Extraction of metals from a contaminated sandy soil using citric acid

Bassi, R.; Prasher, Shiv O.; Simpson, Benjamin K.

doi:10.1002/ep.670190415

Cited by 93 publications

(44 citation statements)

References 23 publications

(2 reference statements)

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“…Because structural Si was decreased by 0.74 from 100 g of raw biomass sample treated with 5 g sodium citrate, citrate might not act strictly as a trivalent binder. Sometimes, citrate can release a hydroxy ion and become a tetra-valent chelating agent [19], in which case it can potentially bind as much as one Si atom per citrate. The exact electronic state of Si in corn stover is not known, and further research is required.…”

Section: Inorganic Analysis Of Sodium Citrate-treated Solid Residuementioning

confidence: 99%

“…The chelation of essential metal nutrients with citric acid is very popular in the food and fertilizer industries. The citrate ion can form bi-, tri-, and multi-dentate complexes, depending upon the type of metal ion [19]. For example, metals like iron and nickel form bi-dentate, mononuclear complexes with two of the carboxylic acid groups of the citric acid molecule.…”

Section: Introductionmentioning

confidence: 99%

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Ash reduction of corn stover by mild hydrothermal preprocessing

Reza

Emerson

Uddin

et al. 2014

Biomass Conv. Bioref.

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Lignocellulosic biomass such as corn stover can contain high ash content, which may act as an inhibitor in downstream conversion processes. Most of the structural ash in biomass is located in the cross-linked structure of lignin, which is mildly reactive in basic solutions. Four organic acids (formic, oxalic, tartaric, and citric) were evaluated for effectiveness in ash reduction, with limited success. Because of sodium citrate's chelating and basic characteristics, it is effective in ash removal. More than 75 % of structural and 85 % of whole ash was removed from the biomass by treatment with 0.1 g of sodium citrate per gram of biomass at 130°C and 2.7 bar. FTIR, fiber analysis, and chemical analyses show that cellulose and hemicellulose were unaffected by the treatment. ICP-AES showed that all inorganics measured were reduced within the biomass feedstock, except sodium due to the addition of Na through the treatment. Sodium citrate addition to the preconversion process of corn stover is an effective way to reduced physiological ash content of the feedstock without negatively impacting carbohydrate and lignin content.

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Section: Inorganic Analysis Of Sodium Citrate-treated Solid Residuementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ash reduction of corn stover by mild hydrothermal preprocessing

Reza

Emerson

Uddin

et al. 2014

Biomass Conv. Bioref.

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“…Immobilization is thus not a permanent solution. Soil washing, a water based process that employs chemical and physical extraction processes to remove contaminants from the soil, has recently become a common ex-situ technique for remediating sites contaminated with organic and inorganic pollutants [10]. These techniques, to be economically and technically feasible, should lead to a volume reduction of hazardous materials and/or chemical transformation of contaminants to non-hazardous substances [9,11].…”

Section: Introductionmentioning

confidence: 99%

Polymer assisted ultrafiltration for copper?citric acid chelate removal from wash solutions of contaminated soil

2005

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The removal of heavy metals from aqueous systems such as wash-solutions of contaminated soil by using PolymerAssisted Ultrafiltration (PAUF) has been studied. For the extraction of metal ions from contaminated soil citric acid is used as a chelating agent. Cu 2+ as metal ion and the polymer polyethylenimine (PEI) as ligand were used in the various experiments. Optimal chemical conditions for copper complexation by citric acid were determined by means of complexation tests. The results showed that citric acid is able to chelate copper ions at pH 5.5, while decomplexation occurs at pH £ 2. Maximum bonding capacity (saturation condition) was 0.625 mg Cu 2+ per mg citric acid, meaning 2 mol Cu 2+ per mol citric acid. Complexation tests in the system polyethylenimine-citric acid-copper showed that the polymer is able to complex the copper-citric acid chelate at pH = 6 while release occurs at pH < 3. The saturation condition was 0.333 mg Cu 2+ per mg PEI. The ultrafiltration tests, carried out at three trans-membrane pressures (2, 3 and 4 bar), showed the possibility of using the PAUF technique for copper ion removal from aqueous solutions.

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“…[6,2,5,18,19,21]. Chemical leaching may destroy the soil structure and may require the addition of some inorganic acids (e.g., H 2 SO 4 , HNO 3 , HCl), organic acids (e.g., citric acid, malic acid, oxalic acid) or organic chelating agents (e.g., EDDS, EDTA) [2,36], which may lead to secondary pollution. Heavy metals in contaminated soils may be transported to ambient environment through biochemical processes if these soils are covered by unpolluted soils.…”

Section: Introductionmentioning

confidence: 99%