Effect of low molecular weight organic acids on adsorption and desorption
of fluoride on variable charge soils

Xu, Runsheng; Wang, Yayun; Zhao, Aiwu; Ji, Guoliang; Zhang, Hong

doi:10.1007/s10653-005-9023-z

Cited by 20 publications

(6 citation statements)

References 14 publications

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“…These acids, which have one or more carboxyl and hydroxyl groups, can form complexes with metal ions in soils and play an important role in soil processes such as mineral weathering, nutrient mobilization, and detoxification of Al (Hue et al , 1986; Bolan et al , 1994; Van Breemen et al , 2000). LMW organic acids can also change the surface chemical properties of variable charge soils (Xu et al , 2003; Xu et al , 2004a), and affect the adsorption of K + , NO 3 − and Cl − in these soils (Xu et al , 2004b; Xu et al , 2005a,b). Recently, the role of the organic acids in mineral weathering has been questioned, based on the premise that the concentration of the organic acids in soil solution is too small to have any significant effect on mineral dissolution rates (Drever & Stillings, 1997).…”

Section: Introductionmentioning

confidence: 99%

Adsorption of phthalic acid and salicylic acid by two variable charge soils as influenced by sulphate and phosphate

Xiao

Zhang

et al. 2007

European J Soil Science

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Low-molecular-weight (LMW) organic acids exist widely in soils, especially in the rhizosphere, and the adsorption of these acids may affect their reactions in soils. The adsorption behaviour of phthalic acid and salicylic acid by two variable charge soils (a Rhodic Ferralsol and a Haplic Acrisol) was investigated. Both soils exhibited great adsorption capacity for these organic acids, with a greater affinity for phthalic acid. The Rhodic Ferralsol adsorbed more organic acids of both kinds than the Haplic Acrisol, which was consistent with the content of iron and aluminum oxides in the two soils. The iron oxides in these soils played a significant role in adsorption of the organic acids, whilst the soil aluminosilicate minerals, such as kaolinite, showed a small adsorption capacity. The presence of phosphate and sulphate caused a decrease in the adsorption of both organic acids because of their competition with them for sorption sites. The phosphate showed a bigger inhibition on the adsorption than sulphate as a result of a greater amount of phosphate adsorbed by the soils. The adsorption of both organic acids was affected by pH only slightly at pH < 4.5. However, the adsorption decreased with the increase in pH at pH > 4.5. A similar trend was observed for the phosphate system, but the opposite was seen for the sulphate system. This suggests that the inhibition of sulphate on the adsorption of the organic acids decreased with the increase in pH, because the adsorption of sulphate decreased strongly with increasing pH.

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Section: Introductionmentioning

confidence: 99%

Adsorption of phthalic acid and salicylic acid by two variable charge soils as influenced by sulphate and phosphate

Xiao

Zhang

et al. 2007

European J Soil Science

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“…Begin and Fortin (2003) proposed that specific F − adsorption sites, associated with crystalline Al oxides and commonly shared F − and oxalate adsorption sites, involving less crystalline Al oxide phases, were present in a Spodosol A horizon. Xu et al, 2006 also observed that increased oxalate concentration reduced F − adsorption, suggesting competitive adsorption for exchange sites. Ligand exchange between oxalate and F − for common exchange sites was postulated to occur when oxalate concentration >> F − concentration, and that F − re-adsorption on these common sites was possible.…”

Section: Fluoride Additions and Aluminium Transportmentioning

confidence: 85%

“…Similar trends have been observed by Omueti and Jones (1977) for 15 acidic surface horizons and Zhang, Zhang, and Yu (1987) working with Ultisol subsoils. Fluoride sorption by soil has been observed to increase DOC concentrations in solution (Elrashedi and Lindsay, 1987;Totsche et al, 2000), suggesting competitive adsorption-desorption between various LMWOA, such as oxalate and F − for common adsorption sites (Xu, Wang, Zhao, Ji, & Zhang, 2006;Zutic & Stumm, 1984). Several studies have shown competitive adsorption between SO 4 2− , oxalate and F − for similar OH − exchange sites on soil metal oxides (Courchesne & Landry, 1994;Liu, He, Colombo, & Violante, 1999;Zhang et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

Oxalate‐fluoride anion exchange in alpine tundra soil: Impact on aluminium transport

Evans

Jacobs

2020

European J Soil Science

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Anion exchange between ubiquitous low-molecular-weight organic acids (LMWOA), such as oxalate, and surface-retained inorganic anions, such as F − , SO 4 2− and OH − , can play a critical role in Al bioavailability and transport in acidic alpine tundra soil. A series of batch equilibration and composite soil column leaching studies were conducted to examine anion exchange reactions between F − , oxalate and OH − , and the impact of increased soil solution F − concentration on Al transport. The addition of either F − or oxalate to soil suspensions resulted in significantly higher solution pH, suggesting F − and oxalate exchange with surface -OH groups. Distinct stages of OH − release were observed for all soil horizons leached with 1.32 × 10 −3 mol l −1 F − , with OH − release decreasing in the order O/A1~A2> > Bw. A similar OH − release pattern was observed in the O/A1 horizon for the 7.81 × 10 −4 mol l −1 oxalate treatment, suggesting that both F − and oxalate may be competing for common exchange sites in the O/A1 horizon. Fluoride displacement by oxalate, in batch equilibration experiments, was observed for both the 2.84 × 10 −4 mol l −1 and 7.81 × 10 −4 mol l −1 oxalate treatment. Individual soil horizons leached with 7.81 × 10 −4 mol l −1 oxalate exhibited increased F − leaching in the order O/A1 > A2~Bw, with pulsed F − movement being observed in the O/A1 horizon. Soil columns eluted with 1.32 × 10 −3 mol l −1 F − exhibited increased Al solubilization and transport, with Al leaching increasing in the order Bw > A2 > O/A1. Sequential leaching of soil columns in the order D. I. H 2 O ! 1.32 × 10 −3 mol l −1 F − ! D.I. H 2 O ! 7.81 × 10 −4 mol l −1 oxalate indicated that previously adsorbed F − was displaced by oxalate. Displacement of F − by oxalate increased in the order O/A1 > A2 > Bw. Hydroxyl displacement by both F − and oxalate may be an important source of acid neutralization in a soil wetting front, affecting Al speciation and transport. Highlights• Oxalate and F − compete for similar OH − exchange sites, increasing soil pH.• Adsorbed F − can be displaced by oxalate anions.• Al solubilization increases with F − adsorption in alpine tundra soil.

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“…This is because when the concentration of organic acid is lower, the pH and negative charges are significantly reduced, which promotes the desorption of heavy metals. However, with the increase of organic acid concentration, organic acids, Cd and Mn form ternary surface complexes on the soil surface, which promote adsorption and inhibit desorption (Xu et al, 2005). Under the fructose treatment, different dosages of fructose did not significantly reduce the soil pH, but the activation of heavy metals still had a positive effect on the first, third and seventh days.…”

Section: Frontiers In Environmental Sciencementioning

confidence: 96%

Effects of single and combined applications of three root exudates of Sedum plumbizincicola on the phytoremediation efficiency of paddy soil contaminated with Cd

Xing

Cao

Tan

et al. 2023

Front. Environ. Sci.

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Root exudates are carriers for the transfer of material, energy and information between plant roots and soils. Plants encountering environmental stresses such as heavy metal pollution adapt to the environment by producing and secreting root exudates. In this study, laboratory soil culture experiment and pot experiment with Sedum plumbizincicola were used to study the effects of single and combined application of three root exudates, citric acid, glycine, and fructose, on the Cd-activation and phytoremediation of Cd-contaminated paddy soil. Results from the soil culture experiment showed that for the single application of root exudates, all three root exudates significantly activated the Cd in soil as presented by the increased content of diethylenetriamine pentaacetic acid extracted Cd (DTPA-Cd). In Particular, citric acid (SC) at a relatively low concentration (2 mmol/kg) exhibited the best Cd activation efficiency by increasing DTPA-Cd in the soil by 66.12%. For the combined application of root exudates, citric acid in combination with glycine (SC + G, 1:3) had the best activation effect on the Cd in the soil. In the phytoremediation pot experiment, both the single application of citric acid at a low concentrate (1 mmol/kg) and the combined application of citric acid and glycine (1:1) significantly reduced the total Cd and DTPA-Cd in the soil and increased the biomass and the content of Cd in S. plumbizincicola; thus, the phytoremediation efficiency of Cd-contaminated soil increased by 42.33% and 35.61%. The results from this study suggest that citric acid plays a crucial role in Cd activation and phytoremediation with single or combined applications with glycine. However, the mechanisms under the synergetic interaction between citric acid and glycine require further investigation.

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Effect of low molecular weight organic acids on adsorption and desorption of fluoride on variable charge soils

Cited by 20 publications

References 14 publications

Adsorption of phthalic acid and salicylic acid by two variable charge soils as influenced by sulphate and phosphate

Adsorption of phthalic acid and salicylic acid by two variable charge soils as influenced by sulphate and phosphate

Oxalate‐fluoride anion exchange in alpine tundra soil: Impact on aluminium transport

Effects of single and combined applications of three root exudates of Sedum plumbizincicola on the phytoremediation efficiency of paddy soil contaminated with Cd

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