Effective Removal Of Iron Research Articles

Pre-oxidation and coagulation-flocculation as a pretreatment to UF-RO applied for surface water treatment and arsenic removal

In this paper, the effects of applying pre-oxidation, coagulation, and flocculation (C/F) as pretreatment of an ultrafiltration (UF) - reverse osmosis (RO) system treating water containing arsenic were assessed. For this, the performance of a pilot scale – with a maximum treatment capacity of 2.25 m3/h - UF-RO system with and without pretreatment was evaluated. The membranes were able to generate high-quality permeates, even when the feed presented a remarkable increase in color (>2100 uH) and turbidity (>300 NTU) due to the beginning of the rainy season. UF was not efficient for arsenic removal, so RO was essential to guarantee safe water, generating permeates with concentrations below 0.5 μg/L of arsenic. The effective removal of iron and manganese, among other ions, was verified using membranes. Given the high quality of the permeates, blend formulation strategies were carried out, mixing filtered water from the conventional water treatment plant and RO permeate (Strategy I) and mixing filtered water, UF permeate, and RO permeate (strategy II). Strategy II was viable for arsenic concentrations in filtered water of 13 and 15 μg/L. Pretreatment was important in maintaining a higher membrane permeability and ensured a more stable performance in the face of variations in feed quality, which may be seasonal in some places, as in the present case, where feed quality is significantly altered by the rainy season. Overall, although UF and RO membranes are effective processes for treating surface water containing arsenic, the results suggested that pretreatment, which is already part of the treatment of several water treatment plants, guarantees more robustness to the treatment concerning a higher and more stable membrane permeability, directly impacting operational expenses with membranes operation.

Effective removal of iron, nutrients, micropollutants, and faecal bacteria in constructed wetlands cotreating mine water and sewage treatment plant effluent.

Regulators in England and Wales have set new targets under the Environment Act 2021 for freshwater quality by 2038 that include halving the length of rivers polluted by harmful metals from abandoned mines and reducing phosphorus loadings from treated wastewater by 80%. In this context, an intriguing win-win opportunity exists in the removal of iron from abandoned mines and phosphate from small sewage treatment plants by coprecipitation in constructed wetlands (CWs). We investigated such a CW located at Lamesley, Northeast England, which cotreats abandoned coal mine and secondary-treated sewage treatment plant effluents. We assessed the removal of nutrients, heavy metals, organic micropollutants, and faecal coliforms by the CW, and characterized changes in the water bacteriology comprehensively using environmental DNA. The CW effectively removed ammonium-nitrogen, phosphorus, iron, and faecal coliforms by an average of 86, 74, 98, and 75%, respectively, to levels below or insignificantly different from those in the receiving river. The CW also effectively removed micropollutants such as acetaminophen, caffeine, and sulpiride by 70-100%. Molecular microbiology methods showed successful conversion of sewage and mine water microbiomes into a freshwater microbiome. Overall, the CW significantly reduced impacts on the rural water environment with minimal operational requirements.

Challenges and Possible Solutions for Riverbank Filtration: Case Studies of Three Sites in Egypt

In response to Egypt’s escalating water scarcity and pollution, Riverbank Filtration (RBF) technology is emerging as an effective solution to enhance water quality and simplify drinking water provision. This study evaluates RBF at three sites in Upper Egypt by assessing hydrogeological conditions and water quality based on 36 parameters from 2022 to 2023. Findings indicate that RBF efficiently treats infiltrated river water, with all sites meeting turbidity and microbiological standards (Total Bacterial Count and Coliforms), achieving removal rates of approximately 90% and 99%, respectively. Despite these successes, challenges persist in reducing manganese to safe levels, with concentrations at Alsaayda site reaching 0.51 mg/L, over the drinking water safe limit of 0.4 mg/L. To address this, further post-treatment strategies are proposed to remove the excess manganese. A practical application of an Oxidizer at the Bani Murr groundwater treatment plant has demonstrated the effective removal of iron and manganese, bringing their levels down to safe drinking water standards. This case exemplifies a successful solution for iron and manganese removal. This research highlights RBF’s potential in water treatment in developing countries, while emphasizing the need for supplementary measures to manage specific contaminants.

Iron removal from kaolinitic coal gangue via magnetic separation after oxidizing calcination with the crystal structure of kaolinite protected

Iron is a harmful color-staining impurity that degrades the performance of coal gangue (CG) products, and pyrite is the predominant form of iron in kaolinitic coal gangue. In addition, iron extraction from CG as a supplemental iron ore resource is significant for increasing the added value of CG comprehensive utilization. Herein, calcination in a mild oxidizing atmosphere was implemented to enhance the magnetic properties of pyrite for subsequent magnetic separation. The sample was calcined at 300–1000 °C for 30–180 min, and the maximum magnetic susceptibility reached approximately 17 times that of the original ore. The iron recovery rates of the gangue calcined for 60–120 min were increased remarkably to 83.17–83.61%, while the iron recovery rate of the raw gangue was almost zero. After magnetic separation, the Fe2O3 content decreased from 5.58% for the raw gangue to 1.00% for the nonmagnetic products of gangues calcined for 60–120 min. Retention of the strongly magnetic magnetite, which was an intermediate product in the oxidation of pyrite to hematite, enabled the effective removal of iron from the gangue. Additionally, the kaolinite in the iron-removed coal gangue basically maintained its crystal structure.

Study on Catalytic Oxidation, Flocculation and Sedimentation of Acidizing and Fracturing Wastewater

The acidizing and fracturing waste fluid in a wellsite in northern Shaanxi was treated by catalytic oxidation and flocculation precipitation. It investigated the effect of different coagulants and their dosage and the wastewater pH on coagulation precipitation. As for chemical oxidation experiment, it investigated the effect of oxidant dosage and reaction time on its treatment effect. The results showed that when 30% hydrogen peroxide (volume percentage) was added at the dosage of 0.3% and oxidized for 50 min, the pH was adjusted to 7.5 and 350 mg/L polyaluminum chloride (PAC) and 4 mg/L polyacrylamide were added (PAM); after processing the waste liquid, total iron, chemical oxygen demand (COD), chromaticity, and average corrosion rate were reduced from 252.75 mg/L, 3427.50 mg/L, 624.15°, and 0.1226 mm/a to 0.12 mg/L, 275.18 mg/L, 125° and 0.0217 mm/a, respectively; effective removal of iron and color, reduced COD, and controlled corrosion was achieved.

Effective Removal of Iron (II) from Aqueous Solution by Adsorption using Zn/Cr Layered Double Hydroxides Intercalated with Keggin Ion

Effective Removal of Iron (II) from Aqueous Solution by Adsorption using Zn/Cr Layered Double Hydroxides Intercalated with Keggin Ion

MRI Evaluation of Liver and Cardiac Iron Overload Impact on Hematopoietic Stem Cell Transplantation with β-Thalassemia Major

OBJECTIVE: To assess the effects of liver and cardiac iron overload detected by magnetic resonance imaging (MRI) T2* on hematopoietic stem cell transplantation in children with β-thalassemia major. METHODS:Summary of 380 cases of β-thalassemia major patients more than 5 years old in Nanfang hospital, southern medical university from 2012 to 2019.Iron concentrations in the liver and heart were calculated based on MRI T2* test results of liver and heart. Age, serum ferritin, left ventricular ejection fraction (LVEF), and liver function were compared to evaluate the effect of iron overload on organ function in patients with β-thalassemia major before transplantation.168 patients underwent allogeneic hematopoietic stem cell transplantation, 48 were HLA-mismatched transplantation, and 120 were HLA-identical allogeneic hematopoietic stem cell transplantation.To analysis the influence between implantation rate, hematopoietic reconstruction time, mortality, and common complications after transplantation such as graft-versus-host disease, hepatic venous obstruction, infection, immune hemolysis, and pancytopenia and liver and cardiac iron overload detected by magnetic resonance imaging (MRI) T2*. RESULTS:Myocardial iron overload occurred in 73 cases (19.2%), including 29 cases of cardiac T2*15~20 ms (mild), 23 cases of 10~14 ms (moderate), and 21 cases of <10 ms (severe).There were 305 cases (80.2%) with liver iron overload, including 98 cases with 2.7~6.3 ms (mild), 166 cases with 1.4~2.7 ms (moderate), and 41 cases with <1.4 ms (severe).LVEF decreased in 5 cases (1.6%).Liver iron was positively correlated with serum ferritin (r=0.523, P=0.001), cardiac iron concentration was positively correlated with serum ferritin (r=0.33, P=0.1), age was positively correlated with cardiac iron concentration (r=0.4, P=0.14), and age was negatively correlated with left ventricular ejection fraction (r=-0.36, P=0.001).After transplantation, liver iron concentration was positively correlated with hemoglobin implantation time (r=0.49, P=0.043), heart iron concentration was positively correlated with mortality (r=0.39, P=0.012), serum ferritin was negatively correlated with implantation rate (r=-0.26, P=0.012), and serum ferritin was positively correlated with infection incidence correlation (r=0.441, P=0.034).There were no statistically significant differences in liver, heart MRI T2*, liver iron concentration and heart iron concentration between the two groups before and after transplantation. CONCLUSION:Magnetic resonance imaging (T2*) is an effective and non-invasive method to detect the iron overload in the heart and liver caused by blood transfusion in β-thalassemia patients. Iron overload can have adverse effects on hematopoietic stem cell transplantation,and effective iron removal before transplantation can improve the success rate of transplantation.Quantitative assessment of iron overload in the liver and heart by MRI can be used as a necessary examination before transplantation. Disclosures No relevant conflicts of interest to declare.

Coordinated Optimization for the Descent Gradient of Technical Index in the Iron Removal Process.

In the iron removal process, which is composed of four cascaded reactors, outlet ferrous ion concentration (OFIC) is an important technical index for each reactor. The descent gradient of OFIC indicates the reduced degree of ferrous ions in each reactor. Finding the optimal descent gradient of OFIC is tightly close to the effective iron removal and the optimal operation of the process. This paper proposes a coordinated optimization strategy for setting the descent gradient of OFIC. First, an optimal setting module is established to determine the initial set-points of the descent gradient. The oxygen utilization ratio (OUR), an important parameter in this module, cannot be measured online. Therefore, a self-adjusting RBF (SARBF) neural network with an adaptive learning rate is developed to estimate the OUR. The convergence of the SARBF neural network is discussed. Then, a coordinated optimization strategy is proposed to adjust the set-points of the descent gradient when the measured OFICs drift away from their desired set-pints. If the final OFIC does not satisfy the process requirements, a compensation mechanism is developed to provide a compensation for the set-points of the descent gradient. Finally, industrial experiments in the largest zinc hydrometallurgy plant validate the effectiveness of the proposed coordinated optimization strategy. Our strategy improves the qualified ratio of the OFIC and the quality of the goethite precipitate. More profit is created to the iron removal process after our strategy is applied.

СКЛАД І ВЛАСТИВОСТІ МІНЕРАЛЬНИХ НОВОУТВОРЕНЬ НА ФІЛЬТРАЦІЙНОМУ СУБСТРАТІ ПРИ ОЧИЩЕННІ ПІДЗЕМНИХ ВОД ВІД ЗАЛІЗА І МАРГАНЦЮ

Purpose. To determine composition and properties of iron-manganese crusts formed on grainy filtration load granules surface in the process of underground waters cleaning from Fe2+ and Mn2+, and to determine the application limits and perspective trends of the offered water preparation technology development, conditioned by the properties of these crusts. Method. For the analysis of physical and chemical properties of iron-manganese crusts analytical methods are used on the base of leaching and determination of iron and manganese content in solution and for more precise definition of crust qualitative composition an X-ray fluorescent photography spectrometry is used. For determination of crystalline structure an X-ray photography diffractometry was used, and the thickness of film was determined by mechanical micrometry. Processing of the received information and graphic interpretation of data is executed with application of LibreOffice Cacl, Gnumeric and PSPP software. Results. Determined physicochemical characteristics of iron-manganese crust formed on granules surface of grainy filtration load, the metrical sizes of film are determined: thickness and mass, analytically determined by lixiviating contents of iron and manganese in a crust. Manganites, that form a crust, are dispersion characterized; on some occasion considerable amount of roentgenoamorphous phase is formed, and in other - a crystalline form predominates as todorokite. In our opinion, it is determined by correlation of Mn/Fe concentrations in initial water. Results of crust measuring on the granules of filtration load on the water treatment station in town of Uzin is the following: thickness 0,518±0,209 mm; mass 0,0039±0,0004 g, manganese contents and total iron, accordingly, 115,59±4,33 mg/dm3 and 55,33±30,85 mg/dm3. Manganese and iron contents, which were lixiviated from the crusts of filtration load on the water treatment station in Chervona Sloboda village, accordingly: 55,067±10,946 mg/dm3; 100,476±4,284 mg/dm3. Scientific novelty. Firstly possibility of forming catalytic crust (film) from iron-manganese compositions on the filtration load surface is experimentally proved, among those compositions there are higher oxides of manganese in considerable volumes. Having determined their crystalline and chemical structure, it was proved that they provide the effective removal of iron and manganese over the norm contents from water and in a perspective can be used for the removal of a number of low valency cations among which the removal of Ñà2+ and Âr2+ is experimentally confirmed. Practical significance. Based on the known geobiochemical cycles of iron and manganese a new water treatment technology and also a new filter material with considerable potential of subsequent improvement and application are gotten, unlike classic technologies of manganese removal this method does not require bringing in additional reagents at Mn(II) → Mn(IV) oxidation.

Immobilization of iron- and manganese-oxidizing bacteria with a biofilm-forming bacterium for the effective removal of iron and manganese from groundwater

In this study, three bacteria with high Fe- and Mn-oxidizing capabilities were isolated from groundwater well sludge and identified as Acinetobacter sp., Bacillus megaterium and Sphingobacterium sp. The maximum removal ratios of Fe and Mn (99.75% and 96.69%) were obtained by an optimal combination of the bacteria at a temperature of 20.15°C, pH 7.09 and an inoculum size of 2.08%. Four lab-scale biofilters were tested in parallel for the removal of iron and manganese ions from groundwater. The results indicated that the Fe/Mn removal ratios of biofilter R4, which was inoculated with iron- and manganese-oxidizing bacteria and a biofilm-forming bacterium, were approximately 95% for each metal during continuous operation and were better than the other biofilters. This study demonstrated that the biofilm-forming bacterium could promote the immobilization of the iron- and manganese-oxidizing bacteria on the biofilters and enhance the removal efficiency of iron and manganese ions from groundwater.

Chitosan—The Application of a Natural Polymer against Iron Hydroxide Deposition

As a consequence of mining, heavy metal ions can be exposed to the environment hence contaminate ground water and surface water amongst others. The natural polymer chitosan was proved to be an excellent adsorber material for the effective removal of iron and sulfate ions in batch as well as in column experiments. The adsorption behavior of iron ions, as well as sulfate ions was investigated by utilizing chitosan flakes as a natural adsorbent. The removal was studied using adsorbance measurements, SEM and SEM-EDX. The adsorption capacity of chitosan was determined at different times. The received adsorption capacities for iron ions were very promising with a maximum adsorption capacity of 85 mg/g and a rate of separation of 100%. The maximum adsorption capacity obtained for sulfate ions was 188.8 mg/g and a rate of 80%.

Nano-ZnO-loaded poly (acrylamide-co-itaconic acid) hydrogel as adsorbent for effective removal of iron from contaminated water

The present research focuses on the adsorptive efficiency of nano-ZnO-loaded poly (acrylamide-co-itaconic acid) hydrogel for iron removal from synthetic as well as contaminated water by batch and column adsorption techniques. The influence of pH, contact time, adsorbent dose, temperature, and metal ion concentration on the sensitivity of the removal process was inspected. The copolymer was synthesized and nano-ZnO particles were incorporated within the polymeric matrix by in situ technique. The size, structure, and coating of nano-ZnO particles were characterized by TEM, SEM, Fourier transform infrared spectroscopy, and AFM analysis, respectively. The sorption data were analyzed and fitted to linearized adsorption isotherm of the Langmuir, Freundlich, and Temkin equations, respectively. Equilibrium data fitted very well to the Freundlich model. The kinetics of sorption was analyzed using pseudo-first-order and pseudo-second-order kinetic models. Kinetic parameters, rate constants, equilibrium sorption capacities, and related correlation coefficients for each kinetic model were calculated. Different thermodynamic parameters, i.e. ΔG°, ΔH° and ΔS° were also evaluated which proved the sorption to be feasible, spontaneous, and exothermic in nature. This hydrogel has been found to be an efficient adsorbent for iron removal from water (>99% removal) and could be regenerated efficiently for further experiments.

Long Term Efficacy Of Iron Chelation Therapy With Deferasirox On Endocrine Function In Thalassemia Major

Although the heart and liver have traditionally been the organs of interest for iron-related complications in Thalassemia Major (TM), endocrine disorders are common and carry significant morbidity. This is thought to result from iron accumulation in multiple organs functioning as part of endocrine systems. Deferasirox chelation therapy is well tolerated in TM and reduces iron burden effectively in the heart and liver. The impact of deferasirox on endocrine parameters remains unclear. The aim of this study was to examine the long-term efficacy of deferasirox for both the prevention of endocrine dysfunction in patients free of endocrine complications, and in improving endocrine parameters in those with pre-existing endocrine disorders.This was a multicentre retrospective cohort study of TM patients over 2 years of age receiving chelation treatment with once daily oral deferasirox monotherapy. Data on relevant clinical and laboratory parameters, including glycaemia, bone mineral density (BMD) z-scores, and testing of the pituitary, gonadal, thyroid and adrenal axes were collected at baseline and follow-up. Dosing regimens were titrated according to standard practice and only patients treated for at least 3 years were included in the present analysis. Data are presented as mean with standard deviation unless otherwise stated. Statistical comparisons were made using paired t-tests for continuous data, and chi-square test or Fisher's exact test to compare categorical data distributions.A total of 72 patients (69% female) with a mean age 26 ± 15 years were included. Mean duration of exposure to deferasirox was 6.9 ± 2.7 years with a mean daily dose of 25 ± 5 mg/kg. Myocardial T2* significantly increased from baseline to follow up (29.30 ± 10.29ms vs. 33.5 ± 13.06ms, P=0.01), signifying effective removal of iron from the heart. Among patients free of thyroid dysfunction at baseline, we observed no significant difference in mean TSH (2.10 ± 1.00 mi/u/ml vs. 2.28 ± 1.06 mi/u/ml, P=0.23 ), FT4 (6.89 ± 4.50 ng/ml vs. 7.10 ± 4.71 ng/ml, P=0.34) or FT3 (2.87 ± 1.16 pg/ml vs. 3.00 ± 0.58 pg/ml, P=0.35) during the study period. Of 9 patients with biochemical hypothyroidism at baseline, including 4 receiving thyroxine, we observed no significant change in thyroid function tests or thyroxine requirements. Two new incidences of subclinical hypothyroidism were noted. Among patients free of diabetes mellitus at baseline, we observed no significant variation in blood glucose measurements (pooled over 3 consecutive readings) at the end of treatment (88.62 ± 10.53 mg/dl vs. 88.36 ± 9.35 mg/dl, P=0.83). There was 1 incidence of type 2 diabetes during the study period. No significant difference was seen in blood sugar control or insulin requirements between baseline and end of treatment in patients with type 1 diabetes. Excluding normal pre-pubertal paediatric patients, there was no significant increase in the prevalence of hypogonadism between baseline and the end of study, 21 patients (38%) vs. 24 (44%) were diagnosed with hypogonadism respectively (P=0.56). Biochemical indices of bone metabolism showed no significant difference in calcium levels or vitamin D from baseline to follow up. BMD was improved from baseline to follow-up, with normal Z scores in 7 (20%) patients, 20 (57%) osteopenic, and 8 (23%) osteoporotic, compared with 7 (20%), 24 (69%), and 4 (11%) at end of treatment, respectively. Adverse effects were infrequent and of low grade, effecting 7 (9.7%) patients.Endocrine disorders are common sequelae of iron overload in patients with TM, and follow an insidious course of progressive dysfunction. We report infrequent development and progression of endocrine abnormalities, and significant improvement in bone density in TM patients treated with deferasirox over a 7-year follow-up period. In comparison with the incidence of complications from other studies of TM, deferasirox appears effective in reducing risk of developing endocrine disorders. Increasing myocardial T2* values confirmed effective removal of iron from the heart. Although multiple biological pathways are likely responsible, reduction in global iron alleviating siderosis of endocrine organs may be responsible for preserved function and bone mineral metabolism. Our study suggests that chelation therapy with deferasirox may prevent endocrine complications in patients with TM and prevent progression in those with established abnormalities Disclosures:Silverio:Novartis: Consultancy, Research Funding.

The Proceedings Of The 19Th International Conference On Chelation Held In London, United Kingdom: Major Changes In Iron Chelation Therapy In The Last 25 Years Using Deferiprone (L1) Has Resulted In The Complete Treatment Of Iron Overload

Major advances were presented at the 19th International Conference on Chelation (ICOC) in London, UK including changes in iron chelation therapy that led to the complete treatment of transfusional iron overload. The first oral iron chelation results in animals using deferiprone (L1) were published in 1985, and effective iron removal in thalassemia and myelodysplasia patients were reported 2 years later. The results of multicenter clinical trials of L1 were presented at the 1st ICOC in London, UK in 1989. Long-term use of L1 resulted in the reduction of the mortality rate in thalassemia patients due to the effective removal of all excess iron from the heart. In 2008, specific combinations of L1 and deferoxamine (DFO) were reported to cause the complete removal of excess iron load and the achievement of normal range body iron store levels (NRBISL) in thalassemia patients. Patients with NRBISL were identified to require lower doses of L1 for the maintenance of negative iron balance. The introduction of deferasirox (DFRA) may benefit patients not tolerating L1, DFO or their combination. A simple, inexpensive synthesis of L1 has encouraged its manufacture in developing countries for the benefit of patients who could not afford the expensive imported chelating drugs or formulations.

Control of Iron and Manganese Ozone Removal by Differential Turbidity Measurements

A new method for continuous monitoring of ozone concentration and the effective removal of iron and manganese was tested. The offered alternative to the ORP system was comprised of two self-cleaning turbidimeters. The turbidimeters were installed at the same locations as the ORP sensors and initial calibration test was performed with different ozone dosage. The conducted long term monitoring study showed stable performance of the differential turbidity system. The system confirmed the continuous and desired result of increased turbidity immediately after oxidation of the unwanted iron and manganese species. Therefore, the method can be expanded to other similar applications involving ozone.

Introduction of higher doses of deferasirox: better efficacy but not effective iron removal from the heart and increased risks of serious toxicities

Importance of the field: Thousands of iron loaded patients are using deferasirox, who are not aware of the new, fatal and irreversible serious toxic side effects, the need for prophylaxis and the availability of more effective and less toxic chelation therapies.Areas covered in this review: Updating on efficacy issues in relation to the introduction of higher deferasirox doses and comparison to existing chelation therapies. A new maximum dose of 40 mg/kg/day has been introduced for deferasirox in an attempt to achieve negative iron balance in thalassemia and other transfused iron loaded patients. A marginal increase in cardiac iron removal using doses of 30 – 40 mg/kg/day suggests that the rate of iron removal by deferasirox is insufficient by comparison to the deferiprone/deferoxamine combination, where total and rapid clearance of excess cardiac iron and normalization of the body iron stores could be achieved.What the reader will gain: Identification of drug interactions and new fatal and permanent toxic side effects of deferasirox and implications on efficacy, toxicity and cost of using higher doses. Deferasirox has been identified to cause fatal gastrointestinal hemorrhages, renal tubulopathy, hepatic and renal failure, alopecia and anaphylactic reactions in addition to previously reported fatal or serious toxic side effects such as agranulocytosis, renal and hepatic toxicity, skin rash and gastric intolerance. Interactions with UDP-glucuronosyl transferase inducers, CYP2C8 and CYP3A4 substrates and drugs affecting enterohepatic recycling are likely to affect deferasirox's efficacy and toxicity. Increased toxicity is expected from the use of higher doses of deferasirox and regular prophylactic monitoring is required to avoid fatal and permanent toxicity incidences. The increased costs from higher doses of deferasirox will mostly affect patients living in the developing countries.Take home message: Only few patients may benefit from the introduction of higher doses of deferasirox. There is a need for introducing more effective prophylactic measures. Safer, more effective and less costly chelation treatments are available using deferiprone, deferoxamine and their combination.

Subsurface iron and arsenic removal for shallow tube well drinking water supply in rural Bangladesh

Subsurface iron and arsenic removal has the potential to be a cost-effective technology to provide safe drinking water in rural decentralized applications, using existing shallow tube wells. A community-scale test facility in Bangladesh was constructed for injection of aerated water (∼1 m 3) into an anoxic aquifer with elevated iron (0.27 mmol L −1) and arsenic (0.27 μmol L −1) concentrations. The injection (oxidation) and abstraction (adsorption) cycles were monitored at the test facility and simultaneously simulated in the laboratory with anoxic column experiments. Dimensionless retardation factors ( R) were determined to represent the delayed arrival of iron or arsenic in the well compared to the original groundwater. At the test facility the iron removal efficacies increased after every injection-abstraction cycle, with retardation factors ( R Fe) up to 17. These high removal efficacies could not be explained by the theory of adsorptive-catalytic oxidation, and therefore other ((a)biotic or transport) processes have contributed to the system’s efficacy. This finding was confirmed in the anoxic column experiments, since the mechanism of adsorptive-catalytic oxidation dominated in the columns and iron removal efficacies did not increase with every cycle (stable at R Fe = ∼8). R As did not increase after multiple cycles, it remained stable around 2, illustrating that the process which is responsible for the effective iron removal did not promote the co-removal of arsenic. The columns showed that subsurface arsenic removal was an adsorptive process and only the freshly oxidized adsorbed iron was available for the co-adsorption of arsenic. This indicates that arsenic adsorption during subsurface treatment is controlled by the amount of adsorbed iron that is oxidized, and not by the amount of removed iron. For operational purposes this is an important finding, since apparently the oxygen concentration of the injection water does not control the subsurface arsenic removal, but rather the injection volume. Additionally, no relation has been observed in this study between the amount of removed arsenic at different molar Fe:As ratios (28, 63, and 103) of the groundwater. It is proposed that the removal of arsenic was limited by the presence of other anions, such as phosphate, competing for the same adsorption sites.

Patients with Chronic Hepatitis C May be More Sensitive to Iron Hepatotoxicity than Patients with HFE-Hemochromatosis

In chronic hepatitis C, iron might play an important role as a hepatotoxic co-factor. Therefore, venesection, a standard treatment for hemochromatosis, has been proposed as an alternative for patients who respond poorly to anti-viral therapy. To improve our understanding of iron-induced hepatotoxicity, we compared the responses to venesection between patients with chronic hepatitis C and those with HFE-hemochromatosis. Fourteen Japanese patients with chronic hepatitis C and eight Italian patients with HFE-hemochromatosis underwent repeated venesection with a serum ferritin endpoint of 20 and 50 ng/mL, respectively. Serum iron indices and liver function tests were measured in pre- and post treatment blood samples from each patient. Body iron stores were calculated using the removed blood volume. In both patients with hepatitis and hemochromatosis, serum ferritin, aminotransferase and hepcidin 25 were reduced after venesection. The serum aminotransferase activity, but not the serum ferritin level, was predictive of effective iron removal treatment. Hepcidin regulation was set at an inappropriately low level in hemochromatosis patients (11.1 ± 9.2 ng/mL), but not so in hepatitis patients (30.7 ± 14.5 ng/mL). Inversely, the estimated body iron stores of hemochromatosis patients were 5,960 ± 2,750 mg, while those of hepatitis patients were 730 ± 560 mg. Judging from the liver enzyme reduction ratio, patients with hepatitis seemed to be more sensitive to iron hepatotoxicity than hemochromatosis patients. Even though the threshold of iron hepatotoxicity and benefit of its removal differ between patients with chronic hepatitis C and those with HFE-hemochromatosis, venesection is a valid choice of treatment to reduce liver disease activity in both diseases.

Determination of Hydraulic Residence Times in Several UK Mine Water Treatment Systems and their Relationship to Iron Removal

In the UK, the Coal Authority has more than 40 mine water treatment systems, most of which are wetland systems with settlement lagoon pretreatment. The purpose of treatment in wetlands is the oxidation of ferrous to ferric iron and the subsequent hydrolysis and precipitation of ferric hydroxide within the wetland. It is generally accepted (Hedin et al., Passive treatment of coal mine drainage, 1994, p 35; Skousen and Ziemkiewicz, Acid mine drainage control and treatment, 1996, p 362; Younger et al., Mine water: hydrology, pollution, remediation, 2002, p 442) that this process proceeds by a first-order rate law, although most systems are designed based on an areal removal rate (10 g/m2/day) developed by the U.S. Bureau of Mines (Hedin et al., Passive treatment of coal mine drainage, 1994, p 35); this design guideline inherently assumes a constant removal rate. Given the actual kinetics of iron removal in wetlands, it follows that residence time will control iron removal; given the wide range of system geometries and aspects, it is logical to ascertain the actual hydraulic residence time of wetlands and settlement lagoons and determine the effect this has on iron removal. To make a preliminary assessment of this link, hydraulic residence time of two Coal Authority wetlands (Lambley and Whittle) and two Coal Authority settlement lagoons (Acomb East, Acomb West and Whittle) were measured using bromide tracer tests. Water samples for iron analysis and flow measurements were taken during each tracer test. The Lambley wetland performs well in terms of residence time, and, as reeds become established and adsorptive processes increase, its iron removal performance (currently 58% removal) may improve, but the low influent iron concentration appears to be a significant impediment to meeting the original performance target. In contrast, the hydraulic performance of the Whittle wetland system is poor, which appears to be due to accumulation of dead plant material coupled with a high length to width ratio. However, performance in terms of iron removal is good (92% removal), which appears to be due to the higher influent iron concentration, and especially the fact that the iron enters the wetland largely in particulate form. The longer residence time of water within the Acomb lagoons (≈12 h) resulted in far more effective iron removal (72% in the east lagoon and 85% in the west lagoon) than the shorter residence time at Whittle (24% iron removal, ≈5 h residence time). Performance (in terms of iron removal) of the settlement lagoon systems appears to be far more closely related to the hydraulic residence time (albeit this conclusion must be tentative, given that only three systems have been investigated, and the Acomb system receives chemical addition). Based on this study, treatment system sizing using 100 m2 lagoon area per 1 L/s flow appears to be a more appropriate basis for design rather than an areal iron removal rate.

Sustained Protection from Labile Plasma Iron (LPI) with the Once-Daily, Oral Iron Chelator Deferasirox (Exjade®, ICL670) in Iron-Overloaded β-Thalassemia Patients.

Excess iron leads to the appearance of NTBI in the blood, which has been hypothesized to increase the risk for developing co-morbidities. LPI, one form of NTBI, is redox-active and can produce harmful reactive oxygen species. LPI is readily taken up by cells, resulting in expansion of the cellular iron pool. As LPI is produced 24 hours per day, the constant presence of an iron chelator in the plasma may help avoid accumulation of excess iron. Due to its long t½, clinically significant levels of deferasirox are present in the plasma for 24 hours following once-daily administration. This 1-year substudy has evaluated whether deferasirox treatment produced a sustained reduction in LPI.LPI, liver iron concentration (LIC; by biopsy) and serum ferritin (SF) levels over 1 year of treatment with deferasirox 20–30 mg/kg/day have been analyzed in a subgroup of 14 β-thalassemia patients from the ESCALATOR trial, all of whom had previously received DFO/deferiprone combination therapy. Blood samples for LPI and PK assessments were taken pre dose (predicted LPI daily peak) and 2 hours post dose (predicted daily LPI nadir), at baseline and following repeat dosing at weeks 4, 16, 28, 40 and 52. Efficacy and safety were assessed monthly, primarily by evaluating SF and the incidence and type of adverse events (AEs). LIC was measured at baseline and study end.The subgroup comprised 6 males and 8 females with a mean age of 17.5 years (range 12–27). Mean baseline iron parameters were: LPI 0.99 ± 0.82 μmol/L, LIC 28.6 ± 10.3 mg Fe/g dw, SF 7122 ± 3282 ng/mL. Baseline LPI levels were well correlated with LIC (R=0.66). Median deferasirox dose was 27.5 mg/kg/day. Mean steady-state deferasirox trough plasma levels at week 4 were 22.4 ± 18.5 μM (pre dose). Significant LPI reductions were observed post versus pre dose at baseline and week 4 (P<0.0001 and P=0.0077, respectively; Table). Pre dose LPI levels were close to normal (0–0.4 μmol/L) by week 4, and within the normal range by week 16 and thereafter throughout the study.LPI, pre and post deferasirox dose (corresponding to nadir and Cmax, respectively), at baseline and after repeat doses*LPI, μmol/LWeekMean ± SDBaseline vs repeat preBaselinePre0.99 ± 0.82Post0.12 ± 0.164Pre0.45 ± 0.58P=0.0735Post0.08 ± 0.2016Pre0.21 ± 0.27P=0.0015Post0.02 ± 0.0628Pre0.15 ± 0.18P=0.0006Post0.04 ± 0.0540†Pre0.11 ± 0.15P=0.0007Post0.30 ± 0.3652‡Pre0.27 ± 0.74P=0.0070Post0.08 ± 0.21*As 1 pt died between wks 4–16, LPI data are taken from 13 pts, except †n=11 and ‡n=12 due to lost samplesDuring the study, LIC decreased by 6.8 ± 6.2 mg Fe/g dw, while SF decreased by 752 ± 1500 ng/mL. Deferasirox treatment was well tolerated, with no discontinuations due to AEs. The most common AEs were mild nausea (n=4) and vomiting (n=3).Conclusions: Despite a high baseline iron burden in these patients, these results highlight the ability of once-daily deferasirox 20–30 mg/kg/day to reduce levels of toxic LPI and maintain them within normal limits. Deferasirox daily trough levels were within the therapeutic range, demonstrating constant 24-hour chelation coverage. Decreases in LPI were accompanied by decreases in mean LIC and SF, indicating effective iron removal by deferasirox.