Synthesis and Chemical Stability Studies of Sodium Ferrate(VI) Solution

Ramontja

et al. 2021

Water

The screening and treatment of acid mine drainage (AMD) using Na2FeO4 was explored. Elemental composition was performed, using an Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) for the raw and treated AMD. The AMD samples were collected from three different sampling sites:(Raw Tailing Water 1 (RTW1), Raw Tailing Water 2 (RTW2) and Raw Tailing Water 3 (RTW3)) in Pretoria, South Africa, with acidic pH ranging between 2.50 and 3.13. Total dissolved solids and the electrical conductivity of AMD samples ranged between 960 and 1000 mg L−1, 226 and 263 µS. cm−1, respectively. The final pH of treated water samples increased up to ≥9.5 after treatment with sodium ferrate (VI) (Na2FeO4). Liquid Na2FeO4 was quantitatively produced through a wet oxidation method and was fully characterized, using Fourier Transform Infra-Red (FTIR), X-ray Diffraction spectroscopy (XRD) and UV-Vis instruments. Na2FeO4 showed dual functions by removing metals and raising the pH of the treated water. Concentrations of most trace elements did not comply with WHO and DWAF guideline standards in raw AMD while after treatment with Na2FeO4, the concentrations were below guidelines for domestic and irrigation purposes.

Section: Preparation Of Liquid Sodium Ferrate (Vi)mentioning

confidence: 99%

Effective Desalination of Acid Mine Drainage Using an Advanced Oxidation Process: Sodium Ferrate (VI) Salt

Ramontja

et al. 2021

Water

“…Liquid Na 2 FeO 4 was previously prepared by a wet chemical method and its concentration was determined using UV-Visible spectroscopy. Na 2 FeO 4 solution was characterized by its intense purple colour confirming the presence of high valent of iron (Fe (VI)) ( Munyengabe and Zvinowanda, 2019 ). To generate the AMD sludge, an amount of synthetic AMD solution with the composition given in Table 1 was treated using a liquid Na 2 FeO 4 (0.05 M) (4:1 v/v) within a contact time of 30 min as an optimum condition obtained in the previous study in which all iron (II) (pale green colour) and Fe (VI) (purple colour) were fully converted into a yellow precipitate (Fe (III)) ( Munyengabe et al, 2020 ).…”

Section: Methodsmentioning

confidence: 99%

Characterization and reusability suggestions of the sludge generated from a synthetic acid mine drainage treatment using sodium ferrate (VI)

Zvimba

et al. 2020

Heliyon

Mining activities are the main cause of generation of the voluminous sludge waste, loaded with metals precipitated from the treatment of acid mine drainage (AMD) and this is always disposed to the landfill. This study aimed at characterizing and suggesting the reusability potential of AMD sludge to reduce the environmental problem caused by its accumulation so that it could become a valuable material. The sludge was obtained after treating a synthetic AMD with a green oxidant sodium ferrate (VI) (Na 2 FeO 4 ) that was prepared by a wet oxidation method. Chemical and physical characterization of a dried sludge generated after treatment was then performed using the Fourier Transform-Infrared and X-Ray powder Diffraction spectroscopy. Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy also served to identify the surface morphology of the sludge. The sludge presented a high weight percentage of Fe and O and lower concentrations of other metals such as Al, Mn, Si, and Na. Nitrogen adsorption/desorption isotherms or Brunauer-Emmett-Teller (BET) was used to assess the surface area, pore volume and diameter of the sludge. The BET results showed that the surface area of the sludge obtained after treating the synthetic AMD using Na 2 FeO 4 was 31.50 ± 0.03 m 2 /g with pore diameter and volume of 52.50 nm and 0.41 cm 3 /g, respectively. However, the produced sludge could serve as an adsorbent to remove pollutants from water or to synthesize different magnetic nanocomposites due to its high surface area (>natural zeolite) and high composition of Fe and O.

“…These include temperature, pH, turbidity, colour and electrical conductivity (EC). Liquid sodium ferrate (VI) was synthesized using liquid sodium ferric chloride (43%), sodium hydroxide (43%) and hypochlorite (15%) in the ratio of 1:5:10 v/v through a wet chemical method (Munyengabe, & Zvinowanda, 2019). Equation 1 of its synthesis which was firstly proposed by Thompson et al (1951) was considered in this study.…”

Section: Study Area and Physical Parameters Of Raw Water Samplesmentioning

confidence: 99%

“…The working calibration curve (0 to 50 mg/L) was elaborated using potassium ferrate (VI) as a standard. The concentration of liquid Na2FeO4 was determined using Ultraviolet-Visible spectrophotometer, Cary 60 (λmax = 510 nm for FeO4 2-) (Munyengabe, & Zvinowanda, 2019).…”

Section: Study Area and Physical Parameters Of Raw Water Samplesmentioning

confidence: 99%

Exploring the effectiveness of in-situ sodium ferrate (VI) during the bench-scale of manganese removal from raw water collected from a South African WTP

Masindi

2021

Preprint

Manganese (Mn) is an essential element for human body and several enzymes rely on its redox properties. Its elevated concentrations in water can be toxic to humans, stain porcelains and can generate an undesirable taste in beverages. Several methods including adsorption, biologically active filtration oxidation and precipitation have been used to reduce it from water. Unfortunately, most of these methods have disadvantages of generating harmful by-products. Ferrate (VI) has been considered as a supplant to common oxidants during the treatment of drinking water. It has main advantages such as production of ferric ion, high oxidation potential, which may support coagulation, and the lack of significant halogenated by-product generation. However, this study aimed at exploring the effectiveness of in-situ liquid sodium ferrate (Na2FeO4) during the removal of Mn from raw water collected from Cullinan water treatment plant (CWTP) at the bench-scale. Na2FeO4 was produced using a wet oxidation method. The treatment of raw water collected from CWTP presented the removal percentage of Mn ranging between 82.70 and 99.20%. The pH of the drinking water sample raised from 7.25 to 10.97 after treatment. The treatability index (TI) was also studied. Only the TI of pH value was less than one. The TI results indicated high value of EC and authors would like to replace sodium by calcium in the ferrate product to reduce EC of the treated water and recommend the application of FeO42- ions for the treatment of raw water in a full-scale as it showed to be a promising a green oxidant.