Ferrous Concentration Research Articles

Ferric Ion Diffusion for MOF-Polymer Composite with Internal Boundary Sinks.

Simple and economical ferric ion detection is necessary in many industries. An europium-based metal organic framework has selective sensing properties for solutions containing ferric ions and shows promise as a key component in a new sensor. We study an idealised sensor that consists of metal organic framework (MOF) crystals placed on a polymer surface. A two-dimensional diffusion model is used to predict the movement of ferric ions through the solution and polymer, and the ferric ion association to a MOF crystal at the boundary between the different media. A simplified one-dimensional model identifies the choice of appropriate values for the dimensionless parameters required to optimise the time for a MOF crystal to reach steady state. The model predicts that a large non-dimensional diffusion coefficient and an effective association with a small effective flux will reduce the time to steady-state. The effective dissociation is the most significant parameter to aid the estimation of the ferric ion concentration. This paper provides some theoretical insight for material scientists to optimise the design of a new ferric ion sensor.

Kinetic limitations of gold leaching in ferric chloride media Part II: Potentiodynamic polarization and electrochemical impedance spectroscopy

The gold industry is in search of an alternative to cyanidation due to its inefficiency in treating challenging ores and increasing public scrutiny of its effects on human health and the environment. Chloride has been used in the past for gold extraction and has been identified as a promising candidate to replace cyanide. The Part I of this research found that gold extraction plateaued under all leaching conditions relevant to heap leaching. The hypothesis was that the formation and accumulation of an intermediate, AuClads, on the gold surface passivated the surface as leaching progressed. The Part II of this research tested this hypothesis using potentiodynamic polarization and electrochemical impedance spectroscopy. The potentiodynamic polarization results show that the kinetics of gold dissolution was restricted by the cathodic reduction of ferric species when the ferric concentration was below 0.3 M; the anodic oxidation of gold was the rate-limiting step when the free chloride activity was low. The gold dissolution was faster in the presence of the monovalent salts. The electrochemical impedance spectroscopy analysis revealed that the low chloride activity allowed the accumulation of the adsorbed species on the gold electrode surface, thereby restricting the charge transfer process and hindering gold dissolution.

Kinetic limitations of gold leaching in ferric chloride media Part III: Comparison of kinetics in batch leaching and electrochemical studies

Extensive research efforts have been devoted to developing a technology capable of replacing cyanidation for gold extraction. Sponsored by Barrick Gold Corporation, we investigated the kinetic limitations of using ferric chloride for gold leaching under conditions relevant to heap leaching. The batch reactor studies (Part I) found that gold leaching plateaued in all leaching tests performed at 35 °C. In the subsequent electrochemical studies (Part II), it was found that the formation and adsorption of AuClads during leaching passivated the surface hindering gold dissolution. In Part III of this study, we compared the leaching kinetics obtained by the batch reactor and the electrochemical studies under the same conditions. This analysis helps understand the similarities and differences in the leaching kinetics and mechanisms obtained with the two techniques. A kinetic equation with surface passivation was derived that relates the batch leaching of gold to the concentrations of total ferric and total chloride. This model supported that the accumulation of adsorbed species, AuClads, led to the plateauing of the leaching curves. The reaction order with respect to the total ferric concentration approximated to the theoretical value of 0.5 for both techniques. However, the reaction order with respect to the total chloride concentration could vary between one and two, with one indicating the electrochemical step being rate-limiting and two indicating the solubilization step restricting the leaching process.

Kinetic limitations of gold leaching in ferric chloride media Part I: Batch reactor studies

The global gold industry is under increasing pressure to search for alternative technologies to replace cyanidation due to the inefficiency of cyanide in treating low grade refractory gold ores and increased public scrutiny on the use of cyanide in gold mining. Chloride has been identified as a promising candidate to replace cyanide. Despite extensive efforts to investigate gold leaching in chloride media, gold leaching in ferric chloride media at moderate temperatures relevant to heap leaching has not been well studied. Sponsored by Barrick Gold Corporation, we investigated the thermodynamics and kinetics of gold dissolution in ferric chloride media at moderate temperatures using batch leaching and electrochemical techniques. The Part I of this study reports the effects of four key process variables, initial ferric concentration, total chloride concentration, redox potential of the leaching solution, and the type of chloride salts, on the rate and extent of gold dissolution in ferric chloride media. A series of batch reactor leaching tests was carried out using pure gold as the model mineral. The experimental results showed that the leaching process was either under thermodynamic or kinetic control depending on the leaching conditions. The gold extraction increased with the initial ferric concentration up to 0.3 M, after which a negative effect was observed. This was thought to be caused by the transition from cathodic reduction of the oxidant controlling the kinetics to anodic oxidation of gold controlling the kinetics. Increasing total chloride concentration and the redox potential of the leaching solution also increased the gold extraction. Gold extraction was higher in the presence of the monovalent salts than in the presence of the divalent salts.

Treatment of arsenite contaminated water by electrochemically activated persulfate oxidation process

Arsenic pollution in the groundwater is a serious worldwide problem, where arsenite and arsenate are the most prevalent forms in groundwater. Most of the conventional methods are able to remove arsenate effectively as compared with arsenite. Hence, for complete elimination of arsenic, prior oxidation of arsenite to arsenate is needed. The present work assessed the possibility of electrochemically activated persulfate (PS) based advanced oxidation process (EAOP) for arsenite removal from the aqueous medium. EAOP using Pt/Ti as both anode and cathode, can completely oxidize arsenite with an initial concentration of 1 mg L-1 within 60 min of electrolysis at pH 3; ferrous ion concentration 250 mg L-1, persulfate concentration 500.

Green synthesis of fluorescent carbon dots from canon ball fruit for sensitive detection of Fe3+ and catalytic reduction of textile dyes

In this work, a simple, sustainable and economically feasible approach has been reported to synthesis Carbon Dots (CDs) by taking Canon Ball (CB) fruit as a bio-mass precursor. The properties of the synthesized CDs were analysed using various characterization techniques such as TEM, FTIR, PSA, Raman, UV–Visible and Fluorescence spectroscopy. The CDs have particle size of 11.2 nm, showed blue emission when exposing to UV light at wavelength of 365 nm and excitation dependent fluorescence behaviour with appreciable quantum yield of 7.01%. The synthesized CDs have excellent stability on exposure to different environments like pH, ionic concentrations and storage time. Further, it served as a probe for sensing Fe3+ ions selectively among different metal ions investigated. The Limit of Detection (LOD) was found to be 0.071 μM in the dynamic range of 0.6–3.3 μM of ferric ion concentration. Additionally, the CDs showed excellent catalytic activity in the treatment of two harmful textile dyes Azure B (AB) and Toluidine Blue (TB) via catalytic reduction with the assistance of NaBH4.

Green metallochromic cellulose dipstick for Fe(III) using chitosan nanoparticles and cyanidin-based natural anthocyanins red-cabbage extract

Environmentally-friendly, cyanidin(Cy)-based anthocyanin isolated from red-cabbage served as a spectroscopic probe imprinted onto chitosan nanoparticles (CsNPs), which were in turn integrated onto cellulose paper strip (CPS) as a host matrix to develop a metallochromic solid state sensor for real-time selective determination of ferric ions in an aqueous medium. The ferric transition metal ions in aqueous environments were detected using a novel, simple, portable, fast responsive, low-cost, real-time, environmentally safe, reversible and colorimetric sensor based on chitosan nanoparticles as a hosting biopolymer and cyanidin phenol chromophore as a biomolecular probe. In order to use the cyanidin biomolecule as a pH indicator and chelating agent, it was purified from red-cabbage and added into the CsNPs biosensor film. The colorimetric shift increased in direct proportion to the ferric ion concentration. As a result, the current research that was both qualitative and quantitative was carried out. While the Cy-CsNPs-CPS sensor showed high selectivity for ferric ions, no color change was detected for other metal cations. It was discovered that the detection process occurred as a result of a coordination complex formed between the active sites of phenolic cyanidin and Fe(III) ions.

Evidence of weak interaction between ferric iron and extracellular polymeric substances of Acidithiobacillus ferrooxidans

Although ferric iron in extracellular polymeric substances (EPS) was believed to be pivotal in bioleaching, the real existing form of ferric iron in EPS has remained poorly understood. In this study, whole cells of Acidithiobacillus ferrooxidans were used to study the composition and properties of EPS. The components sugars, proteins and uronic acids could be extracted from cells rich in EPS. Four distinct surface functional groups were characterized on the bacterial surfaces by the fitting of titration data. Subsequently, these functional groups were confirmed as carboxyl groups, phosphoryl groups, thiol groups, and amine groups by combining FTIR and XPS. However, with the help of modeling results and FTIR, these functional groups failed to dissociate protons in a strong acidic environment. The protonated functional groups could unlikely complex ferric iron according to the site-specific surface complexation theory. Besides, the isolated EPS could not sharply reduce the concentration of free ferric ions, and the ferric iron could be removed by washing the cell surfaces with HClO4. These results indicate that there is no strong chemical interaction between bacteria and ferric iron. This study suggests a weak interaction of ferric iron with the EPS of A. ferrooxidans, and gives some deeper insight into the microenvironment of EPS.

Development of Solar Photo-Fenton Process for the Removal of Color, COD, and Turbidity from Institutional Wastewater

In recent years, hard research has been aimed to develop effective technology for the treatment of wastewater and industrial effluent containing organic/inorganic contaminants. Amongst several technologies, the advanced oxidation processes (AOPs) recently have played a major role in the treatment of wastewater. In this study, the treatment of institutional wastewater by solar-photo-Fenton (UV/Fe²⁺/H₂O₂) process based on AOPs was examined in terms of % color, % turbidity, and % COD removal. The solar-UV/Fe²⁺/H₂O₂process has revealed a higher removal of color (91%), turbidity (90%), and COD (86%) than the other processes. The effect of various experimental parameters such as hydrogen peroxide (H₂O₂) concentration (0.25 to 1.25 g/L) and Ferrous ion (Fe²⁺) concentration (0.005 to 0.12 g/L), initial pH (2 to 10), reaction time (30 to 180 min) on the color, turbidity and COD removal has been studied to find out the optimum conditions leading to maximum removal efficiency of the solar UV/Fe²⁺/H₂O₂process. The best results of the solar UV/Fe²⁺/H₂O₂process of institutional wastewater treatment have been found using 0.75 g/L of H₂O₂, 0.045 g/L of Fe²⁺, pH of 4, after 120 min of reaction time. The present study revealed that the solar-UV/Fe²⁺/H₂O₂process in an AOPs was well efficient in the institutional wastewater treatment, accomplishing a higher pollutant removal rate. The solar-UV/Fe²⁺/H₂O₂process is an effective treatment technique for the removal of pollutants from institutional wastewater.

Optimization of Synthesis Conditions of β‐FeOOH Nanorods towards Antimicrobial Benefits

FeOOH nanoparticles have recently appealed to wide‐ranging applications due to their physicochemical properties and size‐tunable synthesis; however, a few studies were performed on the antimicrobial potentials of iron oxyhydroxide nanoparticles. In this regard, we aimed to design various synthesis experiments to optimize the fabrication of β‐FeOOH nanorods (NRs) with a desirable size of NRs and high antimicrobial potential. For this purpose, ten experiments were designed by manipulating reaction conditions of the standard hydrolysis method, including the initial concentration of ferric ions, reaction time, reaction temperature, and different concentrations of surfactants of PEI and PEG as process control agents. The structural characteristics of prepared NRs were analyzed using FE‐SEM, FTIR, and XRD. The ImageJ software was also used to measure the length, width, and aspect ratio of NRs. Five microbial species, including the Gram‐positive and Gram‐negative bacteria and fungi species, were applied to investigate the antimicrobial potentials of NRs. The initial concentration of ferric ions revealed a dominant effect in NRs’ morphology, though other reaction conditions also played essential roles. The crystal structure of NRs was preserved in all synthesis experiments (β‐phase) due to using the same iron salt precursors. The synthesized NRs exhibited dose‐dependent antimicrobial activities against all tested microbial species. Additionally, the presence of surfactants exhibited an excellent capability of controlling effects on the size and growth pattern of NR crystals and improving their antimicrobial potentials; PEI could also be more effective on the antimicrobial efficacy of final NRs. Besides, our findings exhibited an inverse correlation between aspect ratio and antimicrobial potentials of β‐FeOOH NRs. To sum up, it seems that optimization of synthesis conditions could provide tunable size and structure patterns of β‐FeOOH NRs to achieve a promising tool for biomedical applications, particularly in combat with resistant microbial species, though further studies are needed in this regard.

BIOACCUMULATION OF IRON (Fe) IN Bacillus JA1, Sporosarcina JA4, AND Lysinibacillus JB2

Carbonatogenic bacteria are able to produce calcium carbonate (CaCO3). Steel reinforcement of concrete is mainly made of a mixture of carbon (C) and ferrous (Fe) elements. Fe is classified as heavy metal, when in high concentrations it is toxic to bacteria. The purpose of this study was to determine the bioaccumulation of carbonatogenic bacteria to Fe. The isolates used in this study were Bacillus JA1, Sporosarcina JA4, and Lysinibacillus JB2. All isolates were subcultured on nutrient agar slant media. Cultures were made on minimal salt medium: nutrient broth (95% : 5%) with 24 hours incubation. Bioaccumulation test using minimal salt medium: nutrient broth (95% : 5%) containing ferrous 5 ppm and 10 ppm. Accumulated ferrous concentration was measured using atomic absorption spectrophotometry. The result of this research is that the bioaccumulation of ferrous by the isolates after 2 hours of incubation is greater than 1 hour of incubation. Bacillus JA1 has the highest bioaccumulation ability which was 9,19 ppm after 2 hours exposure of 10 ppm ferrous and its ferrous bioaccumulation efficiency was 91,85%.

New technology of increasing the operation of local sewage treatment facilities, providing electric activation treatment of alkaline process solutions

The results of laboratory testing of the process of intensification of unconventional cleaning of electroplating drains of an instrument-making enterprise, which provides for electroactivation treatment of technological solutions of sodium hydroxide in a membrane electrolyzer with steel anodes, are presented. It was found that the electroactivation treatment of a 40 % aqueous sodium hydroxide solution in a membrane electrolyzer for T = 1.5 h at an anodic current density i = 400 А/м2 makes it possible to achieve the concentration of sodium ferrate in the activated alkaline solution Сf = 12 g / L, while the value of the current efficiency of sodium ferrate is Кv = 0.47. The use of an alkaline solution that has undergone electro-activation treatment in the technological process of neutralization treatment at local treatment facilities of an instrument-making enterprise equipped with filtration additional treatment units will significantly increase the barrier function, improve the quality of treated galvanic wastewater and bring the concentration of metal ions contained in them to a level, mg / l: iron 0.03; copper 0.01 mg / l; chromium 0.02; zinc 0.01; nickel 0.02.

Textile Wastewater Treatment in a Spinning Disc Reactor: Improved Performances—Experimental, Modeling and SVM Optimization

The paper presents an experimental study regarding the treatment of a real textile wastewater using the spinning disc (SD) technology, either individually or associated with an advanced Fenton oxidation step. The SD efficiency was investigated by studying the color, suspended solids, or turbidity removals, at distinctive feeding flowrates (10–30 L/h) and disc rotating speeds (100–1500 rpm). The data revealed increasing removal trends and allowed to establish the highest removal values. Based on obtained experimental results, the wastewater treatment efficiency by SD technology was reasonably good and thus, the WW indicators can be improved within relatively short periods of time. Additionally, based on supervised learning algorithms, the study includes treatment modeling for turbidity and color removal, followed by turbidity removal optimization relying on the best learned models. Satisfactory results obtained with the modeling and optimization procedures provide useful predictions for the approached treatment processes. Furthermore, within this study, a Fenton oxidation process was applied to SD technology to minimize the color and solids content. The influence of pH, hydrogen peroxide and ferrous ions concentrations was also investigated in order to establish the highest removal efficiencies. Overall, the SD technology applied in textile effluents treatment proved to be an appropriate and efficient alternative to classical mechanical step applied within the primary treatment step and, when associated with an advanced oxidative process in the secondary step, rendered good improvement, namely of 62.84% and 69.46% for color and respectively, suspended solids removal.

Optimization of elemental recovery from electronic wastes using a mild oxidizer.

In this work, metals were recovered from electronic wastes under optimized conditions. The columnar extraction was used to increase the contact between the leachate solution and solid-state wastes. Industrial metals were recovered by an electrochemical process using a regenerated mild oxidizer under optimized operating parameters to enrich the metal concentrations and reduce waste generation. The maximum recovery rate (1.135mg·min-1) was recorded under the optimized conditions (160 A·m-2 current density, 7mL·min-1 leachate flow rate, and 0.8mol·L-1 ferric concentration). The selective columnar extraction process was employed to extract gold, wherein the highest extraction efficiency (69.39%) was obtained under optimized conditions of 0.7mol·L-1 thiourea, 0.6mol·L-1 hydrochloric acid, 0.8mol·L-1 ferric chloride, 120min circulation time, and 6mL·min-1 leachate flow rate. The adsorption process was used for the recovery of gold, which was investigated under the kinetic as well as equilibrium adsorption processes. The adsorption curves conformed to the Langmuir model and followed the first-order kinetics. The adsorption rate decreased with the increasing values of pH, temperature, adsorbent size, while the rate increased with the stirring speed and adsorbent quantity. Finally, acidic extraction under anaerobic and optimal conditions was performed to extract and selectively recover rare-earth elements. The rare-earth elements were initially precipitated in their sulfate forms and subsequently transformed into corresponding hydroxides and oxides. The total recovery efficiencies for cerium and neodymium were found to be 91.7% and 86.7%, respectively.

Degradation of the endocrine-disrupting 4-nonylphenol by ferrate(VI): biodegradability and toxicity evaluation.

4-Nonylphenol (4-NP) is an endocrine-disrupting and persistent chemical and is partially degraded in conventional wastewater treatment processes. Ferrate(VI) can be used as an environment-friendly oxidizing agent to mediate 4-NP degradation. Thus, this paper evaluates the biodegradability of 4-NP and its degradation products after the addition of ferrate(VI). The biodegradability was examined using NP labeled with 14C as a tracer and activated sludge microorganisms as an inoculum. The addition of ferrate(VI) to the 4-NP solution spiked with the tracer resulted in no remarkable decrease in the concentration of 14C, indicating incomplete mineralization of 4-NP and formation of degradation products. The degradation products from 4-NP with Fe(VI) were estimated based on mass spectra, which detected a unique peak at m/z 223 at low intensity. Four hydrogen atoms might have been added to 4-NP by degradation with Fe(VI). In addition, the effect of ferrate(VI) concentration on the estrogenic activity of 4-NP in an aqueous solution was investigated using a yeast bioassay. The results show that estrogenic activity was significantly decreased at a mass ratio of Fe(VI) to 4-NP greater than or equal to 2.5.

NiFe2O4 nanospheres with size-tunable magnetic and electrochemical properties for superior supercapacitor electrode performance

Hereby, we present our efforts to understand the influence of ferric ions in the preparation of NiFe2O4 magnetic nanoparticles (MNPs) by facile chemical oxidation method. The variation in the Ferric ions content provoked size tunability of the MNPs (particle size reduced with increasing ferric ions content). The effect of ferric ions content on the prepared MNPs were analyzed for phase, morphological and magnetic characteristics by using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Vibrating Sample Magnetometer (VSM) and Thermomagnetic Analysis (TMA) measurements. The saturation magnetization and coercivity values were observed to be 45 emu/g and 90 Oe for the nanoparticles prepared without ferric ions. The size depended reduction in magnetization and coercivity values were evident for increased ferric ion concentration. The curie transition temperature was observed to be 584 °C from TMA analysis. The cyclic voltammogram, galvanostatic charge/discharge and electrochemical impedance measurements were carried out to evaluate the electrochemical characteristics of prepared NiFe2O4 nanoparticles for supercapacitor application. The highest specific capacitance of 277 F/g was observed for the NiFe2O4 nanoparticles that prepared with 50 % of ferric ions (NF50). From the cyclic stability study, 101 % of capacitance retention was demonstrated up to 5000 cycles. An asymmetric two-electrode cell that fabricated with NF50 exhibited a maximum specific capacitance of 56 F/g (with an applied current density of 1 A/g) and higher energy density of 22.5 Wh/ Kg (with a power density of 0.85 kW/Kg). The cyclic stability study of the cell revealed the increased capacity retention (126 % up to 5000 cycles) due to the particle size reduction. The observed enhancements in the magnetic and electrochemical properties with the size reduction are discussed in-detail. The facile strategy presented by this work would give insights for high-performance supercapacitor electrode material.

Development of new homogeneous photo-Fentoncatalytic systems using oxalic acid and ferric ions in very low concentrations

In this work, we proposed to combine oxalic acid and ferric ions in very low concentrations to create new, economic, and effective homogeneous photo-Fenton catalytic systems for the degradation of methylene blue. The effects of ferric concentration, H2C2O4 concentration, pH, and tert-butanol on the catalytic activity were also investigated. According to the experimental results, Fe3+ ions exhibited impressive catalytic performances in the presence of H2C2O4 at concentrations below type B (5.0 mg.l–1) from the Vietnam National Technical Regulation on Industrial Wastewater. Specifically, a ferric concentration of 3.0 mg.l–1, H2C2O4 concentration of 10–3 mol.l–1, and pH value of 3 were found to be the best conditions for MB degradation under UVA light. Furthermore, owing to a very low concentration of ferric ions, iron sludge formation can be avoided after wastewater treatment, which makes the photo-Fenton process suitable for practical applications.

Flotation separation of hazardous polyvinyl chloride towards source control of microplastics based on selective hydrophilization of plasticizer-doping surfaces

As the single largest chlorine source of plastics, hazardous polyvinyl chloride (PVC) has become an increasing environmental concern with the rapid microplastics accumulation. An advanced separation method is advocated to purify waste PVC plastics, optimize physical recycling, and protect aquatic and terrestrial environment safety. In this study, we proposed a novel scheme for the flotation separation of PVC plastics with diverse plasticizer contents (PVCs) via regulating hydrophilicity based on a selective ferric deposition. Rigid PVCs were prone to loading ferric ions and generating hydrophilic shells than flexible PVCs. Plasticizers can diffuse freely through the interior and surface of PVC plastics. Abundant plasticizers thereby overlaid the surface of flexible PVC and shielded PVC matrix from ferric ions. By regulating the ferric concentration, the wettability of PVCs was adjusted to separate rigid and flexible PVCs by froth flotation. Waste PVCs could also be separated from each other through the compound process of ferric deposition and flotation, further confirming its feasibility and stability. Thus far, this study supplies distinctive insights into the wettability regulation of plasticizer-doping PVC surfaces, contributes a pioneering hydrophilization method to PVCs separation and recycling, and mitigates hazardous PVC microplastics by source control.

Effect of ferric ion [Fe3+] and [Fe2+] on SO2 adsorption ability of γ-Fe2O3 nanoparticles for mass-type gas sensors

The sensing material plays a very important role in determining the sensing properties of a gas sensor. In order to synthesise the sensing material, the precursors have a large effect on the properties of the sensing material. In this study, three types of γ-Fe2O3 nanoparticles were prepared with different ferric ion concentrations of [Fe3+] and [Fe2+] as precursors, by a typical facile chemical precipitation process and a following annealing treatment. A mass-type gas sensor was fabricated by using a quartz crystal microbalance (QCM) coated with various γ-Fe2O3 nanoparticles. The morphology, crystallisation, and gas adsorption characteristics of the γ-Fe2O3 nanoparticles were investigated. The effect of ferric ion concentrations of [Fe3+] and [Fe2+] on sensing properties is discussed in detail. Interestingly, the sensor based on γ-Fe2O3 nanoparticles synthesised with ferric ion [Fe3+] showed excellent sensing properties for the detection of SO2 gas, with high sensitivity and repeatability at room temperature. The experimental results clearly demonstrate that the γ-Fe2O3 nanoparticle is an excellent sensing material which may be suitable for practical sensing applications.

Oxidative hydrolysis of Fe(Ⅱ) in the process of hydrothermal synthesis of hematite

Abstract Iron removal is an important step in zinc hydrometallurgy, and hematite process not only can effectively remove iron, but also is environmentally friendly and has certain economic benefits, so it has great application potential in zinc hydrometallurgy. The oxidative hydrolysis of Fe(Ⅱ) was studied by the change of ions in solution with different initial ferrous ion concentration. Meanwhile, the oxidation rates of Fe(Ⅱ) at different initial Zn(Ⅱ) concentrations were also studied. The results show that temperature has an important influence on the oxidative hydrolysis of Fe(Ⅱ). Increasing the temperature can inhibit the formation of complex and make more Fe(Ⅱ) precipitate directly in the form of hematite, which is not limited by the hydrolysis rate of Fe(Ⅲ). The oxidation reaction of Fe(Ⅱ) approximately conforms to the second order reaction rate. Zinc sulfate can promote the oxidation of Fe(Ⅱ). When the initial Zn(Ⅱ) concentration was 20, 40, 60 and 80 g/L, the oxidation kinetic constants of Fe(Ⅱ) were 2.433, 4.492, 10.106 and 14.857 L·mol−1·min−1, respectively.