Heavy-ion Potentials Research Articles

Biogenic synthesis of iron oxide nanoparticles using leaf extract of Spilanthes acmella: antioxidation potential and adsorptive removal of heavy metal ions.

The sequestration of contaminants from wastewater, such as heavy metals, has become a major global issue. Multiple technologies have been developed to address this issue. Nanotechnology is attracting significant interest as a new technology, and numerous nanomaterials have been produced for sequestrating heavy metals from polluted water due to their superior properties arising from the nanoscale effect. This study reports biosynthesis of iron oxide nanoparticles (IO-NPs) and their applications for adsorptive sequestration of various metal ions from aqueous solutions. Biosynthesis of IO-NPs has been carried out by using leaf extract of Spilanthes acmella, a medicinal plant. FTIR analysis of the leaf extract and biosynthesized IO-NPs marked the role of various functional groups in biosynthesis of IO-NPs. FESEM analysis revealed the average size range of IO-NPs as 50 to 80nm, while polydisperse nature was confirmed by DLS analysis. EDX analysis revealed the presence of Fe, O, and C atoms in the elemental composition of the NPs. The antioxidant potential of the biosynthesized IO-NPs (IC50 = 136.84µg/mL) was confirmed by DPPH assay. IO-NPs were also used for the adsorptive removal of As3+, Co2+, Cd2+, and Cu2+ ions from aqueous solutions with process optimization at an optimized pH (7.0) using dosage of IO-NPs as 0.6g/L (As3+ and Co2+) and 0.8g/L (Cd2+ and Cu2+). Adsorption isotherm analysis revealed the maximum adsorption efficiency for As3+ (21.83mg/g) followed by Co2+ (20.43mg/g), Cu2+ (15.29mg/g), and Cd2+ (13.54mg/g) using Langmuir isotherm model. The biosynthesized IO-NPs were equally efficient in the simultaneous sequestration of these heavy metal ions signifying their potential as effective nanoadsorbents.

Study of synergistic effects induced by novel base composites on heavy metals removal and pathogen inactivation

The green-collar strategies for nanomaterial synthesis with novel structural competencies have received significant attention in nanotechnology owing to their potential benefits. The utilization of silica nanoparticles for wastewater treatment through heavy metal ions remediation is the focal point of the present study. With this intent, silica was extracted from bagasse ash by the sol-gel method and modified using chitosan. Chemical and physical characteristics of silica(S), silica/Chitosan (SCs), were reckoned through X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) and the efficiency of synthesized biomaterials for removing heavy metal ions. Cadmium and Lead from wastewater was evaluated by conducting closed batch experiments. Isotherm and kinetics models were applied to understand the adsorption mechanism. Results of heavy metal ions removal showed that the S possesses the highest removal efficiency of 88% for cadmium. Equilibrium was established within 56 min following a Langmuir isotherm model and pseudo-second-order reaction. The synthesized biomaterials were also tested against the fungal (Aspergillus Niger) and bacterial strains (Escherichia coli and Staphylococcus aureus) to determine their antimicrobial properties Maximum inhibition of 26 mm was shown by SCs for E.coli. Synthesized samples were not so effective for A.niger. The high adsorption potential of silica nanoparticles reveals their potential to treat wastewater containing inorganic pollutants like calcium and lead released from the sugar industry firsthand, thereby building a circular economy by controlling the pollution from source to sink. The synthesized silica nanoparticles and silica/chitosan biomaterials demonstrated high adsorption potential for heavy metal ions, making them promising candidates for integration into Algal Membrane Bioreactors to enhance wastewater treatment efficiency and remove toxic pollutants. Their multifunctional properties, including antimicrobial activity, also offer potential for improving microbial control within AMBRs, ensuring a more effective and sustainable wastewater treatment process.

Expression for the heavy-ion fusion cross section

The expression for calculation of the heavy-ion fusion cross section is obtained in the case of approximation of the total heavy-ion potential around the barrier by the Morse potential. The approximation of the total heavy-ion potential around the barrier by the Morse potential is more realistic than the parabolic one. The asymptotic expressions of the fusion cross section at sub-barrier energies obtained for the Morse and parabolic approximations of the total heavy-ion potential have different dependencies on collision energy. The fusion cross sections calculated for the Morse and parabolic approximations of the total heavy-ion potential are discussed for the reactions $^{12}\mathrm{C}+^{24}\mathrm{Mg}$ and $^{12}\mathrm{C}+^{30}\mathrm{Si}$ in detail.

Research on the adsorption of melamine for Cu(II) and Pb(II)

Melamine contains three aromatic nitrogen atoms and three free amino groups, which have great adsorption potential for heavy metallic ions in wastewater. The sorption performances of melamine for Cu(II) and Pb(II) ( They are denoted as Cu&Pb) were studied. Some major effects such as adsorption time, original concentration, and temperature on its adsorption performances were studied. The effects confirmed that melamine had true adsorption for Cu&Pb, and higher selectivity for the adsorption of Cu&Pb in a binary blended system. The adsorption amount of Pb(II) on melamine reached 4.91 mg/g at pH 5, adsorption equilibrium time of 12 h, and temperature of 55 °C, while the sorption amount of Cu(II) was only 2.70 mg/g, with a difference of about 1.8 times. The adsorption mechanism shows that the sorption of Cu&Pb on melamine follows the Lagergren quasi-second-order kinetic model. This result indicates that the mixture of Cu&Pb can be separated by stepwise processes from a binary mixed system.

Physics and biomedical challenges of cancer therapy with accelerated heavy ions.

Radiotherapy should have low toxicity in the entrance channel (normal tissue) and be very effective in cell killing in the target region (tumour). In this regard, ions heavier than protons have both physical and radiobiological advantages over conventional X-rays. Carbon ions represent an excellent combination of physical and biological advantages. There are a dozen carbon-ion clinical centres in Europe and Asia, and more under construction or at the planning stage, including the first in the USA. Clinical results from Japan and Germany are promising, but a heated debate on the cost-effectiveness is ongoing in the clinical community, owing to the larger footprint and greater expense of heavy ion facilities compared with proton therapy centres. We review here the physical basis and the clinical data with carbon ions and the use of different ions, such as helium and oxygen. Research towards smaller and cheaper machines with more effective beam delivery is necessary to make particle therapy affordable. The potential of heavy ions has not been fully exploited in clinics and, rather than there being a single 'silver bullet', different particles and their combination can provide a breakthrough in radiotherapy treatments in specific cases.

Development of Kraft Lignin Chemically Modified as a Novel Crosslinking Agent for the Synthesis of Active Hydrogels

In this research a chemical modification of kraft lignin was carried out using a basic nucleophilic substitution reaction (NSA) in order to functionalize it as a novel crosslinking agent for the synthesis of active hydrogels. The chemical modification success of the synthesized crosslinker was demonstrated by using several techniques such as volumetry probes, FTIR, 1H-NMR and DSC. Thus, the obtained materials were employed during the synthesis of acrylic acid-based hydrogels, due to its high-water absorption capacity to evaluate their retention potential of heavy metal ions. Characterization of the active hydrogels were performed by FTIR and SEM, showing the specific signals corresponding to the base monomers into the polymer skeleton and the efficiency of modified kraft lignin as a novel crosslinking agent. Additionally, to demonstrate the potential use of these hydrogels in wastewater treatment, metal ions adsorption experiments were conducted, showing adsorption percentages higher than 90% and 80% for Pb2+ and Cu2+, respectively.

Efficient BiVO4 photoanode decorated with Ti3C2TX MXene for enhanced photoelectrochemical sensing of Hg(II) ion

A highly sensitive photoelectrochemical (PEC) sensing platform was constructed for Hg2+ determination based on the Schottky heterojunction between an emerging 2D material Ti3C2TX MXene and a promising semiconductor material BiVO4. Through simply spin-coating the single-layer Ti3C2TX onto the surface of BiVO4 film, the modified electrode exhibited significantly enhanced PEC activity. However, the boost in photocurrent could be noticeably suppressed due to the consumption of hole-scavenging agents (reduced glutathione) by the added Hg2+. Owing to the selective decrease in the photocurrent with the addition of Hg2+, the PEC sensor based on BiVO4/Ti3C2TX displayed a wide linear range from 1 pM to 2 nM with the limit of detection down to 1 pM. Moreover, the PEC sensor also exhibited satisfactory accuracy and repeatability in practical sample water, the Yangtze River water, demonstrating the great potential for monitoring heavy metal ions in natural water resources.

Neutron excess dependence of fusion barrier parameters

The neutron excess dependence of heavy ion fusion barrier parameters is investigated, guided by predictions of different heavy ion potentials. We develop parametrizations for the fusion barrier height and radius which explicitly involve the entrance channel mass asymmetry and neutron excess of the projectile and target. The developed expressions reproduce theoretical barrier parameters within 0.2%, which represents a big improvement over previous parametrizations. Furthermore, they provide a means to assess the importance of the neutron excess degree of freedom implied by each potential. Application of these expressions to systematics of experimental barrier parameters will be discussed.

Low and high dose rate heavy ion radiation-induced intestinal and colonic tumorigenesis in APC1638N/+ mice

Ionizing radiation (IR) is a recognized risk factor for colorectal cancer (CRC) and astronauts undertaking long duration space missions are expected to receive IR doses in excess of permissible limits with implications for colorectal carcinogenesis. Exposure to IR in outer space occurs at low doses and dose rates, and energetic heavy ions due to their high linear energy transfer (high-LET) characteristics remain a major concern for CRC risk in astronauts. Previously, we have demonstrated that intestinal tumorigenesis in a mouse model (APC1638N/+) of human colorectal cancer was significantly higher after exposure to high dose rate energetic heavy ions relative to low-LET γ radiation. The purpose of the current study was to compare intestinal tumorigenesis in APC1638N/+ mice after exposure to energetic heavy ions at high (50cGy/min) and relatively low (0.33cGy/min) dose rate. Male and female mice (6–8 weeks old) were exposed to either 10 or 50cGy of 28Si (energy: 300MeV/n; LET: 70keV/μm) or 56Fe (energy: 1000MeV/n; LET: 148keV/μm) ions at NASA Space Radiation Laboratory in Brookhaven National Laboratory. Mice (n=20 mice/group) were euthanized and intestinal and colon tumor frequency and size were counted 150days after radiation exposure. Intestinal tumorigenesis in male mice exposed to 56Fe was similar for high and low dose rate exposures. Although male mice showed a decreasing trend at low dose rate relative to high dose rate exposures, the differences in tumor frequency between the two types of exposures were not statistically significant after 28Si radiation. In female mice, intestinal tumor frequency was similar for both radiation type and dose rates tested. In both male and female mice intestinal tumor size was not different after high and low dose rate radiation exposures. Colon tumor frequency in male and female mice after high and low dose rate energetic heavy ions was also not significantly different. In conclusion, intestinal and colonic tumor frequency and size was similar irrespective of energetic heavy ion radiation dose rate suggesting that carcinogenic potential of energetic heavy ions is independent of dose rate.

Comparison between different proximity potentials and the double-folding model for spherical–deformed interacting nuclei

The Coulomb barrier parameters have been calculated for a spherical–deformed interacting pair of nuclei using 14 different versions of the proximity approaches and a simple analytical formula for the Coulomb part of the heavy ion potential. The results of these proximity versions have been compared with more accurate results obtained from the double-folding model (DFM). We have considered the interacting pair 48Ca + 238Pu as an example and assumed the presence of the quadrupole, octupole, and hexadecapole deformation parameters for 238Pu. The orientation angle dependence of the Coulomb barrier parameters has been computed for different sets of deformation parameters. We found that the proximity types named Prox77, BW Prox91, AW Prox95, Bass Prox77, and Bass Prox80 are the best ones of the available 14 versions of the proximity approaches for calculating the nuclear part of the interaction potential for a spherical–deformed pair of nuclei.

A study of the photodeposition over Ti/TiO2 electrode for electrochemical detection of heavy metal ions

Abstract Here we reported that UV light irradiation can significantly enhance sensitivity of Ti/TiO 2 electrode for determination of trace heavy metal ions (such as Cu 2 + , Pb 2 + and Cd 2 + ) owing to the photodeposition of metal ions on the surface of electrodes. The sensitivity of heavy metal ions can be selectively enhanced over the Ti/TiO 2 electrode, which is attributed to matching between potential of heavy metal ions and the position of the conduction band of TiO 2 .

Inverse scattering: Revisited

Using recent data, we calculate the heavy-ion optical-model potential via an inversion solution that had been previously obtained based on the McIntyre parametrization of the S-matrix.The results are compared with previous works and with the recently-available experimental data for the 12 C -12 C system. Moreover, the calculations were carried out for several energies not available before for the same system, these calculations need to be checked against future experimental data.

Nucleus-nucleus potential with shell-correction contribution and deep sub-barrier fusion of heavy nuclei

It is suggested that the full nucleus-nucleus potential consists of the macroscopic and shell-correction parts. The deep sub-barrier fusion hindrance takes place in a nucleus-nucleus system with a strong negative shell-correction contribution to the full heavy-ion potential, while a strong positive shell-correction contribution to the full potential leads to weak enhancement of the deep sub-barrier fusion cross section.

The more important heavy charged particle radiotherapy of the future is more likely to be with heavy ions rather than protons

The more important heavy charged particle radiotherapy of the future is more likely to be with heavy ions rather than protons

Microscopic DC-TDHF study of heavy-ion potentials and fusion cross sections

We study heavy-ion fusion reactions at energies near the Coulomb barrier, in particular with neutron-rich radioactive ion beams. Dynamic microscopic calculations are carried out on a three-dimensional lattice using the Density-Constrained Time-Dependent Hartree-Fock (DC-TDHF) method. New results are presented for the 132Sn+40Ca system which are compared to 132Sn+48Ca studied earlier. Our theoretical fusion cross-sections agree surprisingly well with recent data measured at HRIBF. We also study the near- and sub-barrier fusion of 24,16O on 12C which is important to determine the composition and heating of the crust of accreting neutron stars.

Microscopic analysis of sub-barrier fusion enhancement in132Sn+40Ca versus132Sn+48Ca

We provide a theoretical analysis of recently measured fusion cross sections which show a surprising enhancement at low $E_\mathrm{c.m.}$ energies for the system $^{132}$Sn+$^{40}$Ca as compared to the more neutron-rich system $^{132}$Sn+$^{48}$Ca. Dynamic microscopic calculations are carried out on a three-dimensional lattice with a time-dependent density-constrained density functional theory. There are no adjustable parameters, the only input is the Skyrme effective NN interaction. Heavy-ion potentials $V(R)$, coordinate-dependent mass parameters $M(R)$, and total fusion cross sections $\sigma(E_\mathrm{c.m.})$ are calculated for both systems. We are able to explain the measured fusion enhancement in terms of the {\it narrower width} of the ion-ion potential for $^{132}$Sn+$^{40}$Ca, while the barrier heights and positions are approximately the same in both systems.

Microscopic calculation of heavy-ion potentials based on TDHF

We present the numerical details of a new method for calculating ion-ion interaction potentials from time-dependent Hartree-Fock calculations using density as a constraint.

Consistent description of hindrance in sub-barrier fusion ofCa48withS36,Ca48, andZr96

Recent fusion reaction data for the systems ${}^{36}\mathrm{S}+{}^{48}\mathrm{Ca}$, ${}^{48}\mathrm{Ca}+{}^{48}\mathrm{Ca}$, and ${}^{96}\mathrm{Zr}+{}^{48}\mathrm{Ca}$ are analyzed within the coupled-channel formalism. The heavy-ion entrance channel potential is calculated employing an improved double-folding prescription. The nonlocal kernel arising from the knock-on exchange component of the effective $N\ensuremath{-}N$ interaction is localized within the lowest order of the Perey-Saxon approach, including full recoil. The single-particle densities entering the folding integrals are prescribed according to the density matrix expansion method. The investigation is more elaborated because each case is tested with four different types of $N\ensuremath{-}N$ effective forces: The two standard parametrizations of the density-independent M3Y force (Reid and Paris) and two parametrizations of the density-dependent Gogny force (D1S and D1N). A consistent description of all three reactions is achieved by keeping fixed the nuclear structure input for $^{48}\mathrm{Ca}$. The inclusion of 2${}^{+}$ and 3${}^{\ensuremath{-}}$ phonon states in the coupled-channel calculation, within an energy excitation window identical for all three reactions explains better the hindrance in extreme sub-barrier fusion cross sections. The interactions providing the best fit to the data are not pointing to a possible maximum in the astrophysical $S$ factor, thereby confirming the conclusion reached by the Legnaro group for these cases.

Heavy Cluster Knockout ReactionO16(C12,2C12)He4and the Nature of theC12−C12Interaction Potential

The heavy cluster knockout reaction $^{16}\mathrm{O}(^{12}\mathrm{C},2^{12}\mathrm{C})^{4}\mathrm{He}$ performed for the first time, reveals the true nature of the $^{12}\mathrm{C}\mathrm{\text{\ensuremath{-}}}^{12}\mathrm{C}$ interaction. The observed cross section is enhanced by almost 2 orders of magnitude over the conventional zero range distorted wave impulse approximation (DWIA) predictions. An attractive $^{12}\mathrm{C}\mathrm{\text{\ensuremath{-}}}^{12}\mathrm{C}$ optical potential, as obtained in the folding model, does not explain the enhanced cross section in the finite range (FR) DWIA framework. The inclusion of a hard core of fairly long range $\ensuremath{\sim}3.65\text{ }\text{ }\mathrm{fm}$ explains the data. The present investigation of $^{16}\mathrm{O}(^{12}\mathrm{C},2^{12}\mathrm{C})^{4}\mathrm{He}$ along with the $^{12}\mathrm{C}\mathrm{\text{\ensuremath{-}}}^{12}\mathrm{C}$ elastic scattering also proves beyond doubt that the folding model's deep attractive heavy ion potentials are unsuitable to describe the highly overlapping heavy ions. The application of FR-DWIA opens up new avenues to use the heavy core knockout for the detailed investigation of heavy as well as Borromean halo nuclei.

Silica aerogels modified with mercapto functional groups used for Cu(II) and Hg(II) removal from aqueous solutions

A new adsorbent, silica aerogel modified with mercapto (-HS) functional group, was synthesized by standard sol–gel synthesis. Excellent properties of aerogels, obtained with the sol–gel synthesis, were preserved with supercritical drying with CO2. The adsorbent was characterized by Fourier transform infrared spectra (FTIR), differential scanning calorimetry (DSC) and thermal gravimetry (TG) measurements, nitrogen physisorption and scanning electron microscope (SEM). The ability of modified silica aerogel with mercapto group to remove Cu(II) and Hg(II) from aqueous solutions was assessed using batch adsorption technique under equilibrium conditions. Adsorbent exhibits very high adsorption potential for both heavy metal ions and more than 99.0% removal was achieved in the pH range 4–6. The equilibrium data were fitted well by the Freundlich and Langmuir isotherm model (R2>0.9).