Transport of stabilized iron nanoparticles in porous media: Effects of surface and solution chemistry and role of adsorption

Zhang, Man; He, Feng; Zhao, Dongye; Hao, Xiaodi

doi:10.1016/j.jhazmat.2015.12.071

Cited by 69 publications

(23 citation statements)

References 69 publications

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“…The model simulation results indicated that once CMC-stabilized nZVI is delivered, 99% of the nanoparticles would be removed by the soil matrix within cm at a groundwater flow velocity of 0.1 m/day, but may travel over m at pore flow velocity of 61 m/day, indicating that the transport distance of the nanoparticles can be controlled by manipulating the injection pressure. Zhang et al (2016) proposed a mechanistically sounder transport model by incorporating a Langmuir-type adsorption rate law term into the classic convection-dispersion equation with the adsorption parameters derived from independent batch adsorption experiments. The model allows for a quantitative evaluation of the role of adsorption, which is an important mechanism for the retention of stabilized nZVI, especially for soils rich in metals.…”

Section: Transport Of Stabilized Nzvimentioning

confidence: 99%

An overview of preparation and applications of stabilized zero-valent iron nanoparticles for soil and groundwater remediation

et al. 2016

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Nano-scale zero-valent iron (nZVI) is one of the most intensively studied materials for environmental cleanup uses over the past 20 years or so. Freshly prepared nZVI is highly reactive due to its high specific surface area and strong reducing power. Over years, the classic borohydride reduction method for preparing nZVI has been modified by use of various stabilizers or surface modifiers to acquire more stable and soil deliverable nZVI for treatment of different organic and inorganic contaminants in water and soil. While most studies have been focused on testing nZVI for water treatment, the greater potential or advantage of nZVI appears to be for in situ remediation of contaminated soil and groundwater by directly delivering stabilized nZVI into the contaminated subsurface as it was proposed from the beginning. Compared to conventional remediation practices, the in situ remediation technique using stabilized nZVI offers some unique advantages. This work provides an update on the latest development of stabilized nZVI for various environmental cleanup uses, and overviews the evolution and environmental applications of stabilized nZVI. Commonly used stabilizers are compared and the stabilizing mechanisms are discussed. The effectiveness and constraints of the nZVI-based in situ remediation technology are summarized. This review also reveals some critical knowledge gaps and research needs, such as interactions between delivered nZVI and the local biogeochemical conditions.

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Section: Transport Of Stabilized Nzvimentioning

confidence: 99%

An overview of preparation and applications of stabilized zero-valent iron nanoparticles for soil and groundwater remediation

et al. 2016

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“…Interest in the application of nanoscale zero-valent iron (nZVI) particles in remediation of point-source polluted sites has grown dramatically in recent years [1,2]. nZVI are characterized by a large surface area, high reactivity, and possible mobility in the subsurface due to its small size.…”

Section: Introductionmentioning

confidence: 99%

Effect of Flow Rate and Particle Concentration on the Transport and Deposition of Bare and Stabilized Zero-Valent Iron Nanoparticles in Sandy Soil

et al. 2019

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Efficient application of nanoscale zero-valent iron (nZVI) particles in remediation processes relies heavily on the ability to modify the surfaces of nZVI particles to enhance their stability and mobility in subsurface layers. We investigated the effect of sodium carboxy-methyl-cellulose (CMC) polymer stabilizer, pH, particle concentration, and flow rate on the transport of nZVI particles in sand columns. Breakthrough curves (BTCs) of nZVI particles indicated that the transport of nZVI particles was increased by the presence of CMC and by increasing the flow rate. The relative concentration (RC) of the eluted CMC-nZVI nanoparticles was larger at pH 9 as compared to RC at pH 7. This is mainly attributed to the increased nZVI particle stability at higher pH due to the increase in the electrostatic repulsion forces and the formation of larger energy barriers. nZVI particle deposition was larger at 0.1 cm min −1 flow due to the increased residence time, which increases the aggregation and settlement of particles. The amount of CMC-nZVI particles eluted from the sand columns was increased by 52% at the maximum flow rate of 1.0 cm min −1 . Bare nZVI were mostly retained in the first millimeters of the soil column, and the amount eluted did not exceed 1.2% of the total amount added. Our results suggest that surface modification of nZVI particles was necessary to increase stability and enhance transport in sandy soil. Nevertheless, a proper flow rate, suitable for the intended remediation efforts, must be considered to minimize nZVI particle deposition and increase remediation efficiency.

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“…where L is the length of porous media (m), and C/C 0 is the maximum normalized effluent concentration. Other models incorporate a Langmuir-type adsorption isotherm in the traditional advection-dispersion equation (Zhang et al 2017). It is also important to note that in porous media, the mobility of iron particles can be affected by the presence of biofilm (Basnet et al 2016;Crampon et al 2018).…”

Section: Injection Of Particular Solidsmentioning

confidence: 99%

In Situ Chemical Reduction of Chlorinated Organic Compounds

Rodrigues

Betelu

Colombano

et al. 2020

Applied Environmental Science and Engineering for a Sustainable Future

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Chlorinated organic compounds (COCs) are common anthropogenic contaminants of soil and groundwater. COCs were industrially produced for different applications, such as dry cleaning, degreasing, or as pesticides. The presence of COCs in the environment is a major concern because of their toxicity and persistence.The most widely used method for their remediation is the conventional pump-and-treat system. However, this technology can hardly achieve a complete remediation because of geological characteristics and the presence of pore space pollution/adsorbed pollution, leading to a residual saturation. Hence, in addition to the improvement of pump-and-treat systems, in situ chemical processes have been largely developed. These chemical processes involve the injection of chemical reagents for the removal of residual source pollution and/or the treatment of plume contamination. Chemical degradation of COCs can be achieved by oxidative or reductive processes. If chemical oxidation has been first developed for in situ application, chemical reduction is one of the most important emerging remediation techniques for COCs treatment. Due to the electronegative character of chlorine substituents, COCs can effectively be transformed via reductive pathways. Moreover, reductive dechlorination has shown higher efficiency on highly chlorinated compounds. This chapter focuses on the presentation of the chemical reduction of the most common COCs pollutants, followed by kinetic and mechanistic approaches related to the use of iron-based particles. Developments on in situ chemical reduction technologies in order to enhance remediation rates are also exposed. Influence of environmental conditions for in situ applications is then developed. Finally, a case study is presented.

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Transport of stabilized iron nanoparticles in porous media: Effects of surface and solution chemistry and role of adsorption

Cited by 69 publications

References 69 publications

An overview of preparation and applications of stabilized zero-valent iron nanoparticles for soil and groundwater remediation

An overview of preparation and applications of stabilized zero-valent iron nanoparticles for soil and groundwater remediation

Effect of Flow Rate and Particle Concentration on the Transport and Deposition of Bare and Stabilized Zero-Valent Iron Nanoparticles in Sandy Soil

In Situ Chemical Reduction of Chlorinated Organic Compounds

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