A Continuous System for Fe 0 Reduction of Nitrobenzene in Synthetic Wastewater

Abstract:In order to investigate the dissolved oxygen increase caused by air suction in a horizontal Venturi flow with two holes, a 3-D computational fluid dynamics model was used to explore the water and bubble mixture flow, coupled with a dissolved oxygen transfer model. A series of experiments were conducted to validate the mathematical model. A relative saturation coefficient correlation was examined factoring in dissolved oxygen concentration at the inlet, water velocity at the inlet, the hole's diameter, contraction ratio at throat section, and the downstream length of Venturi pipe. It was found that the relative saturation coefficient increases with increasing dissolved oxygen concentration at the inlet and downstream length of Venturi pipe respectively. However, it increases with decreasing water velocity at the inlet and contraction ratio at the throat section to some extent. The hole's diameter plays a complex role in the relative saturation coefficient. The dimensional analysis method and the least square method were used to deduce a simple formula for the relative saturation coefficient, and this was consistent with related data.

Section: Experimental Procedures and Phenomenamentioning

confidence: 99%

3-D Numerical Investigation on Oxygen Transfer in a Horizontal Venturi Flow with Two Holes

Yin¹,

Feng²,

Wang³

et al. 2018

“…It strongly masks the real mechanisms of contaminant removal as that is a complex interplay between Fe 0 particles, Fe II released into solution and Fe II /Fe III precipitation [89][90][91][92][93][94][95][96]. In particular, the transformation of Fe 0 to Fe oxides goes through colloids and hydroxides.…”

Section: Contaminant Removal In Fe 0 /H 2 O Systemsmentioning

confidence: 99%

“…On the other hand, regarding the abundance of (partly nascent) adsorbing sites and continuous generation of Fe II species, contaminant chemical reduction by so-called structural Fe II (adsorbed Fe II ) is favored [96]. The abundance of Fe II /Fe III hydroxides/oxides in Fe 0 /H 2 O systems has been experimentally demonstrated by [92]. However, the authors have suggested adsorptive removal as an important removal mechanism accompanying direct reduction, which is in contradiction to the mechanisms presented in Section 2.…”

Section: Contaminant Removal In Fe 0 /H 2 O Systemsmentioning

confidence: 99%

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

Noubactep

2016

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.

“…In an independent approach, Fe 0 was used as a reducing agent or generator of iron hydroxides for water treatment [33][34][35]. By 2002, Fe 0 had already been tested for many relevant groups of chemical contamination.…”

Section: The Suitability Of Fe 0 Filters For Safe Water Provision In mentioning

confidence: 99%

Testing Metallic Iron Filtration Systems for Decentralized Water Treatment at Pilot Scale

Tepong-Tsindé

Crane

Noubactep

et al. 2015

There are many factors to consider for the design of appropriate water treatment systems including: cost, the concentration and type of biological and/or chemical contamination, concentration limits at which contaminant(s) are required to be removed, required flow rate, level of local expertise for on-going maintenance, and social acceptance. An ideal technology should be effective at producing clean, potable water; however it must also be low-cost, low-energy (ideally energy-free) and require low-maintenance. The use of packed beds containing metallic iron (Fe 0 filters) has the potential to become a cheap widespread technology for both safe drinking water provision and wastewater treatment. for decentralized water treatment particularly in the developing world. A design for safe drinking water to a community of 100 people is also discussed as starting module. It is suggested that Fe 0 filters have the potential for significant worldwide applicability, but particularly in the developing world. The appropriate design of Fe 0 filters, however, is site-specific and dependent upon the availability of local expertise/materials.