Nanoparticles in the Soil Environment

Theng, B. K. G.; Yuan, Guodong

doi:10.2113/gselements.4.6.395

Cited by 232 publications

(127 citation statements)

References 30 publications

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“…The unit particle of allophane is a hollow spherule with an outer diameter of 3.5-5.0 nm and a wall thickness of 0.7-1.0 nm [6,7]. Allophane is fundamentally composed of an outer layer of gibbsite-like sheet with SiO 4 tetrahedral attached to its interior and having defects or pores in the wall structure with diameters of around 0.3 nm [8].…”

Section: Introductionmentioning

confidence: 99%

Adsorption and co-precipitation behavior of arsenate, chromate, selenate and boric acid with synthetic allophane-like materials

Opiso

Satō

Yoneda

2009

Journal of Hazardous Materials

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Pollution caused by boric acid and toxic anions such as As(V), Cr(VI) and Se(VI) is hazardous to human health and environment. The sorption characteristics of these environmentally significant ionic species on allophane-like nanoparticles was investigated in order to determine whether allophane can reduce their mobility in the subsurface environment at circum-neutral pH condition. Solutions containing 100 or 150 mmol of AlCl 3 . 6H 2 O were mixed to 100 mmol of Na 4 SiO 4 and the pH were adjusted to 6.4±0.3. The mineral suspensions were shaken for 1 hr and incubated at 80 o C for 5 days. Appropriate amounts of As, B, Cr and Se solutions were added separately during and after allophane precipitation. The results showed that As(V) and boric acid can be irreversibly fixed during co-precipitation in addition to surface adsorption. However, Cr(VI) and Se(VI) retention during and after allophane precipitation is mainly controlled by surface adsorption. The structurally fixed As(V) and boric acid were more resistant to release than those bound on the surface. The sorption characteristics of oxyanions and boric acid was also influenced by the final Si/Al molar ratio of allophane in which Al-rich allophane tend to have higher uptake capacity. The overall results of this study have demostrated the role of allophane-like 3 nanoparticles and the effect of its Si/Al ratio on As, B, Cr and Se transport processes in the subsurface environment.

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Section: Introductionmentioning

confidence: 99%

Adsorption and co-precipitation behavior of arsenate, chromate, selenate and boric acid with synthetic allophane-like materials

Opiso

Satō

Yoneda

2009

Journal of Hazardous Materials

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“…Unlike the polymer residue from current slow-release fertilizers, the residue of organoclay in soil would be of little concern because its organic component is held in the nm space between clay mineral layers and thus not accessible to microorganisms (μm in size), and the mineral component (montmorillonite) is a naturally occurring nanoparticle in many types of soils (Theng and Yuan, 2008).…”

Section: Resultsmentioning

confidence: 99%

An organoclay formula for the slow release of soluble compounds

Yuan¹

2014

Applied Clay Science

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Keywords: Organoclays Nanoclays Slow-release formula Fertilizer DCD Slow-release formulations have been developed to enhance the effective use of active ingredients. In the case of fertilizers the formulations reduce nutrient leaching and greenhouse gas emissions. While polymer-coating is the dominant technology in producing slow-release fertilizers there is a demand for alternative options for different usages. To this end, a commercially available organoclay, with a basal spacing of 3.67 nm, was used as matrix to produce pellets of CuSO 4 and dicyandiamide (DCD) of different sizes by a die set and hand press. Both CuSO 4 and DCD pellets showed a good slow-release performance in dissolution tests. Large pellets (1.2 cm in diameter) of CuSO 4 had a better performance in slow-release than small ones (0.7 cm). For DCD pellets (0.7 cm in diameter) it took 6 days for a complete dissolution. The slow-release effect is probably due to the hydrophobic nature and high aspect ratio of the organoclay. The former makes soluble compounds between organoclay particles less susceptible to dissolution in water, whereas the latter hinders the dissolution of solutes inside a pellet by making their diffusion passage tortuous. The organoclay formulation is easy to make, and the rate of solute release can be adjusted by changing pellet size.

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“…Natural nanoparticle widely exists in environment, such as airborne nanocrystals of sea salts, biogenic magnetite, carbon nanotubes, fullerenes, etc. (Buffle 2006;Nowack and Bucheli 2007), and soils also contain different kinds of organic and inorganic nanoparticles, such as humic substances, clay minerals, hydroxides and metal oxides, and imogolite and allophone (Theng and Yuan 2008;Miao et al 2010Miao et al , 2011. The anthropogenic sources of exposure to MNPs mainly include soot exhaust, furnaces, power plants, pigments from paint and toner, welding fumes, construction sites, etc.…”

Section: Nanoparticle Source and Its Lifecycle Nanoparticle Sourcementioning

confidence: 99%

“…Some of these naturally occurring nanoparticles are considered toxic to human health while others are not. A small percentage even exists within living organisms (Theng and Yuan 2008). Globally, the ongoing development of nanotechnology is rapid, and both of the absolute quantity and diversity of MNPs are promptly increasing from time to time.…”

Section: Nanoparticle Source and Its Lifecycle Nanoparticle Sourcementioning

confidence: 99%

Nanoparticle pollution and associated increasing potential risks on environment and human health: a case study of China

Gao

Yang

Jin³

2015

Environ Sci Pollut Res

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The aims of this study are (1) to discuss the mechanism of nanoparticle lifecycle and estimate the impacts of its associated pollution on environment and human health; and (2) to provide recommendation to policy makers on how to leverage nanopollution and human health along with the rapid development of economics in China. Manufactured nanoparticles (MNPs) could either directly or indirectly impair human health and the environment. Exposures to MNP include many ways, such as via inhalation, ingestion, direct contact, or the use of consumer products over the lifecycle of the product. In China, the number of people exposed to MNP has been increasing year by year. To better provide medical care to people exposed to MNP, the Chinese government has established many disease control and prevention centers over China. However, the existing facilities and resources for controlling MNP are still not enough considering the number of people impacted by MNP and the number of ordinary workers in the MNP related industry applying for their occupational identification through the Center for Disease Control and Prevention. China should assess the apparent risk environment and human health being exposed to MNP and develop action plans to reduce the possibility of direct contacts between human beings and the emerging nanomaterials. In addition, we suggest more comprehensive studies on the MNP behavior and the development of quantitative approaches to measure MNP transport, and persistence should be carried out.

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Nanoparticles in the Soil Environment

Cited by 232 publications

References 30 publications

Adsorption and co-precipitation behavior of arsenate, chromate, selenate and boric acid with synthetic allophane-like materials

Adsorption and co-precipitation behavior of arsenate, chromate, selenate and boric acid with synthetic allophane-like materials

An organoclay formula for the slow release of soluble compounds

Nanoparticle pollution and associated increasing potential risks on environment and human health: a case study of China

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