Effects of heavy metal ions Cu^(2+)/Pb^(2+)/Zn^(2+)on kinetic rate constants of struvite crystallization

Struvite(MAP)crystallization technology is widely used to treat ammonia nitrogen in waste effluents of its simple operation and good removal efficiency.However,the presence of heavy metal ions in the waste effluents causes problems such as slow crystallization rate and small crystal size,limiting the recovery rate and economic value of the MAP.The present study was conducted to investigate the effects of concentrations of three heavy metal ions(Cu^(2+),Zn^(2+),and Pb^(2+))on the crystal morphology,crystal size,average growth rate,and crystallization kinetics of MAP.A relationship was established between the kinetic rate constant Ktcalculated by the chemical gradient model and the concentrations of heavy metal ions.The results showed that low concentrations of heavy metal ions in the solution created pits on the MAP surface,and high level of heavy metal ions generated flocs on the MAP surface,which were composed of metal hydroxides,thus inhibiting crystal growth.The crystal size,average growth rate,MAP crystallization rate,and kinetic rate constant Ktdecreased with the increase in heavy metal ion concentration.Moreover,the Ktdemonstrated a linear relationship with the heavy metal concentration ln(C/C~*),which provided a reference for the optimization of the MAP crystallization process in the presence of heavy metal ions.

Heavy ion energy influence on multiple-cell upsets in small sensitive volumes:from standard to high energies

The 28 nm process has a high cost-performance ratio and has gradually become the standard for the field of radiation-hardened devices.However,owing to the minimum physical gate length of only 35 nm,the physical area of a standard 6T SRAM unit is approximately 0.16μm^(2),resulting in a significant enhancement of multi-cell charge-sharing effects.Multiple-cell upsets(MCUs)have become the primary physical mechanism behind single-event upsets(SEUs)in advanced nanometer node devices.The range of ionization track effects increases with higher ion energies,and spacecraft in orbit primarily experience SEUs caused by high-energy ions.However,ground accelerator experiments have mainly obtained low-energy ion irradiation data.Therefore,the impact of ion energy on the SEU cross section,charge collection mechanisms,and MCU patterns and quantities in advanced nanometer devices remains unclear.In this study,based on the experimental platform of the Heavy Ion Research Facility in Lanzhou,low-and high-energy heavy-ion beams were used to study the SEUs of 28 nm SRAM devices.The influence of ion energy on the charge collection processes of small-sensitive-volume devices,MCU patterns,and upset cross sections was obtained,and the applicable range of the inverse cosine law was clarified.The findings of this study are an important guide for the accurate evaluation of SEUs in advanced nanometer devices and for the development of radiation-hardening techniques.

Effect of high-energy Ne ions irradiation on mechanical properties difference between Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5)metallic glass and crystalline W

In this paper,high-energy Ne ions were used to irradiate Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) metallic glass(MG)and crystalline W to investigate their difference in mechanical response after irradiation.The results showed that with the irradiation dose increased,the tensile micro-strain increased,nano-hardness increased from 7.11 GPa to 7.90 GPa and 8.62 GPa,Young’s modulus increased,and H3/E2 increased which indicating that the plastic deformability decreased in crystalline W.Under the same irradiation conditions,the Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG still maintained the amorphous structure and became more disordered despite the longer range and stronger displacement damage of Ne ions in Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG than in crystalline W.Unlike the irradiation hardening and embrittlement behavior of crystalline W,Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG showed the gradual decrease in hardness from 6.02 GPa to 5.89 GPa and 5.50 GPa,the decrease in modulus and the increase in plastic deformability with the increasing dose.Possibly,the irradiation softening and toughening phenomenon of Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG could provide new ideas for the design of nuclear materials.

Uniformity Control of Scanned Beam in 300 MeV Proton and Heavy Ion Accelerator Complex at SESRI

In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiation area is required for the extracted ion beams,which is crucial because it directly affects the experimental precision and therapeutic effect.Specifically,ultra-large-area and high-uniformity scanning are crucial requirements for spacecraft radiation effects assessment and serve as core specification for beamline terminal design.In the 300 MeV proton and heavy ion accelerator complex at the Space Environment Simulation and Research Infrastructure(SESRI),proton and heavy ion beams will be accelerated and ultimately delivered to three irradiation terminals.In order to achieve the required large irradiation area of 320 mm×320 mm,horizontal and vertical scanning magnets are used in the extraction beam line.However,considering the various requirements for beam species and energies,the tracking accuracy of power supplies(PSs),the eddy current effect of scanning magnets,and the fluctuation of ion bunch structure will reduce the irradiation uniformity.To mitigate these effects,a beam uniformity optimization method based on the measured beam distribution was proposed and applied in the accelerator complex at SESRI.In the experiment,the uniformity is successfully optimized from 75%to over 90%after five iterations of adjustment to the PS waveforms.In this paper,the method and experimental results were introduced.

Relativistic Heavy Ion Collider and the Large Hadron Collider for Heavy Ion Fusion

Heavy Ion Fusion makes use of the Relativistic Heavy Ion Collider at Brookhaven National Lab and the Large Hadron Collider in Geneva, Switzerland for Inertial Confinement Fusion. Two Storage Rings, which may or may not initially be needed, added to each of the Colliders increases the intensity of the Heavy Ion Beams making it comparable to the Total Energy delivered to the DT target by the National Ignition Facility at the Lawrence Livermore Lab. The basic Physics involved gives Heavy Ion Fusion an advantage over Laser Fusion because heavy ions have greater penetration power than photons. The Relativistic Heavy Ion Collider can be used as a Prototype Heavy Ion Fusion Reactor for the Large Hadron Collider.

Enhancement of removal efficiency of heavy metal ions by polyaniline deposition on electrospun polyacrylonitrile membranes

This paper describes the preparation of a membrane of polyacrylonitrile(PAN)and its corresponding membrane coated with polyaniline(PANI)for the adsorption of heavy metal ions.Scanning electron microscopy micrographs revealed that all the membranes exhibited nanofibrous morphology.The prepared membranes were characterized by Fourier transform infrared spectroscopy(FTIR).The prepared membranes were used as an adsorbent for hazardous heavy metal ions Pb^(2+) and Cr_(2)O^(2-)_(7).The adsorption capacity and the removal efficiency of the membranes were examined as function of the initial adsorbate concentration and pH of the medium.Coated membranes with PANI showed better adsorption performance and their direct current(DC)conductivities were correlated to heavy metal ion concentrations.Adsorption isotherms were also performed,and the adsorption process was tested according to the Langmuir and Freundlich models.The regeneration and reuse of the prepared membranes to re-adsorb heavy metal ions were also investigated.The enhancement in adsorption performance and reusability of PANI-coated membranes in comparison with non-coated ones is fully discussed.The results show that the maximum adsorption capacities of lead and chromate ions on the PANI-coated membranes are 290.12 and 1202.53 mg/g,respectively.

Biodegradation of high concentration phenol containing heavy metal ions by functional biofilm in bioelectro-reactor

Functional microorganisms to high concentration phenol containing Cr^6＋ and Pb^2＋ were cultured and biofilm was formed on polypropylene packings in bioelectro-reactor. It was found that the biodegradation capability of such biofilm to phenol changed with the applied voltage. Under the optimal electric field conditions （voltage of 3.0 V, electric field of strength 17.7 V/m and current density of 1.98 A/m2）, biodegradation efficiency of phenol aof concentration of 1200 mg/L increased 33% compared to the instance without applying electric field. However, voltage had inverse effect on biodegradation, as microorganisms were killed under strong electric field. Voltage had little effect on heavy ions elimination. Higher absorption rate of Cr^6＋ and Pb^2＋ was observed when changing pH fi＇om acidic to neutral. The experiment results indicated that, after treatment, 10 L phenol of 2400 mg/L was biodegraded completely within 55 h and concentrations of Cr^6＋ and Pb^2＋ dropped to less than 1 mg/L within 12 h and 6 h, fi＇om initial values of 50 mg/L and 30 mg/L, respectively.

Heavy ion‑induced MCUs in 28nm SRAM‑based FPGAs:upset proportions,classifications,and pattern shapes

For modern scaling devices,multiple cell upsets(MCUs)have become a major threat to high-reliability field-programmable gate array(FPGA)-based systems.Thus,both performing the worst-case irradiation tests to provide the actual MCU response of devices and proposing an effective MCU distinction method are urgently needed.In this study,high-and medium-energy heavy-ion irradiations for the configuration random-access memory of 28 nm FPGAs are performed.An MCU extraction method supported by theoretical predictions is proposed to study the MCU sizes,shapes,and frequencies in detail.Based on the extraction method,the different percentages,and orientations of the large MCUs in both the azimuth and zenith directions determine the worse irradiation response of the FPGAs.The extracted largest 9-bit MCUs indicate that high-energy heavy ions can induce more severe failures than medium-energy ones.The results show that both the use of high-energy heavy ions during MCU evaluations and effective protection for the application of high-density 28 nm FPGAs in space are extremely necessary.

Impact of the displacement damage in channel and source/drain regions on the DC characteristics degradation in deep-submicron MOSFETs after heavy ion irradiation

This paper mainly reports the permanent impact of displacement damage induced by heavy-ion strikes on the deepsubmicron MOSFETs. Upon the heavy ion track through the device, it can lead to displacement damage, including the vacancies and the interstitials. As the featured size of device scales down, the damage can change the dopant distribution in the channel and source/drain regions through the generation of radiation-induced defects and thus have significant impacts on their electrical characteristics. The measured results show that the radiation-induced damage can cause DC characteristics degradations including the threshold voltage, subthreshold swing, saturation drain current, transconductanee, etc. The radiation-induced displacement damage may become the dominant issue while it was the secondary concern for the traditional devices after the heavy ion irradiation. The samples are also irradiated by Co- 60 gamma ray for comparison with the heavy ion irradiation results. Corresponding explanations and analysis are discussed.

Reconstruction of fission events in heavy ion reactions with the compact spectrometer for heavy ion experiment

We report a reconstruction method for fast-fission events in 25 MeV/u^(86)Kr +^(208)Pb reactions at the Compact Spectrometer for Heavy Ion Experiment(CSHINE). The fission fragments(FFs) are measured using three large-area parallel-plate avalanche counters, which can deliver the position and arrival timing information of the fragments. The start timing information is provided by the radio frequency of the cyclotron. Fission events were reconstructed using the velocities of the two FFs. The broadening of both the velocity distribution and azimuthal difference of the FFs decreases with the folding angle, in accordance with the picture that fast fission occurs. The anisotropic angular distribution of the fission axis also consistently reveals the dynamic features of fission events.

Comparative adsorption of heavy metal ions in wastewater on monolayer molybdenum disulfide

To maximize the potential of monolayer molybdenum disulfide(MoS2)sheet in the disposal of heavy metal ions in wastewater,we compared the adsorption of several common heavy metal ions(including Cr^(3+),Ni^(2+),Cu^(2+),Zn^(2+),Cd^(2+),Hg^(2+),and Pb^(2+))in wastewater on the monolayer MoS2 sheet through first-principles calculation.Our simulation results show that the monolayer MoS2 sheet is a potential heavy metal adsorption material because of the attractive interaction between them.The most negative adsorption energy determines that the TMo site is the most stable adsorption site for the heavy metal ions.The attractive interaction is considered as chemical adsorption,and it is closely related to charge transfer.The orbital hybridization between S p and heavy metal ions p and d states electrons contributes to the adsorption,except the orbital hybridization between S p and Pb p states electrons contributes to the Pb^(2+) adsorption.All the results show that the monolayer MoS2 sheet is most suitable for removing Ni^(2+) and Cr^(3+) ions from wastewater,followed by Cu^(2+) and Pb^(2+).For the ions Cd^(2+),Zn^(2+),and Hg^(2+),its adsorption strength remains to be improved.

Electrochemical Sensing of Heavy Metal Ions based on Monodisperse Single-crystal Fe_3O_4 Microspheres

Single-crystal FeOwith monodisperse microspheres structure has been used for individual electrochemical detection of heavy metal ions. Morphology and structure of the as-prepared FeOmicrospheres were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM) and X-ray diffraction(XRD). Meanwhile the electrochemical properties of the FeOmicrospheres modified glass carbon electrodes(GCE) were characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS), and the enhanced electrochemical response in stripping voltammetry for individual detection of Pb(Ⅱ), Hg(Ⅱ), Cu(Ⅱ), and Cd(Ⅱ) was evaluated using square wave anodic stripping voltammetry(SWASV). With high specific surface area and excellent catalytic activity toward heavy metal ions, the as-prepared monodisperse and single-crystal FeOmicrospheres show a preferable sensing sensitivity(22.2 μA/μM) and limit of detection(0.0699 μM) toward Pb(Ⅱ). Furthermore, the electrochemical sensor of FeOmicrospheres exhibits excellent stability and it also offers potential practical applicability for the determination of heavy metal ions in real water samples. This study provides a potential simple and low cost iron oxide for the construction of sensitive electrochemical sensors applied to monitor and control the pollution of toxic metal ions.

Sorption Characteristics for Multiple Adsorption of Heavy Metal Ions Using Activated Carbon from Nigerian Bamboo

Sorption characteristics of multiple adsorption of six heavy metal ions often found in refinery waste waters using activated carbon from Nigerian bamboo was investigated. The bamboo was cut, washed and dried. It was carbonized between 350℃ - 500℃, and activated at 800℃ using nitric acid. Simultaneous batch adsorption of different heavy metal ions (Cd2+, Ni2+, Pb2+, Cr3+, Cu2+ and Zn2+) in same aqueous solution using activated carbon from Nigerian bamboo was carried out. The adsorption process had a better fit for the Freundlich, Temkin isotherm and Dubinin-Radushke-vich (DRK) isotherm models but could not fit well into Langmuir isotherm. Adsorption isotherms showed that there is competition among various metals for adsorption sites on Nigerian bamboo. The DRK model was used to determine the nature of the sorption process and was found to be physical and chemical, with sorption energy of metal ions ranging from (7 - 10 kJ/mol). The adsorption of Cd2+, Zn2+, Pb2+ and Ni2+ ions was chemisorptions and that of Cu2+ and Cr3+ ions was cooperative adsorption. Therefore, this study revealed that Nigerian bamboo can serve as a good source of activated carbon with multiple and simultaneous metalions—removing potentials and may serve as a better replacement for commercial activated carbons in applications that warrant their use.

Robust Waterborne Polyurethane/Wool Keratin/Silk Sericin Freeze-Drying Composite Membrane for Heavy Metal Ions Adsorption

Wool keratin(WK)and silk sericin(SS)have the ability to interact with metal ions.In order to take advantage of this potential,a novel environmentally friendly waterborne polyurethane(WPU)/WK/SS membrane named as WPU&WK&SS membrane with crosslinked structure was constructed by freeze-drying via self-assembly style.Surface morphology and chemical structure characterization were investigated by scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR).In addition,the adsorption experiments of Cu2+and Cr6+were performed to evaluate the adsorption of WPU&WK&SS membrane,including adsorption kinetics,adsorption isotherm models and various factors affecting adsorption.Further investigation indicates that the maximum adsorption capacity of Cu2+and Cr6+can reach 54.21 mg·g-1and 85.21 mg·g-1,respectively,which are higher than most of the reported adsorbents.Through adsorption kinetics and thermodynamic analysis,it is find that the pseudo-second-order kinetic equation and the Langmuir adsorption isotherm model are more suitable for the static adsorption of Cu2+and Cr6+by WPU&WK&SS membrane.

Experiment and simulation on degradation and burnout mechanisms of SiC MOSFET under heavy ion irradiation

Experiments and simulation studies on 283 MeV I ion induced single event effects of silicon carbide(SiC) metal–oxide–semiconductor field-effect transistors(MOSFETs) were carried out. When the cumulative irradiation fluence of the SiC MOSFET reached 5×10^(6)ion·cm^(-2), the drain–gate channel current increased under 200 V drain voltage, the drain–gate channel current and the drain–source channel current increased under 350 V drain voltage. The device occurred single event burnout under 800 V drain voltage, resulting in a complete loss of breakdown voltage. Combined with emission microscope, scanning electron microscope and focused ion beam analysis, the device with increased drain–gate channel current and drain–source channel current was found to have drain–gate channel current leakage point and local source metal melt, and the device with single event burnout was found to have local melting of its gate, source, epitaxial layer and substrate. Combining with Monte Carlo simulation and TCAD electrothermal simulation, it was found that the initial area of single event burnout might occur at the source–gate corner or the substrate–epitaxial interface, electric field and current density both affected the lattice temperature peak. The excessive lattice temperature during the irradiation process appeared at the local source contact, which led to the drain–source channel damage. And the excessive electric field appeared in the gate oxide layer, resulting in drain–gate channel damage.

Raman spectrum study of graphite irradiated by swift heavy ions

Highly oriented pyrolytic graphites are irradiated with 40.5-Me V and 67.7-Me V ^112Sn-ions in a wide range of fluences： 1×10^11 ions/cm^2–1×10^14ions/cm^2. Raman spectra in the region between 1200 cm^-1 and 3500cm^-1 show that the disorder induced by Sn-ions increases with ion fluence increasing. However, for the same fluence, the amount of disorder is greater for 40.5-Me V Sn-ions than that observed for 67.7-Me V Sn-ions, even though the latter has a slightly higher value for electronic energy loss. This is explained by the ion velocity effect. Importantly, ～ 3-cm^-1frequency shift toward lower wavenumber for the D band and ～ 6-cm^-1 shift toward lower wavenumber for the 2D band are observed at a fluence of 1×10^14 ions/cm^2, which is consistent with the scenario of radiation-induced strain. The strain formation is interpreted in the context of inelastic thermal spike model, and the change of the 2D band shape at high ion fluence is explained by the accumulation of stacking faults of the graphene layers activated by radiation-induced strain around ion tracks. Moreover,the hexagonal structure around the ion tracks is observed by scanning tunneling microscopy, which confirms that the strains near the ion tracks locally cause electronic decoupling of neighboring graphene layers.

Irradiation effects of graphene and thin layer graphite induced by swift heavy ions

Graphene and thin graphite films deposited on SiO2/Si are irradiated by swift heavy ions(209Bi, 9.5 Me V/u) with the fluences in a range of 1011ions/cm2–1012ions/cm2 at room temperature. Both pristine and irradiated samples are investigated by Raman spectroscopy. For pristine graphite films, the 'blue shift' of 2D bond and the 'red shift' of G bond with the decrease of thickness are found in the Raman spectra. For both irradiated graphene and thin graphite films, the disorder-induced D peak and D' peak are detected at the fluence above a threshold Φth. The thinner the film, the lower the Φthis. In this work, the graphite films thicker than 60 nm reveal defect free via the absence of a D bond signal under the swift heavy ion irradiation till the fluence of 2.6 × 1012ions/cm2. For graphite films thinner than 6 nm, the area ratios between D peak and G peak increase sharply with reducing film thickness. It concludes that it is much easier to induce defects in thinner films than in thicker ones by swift heavy ions. The intensities of the D peak and D' peak increase with increasing ion fluence, which predicts the continuous impacting of swift heavy ions can lead to the increasing of defects in samples. Different defect types are detected in graphite films of different thickness values. The main defect types are discussed via the various intensity ratios between the D peak and D' peak(HD/HD).

Synthesis and Characteristics of A Novel Heavy Metal Ions Chelator

Polyacrylamide-urea-sulfanilamide（PUS） was prepared as a novel heavy metal ions chelator and successfully used to simultaneously remove heavy metals from wastewater effluents.The effects of reaction parameters（sodium hydroxide,material ratio,temprature and contact time） were monitored to specify the best synthesis conditions.PUS was chemically characterized by means of infrared spectroscopy（FTIR） and ultraviolet-visible（UV-Vis）.The simultaneous chelation performance of PUS towards selected heavy metals ions,Ni2＋,Cu2＋,Pb2＋,Zn2＋,Cd2＋ was discussed,showing that Ni2＋,Cu2＋,Pb2＋,Zn2＋ could be better chelated.It is indicated that the synthesized PUS is a potential remediation material when used for the treatment of wastewater containing metal ions.

Vickers hardness change of the Chinese low-activation ferritic/martensitic steel CLF-1 irradiated with high-energy heavy ions

In the present work,the irradiation hardening behavior of a Chinese low-activation ferritic/martensitic steel CLF-1,a candidate for fusion reactor blankets,is studied.Specimens were irradiated with high-energy14N and56Fe ions at the terminal of a cyclotron to three successively increasing damage levels of 0.05,0.1 and 0.2 displacements per atom(dpa)at about-50°C.The energy of the incident ions was dispersed to 11 successively decreasing grades using an energy degrader,thereby generating an atomic displacement damage plateau in the specimens from the surface to a depth of 25μm,which is sufficiently broad for the Vickers hardness test.Eight different loads(i.e.98 mN,196 m N,490 m N,980 m N,1.96 N,4.9 N,9.8 N and 19.6 N)were applied to the specimens to obtain the depth profiles of the Vickers hardness by using a microhardness tester.Hardening was observable at the lowest damage level,and increased with increasing irradiation dose.A power-law correlation of the Vickers hardness with the damage level(HV0=1.49+0.76 dpa0.31)is proposed.Testing with a nano-indentation technique was also performed,and a linear relationship between the Vickers micro-hardness and the nanohardness(HV0=0.83 H0)was observed.A comparison with other RAFM steels(CLAM,JLF-1,F82 H,EUROFER97 etc.)under neutron or charged particle irradiation conditions shows that most of the RAFM steels exhibit similar power-law exponents in the dose dependence of irradiation hardening.The difference in the irradiation hardening may be attributed to differences in microstructure prior to irradiation.

Anisotropic emission of charged mesons and structure characteristic of emission source in heavy ion collisions at 1-2A GeV

Angular distributions of pious and kaons produced in heavy ion collisions at the low-energy end of high energies （1-2 A GeV） have been investigated by using a multisource ideal gas model. The model covers the expansions and movements of the emission sources, and it is related to the collective flows. By using the analytic expression and the Monte Carlo method, the azimuthal and polar angle distributions of mesons are calculated by the model and compared with the experimental data of the KaoS Collaboration.