Iron Loading Research Articles

Deeply removal of trace Cd2+ from water by bacterial cellulose membrane loaded with nanoscale zerovalent iron: Practical application and mechanism

Cadmium (Cd2+) ions in drinking water are typical heavy metal contaminants, even trace amounts of Cd2+ can accumulate in the body, leading to serious irreversible damage to human bones and kidneys. Herein, we propose an effective and green strategy for the deep removal of trace Cd2+ from water by dispersed loading of nanoscale zero-valent iron (nZVI) onto bacterial cellulose membranes (BCM). BCM-nZVI can effectively remove Cd2+ from water in a wide pH range (5–8) with 99.96% removal rate. Freundlich isotherm model and the pseudo-second-order model reveal the adsorption process with a maximum adsorption capacity of 134.0 mg·g−1 at 30 °C. Impressively, the Cd2+ concentration in actual Cd2+ containing drinking water is below the target of 5 μg·L−1 (drinking water standard in China, USA and EU) after treated by the BCM-nZVI, and no additional pollutants are introduced. The excellent stability (stored stably for 120 days) and economic cost analysis ($75.6 m−3 for Cd2+ containing drinking water) of BCM-nZVI indicated they are viable for practical application in actual water treatment. Most importantly, the reduction reaction and mechanism study of BCM-nZVI revealed that the toxic Cd2+ is converted into non-toxic Cd0 assisted by the hydrated electrons and it has been systemically verified in our paper. This work sheds light on BCM-nZVI can be used as an ideal green material to removal Cd2+ in trace amounts of actual drinking water with high-efficiency, economical, environmentally friendly and has great potential for application in real environments.

Iron Delivery through Membrane Vesicles in Corynebacterium glutamicum.

Bacterial cells form and release membrane vesicles (MVs) originating from cellular membranes. In recent years, many biological functions of bacterial MVs have been identified. Here, we show that MVs derived from Corynebacterium glutamicum, a model organism for mycolic acid-containing bacteria, can mediate iron acquisition and other phylogenetically related bacteria. Lipid/protein analysis and iron quantification assay indicate that C. glutamicum MVs formed by outer mycomembrane blebbing can load ferric iron (Fe3+) as its cargo. Iron-loaded C. glutamicum MVs promoted the growth of producer bacteria in iron-limited liquid media. MVs were received by C. glutamicum cells, suggesting a direct transfer of iron to the recipient cells. Cross-feeding of C. glutamicum MVs with phylogenetically close (Mycobacterium smegmatis and Rhodococcus erythropolis) or distant (Bacillus subtilis) bacteria indicated that C. glutamicum MVs could be received by the different species tested, while iron uptake is limited to M. smegmatis and R. erythropolis. In addition, our results indicate that iron loading on MVs in C. glutamicum does not depend on membrane-associated proteins or siderophores, which is different from what has been shown in other mycobacterial species. Our findings illustrate the biological importance of MV-associated extracellular iron for C. glutamicum growth and suggest its ecological impact on selected members of microbial communities. IMPORTANCE Iron is an essential element of life. Many bacteria have developed iron acquisition systems, such as siderophores, for external iron uptake. Corynebacterium glutamicum, a soil bacterium known for its potential for industrial applications, was shown to lack the ability to produce extracellular, low-molecular-weight iron carriers, and it remains elusive how this bacterium acquires iron. Here, we demonstrated that MVs released from C. glutamicum cells could act as extracellular iron carriers that mediate iron uptake. Although MV-associated proteins or siderophores have been shown to play critical roles in MV-mediated iron uptake by other mycobacterial species, the iron delivery through C. glutamicum MVs is not dependent on these factors. Moreover, our results suggest that there is an unidentified mechanism that determines the species specificity of MV-mediated iron acquisition. Our results further demonstrated the important role of MV-associated iron.

Fetal factors disrupt placental and maternal iron homeostasis in murine β-thalassemia

AbstractPregnancy rates in β-thalassemia are increasing but the risk of complications is higher; thus, better understanding of maternal and fetal iron homeostasis in this disorder is needed. HbbTh3/+ (Th3/+) mice model human β-thalassemia. Both the murine and human diseases are characterized by low hepcidin, high iron absorption, and tissue iron overload, with concurrent anemia. We hypothesized that disordered iron metabolism in pregnant Th3/+ mice would negatively affect their unborn offspring. The experimental design included these groups: wild-type (WT) dams carrying WT fetuses (WT1); WT dams carrying WT and Th3/+ fetuses (WT2); Th3/+ dams carrying WT and Th3/+ fetuses (Th3/+); and age-matched, nonpregnant adult females. Serum hepcidin was low, and mobilization of splenic and hepatic storage iron was enhanced in all 3 groups of experimental dams. Intestinal 59Fe absorption was lower in Th3/+ dams (as compared with WT1/2 dams) but splenic 59Fe uptake was higher. Th3/+ dams had hyperferremia, which led to fetal and placenta iron loading, fetal growth restriction, and placentomegaly. Notably, Th3/+ dams loaded Th3/+ and WT fetuses, with the latter situation more closely mirroring human circumstances when mothers with thalassemia have relatively unaffected (thalassemia trait) offspring. Iron-related oxidative stress likely contributed to fetal growth impairment; enhanced placental erythropoiesis is a probable cause of placental enlargement. Moreover, high fetal liver iron transactivated Hamp; fetal hepcidin downregulated placental ferroportin expression, limiting placental iron flux and thus mitigating fetal iron loading. Whether gestational iron loading occurs in human thalassemic pregnancy, when blood transfusion can further elevate serum iron, is worth consideration.

Effect of Eculizumab on Iron Metabolism in Transfusion-independent Patients With Paroxysmal Nocturnal Hemoglobinuria

Effect of Eculizumab on Iron Metabolism in Transfusion-independent Patients With Paroxysmal Nocturnal Hemoglobinuria

Frontal Plane QRS-T Angle as a Marker of Cardiac Iron Overload in Patients with Beta Thalassemia Major.

Cardiomyopathy due to myocardial iron deposition is the leading cause of death in transfusion- dependent beta-thalassemia major (β-TM) patients. Although cardiac T2* magnetic resonance imaging (MRI) can be used for the early detection of cardiac iron level before the onset of symptoms associated with iron overload, this expensive method is not widely available in many hospitals. Frontal QRS-T angle is a novel marker of myocardial repolarization and is associated with adverse cardiac outcomes. We aimed to investigate the relationship between cardiac iron load and f(QRS-T) angle in patients with β-TM. The study included 95 β-TM patients. Cardiac T2* values under 20 were considered to indicate cardiac iron overload. The patients were divided into two groups according to the presence or absence of cardiac involvement. Laboratory and electrocardiography parameters, including frontal plane QRS-T angle, were compared between the two groups. Cardiac involvement was detected in 33 (34%) patients. Multivariate analysis showed that frontal QRS-T angle independently predicted cardiac involvement (p < 0.001). An f(QRS-T) angle of ≥ 24.5° had a sensitivity of 78.8% and a specificity of 79% in detecting the presence of cardiac involvement. In addition, a negative correlation was found between cardiac T2* MRI value and f(QRS-T) angle. A widening f(QRS-T) angle could be considered a surrogate marker of MRI T2* to detect cardiac iron overload. Therefore, calculating the f(QRS-T) angle in thalassemia patients is an inexpensive and simple method for detecting the presence of cardiac involvement, especially when cardiac T2* values cannot be determined or monitored.

Prussian blue derived Ca-Fe bifunctional materials for chemical looping CO2 capture and in-situ conversion

Chemical looping CO2 capture and in-situ reverse water gas shift (CL-ICCC-RWGS) is a promising way to realize integrated CO2 capture and conversion for responding CO2 emission issue. Most bifunctional materials are performed in a reaction configuration of sorbent-catalyst, however, altering the reaction configuration into a sorbent-oxygen-carrying form by introducing a redox couple would result in a new CL-ICCC-RWGS scheme. In this work, a new integrated CO2 capture and conversion scheme is proposed and experimentally demonstrated by synthesizing a series of Prussian blue derived Ca-Fe bifunctional materials with varying iron loadings and exploring their cyclic capture-conversion reactivity. The bifunctional materials with both Ca and Fe species show CO production during isothermal cycles, since CO2 re-oxidation of metallic iron and reverse water gas shift occur in capture and conversion half-cycles, respectively. FCZ136 exhibits the best averaged CO space time yield (238.25 mmolCO∙s−1∙kgFe2O3−1 and 3.00 mmolCO∙s−1∙kgCaO−1) and CO yield (142.95 molCO∙kgFe2O3−1 and 1.80 molCO∙kgCaO−1) with no deactivation after ten isothermal cycles at 650 °C. This is mainly ascribed to two aspects: (i) high iron dispersion improves CO generation rate, (ii) the presence of two inert promoters (t-ZrO2 and CaZrO3) maintains a superior stability. The result provides a new strategy to design efficient bifunctional material and achieve integrated CO2 capture and conversion.

Enhanced Fischer–Tropsch synthesis performance on MOFs‐derived Fe‐based catalysts constrained by SiO2

Fischer–Tropsch synthesis (FTS) is an essential technology to produce clean fuel, and catalyst will affect syngas conversion efficiency and product distribution. For traditional oxides‐supported catalysts, the mutual constraint between active metal loading and dispersion at high metal loading is hard to overcome, which will hinder the synthesis of high‐performance FTS catalysts. Herein, we report an efficient method for synthesizing iron‐based catalysts with not only high loading but also high dispersion. By using metal–organic frameworks Fe‐MIL‐88B as the precursor, we synthesized a series of Fe@C@SiO2 catalysts by tuning the amount of tetraethyl orthosilicate (TEOS) through a one‐step method; TEOS was in situ introduced and followed by high‐temperature carbonization. The prepared catalyst possesses a Fe@C core–shell structure with carbon layer encapsulation. Meanwhile, the SiO2 in the catalyst can effectively confine iron particles and avoid the agglomeration of iron species during high‐temperature carbonization. Among these catalysts, the Fe@C@SiO2‐0.005 showed the greatest FTS performance because high iron dispersion was achieved at high iron loading. Further increase SiO2 content enhanced the confinement effect of SiO2 but generated inert Fe2SiO4 species, which decreased the adsorption and activation of reactants and FTS activity.

Xue-Jie-San restricts ferroptosis in Crohn's disease via inhibiting FGL1/NF-κB/STAT3 positive feedback loop.

Crohn's disease (CD) is an incurable inflammatory bowel disease due to unclear etiology and pathogenesis. Accumulating evidences have shown the harmful role of ferroptosis in CD onset and development. Additionally, fibrinogen-like protein 1 (FGL1) has been verified to be a potential therapeutic target of CD. Xue-Jie-San (XJS) is an effective prescription for treating CD. However, its therapeutic mechanism has not been fully elucidated. This study aimed to determine whether XJS alleviating CD via regulating ferroptosis and FGL1 expression. A colitis rat model was induced by 2,4,6-trinitrobenzene sulfonic acid and treated with XJS. The disease activity indices of the colitis rats were scored. Histopathological damage was assessed using HE staining. ELISA was performed to examine inflammatory cytokines. Transmission electron microscopy was utilized to observe ultrastructure changes in intestinal epithelial cells (IECs). Iron load was evaluated by examining iron concentrations, the expressions of FPN, FTH and FTL. Lipid peroxidation was investigated through detecting the levels of ROS, 4-HNE, MDA and PTGS2. Furthermore, the SLC7A11/GSH/GPX4 antioxidant system and FGL1/NF-κB/STAT3 signaling pathway were examined. The results showed that colitis was dramatically ameliorated in the XJS-treated rats as evidenced by relief of clinical symptoms and histopathological damages, downregulation of pro-inflammatory cytokines IL-6, IL-17 and TNF-α, and upregulation of anti-inflammatory cytokine IL-10. Furthermore, XJS administration led to ferroptosis inhibition in IECs by reducing iron overload and lipid peroxidation. Mechanistically, XJS enhanced the SLC7A11/GSH/GPX4 antioxidant system negatively regulated by the FGL1/NF-κB/STAT3 positive feedback loop. In conclusion, XJS might restrain ferroptosis in IECs to ameliorate experimental colitis by inhibition of FGL1/NF-κB/STAT3 positive feedback loop.

A dynamic compartment model for xylem loading and long-distance transport of iron explains the effect of kanamycin on metal uptake in Arabidopsis.

Arabidopsis plants exposed to the antibiotic kanamycin (Kan) display altered metal homeostasis. Further, mutation of the WBC19 gene leads to increased sensitivity to kanamycin and changes in iron (Fe) and zinc (Zn) uptake. Here we propose a model that explain this surprising relationship between metal uptake and exposure to Kan. We first use knowledge about the metal uptake phenomenon to devise a transport and interaction diagram on which we base the construction of a dynamic compartment model. The model has three pathways for loading Fe and its chelators into the xylem. One pathway, involving an unknown transporter, loads Fe as a chelate with citrate (Ci) into the xylem. This transport step can be significantly inhibited by Kan. In parallel, FRD3 transports Ci into the xylem where it can chelate with free Fe. A third critical pathway involves WBC19, which transports metal-nicotianamine (NA), mainly as Fe-NA chelate, and possibly NA itself. To permit quantitative exploration and analysis, we use experimental time series data to parameterize this explanatory and predictive model. Its numerical analysis allows us to predict responses by a double mutant and explain the observed differences between data from wildtype, mutants and Kan inhibition experiments. Importantly, the model provides novel insights into metal homeostasis by permitting the reverse-engineering of mechanistic strategies with which the plant counteracts the effects of mutations and of the inhibition of iron transport by kanamycin.

Scalable and facile preparation of Fe3O4/2D-MoS2 and its application in peroxymonosulfate-based advanced oxidation processes for tetracycline degradation

In this paper, a magnetic ferrosoferric oxide/two-dimensional molybdenum disulfide (Fe3O4/2D-MoS2) composite material was successfully prepared by combining liquid phase exfoliation and in-situ liquid phase co-precipitation methods with scalable and facile characteristics and applied to catalyze the degradation of tetracycline (TC) during the peroxymonosulfate-based advanced oxidation processes (PMS-AOPs), which is a typical and widely used antibiotic. The morphology and crystallinity of the composites were determined by scanning electron microscopy, transmission electron microscope and X-ray diffraction, respectively. And its BET surface area was tested by N2 adsorption and desorption curves. For the PMS-AOPs, the effects of iron loading, different systems, initial concentration of pollutants, dosage of the composites, concentration of peroxymonosulfate (PMS) and solution initial pH on the removal of TC were researched in details. The results showed that it could reach 89.0% degradation efficiency within 90 min for 50 mg/L TC with the as-prepared composites as catalyst, showing good catalytic performances. In addition, the mechanisms of the reaction were deduced by quenching experiments and X-ray photoelectron spectroscopy analysis. It was turned out that the as-synthsized material has a broad applying prospect in PMS-AOPs.

Optical Monitoring of In Situ Iron Loading into Single, Native Ferritin Proteins.

Ferritin is a protein that stores and releases iron to prevent diseases associated with iron dysregulation in plants, animals, and bacteria. The conversion between iron-loaded holo-ferritin and empty apo-ferritin is an important process for iron regulation. To date, studies of ferritin have used either ensemble measurements to quantify the characteristics of a large number of proteins or single-molecule approaches to interrogate labeled or modified proteins. Here we demonstrate the first real-time study of the dynamics of iron ion loading and biomineralization within a single, unlabeled ferritin protein. Using optical nanotweezers, we trapped single apo- and holo-ferritins indefinitely, distinguished one from the other, and monitored their structural dynamics in real time. The study presented here deepens the understanding of the iron uptake mechanism of ferritin proteins, which may lead to new therapeutics for iron-related diseases.

Gaussian Model of Anti-Radar Properties for Coatings Based on Carbonyl Iron Powder.

The article presents the Gaussian model of the electromagnetic radiation attenuation properties of two resin systems containing 75% or 80% of a carbonyl iron load as an absorber in the 4-18 GHz range. For the attenuation values obtained in the laboratory, mathematical fitting was performed in the range of 4-40 GHz to visualize the full curve characteristics. The simulated curves fitted up to a 0.998 R2 value of the experimental results. The in depth analysis of the simulated spectra allowed a thorough evaluation of the influence of the type of resin, absorber load, and layer thickness on reflection loss parameters such as the maximum attenuation, peak position, half-height width, and base slope of the peak. The simulated results were convergent with the literature findings, allowing a much deeper analysis. This confirmed that the suggested Gaussian model could provide additional information, useful in terms of comparative analyses of datasets.

POST COVID JAW OSTEOMYELITIS WITH MUCORMYCOSIS - AN INSTITUTIONAL STUDY

Mucoraceae are ubiquitous fungi and are found in, soil, air, contaminated water and hospital environments too. These fungi usually gain entry into host through respiratory tract and sinuses either by direct spread or by angioinvasion. Major sites of infection are sinuses, lungs, skin, brain, and gastrointestinal tract. From sinus it may invade maxilla causing osteomyelitis of jaw. Mucormycosis is an opportunistic infection and the major risk factors include poorly controlled diabetes mellitus (DM), iron overload, prolonged corticosteroid use and immunocompromised status. CORONA virus disease 2019 (Covid-19) is an infection caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The majority of patients have a good prognosis, but some patients become critically ill and even deaths occur. Disease itself decreases cell mediated immunity and increases iron load in covid patients. For treatment of Covid-19 corticosteroids, antiviral drugs and immunomodulatory drugs are being used. Steroid reduces inflammation in covid 19 patients, but it pushes up the blood sugar which causes ketoacidosis, increases iron load, affects cell mediated immunity and favours the mucor mycosis growth. So, there are reported increasing cases of mucormycosis in post COVID-19 patients. Present study includes 25 reported cases of mucormycosis with jaw osteomyelitis in post covid patients with respect to clinical characteristics, past medical history, comorbidities medication received during covid 19, radiographic feature, lab diagnostic methods, histopathological reports, and treatment. So as to gain an insight of this disease as early diagnosis of mucor mycosis and treatment which can significantly reduce the mortality and morbidity of mucormycosis patients&#x0D;

Quantification of cardiac iron in patients with thalassemia with 3-T MRI calibrated by 1.5-T MRI

Due to the small sample size of many studies, it remained unclear what standardized reference range the T2* cutoff at 3 T would be used to assess the severity of cardiac iron load. In addition, the number of patients with moderate to severe cardiac iron load was small in some studies, especially the sample of patients with severe cardiac iron load. To explore the feasibility, reproducibility, and reliability of using T2* values in quantifying cardiac iron load in patients with thalassemia at 3 T. A total of 122 patients with thalassemia underwent cardiac T2* imaging at both 1.5 T and 3 T. Cardiac R2* (1000/T2*) values of the 100 patients at 3 T were fitted against the values at 1.5 T using linear regression and the prediction equation was derived. The remaining 22 cases were used to test the prediction accuracy of the equation. The combined R2* values exhibited a strong linear relationship between 1.5 T and 3 T (r = 0.830，P<0.001). At the center, it had a slope of 1.348 and an intercept of 37.279. According to the equation, the truncated T2* values of cardiac iron overload and cardiac heavy iron overload at 3 T were <10 ms and <6 ms, respectively. The two truncated T2* values were used to diagnose different levels of cardiac iron overloaded of 22 patients at 3 T; the accuracy rates were 95.5% and 100.0%, respectively. T2* quantification of cardiac iron load at 3 T MRI resulted to be feasible, reproducible, and reliable.

5610178 SURVIVAL AND COMPLICATIONS IN PATIENTS WITH HEMOGLOBINOPATHIES: THE EXPERIENCE OF A SINGLE DEPARTMENT OF THALASSEMIA AND SICKLE DISEASE

Background: New medicines and doctors’ expertise have increased hemoglobinopathies patients’ survival from 35 to 60 years in the last few decades. This report presents the underlying causes of death in a thalassemia and sickle cell disease unit during the past decade and examines potential risk factors. All causes of death were reported and correlated with comorbidities that may have contributed to this outcome. Methods: The records of 32 patients (17 women/15 men) who died in the Thalassemia and Sickle Cell Disease Unit in the last 10 years were reviewed: 11 had thalassemia, 10 had thalassemia/sickle cell disease, 9 had NTD, and 2 had sickle cell disease. Patients died at a median age of 42 years (range 29-71). Results: Heart failure (8, 25%), HCC (72%), and sepsis (6, 19%) were the leading reasons of mortality.The immediately subsequent causes of death that were recorded were as follows: sudden death three cases (9.5%), liver failure three cases (9.5%), brain aneurysm one case (1%), motor neuron disease one case (1%), and an car accident one time respectively. Using the Pearson Correlation Coefficient, a positive correlation (r:0.8) was found between deaths from heart failure, HCC, and liver failure in patients with a high iron load, as well as a moderate correlation (r:0.3) of HCV infection in patients who died of HCC and liver failure, with no correlation in the remaining deaths. Similarly, no death was associated with splenectomy or the number of transfusions. Conclusions: Despite improvements in better treatment options, heart failure and HCC caused by iron overload continue to be major causes of morbidity and mortality in people with hemoglobinopathies.

Exploring a ferroptosis and oxidative stress-based prognostic model for clear cell renal cell carcinoma.

Ferroptosis is a newly defined cell death process triggered by increased iron load and tremendous lipid reactive oxygen species (ROS). Oxidative stress-related ferroptosis is of great important to the occurrence and progression of clear cell renal cell carcinoma (ccRCC), which is particularly susceptibility to ferroptosis agonist. Therefore, exploring the molecular features of ferroptosis and oxidative stress might guide the clinical treatment and prognosis prediction for ccRCC patients. The differentially expressed ferroptosis and oxidative stress-associated genes (FPTOSs) between normal renal and ccRCC tissues were identified based on The Cancer Genome Atlas (TCGA) database, and those with prognostic significances were applied to develop a prognostic model and a risk scoring system (FPTOS_score). The clinical parameter, miRNA regulation, tumor mutation burden (TMB), immune cell infiltration, immunotherapy response, and drug susceptibility between two FPTOS-based risk stratifications were determined. We have identified 5 prognosis-associated FPTOSs (ACADSB, CDCA3, CHAC1, MYCN, and TFAP2A), and developed a reliable FPTOS_socre system to distinguish patients into low- and high-risk groups. The findings implied that patients from the high-risk group performed poor prognoses, even after stratified analysis of various clinical parameters. A total of 30 miRNA-FPTOS regulatory pairs were recognized to identify the possible molecular mechanisms. Meanwhile, patients from the high-risk group exhibited higher TMB levels than those from the low-risk groups, and the predominant mutated driver genes were VHL, PBRM1 and TTN in both groups. The main infiltrating immune cells of high- and low-risk groups were CD8+ T cells and resting mast cells, respectively, and patients from the high-risk groups showed preferable drug responsiveness to anti-PD-1 immunotherapy. Eventually, potential sensitive drugs (cisplatin, BI-D1870, and docetaxel) and their enrichment pathways were identified to guide the treatment of ccRCC patients with high-risk. Our study comprehensively analyzed the expression profiles of FPTOSs and constructed a scoring system with considerable prognostic value, which would supply novel insights into the personalized treatment strategies and prognostic evaluation of ccRCC patient.

Development and Characterization of Pullulan-Based Orodispersible Films of Iron.

Iron deficiency is the principal cause of nutritional anemia and it constitutes a major health problem, especially during pregnancy. Despite the availability of various non-invasive traditional oral dosage forms such as tablets, capsules, and liquid preparations of iron, they are hard to consume for special populations such as pregnant women, pediatric, and geriatric patients with dysphagia and vomiting tendency. The objective of the present study was to develop and characterize pullulan-based iron-loaded orodispersible films (i-ODFs). Microparticles of iron were formulated by a microencapsulation technique, to mask the bitter taste of iron, and ODFs were fabricated by a modified solvent casting method. Morphological characteristics of the microparticles were identified by optical microscopy and the percentage of iron loading was evaluated by inductively coupled plasma optical emission spectroscopy (ICP-OES). The fabricated i-ODFs were evaluated for their morphology by scanning electron microscopy. Other parameters including thickness, folding endurance, tensile strength, weight variation, disintegration time, percentage moisture loss, surface pH, and in vivo animal safety were evaluated. Lastly, stability studies were carried out at a temperature of 25 °C/60% RH. The results of the study confirmed that pullulan-based i-ODFs had good physicochemical properties, excellent disintegration time, and optimal stability at specified storage conditions. Most importantly, the i-ODFs were free from irritation when administered to the tongue as confirmed by the hamster cheek pouch model and surface pH determination. Collectively, the present study suggests that the film-forming agent, pullulan, could be successfully employed on a lab scale to formulate orodispersible films of iron. In addition, i-ODFs can be processed easily on a large scale for commercial use.

Superefficient separation of Th(IV) and U(VI) by lignin-derived magnetic biochar via competitive adsorption mechanism

Thorium (Th) and uranium (U) separation remains a huge challenge due to their high similarity in chemical behavior. In this study, lignin-derived magnetic biochar (AL-Fe/BC), which can provide functional sites for adsorbing Th(IV) and U(VI), was synthesized for the selective extraction of Th(IV) from the binary U(VI)-Th(IV) matrix. Characterizations results confirm the successful zero-valent iron loading, and the AL-Fe/BC exhibited a developed polyporous structure, high surface area, stable crystallinity, high defects degree, and advantageous magnetic feature of expedient recovery from water without energy consumption. The optimist AL-Fe/BC-800 showed an outstanding adsorption capacity with a maximal Th(IV) uptake of 2000 mg/g, and a small absorption of 3 mg/g of U(VI) (Th(IV) = 180 mg/L, U(VI) = 20 mg/L, AL-Fe/BC-800 = 0.05 g/L). Moreover, the separation factor of Th(IV) from the Th(IV)-U(VI) matrix reached 90,000 even concomitant with high a concentration of co-existing ions. The active adsorption sites on AL-Fe/BC-800, such as COOH, C-OH, C=O, pyridinic N, graphitic N, and pyrrolic N, exhibited a stronger binding affinity with Th(IV) than U(VI), achieving selective Th(IV) adsorption via a chemisorption process on the basis of competitive adsorption. In summary, AL-Fe/BC-800 is a potential adsorbent in industrial application for the superefficient separation of Th(IV) and U(VI) with high-performance magnetic recovery, promoting the sustainable development of nuclear industry, especially considering the necessary development of Th(IV) fuel.

Gaseous toluene heterogeneous oxidative degradation by iron-based hypercrosslinked polymeric resin LXQ-10

Heterogeneous Fenton-like reaction for gaseous toluene removal was enhanced by loading an amount of iron elements onto the hypercrosslinked polymeric resin (LXQ-10) as a novel catalyst. Characterization and experiment results confirmed that Fe/LXQ-10 with great catalytic and stability performance were successfully synthesized. The effects of several key running parameters such as iron loading amount, initial toluene concentration, H2O2 concentration, and reaction temperature were investigated. Under the optimal conditions for a Fenton-like reaction (gaseous toluene concentration, 200 mg/m3; H2O2 concentration, 0.15 mol/L; reaction temperature, 303 K), 3-Fe/LXQ-10 was identified to produce OH radical and the toluene removal efficiency reached 93.56%. Gas chromatography-mass spectrometry (GC–MS) was employed to detect the byproducts in the toluene removal process, and the possible degradation pathway of toluene was explored. Radical quenching tests and EPR investigation were carried out to clarify the contribution of OH radical in the Fenton-like process. Physical adsorption and OH oxidation were the possible mechanisms of toluene removal. In addition, the catalyst maintained its activity after the six cycles. suggesting strong stability and reusability. All the results demonstrated that Fe/LXQ-10 showed high potential and economic feasibility to remove gaseous toluene through adsorption and Fenton-like oxidation. This research not only presents a promising alternative for the effective removal of gaseous VOCs but also provides a theoretical basis in the field of VOCs control.

EReefs modelling suggests Trichodesmium may be a major nitrogen source in the Great Barrier Reef

Trichodesmium can fix nitrogen that is later released into the water column. This process may be a major source of ‘new’ nitrogen in the Great Barrier Reef (GBR), but to date this contribution is poorly resolved. We have estimated the seasonal, spatial and annual contributions of Trichodesmium to the annual nitrogen budget of the GBR using the eReefs marine models. Models were run for the interval December 2010 to November 2012. During this period La Niña conditions produced record rainfalls and widespread flooding of GBR catchments. Model outputs suggest nitrogen fixation by Trichodesmium in the GBR (which covers about 348,000 km2) contributes approximately 0.5 MT/yr, exceeding the total average annual riverine nitrogen loads (0.05–0.08 MT/yr). Nitrogen fixation loads are exceeded by riverine loads only if the comparison is restricted to inshore waters and during the wet season. The river pollution is likely to have impacts in freshwater wetlands, mangroves, seagrasses and in-shore coral reefs; while Trichodesmium blooms are likely to be less intense but more widespread and affect offshore coral reefs and other oceanic ecosystems. Phosphorus and iron are suggested to be potential drivers of Trichodesmium growth and nitrogen fixation. This result is provisional but reinforces the need for more detailed assessment and reliable quantification of the annual nitrogen contribution from nitrogen fixation in the GBR and other coastal waters. Such advances will improve understandings of the role of terrestrial nitrogen loads in the GBR and of terrestrial phosphorus and iron loads which can modulate Trichodesmium abundance. These findings will help to broaden the focus of water quality management programmes and support management to improve GBR water quality.