Significance of Iron(II,III) Hydroxycarbonate Green Rust in Arsenic Remediation Using Zerovalent Iron in Laboratory Column Tests

2004 ◽  
Vol 38 (19) ◽  
pp. 5224-5231 ◽  
Author(s):  
Chunming Su ◽  
Robert W. Puls
Keyword(s):  
Green Rust ◽  
Zerovalent Iron ◽  
Column Tests ◽  
Arsenic Remediation ◽  
Laboratory Column

scholarly journals Injection of Zerovalent Iron Gels for Aquifer Nanoremediation: Lab Experiments and Modeling

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 826 ◽  
Author(s):  
Federico Mondino ◽  
Amelia Piscitello ◽  
Carlo Bianco ◽  
Andrea Gallo ◽  
Alessandra de Folly D’Auris ◽  
...  
Keyword(s):  
Colloidal Stability ◽  
Guar Gum ◽  
Zerovalent Iron ◽  
Column Tests ◽  
Nanoparticle Transport ◽  
Technical Problems ◽  
Particle Mobility ◽  
Transport Experiment ◽  
Slurry Rheology ◽  
Good Agreement

One of the main technical problems faced during field-scale injections of iron microparticles (mZVI) for groundwater nanoremediation is related to their poor colloidal stability and mobility in porous media. In this study, a shear-thinning gel, composed of a mixture of two environmentally friendly biopolymers, i.e., guar gum and xanthan gum, was employed to overcome these limitations. The slurry rheology and particle mobility were characterized by column transport tests. Then, a radial transport experiment was performed to mimic the particle delivery in more realistic conditions. The gel, even at a low polymeric content (1.75 g/L), proved effective in enhancing the mobility of high concentrated mZVI suspensions (20 g/L) in field-like conditions. The high radius of influence (73 cm) and homogeneous iron distribution were achieved by maintaining a low injection overpressure (<0.4 bar). Based only on the information derived from column tests, the MNMs 2018 software (Micro- and Nanoparticle transport, filtration, and clogging Model-Suite) was able to predict the particle distribution and pressure build-up measured in the radial domain. Experimental and simulated results showed good agreement, thus proving that a simplified experimental-modeling procedure based on 1D column tests could be used to effectively upscale the slurry behavior to more representative scales, e.g., radial domains.

Green Rust and Iron Oxide Formation Influences Metolachlor Dechlorination during Zerovalent Iron Treatment

2003 ◽  
Vol 37 (22) ◽  
pp. 5219-5227 ◽  
Author(s):  
Tunlawit Satapanajaru ◽  
Patrick J. Shea ◽  
Steve D. Comfort ◽  
Yul Roh
Keyword(s):  
Iron Oxide ◽  
Green Rust ◽  
Zerovalent Iron ◽  
Oxide Formation ◽  
Iron Treatment

Modelling long-term hydraulic conductivity behaviour of zero valent iron column tests for permeable reactive barrier design

2016 ◽  
Vol 53 (6) ◽  
pp. 946-961 ◽  
Author(s):  
Nicola Moraci ◽  
Domenico Ielo ◽  
Stefania Bilardi ◽  
Paolo S. Calabrò
Keyword(s):  
Hydraulic Conductivity ◽  
Gas Bubbles ◽  
Zero Valent Iron ◽  
Experimental Results ◽  
Reaction Products ◽  
Iron Corrosion ◽  
Column Tests ◽  
Proposed Model ◽  
Laboratory Column

In this paper, a numerical model to simulate the hydraulic conductivity reduction observed during long-term laboratory column tests is proposed. The column tests are carried out to study dissolved heavy metals removal by using granular zero valent iron (ZVI). The proposed model is also used to analyse the main causes of hydraulic conductivity reduction observed during laboratory column tests. Expansive iron corrosion, precipitation of reaction products, and gas formation are the processes considered in the proposed model. Numerical simulation results show that to reproduce hydraulic behaviour of the experimental systems, the change of pores geometry due to expansive iron corrosion and precipitation of reaction products, which determines a possible stoppage of gas bubbles, should be considered. Furthermore, model results show that only a small percentage of the iron available is corroded during the tests (from 0.4% to 1.9%). According to the model, the average diameter of gas bubbles that better fit the experimental results varies between 0.16 and 0.19 mm. While assuming gas absence (or its possible escape), higher values of iron corrosion rate should be considered to fit the experimental results.

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