Manganese Ions Research Articles

Effect of manganese ion doping on magnetic properties and magnetic induction heating of Zn-Al ferrite nanoparticles

Magnetic induction hyperthermia (MIH) is a new kind of cancer treatment that preferentially targets tumor cells due to their poor heat resistance. In recent years, ferrite magnetic nanoparticles with spinel structures that can self-regulate the temperature of hyperthermia have been widely used in MIH. Importantly, substituting ions with different magnetic moments in magnetic nanoparticles can effectively regulate their Curie temperature and heating efficiency. Here we investigate the influence of Mn2+ doping on the magnetic properties, Curie temperature, and the heating efficiency of hydrothermally synthesized MnxZn1-xAl0.4Fe1.6O4 (0.4 ≤ x ≤ 0.8) nanoparticles. With increasing substitution of Zn2+ content by Mn2+, the mass magnetization increases from 30.2 to 54.2 emu g−1, the Curie temperature increases from 47.5 to 257.8 ℃, and the heating efficiency (specific loss power, SLP) increases from 6.3 to 54.5 W g−1, respectively. Of note, aqueous suspensions of Mn0.5Zn0.5Al0.4Fe1.6O4 nanoparticles demonstrate self-regulated temperature hyperthermia at 45.4 ℃ in vitro with the SLP of 11.1 W g−1 under clinically safe alternating magnetic field, manifesting a combination of high heating efficiency and clinically desirable therapeutic temperature. This study provides a new class of magnetic nanoparticles potentially useful for fast and safe MIH for cancer treatment.

Manganese ion gradient liposomes modified by disulfide bond enhance cellular uptake and tumor immunity

As an activator and alarm signal for tumor innate immune therapy, manganese ions can activate the stimulator of interferon genes (STING) pathway directly or indirectly. However, due to their high positive charge, manganese ions cannot freely penetrate biological membranes, and it is challenging to target them to the cells. Liposomes have been widely used as an effective drug delivery system. Using metal ions as active carriers to establish a gradient is an effective way to load chemotherapy drugs, but its low delivery efficiency and significant degradation of effective drugs by lysosomes may result in reduced therapeutic effects. In this study, we constructed an active drug-loading liposome (LMD@LA) that enters cells through thiol-mediated endocytosis to encapsulate both the chemotherapy drug doxorubicin and manganese ions to achieve sustained manganese ion release. The combination of chemotherapy-induced immunogenic cell death and innate immune therapy with manganese ions was used to treat tumors. The liposome was able to reverse the immunosuppressive tumor microenvironment, reduce the resistance of B16F10 and 4T1 tumors to doxorubicin, and decrease the migration and invasion abilities of tumors by binding with lipoic acid.

Metal-Based Nanoparticles for Cancer Metalloimmunotherapy.

Although the promise of cancer immunotherapy has been partially fulfilled with the unprecedented clinical success of several immunotherapeutic interventions, some issues, such as limited response rate and immunotoxicity, still remain. Metalloimmunotherapy offers a new form of cancer immunotherapy that utilizes the inherent immunomodulatory features of metal ions to enhance anticancer immune responses. Their versatile functionalities for a multitude of direct and indirect anticancer activities together with their inherent biocompatibility suggest that metal ions can help overcome the current issues associated with cancer immunotherapy. However, metal ions exhibit poor drug-like properties due to their intrinsic physicochemical profiles that impede in vivo pharmacological performance, thus necessitating an effective pharmaceutical formulation strategy to improve their in vivo behavior. Metal-based nanoparticles provide a promising platform technology for reshaping metal ions into more drug-like formulations with nano-enabled engineering approaches. This review provides a general overview of cancer immunotherapy, the immune system and how it works against cancer cells, and the role of metal ions in the host response and immune modulation, as well as the impact of metal ions on the process via the regulation of immune cells. The preclinical studies that have demonstrated the potential of metal-based nanoparticles for cancer metalloimmunotherapy are presented for the representative nanoparticles constructed with manganese, zinc, iron, copper, calcium, and sodium ions. Lastly, the perspectives and future directions of metal-based nanoparticles are discussed, particularly with respect to their clinical applications.

Enhancing the operation stability of lithium-rich layered oxide Li1.2Ni0.2Mn0.6O2 by synergistic pinning effect and interface reconstruction for high-energy-density lithium-ion batteries

Lithium-rich manganese-based layered oxides are considered to be promising cathode materials for next-generation lithium-ion batteries (LIBs). However, their practical application is hindered due to both the rapid capacity attenuation and the unsatisfactory rate capability. In this work, to overcome these problems, layered oxide Li1.2Ni0.2Mn0.6O2 (LNMO) is modified via La3+ doping and perovskite type LaMnO3 coating layer, meanwhile, interface layer Li2MnO3 with monoclinic structure is formed between the doped-La3+ Li1.2Ni0.2Mn0.6O2 and LaMnO3 coating layer. The 0.02 wt% La modified Li1.2Ni0.2Mn0.6O2 can deliver much higher rate capability and cyclic stability than original LNMO, attributed that the LaMnO3 coating layer can not only isolate La-doped LNMO from the electrolyte to reduce the dissolution of manganese ions but also can reduces the polarization of electrode interface via inhibiting the continuous growth of SEI during the cycle. Besides, La3+ doping plays a pinning effect role in enhancing the structural stability of LNMO.

Glucose Oxidase Driven Hydrogen Sulfide-Releasing Nanocascade for Diabetic Infection Treatment.

Diabetic ulcers have received much attention in recent years due to their high incidence and mortality, motivating the scientific community to develop various strategies for such chronic disease treatments. However, the therapeutic outcome of these approaches is highly compromised by invasive bacteria and a severe inflammatory microenvironment. To overcome these dilemmas, microenvironment-responsive self-delivery glucose oxidase@manganese sulfide (GOx@MnS) nanoparticles (NPs) are developed by one-step biomineralization. When they encounter the high glucose level in the ulcer site, GOx particles catalyze glucose to decrease the local pH and trigger the steady release of both manganese ions (Mn2+) and hydrogen sulfide (H2S). Mn2+ reacts with hydrogen peroxide to generate hydroxyl radicals for the elimination of bacterial infection; meanwhile, H2S is able to suppress the inflammatory response and accelerate diabetic wound healing through macrophage polarization. The excellent biocompatibility, strong bactericidal activity, and considerable immunomodulatory effect promise GOx@MnS NPs have great therapeutic potential for diabetic wound treatment.

Effect of Electron Correlations on the Electronic Structure and Magnetic Properties of the Full Heusler Alloy Mn2NiAl

In this theoretical study, we investigate the effect of electron correlations on the electronic structure and magnetic properties of the full Heusler alloy Mn2NiAl in the framework of first-principles calculations. We investigate the electron correlation effect as employed within hybrid functional (HSE) and also within the DFT+U method with varied values of parameters between 0.9 and 6 eV. The XA-crystal structure was investigated with antiferromagnetic orderings of the magnetic moments of the manganese. It was found that with a growth of the Coulomb interaction parameter, the manganese ions magnetic moment increases, and it reaches the value of 4.15–4.46 μB per Mn. In addition, the total magnetic moment decreases because of the AFM ordering of the Mn ions and a small magnetic moment of Ni. The calculated total magnetic value agrees well with recent experiments demonstrating a low value of magnetization. This experimental value is most closely reproduced for the moderate values of the Coulomb parameter, also calculated in constrained LDA, while previous DFT studies substantially overestimated this value. It is also worth noticing that for all values of the Coulomb interaction parameter, this compound remains metallic in its electronic structure in agreement with transport measurements.

Manganese facilitated cGAS-STING-IFNI pathway activation induced by ionizing radiation in glioma cells

Purpose After irradiation, double-stranded DNA leaked into the cytoplasm activates the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, leading to the production of type I interferon (IFNI). In this study, we sought to probe the effect of ionizing radiation on activity of cGAS-STING-IFNI pathway in normoxic or hypoxic glioma cells and explore a more effective method to activate the signaling pathway, thereby activating the anti-tumor immune response and improving the therapeutic effect of radiotherapy for glioma. Materials and methods Human glioma cells U251 and T98G cultured in normoxia or hypoxia (1% O2) were irradiated with different doses of X-ray. The relative expressions of cGAS, IFN-I stimulated genes (ISGs), and three-prime repair exonuclease 1 (TREX1) were detected by qPCR. The expression levels of interferon regulatory factor 3 (IRF3) and p-IRF3 proteins were detected by Western blot. The production of cGAMP and IFN-β in the supernatant was detected by ELISA assay. U251 and T98G cell lines with stable knockdown of TREX1 were established after transfection with lentivirus vectors. EdU cell proliferation assay was used to screen suitable metal ions concentrations. The phagocytosis of DCs was observed by immunofluorescence microscope. The phenotype of DCs was detected by flow cytometry. The migration ability of DCs was detected by a transwell experiment. Results We found that cytosolic dsDNA, 2′3′-cGAMP, cGAS and ISGs expression, and IFN-β in cell supernatant were all increased with the doses of X-ray in the range of 0–16 Gy in normoxic glioma cells. Nevertheless, hypoxia significantly inhibited the radiation-induced dose-dependent activation of cGAS-STING-IFNI pathway. Furthermore, manganese (II) ion (Mn2+) significantly improved cGAS-STING-IFNI pathway activation induced by X-ray in both normoxic and hypoxic glioma cells, thereby promoting the maturation and migration of DCs. Conclusions The responses of cGAS-STING-IFNI pathway to ionizing radiation were mainly investigated under normoxic condition, but the experiments described here indicated that hypoxia could hinder the pathway activation. However, Mn2+ showed radiosensitizing effects on the pathway under either normoxic or hypoxic conditions demonstrating its potential as a radiosensitizer for glioma through activating an anti-tumor immune response.

Groundwater Quality of Some Parts of Coastal Bhola District, Bangladesh: Exceptional Evidence

The composition of groundwater governs the drinking and irrigation water suitability. A large part of the coastal region of Bangladesh is affected and is responsible for changing the composition of the groundwater. This research attempted to observe the groundwater quality of the Bhola Sadar and Char Fasson upazilas in coastal Bangladesh. Twenty-eight (28) water samples, 27 at depths of 260–430 m (850–1400 ft) and 1 from a crop field, were collected and analyzed. The quality of water samples was determined through the evaluation of odor, color, turbidity, electrical conductivity, pH, total dissolved solids, nitrate (NO3−), ammonium (NH4+), sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn) and arsenic (As) ions. An Atomic Absorption Spectrophotometer was used for heavy metal analysis. The outcomes were compared with the drinking water quality of Bangladesh and the World Health Organization. The results showed that the average values of nearly all of the parameters were underneath or within the standard level, representing that the groundwater was appropriate for drinking purposes. The water quality parameters were also compared with the irrigation water quality of Bangladesh and the Food and Agriculture Organization. It was found that the collected samples were also suitable for irrigation. To do this, the soluble sodium percentage, sodium adsorption ratio, magnesium adsorption ratio, Kelley’s ratio, and total hardness were calculated. The novelty of this research is that, despite being in a coastal district, the deep aquifer water of Bhola was appropriate for drinking and irrigation purposes.

Bentonite functionalized with magnetite nanoparticles synthesized from mining sludge: a new magnetic material for removing iron and manganese ions from water

Bentonite functionalized with magnetite nanoparticles synthesized from mining sludge: a new magnetic material for removing iron and manganese ions from water

Characterization of a putative metal-dependent PTP-like phosphatase from Lactobacillus helveticus 2126

To date, there are very limited reports on sequence analysis and structure-based molecular modeling of phosphatases produced by probiotic bacteria. Therefore, a novel protein tyrosine-like phosphatase was characterized from L. helveticus 2126 in this study. The purified bacterial phosphatase was subjected to mass spectrometric analysis, and the identity of constructed sequence was analyzed using peptide mass fingerprint. The 3-D structure of protein was elucidated using homology modeling, while its stability was assessed using Ramachandran plot, VERIFY 3D, and PROCHECK. The bacterium produced an extracellular phosphatase of zone diameter 15 ± 0.8 mm on screening medium within 24 h of incubation. This bacterial phosphatase was highly specific towards sodium phytate as it yielded the lowest Km value of 299.50 ± 4.95 μM compared to other phosphorylated substrates. The activity was effectively stimulated in the presence of zinc, magnesium, and manganese ions thereby showing its PTP-like behavior. The phosphatase showed a molecular mass of 43 kDa, and the corresponding M/Z ratio data yielded 46% query coverage to Bacillus subtilis (3QY7). This showed a 61.1% sequence similarity to Ligilactobacillus ruminis (WP_046923835.1). The final sequence construct based on these bacteria showed a conserved motif “HCHILPGIDD” in their active site. In addition, homology modeling showed a distorted Tim barrel structure with a trinuclear metal center. The final model after energy minimization showed 90.9% of the residues in the favorable region of Ramachandran’s plot. This structural information can be used in genetic engineering for improving the overall stability and catalytic efficiency of probiotic bacterial phosphatases.

Activatable Mn2+-Armed nanoagonist augments antitumor immunity in colorectal cancer: A NIR-II Photonic neoadjuvant paradigm

Postoperative recurrence frequently occurs in patients with colorectal cancer (CRC) due to residual microtumors and host cellular immune dysfunction, leading to major setbacks in clinical outcomes and CRC staging. As an increasingly prevalent therapeutic option for CRC patients, neoadjuvant chemoradiotherapy bears unmet challenges of limited tumor targeting and common side effects of gastrointestinal reaction and radiodermatitis. It is highly desirable to develop neoadjuvant treatment paradigms that impart both tumor-targeting accuracy and protection against recurrence of resectable CRC. Here we report a versatile photo-regulated nanoagonist of plasmonic gold blackbody (AuPB) with a polydopamine (PDA) coating carrying manganese ion (Mn2+) payloads (AuPB@PDA/Mn). When armed with second near-infrared (NIR-II) light, AuPB@PDA/Mn with broad-band localized surface plasmon resonance generates local hyperthermia and discharges Mn2+ ions, which evidently amplify the effects of immunogenic cell death in tumor cells and activate the cyclic GMP-AMP synthase/stimulator of interferon genes pathway in dendritic cells (DCs), hence potentiating the maturation of DC and the secretion of type I interferon in a synergistic way. Matured DCs undertake the task of tumor antigen presentation as the crosstalk to adaptive immunity. As such, the administration of AuPB@PDA/Mn coupled with NIR-II laser irradiation has eminently augmented the infiltration of CD8+ T cells as well as the development of memory CD8+ T cells in colorectal tumor models, substantiating enhanced immunomodulatory efficacy against primary and recurrent CRC. Our strategy highlights the potency of an integrated NIR-II photothermal and immunoregulatory modality by photo-activate delivery of Mn2+ ions, as a neoadjuvant paradigm for presurgical tumor debulking and against postoperative tumor recurrence.

Efficient degradation of phenol by MnOOH-rGO composite with high peroxymonosulfate utilization efficiency

A high-performance, durable, low-cost, and environmentally friendly catalyst is highly desired in advanced oxidation processes (AOPs) for water treatment. Considering the activity of Mn(Ⅲ) and the superior catalytic properties of reduced graphene oxide (rGO) in peroxymonosulfate (PMS) activation, rGO-modified MnOOH nanowires (MnOOH-rGO) were fabricated by a hydrothermal method for phenol degradation. The results showed that the composite synthesized at 120 °C with 1 wt% rGO dopant exhibited the best performance for phenol degradation. Nearly 100% of the phenol was removed by MnOOH-rGO within 30 min, which is higher than the removal rate of pure MnOOH (70%). The effects of catalyst dosages, PMS concentration, pH, temperature, and anions (Cl−, NO3−, HPO42−and HCO3−) on phenol degradation were investigated. The removal rate of chemical oxygen demand (COD) reached 26.4%, with a low molar ratio of PMS to phenol at 5:1 and a high PMS utilization efficiency (PUE) of 88.8%. The phenol removal rate remained more than 90% after five recycle with less than 0.1 mg L−1 leakage of manganese ions. Together with the results of radical quenching experiments, X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance spectroscopy (EPR), electron transfer and 1O2 were proved to dominate the activation process. During the direct electrons transfer process, the electrons transfer from the phenol to PMS by using the Mn(Ⅲ) as the mediate with a stoichiometric ratio between PMS and phenol at 1:2, which mainly contributed to the high PUE. This work provides new insight into a high-performance Mn(Ⅲ) based catalyst on PMS activation with high PUE, good reusability, and environmentally friendly for removing organic pollutants.

Anapole, chiral, and orbital states in Mn3Si2Te6

The ferrimagnet Mn3Si2Te6 attracts attention because of a recently discovered colossal magnetoresistance (CMR) with unique magnetic field properties. An improved magnetic structure for the material has emerged from a neutron diffraction study linked to understanding the CMR. A deeper theoretical investigation of the magnetic structure has now revealed anapole, chiral and orbital states of manganese ions not previously mentioned. Moreover, it is shown that existence of these states in the low temperature form of Mn3Si2Te6, with a magnetic field applied, can be tested by neutron and resonant x-ray diffraction.

A comparative study of structural, magnetic and catalytic properties of half doped nanocrystalline La0.5A0.5Mn0.5Fe0.5O3 (A = Ca, Sr) perovskite oxides: Highly efficient and versatile candidates for enhanced oxidative degradation of hazardous organic dyes at ambient conditions

This work presents a systematic study of half doped nanocrystalline La0.5A0.5Mn0.5Fe0.5O3 (A = Ca, Sr) perovskite oxides to examine the effect of A-site cation radius on structural, magnetic and catalytic properties via different characterization techniques. Rietveld refinements of powder X-ray diffraction data confirmed the orthorhombic symmetry for both the samples with Pbnm space group. The results show an increase in lattice parameters and unit cell volume with doping of larger A cation. The BET surface area for Ca and Sr-doped samples has been found to be 32.3 m2/g and 33.8 m2/g respectively. The magnetic properties of nano structured samples show magnetic inhomogeneity due to coexistence of ferromagnetic and antiferromagnetic interactions. The magnetization has enhanced in Sr-doped sample which may be associated with increase in double exchange interactions between mixed valence manganese ions through oxygen. Moreover, the synthesized nano samples have been employed to catalytic degradation of rhodamine B dye as model pollutant under normal atmospheric conditions and it has been found that Sr-doped sample has shown better catalytic dye degradation than Ca-doped (99% degradation in 25 min) due to the presence of greater number of Mn3+/Mn4+ redox couples as determined by iodometric titration. Additionally, methylene blue and methyl orange dyes were also tested for catalytic degradation by more active Sr-doped catalyst in order to check its versability.

Equilibrium, kinetics, and thermodynamics of batch adsorption of Mn(II) ions on blast furnace slag (BFS) and kaolin (KGA)

This article describes the discontinuous adsorption of Mn(II) on kaolin from Guelma, Algeria (KGA), and blast furnace slag from Sider, Algeria (BFS), under the effect of various parameters, namely the contact time, the stirring speed, the pH of the medium, the solution temperature, the adsorbent dosage, the solid particle size, and the initial concentration. Also studied were the models of adsorption, namely the isotherms of adsorption, the kinetics of adsorption, and the thermodynamic study of Mn on the examined adsorbents. Characterization tests have indicated that kaolin consists essentially of hydrated aluminum silicate. The BFS is mainly composed of silicates, aluminates, lime, and magnesium oxide. The specific surface areas of kaolin and BFS calculated using the BET were defined at 134.2 and 238.6m2/g. The adsorption rate of Mn(II) on KGA and BFS is better after 50 and 60 min of contact at Vag: 150 rpm; pH: 5.2; Øs: 100 μm; T: 20 °C; Ms: 1 g, respectively. Maximum adsorption capacities are 36.76 mg/g (KGA) and 59.88 mg/g (BFS). Examination of the adsorption isotherms revealed that the Langmuir model is more appropriate to the experimental data (R2 = 0.99). The values of the Freundlich (n), Langmuir (RL), and Temkin (bt) parameters indicate that the adsorption is favorable. The kinetic examination demonstrated that the pseudo-second-order kinetic model is more adopted for the adsorption of Mn(II) on KGA and BFS (R2 = 0.99). Furthermore, the transfer of Mn(II) from the solution to the surfaces of the investigated adsorbents is controlled by external and internal diffusion. The thermodynamic study brought to light that the adsorption processes carried out were spontaneous, exothermic, and less entropic. This work showed that KGA and BFS can be used as low-cost adsorbents for the removal of Mn(II) ions in aqueous media, and BFS has higher affinities for manganese ion adsorption.

Enhancing STING activation by cyclic dinucleotide-manganese particles for systemic cancer immunotherapy.

2571 Background: Activating the innate immune pathway of stimulator of interferon genes (STING) can elicit potent anti-tumor immunity via the production of type-I interferons (IFN-I). However, cyclic-dinucleotide (CDN) STING agonists have undesirable pharmacological properties. Most CDNs in clinical development are administered intratumorally, thus precluding their applications in treating metastasis, hematologic malignancies, and hard-to-reach solid tumors. Here, we report the development of a new nanoparticle system for the systemic delivery of CDN STING agonists with potent efficacy, favorable pharmaceutical properties, and acceptable safety profiles. Methods: Nutritional metal ions play crucial roles in modulating immune pathways, which could potentially be used for enhancing STING activation. We screened different metal ions and found that manganese ion (Mn2+) achieved strong synergy with CDN STING agonists for inducing IFN-I production. We further developed a new nanoparticle system for co-delivery of Mn2+ and CDN for systemic cancer immunotherapy. Results: Mn2+ induced up to 77-fold enhancement in CDN-mediated STING activation. Mixing CDNs with Mn2+ resulted in the self-assembly of nanocrystals, and the lipid layer coating led to uniform nanoparticles. The resulting STING-activating CDN-Mn nanoparticle (SNP) given intravenously elicited IFN-I responses, attenuated the suppressive functions of myeloid cells, remodeled the immunosuppressive tumor microenvironment, and expanded CD8+ T cells for sustained tumor control. Intravenous SNP therapy resulted in robust anti-tumor efficacy in multiple murine tumor models, including a genetically engineered mouse model of MMTV-PyMT triple-negative breast cancer. We have also demonstrated the robust anti-tumor efficacy of SNP against VX2 head and neck squamous cell carcinomas (HNSCC) in New Zealand white rabbits. Mechanistically, the efficacy of intravenous SNP therapy was dependent on the host STING expression but independent of the tumor STING expression. In addition, the anti-tumor efficacy of SNP was decreased in mice lacking Ifnar1 or Ifngr1 expression in the B16F10 melanoma model, showing the crucial effects of IFN-I and IFN-II responses. Lastly, SNP was effectively uptaken by human PBMCs and elicited IFN-I responses when injected into fresh human tumor biopsies derived from HNSCC patients. Conclusions: SNP empowers highly effective systemic cancer immunotherapy via nanotechnology. It also underscores the potential of utilizing metal ions for immune-mediated disease treatment.

Combined effect of temperature difference across interface and finite size of the ions on interdiffusion in SOFC

In the present study, the combined effect of the temperature difference across the electrode-electrolyte interface and the finite size of ions non-idealities on the cation interdiffusion is investigated using a mathematical model. Here, we build on and add significantly to our previous work 1 where the study was limited only to the finite effect of ions. Considering each non-ideality/effect separately, the diffusion of manganese (Mn3+) ions decreases about 50 nm for a temperature difference (∆ T) of 50 K, and 31 nm for a finite size parameter ( ν) of 1.826. However, it is decreased by 54 nm considering both effects combindly for ∆ T = 50 K and ν = 1.75. Further, under individual effects, the highest electric potential drop is 0.32 for a ∆ T = 50 K and 0.27 for a ν = 1.75. Under combined effects, the electric potential drop is about 0.85 for ∆ T = 50 K and ν = 1.75. A significant variation is observed in the diffusion of Zr4+, Y3+ and Mn3+ ions and the overall electric potential. It is anticipated that the consideration of these effects/non-idealities will help in the better understanding of cation interdiffusion, and contribute towards performance enhancement of SOFCs.

Distribution Characteristics and Genesis of Iron and Manganese Ions in Groundwater of Eastern Sanjiang Plain, China

Groundwater resources are an essential component of global water resources. Long-term consumption of groundwater exceeding the standard levels for iron and manganese can lead to chronic diseases, posing a threat to human health. The Sanjiang Plain is the largest swamp wetland area in China and has high levels of iron and manganese in the groundwater, but the cause still needs to be clarified. Based on the results of water quality tests of 41 groundwater samples in the Eastern Sanjiang Plain, this paper analyzes the distribution characteristics and causes of iron and manganese from the perspectives of the original strata environment, redox conditions, pH conditions, and hydrochemical indicator factors in the research area, using statistical methods and GIS technology. The results show that high iron and manganese content in groundwater is prevalent in the Eastern Sanjiang Plain, and the exceedance rate of manganese is higher than that of iron (87.80% and 82.90%, respectively). The primary sources of iron and manganese in groundwater are iron and manganese minerals in the original strata environment. Influenced by factors such as acidic conditions, reducing environment, and rich organic matter, insoluble high-valent iron and manganese oxides are reduced to low-valent and soluble divalent iron and manganese. At the same time, groundwater’s high mineralization and evaporation concentration are conducive to increased iron and manganese content, while the influence of human activities is small.

Phytoremediation of Wastewater Containing Lead and Manganese Ions Using Algae.

Heavy metal pollution of water from industrial discharge is a major problem worldwide. Thus, the quality of the environment and human health are severely affected. Various conventional technologies have been applied for water treatment, but these can be expensive, especially for industrial water treatment, and may have limited treatment efficiencies. Phytoremediation is a method that is successfully applied to remove metal ions from wastewater. In addition to the high efficiency of the depollution treatment, this method has the advantages of a low cost of the operation and the existence of many plants that can be used. This article presents the results of using algae (Sargassum fusiforme and Enteromorpha prolifera) to treat water containing manganese and lead ions. It was observed that maximum efficiencies for wastewater treatment were obtained when was used the algae Enteromorpha prolifera for a 600 min contact time period. The highest wastewater treatment efficiency obtained using Sargassum fusiforme was 99.46%.

Durable Manganese-Based Li-Excess Electrode Material without Voltage Decay: Metastable and Nanosized Li2MnO1.5F1.5

Li-excess manganese-based oxides have been proposed as high-capacity positive electrode materials, but voltage decay associated with gradual oxygen loss hinders its use for practical applications. Herein, Li-excess manganese oxides with different fluorine contents are synthesized by high-energy mechanical milling. Although Li2MnOF2 with only divalent manganese ions cannot be synthesized, Li2MnO2F and Li2MnO1.5F1.5 are successfully synthesized. When the samples are charged to 5.0 V, both oxyfluorides deliver large reversible capacities, ∼350 mA h g–1 and ∼1000 mWh g–1. However, insufficient capacity retention is also observed because of the instability of anionic redox. In contrast, better capacity retention and higher energy density (730 mWh g–1) are obtained for Li2MnO1.5F1.5 with a 4.4 V cutoff because of the enrichment of fluoride ions and activation of Mn2+/Mn4+ cationic redox. Moreover, electrode durability is significantly improved by using a highly concentrated electrolyte, and good capacity retention without voltage decay is achieved for >180 cycles.