Degradability of natural and synthetic chelating agents applied to a lead-contaminated soil

Freitas, Eriberto Vagner de Souza; Nascimento, Clístenes Williams Araújo do

doi:10.1007/s11368-015-1350-9

Cited by 15 publications

(5 citation statements)

References 33 publications

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“…However, microbial decomposition rapidly decreases their abundance in soil solutions (Fischer, Ingwersen, & Kuzyakov, 2010; Guppy et al., 2005). Ethylenediaminetetraacetate, a synthetic chelating agent, is also known to strongly sorb to soils via inner sphere complexation (Nowack & Sigg, 1996), but their metal complexes degrade more slowly compared with those of citrate (Frietas & Nascimento, 2017). We lack comparable information on degradation and (ad)sorption of noncomplexed and metal‐complexed AVAIL relative to other organic ligands in soils.…”

Section: Resultsmentioning

confidence: 99%

Phosphate solubilization from adsorbents and precipitates by different AVAIL polymers

Doydora

Thompson

Hesterberg

2020

Soil Science Soc of Amer J

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Less than 40% of phosphate fertilizer applied to soils is typically taken up by the intended crop within the year of application because of strong soil retention. AVAIL polymers are fertilizer additives that were commercially developed to enhance availability of fertilizer phosphate. Knowledge of underlying mechanisms of phosphate solubilization would help to optimize the effectiveness of these polymers for different soils. This study compared different types and levels of AVAIL polymers in solubilizing (ad)sorbed and precipitated phosphate to gain insights into the mechanisms involved. Varying inputs of four newer forms of polymers and the original AVAIL (Original) were co‐reacted with one level of phosphate (ad)sorbed on ferrihydrite or noncrystalline Al hydroxide in batch (ad)sorption experiments or with Fe and Ca phosphate precipitates in dissolution experiments. Dissolved phosphate increased with increasing levels of co‐added polymers reacted with (ad)sorbents or phosphate precipitates. Across input levels evaluated, the Original AVAIL generally solubilized more phosphate from ferrihydrite than any of the new formulations. The Original and the new Liquid 2 formulation equally solubilized the greatest phosphate from Fe phosphate, whereas Liquid 2 solubilized more phosphate from Al hydroxide and Ca phosphate. (Ad)sorption and dissolution results implied competitive (ad)sorption and complexometric dissolution as key mechanisms. Our results suggest that the effectiveness of AVAIL polymers in soils depends on the level of added polymer charge relative to phosphate adsorption capacities or the types of phosphate minerals present.

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Section: Resultsmentioning

confidence: 99%

Phosphate solubilization from adsorbents and precipitates by different AVAIL polymers

Doydora

Thompson

Hesterberg

2020

Soil Science Soc of Amer J

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“…Moreover, split doses of EDTA at 2.5 mmol kg −1 was found to be more effective for Pb accumulation in shoots of buckwheat (Fagopyrum esculentum) and sunflowers (Helianthus annuus) than a single dose of 5.0 mmol kg −1 [59]. The selection of an appropriate chelating agent might depend on the soil type, as citric acid has, under certain conditions, been selected as a preferred chelating agent over EDTA or NTA [60]. Citric acid has been proposed as a natural chelation acid because it is readily broken down by microbes, giving it short soil persistence and reducing the risk of metal leaching into groundwater [31].…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Chelating Agents Used in Phytoextraction by Switchgrass of Lead Contaminated Soil

Hart

Koether

McElroy

et al. 2022

Plants

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Soil lead (Pb) contamination is a recognized environmental and global health problem. Phytoextraction of Pb using switchgrass (Panicum virgatum L.), a second-generation biofuel crop, is typically enhanced by soil chelation. The effectiveness of four different chelating agents, phytic acid (inositol hexaphosphate), citric acid, NTA (nitrilotriacetic acid), and EDTA (ethylenediaminetetraacetic acid) was examined in pot culture. Plants treated with EDTA (1 mM) showed significantly higher shoot Pb concentrations compared to control plants and plants treated with other chelates. Lead-solubility following phytoextraction was examined by soil washing using 0.01 and 0.05 M acetic acid as an extractant solution revealed no significant differences in Pb concentrations in soil among different chelate treatments and control. Furthermore, the effects of different concentrations (1, 2, 5 and 10 mM) of NTA on Pb phytoextraction of switchgrass were examined. Plants receiving 5 mM and 10 mM NTA had significantly higher foliage concentrations of Pb compared to plants treated with lower levels (1 and 2 mM) of NTA. Moreover, the effect of NTA application alone was significantly improved by a combined application of Triton X-100, an alkyl polyglucoside (APG); the Pb concentration in the foliage of switchgrass was more than doubled when treated with NTA combined with APG. The use of NTA combined with APG has great potential in improving phytoextraction efficiencies of switchgrass on Pb-contaminated soils.

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“…It seemed that phytoextraction assisted by chelators was technically feasible and should be in commercial use within few years. However, synthetic chelators such as EDTA were soon shown to have a slow degradation rate and high persistence in the soil, which increased the metal leaching risk to unacceptably high levels (Chen, Li, & Shen, 2004;Freitas, Nascimento, Biondi, Silva, & Souza, 2009;Freitas & Nascimento 2016). Consequently, EDTA is no more considered to assist soil phytoextraction, and a search for environmentallyfriendly chelators that could also induce the uptake of metals from contaminated soils started.…”

Section: Phytoextractionmentioning

confidence: 99%

“…Using low citric acid rates (< 30 mmol kg -1 ) also limits the phytoextraction process owing to insufficient metal mobilization from the soil (McGrath et al, 2006;Braud et al, 2019;Nascimento et al, 2020a), and this is the probable reason for unsuccessful results in some trials. Food grade citric acid could be used to make assisted-phytoextraction economically viable (Freitas & Nascimento 2016). A new approach of combining natural phytoextraction (hyperaccumulators) with the use of citric acid has also been proposed (Nascimento et al, 2020a;Nascimento, Hesterberg, Tappero, Nicholas, & Silva, 2020b), but field studies are needed to confirm the positive results obtained in controlled conditions.…”

Section: Phytoextractionmentioning

confidence: 99%

Using plants to remediate or manage metal-polluted soils: an overview on the current state of phytotechnologies

et al. 2021

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Soil contamination by metals threatens both the environment and human health and hence requires remedial actions. The conventional approach of removing polluted soils and replacing them with clean soils (excavation) is very costly for low-value sites and not feasible on a large scale. In this scenario, phytoremediation emerged as a promising cost-effective and environmentally-friendly technology to render metals less bioavailable (phytostabilization) or clean up metal-polluted soils (phytoextraction). Phytostabilization has demonstrable successes in mining sites and brownfields. On the other hand, phytoextraction still has few examples of successful applications. Either by using hyperaccumulating plants or high biomass plants induced to accumulate metals through chelator addition to the soil, major phytoextraction bottlenecks remain, mainly the extended time frame to remediation and lack of revenue from the land during the process. Due to these drawbacks, phytomanagement has been proposed to provide economic, environmental, and social benefits until the contaminated site returns to productive usage. Here, we review the evolution, promises, and limitations of these phytotechnologies. Despite the lack of commercial phytoextraction operations, there have been significant advances in understanding phytotechnologies' main constraints. Further investigation on new plant species, especially in the tropics, and soil amendments can potentially provide the basis to transform phytoextraction into an operational metal clean-up technology in the future. However, at the current state of the art, phytotechnology is moving the focus from remediation technologies to pollution attenuation and palliative cares.

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Degradability of natural and synthetic chelating agents applied to a lead-contaminated soil

Cited by 15 publications

References 33 publications

Phosphate solubilization from adsorbents and precipitates by different AVAIL polymers

Phosphate solubilization from adsorbents and precipitates by different AVAIL polymers

Evaluation of Chelating Agents Used in Phytoextraction by Switchgrass of Lead Contaminated Soil

Using plants to remediate or manage metal-polluted soils: an overview on the current state of phytotechnologies

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