Validating the efficiency of the MB discoloration method for the characterization of Fe 0 /H 2 O systems using accelerated corrosion by chloride ions

Self Cite

Since the realization in the 1930s that elevated fluoride concentrations in drinking water can have detrimental effects on human health, new methods have been progressively developed in order to reduce fluoride to acceptable levels. In the developing world the necessity for filtration media that are both low-cost and sourced from locally available materials has resulted in the widespread use of bone char. Since the early 1990s metallic iron (Fe 0 ) has received widespread use as both an adsorbent and a reducing agent for the removal of a wide range of contaminant species from water. The ion-selectivity of Fe 0 is dictated by the positively charged surface of iron (hydr)oxides at circumneutral pH. This suggests that Fe 0 could potentially be applied as suitable filter media for the negatively charged fluoride ion. This communication seeks to demonstrate from a theoretical basis and using empirical data from the literature the suitability of Fe 0 filters for fluoride removal. The work concludes that Fe 0 -bearing materials, such as steel wool, hold good promise as low-cost, readily available and highly effective decentralized fluoride treatment materials.

Section: Optimizing the Efficiency Fe 0 Filtersmentioning

confidence: 99%

Section: Optimizing the Efficiency Fe 0 Filtersmentioning

confidence: 99%

See 1 more Smart Citation

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

Ndé-Tchoupé

Crane

Mwakabona

et al. 2015

Self Cite

“…Experiments using Fe + organic chemicals have demonstrated [5,6,[193][194][195][196][197][198][199][200] that increases in water salinity are associated with in an increase in the rate of degradation of the organic chemicals and (COx, HxCyOz). This is associated with the construction of simple organic compounds (CxHyOz, alkanes and alkenes), where carbon can act as both an intermediary and reactant and Fe acts as a catalyst [5,6,[193][194][195][196][197][198][199][200]. Trials PS15 and PS16 demonstrate that the presence of CO, CO2 and CH4 can be associated with increases in the rate of desalination.…”

Section: Economic Implications Of Corrosion Scalementioning

confidence: 99%

Desalination of Water Using ZVI (Fe0)

Antia¹

2015

196

Batch treatment of water (0.2 to 240 L) using Fe 0 (44,000-77,000 nm) in a diffusion environment operated (at −8 to 25 °C) using: (a) no external energy; (b) pressurized (<0.1 MPa) air; (c) pressurized (<0.1 MPa) acidic gas (CO2); (d) pressurized (<0.1 MPa) anoxic gas (N2); (e) pressurized (<0.1 MPa) anoxic, acidic, reducing gas (H2 + CO + CO2 + CH4 + N2), reduces the salinity of water. Desalination costs increase with increasing NaCl removal. The cost of reducing water salinity from: (i) 2.65 to 1.55 g·L . Desalination is accompanied by the removal, from the water, of one or more of: nitrate, chloride, fluoride, sulphate, phosphate, As, B, Ba, Ca, Cd, Co, Cu, Fe, Mg, Mn, Na, Ni, P, S, Si, Sr, Zn. The rate of desalination is enhanced by increasing temperatures and increasing HCO3 − /CO3 2− concentrations. The rate of desalination decreases with increasing SO4 2− removal under acidic, or pH neutral, operating conditions.

“…It has been unambiguously demonstrated that all tools used to accelerate lab-scale experiments collectively impair the reliability of the obtained test results [35,[65][66][67]. Relevant tools include adding oxidizing agents to accelerate corrosion [58], increasing flow velocity [34] and using Fe 0 of smaller particle sizes and/or rapid small-scale column tests [65].…”

Section: (Section 2)mentioning

confidence: 99%

Predicting the Hydraulic Conductivity of Metallic Iron Filters: Modeling Gone Astray

Noubactep

2016

Self Cite

Abstract:Since its introduction about 25 years ago, metallic iron (Fe 0 ) has shown its potential as the key component of reactive filtration systems for contaminant removal in polluted waters. Technical applications of such systems can be enhanced by numerical simulation of a filter design to improve, e.g., the service time or the minimum permeability of a prospected system to warrant the required output water quality. This communication discusses the relevant input quantities into such a simulation model, illustrates the possible simplifications and identifies the lack of relevant thermodynamic and kinetic data. As a result, necessary steps are outlined that may improve the numerical simulation and, consequently, the technical design of Fe 0 filters. Following a general overview on the key reactions in a Fe 0 system, the importance of iron corrosion kinetics is illustrated. Iron corrosion kinetics, expressed as a rate constant k iron , determines both the removal rate of contaminants and the average permeability loss of the filter system. While the relevance of a reasonable estimate of k iron is thus obvious, information is scarce. As a conclusion, systematic experiments for the determination of k iron values are suggested to improve the database of this key input parameter to Fe 0 filters.