Iron By-products Research Articles

Efficiency of fenton oxidation and membrane hybrid processes for paracetamol removal in seawater

Traces of Paracetamol (PCT) as a micropollutant in the environment, particularly in seawater (SW), have become a global concern in recent years due to the toxicity effect on humans and environment. Due to special characteristics, conventional wastewater treatment plants are able to degrade PCT partially. Therefore, an alternative treatment was necessary to treat PCT substance. Homogeneous Fenton oxidation is an efficient process to degrade PCT at various levels. Nevertheless, separation of dissolved iron by-products in the effluent caused a problem. Combination of Fenton oxidation and ultrafiltration treatment presents a promising opportunity as one of the alternative treatments for PCT removal across aqueous matrices and removal of iron residue. Despite promising, information related to combine Fenton and membrane process was lacking. Therefore, this study aims to evaluate the efficiency of the hybrid processes to remove PCT, represented in Chemical Oxygen Demand (COD), for both distilled water (DW) and seawater. In this study, crucial parameter Fenton’s reagent with H2O2/Fe2+ ratio (w/w) was observed. In the DW matrix, optimal 1:0.5 ratio resulted 45% COD removal, whereas 1 :1 ratio exhibited 37% COD removal in SW. Flat sheet Polyethersulfone (PES) with pore size of 30 nm and 7 nm (50 kDa) membrane was employed with a constant flux of 120 L/m²·h. A lack of contribution of COD removal in DW and 37% in SW was observed during the ultrafiltration process, respectively. Furthermore, 54% and 92% removal of Fe2+ residue was observed during ultrafiltration at adjusted pH 8.5 in both water matrices using different membrane pore sizes, respectively.

Adding iron shavings in activated sludge system to enhance removal of refractory organics and nitrogen for textile-dyeing wastewater

To improve the biodegradability of textile-dyeing wastewater, reduce the biotoxicity of refractory pollutants to activated sludge, and enhance the removal of refractory organics and nitrogen for wastewater. A new coupled system of adding iron shavings in activated sludge was developed for the treatment of textile-dyeing wastewater. The results showed that the average removal efficiencies of chemical oxygen demand and total nitrogen in the coupled system reached 74.9% and 55.0%, respectively. On day 60, the mean granular size and sludge volume index after 30 min of the coupled system reached 206 µm and 24 mL/g, respectively, and aerobic granular sludge was formed. The microbial community structure and function in the system was changed, especially the increase of autotrophic denitrifiers (Hydrogenophaga, Xanthobacter, and Unclassified_f_Comamonadaceae), hydrolytic acidification bacterias (Ottowia and Limnobacter), which enhanced the performance of simultaneous nitrification and denitrification. The monitoring of different periods showed that the specific oxygen uptake rate associated with ammonia oxidation and heterotrophic bacteria in the coupled system was significantly higher than that in the control group, which indicated that iron shavings act as a detoxification function in refractory wastewater. In addition, the iron content of the sludge in the coupled system was 9.6% higher than that of the control group. These iron by-products were good flocculants, and have a significant performance of the adsorption for pollutants. Furthermore, the mechanism of synergistic treatment of wastewater by the coupled system was proposed.

Phosphorus removal with zero-valent iron: Fixed-bed experiments with long-term monitoring and solid analysis

Zero Valent Iron (ZVI) is considered a good media for contaminant removal in wastewater. Through batches and fixed-bed experiments, phosphate (P) removal performances of iron-based materials were studied. Three iron-based materials, with various grain sizes and compositions, were selected to fill columns in a reactive mix with sand, with two ratios (1 % and 10 % iron). After 300 days, the columns were dismantled and solid analyses performed on the remaining media. Over 50 % P retention was observed for the 1 % ZVI/sand ratio reactors for longer than 6 months. For the 10 % ratio, better performances were attained over a longer lifetime (above 70 % for 7 months). The P distribution was heterogeneous along the column since the activation of the layers were gradually influenced by both oxygen and P concentrations. Solid analyses showed that P was mostly bound to amorphous iron oxides (55 %), with a small percentage being linked to crystalline iron byproducts (10 %). >10 % of P was retained by calcium, highlighting its contribution to P scavenging. In considering the influence of these major parameters, an overview of P removal mechanisms through a continuous upflow fixed-bed was then proposed, that could be helpful for future P treatment reactor's design.

Printability and physical properties of iron slag powder composites using material extrusion-based 3D printing

There have been many studies on three-dimensional (3D) printing using metal compounds. However, 3D printing using a metal compound has disadvantages in that it increases the cost for supplying metal materials. A method of using slag which is a recyclable material has been proposed to reduce costs. With the growing demand for additive manufacturing using by-products, slag has gained attention as a diverse recycling material for 3D printing technologies. A new fabrication approach was analyzed for producing porous bodies via additive manufacturing for blending slag and reinforced metals. However, because of its low quality due to low strength, low durability, and structural defeats, the amount of slag generated is high, and its usability remains uncertain. Also, slag is an excellent material with a huge potential for producing structures with high mechanical properties, and limited research in the area of slag recycling has been conducted due to difficulties in sintering the iron by-products. To develop a recycling approach that utilizes slag in 3D printing powders, a study to increase the industrial usability by mixing slag and ceramic beads was described. A method was presented to compare the physical properties of 3D printed slag parts with the physical properties of those generated by blending iron slag, alumina, and zirconia. In order to find the mixing ratio with the optimum physical properties, the average particle size, bending stress, and maximum compressive stress were tested. The combination ratio to obtain the highest strength was when iron slag powder was 40% and alumina was 60%. In addition, the specimens by composition to which the stress test was applied were cut to analyze the tissue under a microscope. It is thought that cracking in the sintered structure decreases and density increases by mixing alumina and zirconium, contributing to increased strength. When a ceramic bead composed of alumina and zirconium is mixed with slag to form a composite material, a metal compound having a level of physical properties that can be used as a material for 3D printing can be produced. Furthermore, a novel concept of producing lightweight structural materials via additive manufacturing, which entails a fabrication process whereby high-strength metals are stacked inside hollow base steels, was proposed.

Nutrient Removal Structures Using Locally-Sourced Iron and Aluminum By-Products Reduce Nutrient Runoff from Broiler Production Facilities

A common issue with filters designed to remove nutrients from runoff is their reduced effectiveness in high-flow conditions. To overcome this challenge, it was determined that nutrient removal from broiler-house fan dust could be more effective if nutrient removal was conducted at the nutrient source. The objective of this study was to evaluate the effectiveness of containment trays (CTs) holding locally sourced by-products installed adjacent to broiler house fans at the University of Arkansas Savoy broiler production facility to capture nutrients released from dust during rainfall over four years (2013 to 2017). By-products used were locally sourced, iron-based red mud (RM) generated during the manufacture of steel belts for tires and alum-based drinking water treatment residual (WTR), where both materials have large phosphorus (P) sorption capacities. Four-year mean annual concentrations of dissolved P of through-flow from RM CTs were consistently below 0.7 mg·L-1 and below 1.6 mg·L-1 for WTR CT through-flow. This equated to an average 11- and 4-fold decrease for RM and WTR, relative to concentrations in runoff from same-sized plots adjacent to sidewall fans, demonstrating their potential to trap P at the source and decrease P runoff to nearby flowing waters. While there was no significant decline in RM or WTR effective-ness over the four-year study, further work needs to be conducted to determine the lifespan of CTs. Use of RM and WTR in CTs at poultry broiler production facilities, along with their subsequent land application, has the potential to reduce the amount of by-product materials that are currently landfilled.

Abstract 848: The Iron Chelator Deferiprone Clears Hemorrhagic Byproducts Following Acute Myocardial Infarction in a Swine Model of Ischemia-Reperfusion

Current treatments for myocardial infarction (MI) aim to remove the vascular occlusion and reperfuse the infarcted tissue. While reperfusion can salvage myocardium, it can also increase damage to the unsalvageable tissue, one mechanism of which is hemorrhage; the resulting blood and iron deposits increase edema and inflammation. We hypothesize that removing these iron deposits with the iron chelating drug deferiprone (DFP) will reduce inflammation and lead to faster healing post-MI. Using a swine model of ischemia-reperfusion, pigs were administered either DFP or saline for four weeks post-MI. Cardiac MRI tracked heart function, infarct progression (via late gadolinium enhancement), hemorrhage (via T2* imaging), and edema (via T2 imaging) at baseline and 1 day, 1 week, and 4 weeks post-MI. Animals were then sacrificed and hearts were processed for histology. Treatment with DFP decreased the presence of iron in the infarct compared to saline by one week post-MI, as shown by increased T2* values. DFP treatment also decreased end diastolic wall swelling, suggesting less inflammation post-MI. To support this, T2 values and histology both revealed trends toward less edema with DFP. Histology also showed trended increases in fibroblast proliferation and collagen deposition at four weeks post-MI in the treatment group, consistent with a faster resolution to scar. Ventricular remodeling (by ventricular volumes), infarct size (by MRI, histology and blood Troponin I levels), and infarct transmurality were all unaffected, but contractile function improved with DFP treatment: ejection fraction and wall thickening both improved faster. In conclusion, DFP treatment successfully reduced hemorrhagic iron within the infarct as compared to saline, indicating a clearing of the iron byproducts. Treatment also decreased wall swelling, suggesting reduced inflammation, and improved contractile function. In the infarct, reduced swelling could indicate faster remodeling and a faster resolution to scar, and histology confirms a more progressed scar structure with DFP treatment. Overall, iron chelation appears to be a promising therapy that could reduce the negative effects of hemorrhage and speed the functional recovery of patients post-MI.

Degradation of bis-p-nitrophenyl phosphate using zero-valent iron nanoparticles

Phosphate esters are employed in some agrochemical formulations and have long life time in the Environment. They are neurotoxic to mammals and it is very difficult to hydrolyze them. It is easy to find papers in the literature dealing with transition metal complexes used in the hydrolysis processes of organophosphorous compounds. However, there are few reports related with degradation of phosphate esters with inorganic nanoparticles. In this work bis-4-nitrophenyl phosphate (BNPP) was used as an agrochemical agent model. The BNPP interaction with zero-valent iron nanoparticles (ZVI NPs), in aqueous media, was searched. The concentration of BNPP was 1000 times higher than the ZVI NPs concentration. The average size of the used iron nanoparticles was 10.2 ± 3.2 nm. The BNPP degradation process was monitored by means of UV-visible method. Initially, the BNPP hydrolysis happens through the P-O bonds breaking-off under the action of the ZVI NPs. Subsequently, the nitro groups were reduced to amine groups. The overall process takes place in 10 minutes. The reaction products were identified employing standard substances in adequate concentrations. The iron by-products were isolated and characterized by X-RD. These iron derivatives were identified as magnetite (Fe3O4) and/or maghemite (γ-Fe2O3) and lepidocrocite (γ-FeOOH). A suggested BNPP degradation mechanism will be discussed.

Locally Sourced Iron and Aluminum Byproducts Decrease Phosphorus Leached from Broiler House Dust Deposited near Ventilation Fans

Freshwater impairment by eutrophication, as a result of excessive phosphorus (P) inputs from runoff in particular, remains a ubiquitous environmental concern. A common issue with systems designed to remove P and nitrogen (N) from runoff is their reduced effectiveness under high-flow conditions. To over-come this, P removal from broiler-house fan dust would be more effective if removal occurred at the nutrient source, where the water volume is limited to direct rainfall. The P removal efficiencies of different thicknesses of locally sourced, iron-rich red mud (RM) generated during the manufacture of steel belts for tires and alum-based drinking water treatment residual (WT) byproducts were investigated. Byproduct thicknesses of 4, 8, and 12 cm were tested using 57-L leaching columns. The columns were filled with the specified byproduct thickness and a 3-mm thickness of poultry house dust was surface applied prior to receiving six, 30-min simulated rainfalls (at 7 cm·hr-1) at 1-day intervals. The 8-cm thickness of both RM and WT outperformed the other thicknesses in terms of sorbing P released from the added broiler house dust, removing 99 and 96% of the added P, respectively, over the six simulated rainfall events. The 12-cm thickness of both RM and WT showed no additional benefit for P removal over the 8-cm thickness. As the 4-cm-thick WT treatment was less effective (89% of added P removed), the 8-cm thickness was the optimal thickness for field testing. Locally sourced materials with large P-sorbing capacities can offer a convenient, relatively inexpensive alternative for P removal from areas around poultry houses impacted by P-containing, exhausted broiler house dust.

Optimization of Sinter Plant Operating Conditions Using Advanced Multivariate Statistics: Intelligent Data Processing

Blast furnace operators expect to get sinter with homogenous and regular properties (chemical and mechanical), necessary to ensure regular blast furnace operation. Blends for sintering also include several iron by-products and other wastes that are obtained in different processes inside the steelworks. Due to their source, the availability of such materials is not always consistent, but their total production should be consumed in the sintering process, to both save money and recycle wastes. The main scope of this paper is to obtain the least expensive iron ore blend for the sintering process, which will provide suitable chemical and mechanical features for the homogeneous and regular operation of the blast furnace. The systematic use of statistical tools was employed to analyze historical data, including linear and partial correlations applied to the data and fuzzy clustering based on the Sugeno Fuzzy Inference System to establish relationships among the available variables.

Mapping of iron and steelwork by-products using close range hyperspectral imaging: A case study in Thuringia, Germany

This paper presents the first use of close range terrestrial hyperspectral imaging to explore by-products from the iron and steel industry at a dump site cross section, using established mapping approaches in geological remote sensing. Laboratory reflectance measurements, X-Ray diffraction and chemical analysis provided a benchmark for the imaging results. In addition, terrestrial laser scanning was applied to create a high resolution 3D model of the studied section, for hyperspectral image and classification integration. Results demonstrate the applicability of spectral methods for remote discrimination and mapping of materials from iron and steel production which are of potential economic interest. This will aid the appraisal of resource distribution for urban mining and material recycling.

The effect of iron-oxidising bacteria on the stability of gold (I) thiosulphate complex

An acidophilic, iron-oxidising bacterial consortium was collected from Rio Tinto near Berrocal, Spain. This primary enriched culture was used to examine the effect of acidophilic iron-oxidising bacteria on the stability of soluble gold (I) thiosulphate. Stationary phase cultures and separate components of the cultures (i.e., aqueous ferric iron, iron oxyhydroxide precipitates and non-mineralised bacterial cells) were exposed to gold (I) thiosulphate solutions forming different experimental-gold systems. These experimental systems rapidly removed gold from solutions containing 0.002mM–20mM gold thiosulphate. Scanning and transmission electron microscopy demonstrated that the different culture fractions immobilised gold differently: the entire bacterial culture-gold systems precipitated 100nm-size gold colloids; aqueous ferric iron–gold systems precipitated colloidal gold sulphide that ranged in diameter from 200nm to 2μm; iron oxyhydroxide-gold systems precipitated 5nm-size gold sulphide colloids; and the bacteria-gold systems precipitated gold colloids ~2nm in size along the bacterial cell envelope. Aqueous and solid ferric iron was critical in the destabilisation of the gold (I) thiosulphate complex. Analysis of the entire bacterial culture-, aqueous ferric iron- and iron oxyhydroxide-gold systems exposed to 2mM gold using X-ray absorption near edge spectroscopy demonstrated that Au+ was immobilised from solution as gold sulphide (Au2S). The reaction between iron-oxidising bacteria and their ferric iron by-products with gold (I) thiosulphate demonstrated that thiosulphate ions would be an unstable gold complexing ligand in nature. Gold (I) thiosulphate is intuitively transformed into nanometer-scale gold sulphide or elemental gold within natural, acidic weathering environments with the potential to precipitate gold in jarosite that can subsequently be preserved in gossans over geological time.

Adsorption of AsIII, AsV and dimethylarsinic acid onto synthesized lepidocrocite

The trapping of arsenic by zero valent iron is strongly dependant on iron by-products. Among these, lepidocrite has been scarcely studied. In this work, we studied the adsorption of two inorganic (AsIII, AsV) and one organic (dimethylarsinic acid, DMA) arsenic species onto lepidocrocite. pH influence was considered in the range 5 to 9, which corresponds to natural water pH. Langmuir model was used to simulate As adsorption isotherms. Our results showed that lepidocrocite offers high adsorption capacities: up to 0,25, 0,41 and 1 mol for AsV, DMA and AsIII could be respectively trapped per kilogram of zero-valent iron. pH influence varied from one arsenic species to another: increasing pH improve AsIII and DMA sorption whereas it has a very low effect on AsV sorption.

Production of magnesium hydroxide from magnesium silicate for the purpose of CO2 mineralization – Part 2: Mg extraction modeling and application to different Mg silicate rocks

Mineral carbonation of Mg silicates via a gas/solid carbonation of magnesium hydroxide, Mg(OH)2 in a fluidized bed (FB) reactor process route is the most actively investigated route of carbon capture and storage by CO2 mineralization (CCS) research in Finland. This paper reports Mg extraction behavior and production of magnesium hydroxide, Mg(OH)2 from different Mg-silicate rocks from worldwide locations (Finland, Lithuania, Australia and Norway). Magnesium hydroxide, the reactive material for gas/solid mineralization of CO2 can be produced from different Mg-silicate minerals via a staged solid/solid reaction with ammonium sulfate (AS) salt followed by precipitation in aqueous ammonia solution. A comparison is made for five different minerals. The kinetics of Mg extraction from Mg-silicate minerals and the possible effects of iron by-products on reactivity and kinetics were studied and modeled as well.

A field test of porous carbonated blocks used as artificial reef in seaweed beds of Ecklonia cava

Marine forests are the main primary producer in coastal waters, supplying food to fish and shellfish as well as providing their spawning and growing sites. It is important to conserve marine forest in order to protect coastal marine environments. A “Marine Block” comprised of steelmaking slag particles combined by CaCO3 has several merits: (1) solidification of CO2, (2) stability and safety, (3) porous materials covered with CaCO3, (4) harmony with the seabed environment, (5) recycling of iron by-products, and (6) the ability to be mass produced in coastal ironworks. The objectives of this study were to observe the algal succession, the growth of Ecklonia cava and other attached organisms on Marine Blocks and concrete blocks compared to natural seaweed beds. In November 2001, five 1 m3 Marine Blocks and five 1 m3 concrete blocks were installed close to E. cava beds around the coastal frontage of Jogashima at the mouth of Tokyo Bay. Scuba-diving observations were continued until April 2006. In the field, a large number of seaweed and animal species were observed on the Marine Blocks, and it was found that the speed of succession, the plant length and the wet weight of E. cava were greater on Marine Blocks than on concrete blocks. The main advantages of Marine Blocks are considered to be the recycling of steelmaking slag, the absorption and solidification of atmospheric CO2, and the conservation of coastal environments.

Remediation of DDT-Contaminated Water and Soil by Using Pretreated Iron Byproducts from the Automotive Industry

The objective of this study was to quantify the effectiveness of different pretreated iron byproducts from the automotive industry to degrade DDT [(1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane] in aqueous solutions and soil slurry. Iron byproducts from automotive manufacturing were pretreated by three different methods (heating, solvent and 0.5N HCl acid washing) prior to experimentation. All pretreated irons were used at 5% (wt v− 1) to treat 0.014 mM (5 mgL− 1) of DDT in aqueous solution. Among the pretreated irons, acid pretreated iron results in the fastest destruction rates, with a pseudo first-order degradation rate of 0.364 d− 1. By lowering the pH of the DDT aqueous solution from 9 to 3, destruction kinetic rates increase more than 20%. In addition, when DDT-contaminated soil slurry (3.54 mg kg− 1) was incubated with 5% (wt v− 1) acid-pretreated iron, more than 90% destruction of DDT was observed within 8 weeks. Moreover, DDT destruction kinetics were enhanced when Fe(II), Fe(III) or Al(III) sulfate salts were added to the soil slurry, with the following order of destruction kinetics: Al(III) sulfate > Fe(III) sulfate > Fe(II) sulfate. These results provide proof-of concept that inexpensive iron byproducts of the automotive industry can be used to remediate DDT-contaminated water and soil.

Using Low-Cost Iron Byproducts from Automotive Manufacturing to Remediate DDT

Water, soil and sediment contaminated with DDT poses a threat to the environment and human health. Previous studies have shown that zerovalent iron (ZVI) can effectively remediate water contaminated with pesticides like DDT, metolachlor, alachlor. Because the type of iron can significantly influence the efficiency and expense of ZVI technology, finding a cheaper and easily available iron source is one way of making this technology more affordable for field application. This study determined the effects of iron source, solution pH, and presence of Fe or Al salts on the destruction of DDT. Batch experiments demonstrated successful removal of DDT (>95% in 30 d) in aqueous solutions by three different iron sources with the following order of removal rates: untreated iron byproduct (1.524 d−1) > commercial ZVI (0.277 d−1) > surface-cleaned iron byproduct (0.157 d−1). DDT removal rate was greatest with the untreated iron byproduct because of its high carbon content resulted in high DDT adsorption. DDT destruction rate by surface-cleaned iron byproduct increased as the pH decreased from 9 to 3. Lowering solution pH removes Fe (III) passivating layers from the ZVI and makes it free for reductive transformations. By treating DDT aqueous solutions with surface-cleaned iron byproduct, the destruction kinetics of DDT were enhanced when Fe(II), Fe(III) or Al(III) salts were added, with the following order of destruction kinetics: Al(III) sulfate > Fe(III) sulfate > Fe(II) sulfate. Cost analysis showed that the cost for one kg of surface-cleaned iron byproduct was $12.33, which is less expensive than the commercial ZVI. Therefore, using surface-cleaned iron byproduct may be a viable alternative for remediating DDT-contaminated environments.

Gas-Phase Chlorination of Chalcopyrite

AbstractA significant prospect of a process such as the gas-phase chlorination of chalcopyrite is its flexibility both in accommodating a variable feed as well as in the recovery of copper, iron and other byproducts. Before the feasibility of the process can be examined, the rate of chlorination of chalcopyrite must be known. This study was directed toward an understanding of the reaction mechanisms and kinetics by measuring the rate of chlorination of chalcopyrite in powder and pellet form in a TGA system at 673–823 K and ambient pressure. The effects of gas concentration on the reaction of samples of various pellet sizes were studied. Reactions with powder as well as pellets were used to delineate the mechanism. SEM was used to examine the surface structure, element identification and distribution, while X-ray diffraction and wet chemistry aided in identification of the various reaction products. Results show that the reaction proceeds stepwise by chlorination of chalcopyrite to cuprous and ferrous chlo...