arc Oxidation

In order to explore an effective way to shorten treatment time and enhance the quality of treatment coating, AC micro-arc oxidation was conducted to treat the surface of AZ31 B deformation magnesium alloy in KF＋KOH treatment solution. The infl uences of micro-arc oxidation parameters such as concentration of KF, concentration of KOH, output voltage of booster, temperature of treatment solution, and treatment time on treatment coating thickness were raveled out under different conditions. The structure and composition of treatment coating were determined, the growth mechanism of treatment coating was discussed, and the quick surface treatment technology for compact treatment coating with maximum thickness was developed. The experimental results show that： A maximum 33 μm-thick compact treatment coating, consisting of MgF2 and MgO mainly, can be formed on AZ31 B in 112 s under the conditions of 1 132 g/L KF, 382 g/L KOH, 66 V for output voltage of booster and 34 ℃ of treatment solution which were optimized by a genetic algorithm from the model established by artifi cial neural networks. There are no ＂crater-shaped＂ pores in this treatment coating as the heat shock resulting from the smooth variation of AC sinusoidal voltage is far smaller than that of the rigidly varied DC or pulse current. The treatment time is only one sixth of that adopted in the other surface treatment technology at best, principally for the reason that the coating can always grow irrespective of the electric potential of AZ31 B. This investigation lays a fi rm foundation for the extensive application of magnesium alloy.

Effect of Rare Earths on the Wear Resistance and High Temperature Oxidation Resistance of H13 Steel Surface-Treated with S-N-C Co-diffusion

Steel H13 was put in non toxic salt bath with addition of CeO 2 for co diffusion of sulfur, nitrogen and carbon and followed by oxidation treatment. The effect of rare earths on the improvement of wear resistance and high temperature oxidation resistance of steel H13 was studied using scanning electron microscope, energy dispersive spectrometry and X ray diffraction. The results show that compared to the surface treatment without rare earth addition, the treatment with addition of rare earths improves the wear resistance and high temperature resistance to oxidation of steel H13. Under the conditions of 30 N and 2 h, the wear weight loss was decreased by 40%, and the friction coefficient was reduced from 0 25 to 0 22; whereas for 150 N and 0 2 h, the wear weight loss was decreased by 24%, and the friction coefficient was reduced from 0 35 to 0 32. For the oxidation at 700 ℃ and 4 h, the rate of weight gain decreased to only about 1/30 of that without rare earths.

Low-Cost Preparation of Boron Nitride Ceramic Powders

The amorphous boron nitride ceramic powders were prepared at 750-950 ℃ by the low-cost urea route, and the effects of preparation temperatures, molar ratios of the raw materials and oxidation treatment on the composition, structure and surface morphology of the products were investigated through FT-IR, XRD and SEM. The results show that the products ceramize and crystallize gradually with the increase of the temperature. When the molar ratio and reaction temperature are 3：2 and 850 ℃, respectively, the products have high purity, compact structure and nice shape. The oxidation treatment at 450 ℃ will not impair the composition and structure of boron nitride but effectively remove the impurities.

Effect of annealing on properties of Al/steel composite plates prepared by surface oxidation treatment before cold roll bonding

Al/steel composite plate has a wide application prospect,but great differences in properties between Al and steel are observed.It is difficult to obtain high bonding strength by the traditional cold roll bonding process.Al/steel composite plate was thus prepared by cold roll bonding at a reduction rate of 60%after oxidation treatment on the surface to be composited on the steel side.The heat treatment of holding at 400℃ for 1 h and cooling with the furnace was then adopted.The bonding strength,microstructure,and properties of the Al/steel composite plate before and after annealing were analysed and compared through shear test,bending test,tensile test,and micro-characterization.Results show that the shear strengths of the interface before and after annealing are 100 and 80 MPa,respectively.Although the shear strength of the annealed Al/steel composite plate decreases,the bending and overall tensile properties of the composite plate are improved,showing better mechanical properties.

Formation of organic chloride in the treatment of textile dyeing sludge by Fenton system

In the oxidation treatment of textile dyeing sludge,the quantitative and transformation laws of organic chlorine are not clear enough.Thus,this study mainly evaluated the treatment of textile dyeing sludge by Fenton and Fenton-like system from the aspects of the influence of Cl^(-),the removal of polycyclic aromatic hydrocarbons (PAHs) and organic carbon,and the removal and formation mechanism of organic chlorine.The results showed that the organic halogen in sludge was mainly hydrophobic organic chlorine,and the content of adsorbable organic chlorine (AOCl) was 0.30 mg/g (dry sludge).In the Fenton system with pH=3,500 mg/L Cl-,30 mmol/L Fe^(2+)and 30 mmol/L H_(2)O_(2),the removal of phenanthrene was promoted by chlorine radicals (·Cl),and the AOCl in sludge solid phase increased to 0.55 mg/g (dry sludge) at 30 min.According to spectral analysis,it was found that ·Cl could chlorinate aromatic and aliphatic compounds (excluding PAHs) in solid phase at the same time,and eventually led to the accumulation of aromatic chlorides in solid phase.Strengthening the oxidation ability of Fenton system increased the formation of organic chlorines in liquid and solid phases.In weak acidity,the oxidation and desorption of superoxide anion promoted the removal and migration of PAHs and organic carbon in solid phase,and reduced the formation of total organic chlorine.The Fenton-like system dominated by nonhydroxyl radical could realize the mineralization of PAHs,organic carbon and organic chlorines instead of migration.This paper builds a basis for the selection of sludge conditioning methods.

Effects of Surface Oxidation Treatment of Carbon Fibers on Biotribological Properties of CF/PEEK Materials

Carbon Fiber （CF） reinforced polyetheretherketone （PEEK） composite is one of the most promising implant biomaterials used in orthopedics. In this article, unfilled PEEK and CF/PEEK specimens were prepared by vacuum hot pressing method, and their tribological properties were evaluated by sliding against a cobalt-chromium-molybdenum （Co-Cr-Mo） alloy block. The influences of mass fraction of carbon fibers in CF/PEEK and the surface oxidation treatment of carbon fibers were explored. The results showed that the water contact angles on the surfaces of CF/PEEK specimens decreased, indicating that their surface wettability was improved. The hardness value of CF/PEEK was significantly improved, the friction coefficients of CF/PEEK were effectively reduced and its wear resistance was enhanced compared with unfilled PEEK. The leading effect on CF/PEEK tribological properties was the mass fraction of CF, followed by surface oxidation of CF, and the calf serum solution had better lubricity than that of saline and deionized water.

Anti-Thermal-Fatigue Property of 8407 Steel With Surface Aluminization and Oxidation Treatment

Thermal fatigue failure is one of the main failure forms of 8407 steel. Aiming at improving the anti-thermal-fatigue property of 8407 steel, the method of aluminization and subsequent oxidation is employed to form a complex oxide on the die surface. Thermal fatigue test was performed with the cycle heating method to compare thermal fatigue behaviors of 8407 steel samples with and without aluminization and oxidation treatment. In the test, thermal fatigue crack morphology formed on the surface was observed by scanning electron microscope （SEM） and then variations of initiating rate and propagating rate of main crack of thermal fatigue with cycles were investigated. Moreover, the thermal fatigue property was judged according to thermal fatigue main crack length and its reciprocal. Finally, the anti-thermal-fatigue mechanism of oxide film was clarified. The results show that the surface aluminization and oxidation treatment can improve both the initiating resistance and propagating resistance of thermal fatigue crack, which will improve the anti-thermal-fatigue property of 8407 steel.

Effect of Surface Mechanical Attrition Treatment on Tribological Behavior of the AZ31 Alloy

By surface mechanical attrition treatment（SMAT）,a gradient nano structure（GNS） from the surface to center was generated in the AZ31 alloy sheet.The tribological behavior of AZ31 alloy with GNS was systematically investigated by using dry sliding tests,a 3D surface profile-meter and a scanning electron microscope equipped with an energy-dispersive spectrometer.The experimental results indicate that the Mg alloy with GNS exhibits better wear resistance comparing to the as-received sample,which is associated to the alteration of wear mechanism at different sliding speeds.The Mg alloy with GNS presents the wear mechanism of the abrasive wear at 0.05 m/s and the oxidative wear at 0.5 m/s,respectively.Moreover,the GNS can effectively promote the reaction between the oxygen and worn surface,which leads to a compact oxidation layer at 0.5 m/s.The effect of oxidation layer on the wear resistance of the Mg alloy was also discussed.

Characteristics of greenhouse gas emission in three full-scale wastewater treatment processes

Three full-scale wastewater treatment processes, Orbal oxidation ditch, anoxic/anaerobic/aerobic （reversed A^2O） and anaerobic/anoxic/aerobic （A^2O）, were selected to investigate the emission characteristics of greenhouse gases （GHG）, including carbon dioxide （CO2）, methane （CH4） and nitrous oxide （N2O）. Results showed that although the processes were different, the units presenting high GHG emission fluxes were remarkably similar, namely the highest CO2 and N2O emission fluxes occurred in the aerobic areas, and the highest CH4 emission fluxes occurred in the grit tanks. The GHG emission amount of each unit can be calculated from its area and GHG emission flux. The calculation results revealed that the maximum emission amounts of CO2, CH4 and N2O in the three wastewater treatment processes appeared in the aerobic areas in all cases. Theoretically, CH4 should be produced in anaerobic conditions, rather than aerobic conditions. However, results in this study showed that the CH4 emission fluxes in the forepart of the aerobic area were distinctly higher than in the anaerobic area. The situation for N2O was similar to that of CH4： the N2O emission flux in the aerobic area was also higher than that in the anoxic area. Through analysis of the GHG mass balance, it was found that the flow of dissolved GHG in the wastewater treatment processes and aerators may be the main reason for this phenomenon. Based on the monitoring and calculation results, GHG emission factors for the three wastewater treatment processes were determined. The A^2O process had the highest CO2 emission factor of 319.3 g CO2/kg CODremoved, and the highest CH4 and N2O emission factors of 3.3 g CH4/kg CODremoved and 3.6 g N2O/kg TNremoved were observed in the Orbal oxidation ditch process.

Reduction and characterization of bioaerosols in a wastewater treatment station via ventilation

Bioaerosols from wastewater treatment processes are a significant subgroup of atmospheric aerosols. In the present study,airborne microorganisms generated from a wastewater treatment station（WWTS） that uses an oxidation ditch process were diminished by ventilation.Conventional sampling and detection methods combined with cloning/sequencing techniques were applied to determine the groups,concentrations,size distributions,and species diversity of airborne microorganisms before and after ventilation. There were 3021 ± 537 CFU/m3 of airborne bacteria and 926 ± 132 CFU/m3 of airborne fungi present in the WWTS bioaerosol.Results showed that the ventilation reduced airborne microorganisms significantly compared to the air in the WWTS. Over 60% of airborne bacteria and airborne fungi could be reduced after4 hr of air exchange. The highest removal（92.1% for airborne bacteria and 89.1% for fungi） was achieved for 0.65–1.1 μm sized particles. The bioaerosol particles over 4.7 μm were also reduced effectively. Large particles tended to be lost by gravitational settling and small particles were generally carried away,which led to the relatively easy reduction of bioaerosol particles0.65–1.1 μm and over 4.7 μm in size. An obvious variation occurred in the structure of the bacterial communities when ventilation was applied to control the airborne microorganisms in enclosed spaces.

Bioactive Titanium Surfaces with the Effect of Inhibiting Biofilm Formation

Titanium metals and its alloy have been widely used in hard tissue repairing fields due to their good biocampatibility and mechanical properties. However, bioinert response and biomaterial associated infections are the main problems for their clinical application. In this study, we chose titanium plates treated with anodic oxidation （AO-Ti）, alkali-heat （AH-Ti） and acid-alkali （AA-Ti） methods, which have been proved to be bioactive in vivo, to culture with Staphylococcus aureus and Escherichia coli to investigate the interaction between bioactive titanium surfaces and biofilm. We used X-ray diffraction （XRD）, Scanning Electron Microscope （SEM）, roughness measurement to study the physical-chemical properties of the as-received bioactive titanium surfaces, and Confocal Laser Scanning Microscope （CLSM） was employed to study the properties of biofilm formed on the biomaterial surfaces. The results indicate that the titanium surface subjected to anodic oxidation treatment is unfavorable for the formation ofbiofilm in vitro because the titania （TiO2） coating formed by anodizing has superior antimicrobial property than the other surfaces. Therefore, anodic oxidation surface modification is effective to endow titanium surface with bioactivity and antimicrobial property, which has the potential to improve the successful rate of the clinical application of titanium implants.

Decomposition behavior of titanium hydride treated by surface oxidation

Titanium hydride attracts more attention as foaming agent in the fabrication of cellular metal materials. In order to meet most aluminum casting alloy＇s melting properties, the heat treatment processes for Till2 particles were investigated in a rotating device. In the present work, the most two important dynamic parameters, the treating temperature and oxidation interval, were taken under consideration. The decomposition behavior of titanium hydride was measured by differential scanning calorimetry （DSC） and the residual hydrogen content, morphologies and phase conversion were also characterized by hydrogen determinator, scanning electron microscopy （SEM）, and X-ray diffractometer （XRD）, respectively. The results show that the effect of temperature on the formation of oxidation film and decomposition behavior of Till2 is more significant than that of oxidation time. The onset temper- ature and peak value of Till2 decomposition shift from left to right through elevating temperature and extending time. Heat treatment process for Till2 at 500 ℃ between 1 and 5 h in air is favorable for preparing aluminum foam.

Synthesis,characterization and application of ZnO-Ag as a nanophotocatalyst for organic compounds degradation,mechanism and economic study

The current work deals with ZnO-Ag nanocomposites（in the wide range of x in the Zn1-x O-Ag x chemical composition） synthesized using microwave assisted solution combustion method.The structural, morphological and optical properties of the samples were characterized by XRD（X-ray diffraction）, FTIR（Fourier transform infrared spectrometry）, SEM（scanning electron microscopy technique）, EDX（energy dispersive X-ray spectrum）, ICP（inductively coupled plasma technique）, TEM（transmission electron microscopy）, BET（Brunauer–Emmett–Teller method）, UV–Vis（ultraviolet–visible spectrophotometer） and photoluminescence spectrophotometer. The photocatalytic activity of the ZnO-Ag was investigated by photo-degradation of Acid Blue 113（AB 113） under UV illumination in a semi-batch reactor. This experiment showed that ZnO-Ag has much more excellent photocatalytic properties than ZnO synthesized by the same method. The enhanced photocatalytic activity was due to the decrease in recombination of photogenerated electron-holes. The results showed the improvement of ZnO photocatalytic activity and there is an optimum amount of Ag（3.5 mol%） that needs to be doped with ZnO.The effect of operating parameters such as p H, catalyst dose and dye concentration were investigated. The reaction byproducts were identified by LC/MS（liquid chromatography/mass spectrometry） analysis and a pathway was proposed as well. Kinetic studies indicated that the decolorization process follows the first order kinetics. Also, the degradation percentage of AB113 was determined using a total organic carbon（TOC） analyzer. Additionally, cost analysis of the process, the mechanism and the role of Ag were discussed.

Electrodeposition of nanostructured Ti/(Ru+Ti+Ce)O_2 coatings

A nanostructured ternary coating of Ti/（Ru ＋ Ti ＋ Ce）O2 was prepared by the conventional electrodeposition on the titanium substrate as the cathode with different numbers of coating layers. The main objective of this work was to study nanostructured coatings of ceramic materials. For this purpose, the amount of precursor materials in the electrolyte was a variable parameter. Furthermore, the salt of TiCl4/RuCl3·xH2 O/Ce（NO3）3·6 H2 O with different amounts, hydrogen peroxide, methanol, and distilled water were used as an aqueousunaqueous bath. In addition, the coated samples were put to heat at 300, 450, 650, and 850℃ in an electric furnace for1 h. The crystalline phase of the coating was characterized by X-ray diffraction（XRD）. The chemical composition and microstructure of the coating were studied using energydispersive spectroscopy（EDS） and scanning electron microscopy analysis（SEM）. Moreover, the electrochemical measurement of Ti/（Ru ＋ Ti ＋ Ce）O2 coatings was carried out. Results show that with the increase in the number of coating layers, the quality of morphology is improved.Then, the best quality of coatings is obtained at six layers on the titanium substrate with electrolyte including TiO2/RuO2/CeO2 with the molar ratio of 70：5：25 after heat treatment at 450 ℃ for 1 h. Besides,with the increase in Ce02 content from 5 wt% to 25 wt% and the number of coating layers, higher thickness of about（20.0±0.1） μm and minimum over potential for chlorine evolution were obtained.

Low-temperature conversion of ammonia to nitrogen in water with ozone over composite metal oxide catalyst

As one of the most important water pollutants, ammonia nitrogen emissions have increased year by year, which has attracted people＇s attention. Catalytic ozonation technology, which involves production of ·OH radical with strong oxidation ability, is widely used in the treatment of organic-containing wastewater. In this work, MgO-Co3O4 composite metal oxide catalysts prepared with different fabrication conditions have been systematically evaluated and compared in the catalytic ozonation of ammonia（50 mg/L） in water. In terms of high catalytic activity in ammonia decomposition and high selectivity for gaseous nitrogen, the catalyst with MgO-Co3O4 molar ratio 8：2, calcined at 500°C for 3 hr, was the best one among the catalysts we tested, with an ammonia nitrogen removal rate of 85.2% and gaseous nitrogen selectivity of44.8%. In addition, the reaction mechanism of ozonation oxidative decomposition of ammonia nitrogen in water with the metal oxide catalysts was discussed. Moreover, the effect of coexisting anions on the degradation of ammonia was studied, finding that SO2-4 and HCO-3 could inhibit the catalytic activity while CO2-3 and Br-could promote it. The presence of coexisting cations had very little effect on the catalytic ozonation of ammonia nitrogen. After five successive reuses, the catalyst remained stable in the catalytic ozonation of ammonia.

Anode Engineering of Highly Efficient Polymer Solar Cells Using Treated ITO

ITO substrates were treated with organic solvent cleaning（OSC）, SCl treatment[V（NH4OH）：V（Hz02）： V（H2O）=1：1：5], O2 plasma and UV ozone, respectively. Combined investigations of atom force microscopy（AFM）, water contact angle measurements, ultraviolet photoemission spectroscopy（UPS） and X-ray photoemission spec- troscopy（XPS） demonstrated that UV ozone treatment could give rise to the smoothest surface, the most hydrophilic property and the highest work function（WF） of ITO due to the removal of hydrophobic C--O impurity from the ITO surface and the enrichments of more oxygen on the ITO surface. When PEDOT：PSS film[（poly（3,4-ethylenedioxy- thiophene）：poly（styrene sulfonate）] was deposited on the ITO substrates treated with UV ozone, it showed a lower root-mean- square roughness in AFM images, a higher transmission in UV-Vis transmission spectra and a higher WF in UPS spectra than the PEDOT：PSS films deposited on the ITO substrates treated by other three methods. As a result, the power conversion efficiency of polymer solar cells（PSCs） based on PTB7：PC71BM as an active layer and ITO treated by UV ozone as an anode can reach 8.48% because of the simultaneously improved short circuit current, open circuit voltage and fill factor compared to the PSCs with ITO treated with other three methods.

Microwave absorbing properties of NdFeCo magnetic powder

NdFeCo magnetic powder was prepared by the process of smelting, high-energy ball milling and oxidation heat treating. The effects of oxidation heat treatment and Co content on phase composition and microwave absorbing properties of NdFeCo magnetic powder were investigated by an X-ray diffractometer （XRD） and vector network analyzer. The minimum reflectivity of Nd23.25Fe36.75Co40 powder before oxidation heat treatment was 4.2 dB, and that of oxidized powder decreased to -14.0 dB. The microwave absorbing properties of NdFeCo magnetic powder could be improved effectively by oxidation heat treatment. With the increase of Co content, the Fe2O3 reduced and the Nd2O3 increased; Fe3CO7 phase appeared when the content of Co increased to 40% （mass ratio）; the absorption peak was found to move towards lower frequency region first, and then it moved towards a higher frequency region. Nd23.25Fe06.75Co10 powder had better comprehensive properties in absorbing microwave in the frequency band of 3-13 GHz. The value of minimum reflectivity and absorption peak frequency, when the coating thickness （d） was 1.8 mm, were -19.7 dB and 4.8 GHz, respectively.

Microfluidics-generated graphene oxide microspheres and their application to removal of perfluorooctane sulfonate from polluted water

Monodisperse graphene oxide （GO） microspheres were synthesized via microfluidics technology as a novel adsorbent for rapid （in 2 rain） and high efficiency （98%） removal of perfluorooctane sulfonate （PFOS） from water. This novel material is a potential solution for treatment of bioaccumulative organic polluted water. To achieve improved performance, Mg2＋ was introduced into GO, and the metal composite exhibited significantly improved PFOS removal effidency owing to bridging and interaction between Mg~＋ and the PFOS molecules, which was supported by density functional theory and X-ray photoelectron spectroscopy （XPS）. This facile strategy may be extended to the synthesis of other spheres with unique structural features for application in water treatment.