• Korean Journal of Environmental Agriculture
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• v.37 no.1
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• pp.21-27
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• 2018

BACKGROUND: Although 1 M $NH_4OAc$ (pH 7.0) is predominantly used as the extractant of exchangeable cations in agricultural soils, this method is unsuitable for extracting the cations in saline and calcareous soils. This study was performed to select a proper method to determine exchangeable cations in vinyl greenhouse soils. METHODS AND RESULTS: Exchangeable cations (Ca, Mg, K, Na) in saline vinyl greenhouse soils were determined after extraction with 1 M $NH_4OAc$ (pH 7.0 and 8.5) and 1 M alcoholic $NH_4Cl$ (pH 8.5). Sum of exchangeable cations of the soils extracted with 1 M $NH_4OAc$ at pH 7.0 was 1.9-2.5 times greater than soil cation exchange capaity determined at pH 7.0, even though soluble salts were pre-removed. A similar result was found when the cations were extracted with 1 M $NH_4OAc$ at pH 8.5. Those results are mostly due to the overestimation of exchangeable Ca and Mg, linked to a partial dissolution of sparingly soluble salts in $NH_4OAc$ solution. When extracted with 1 M alcoholic $NH_4Cl$ at pH 8.5, extractable Ca and Mg decreased significantly due to the lower solubility of Ca and Mg carbonates in the extractant. And the sum of exchangeable cations was very close to the corresponding exchange capacity of soils. CONCLUSION: Alcoholic $NH_4Cl$ (pH 8.5) is proposed as a reliable extractant in determination of exchangeable cations in saline vinyl greenhouse soils. And soluble salts should be removed prior to the extraction of exchangeable cations.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.457-464
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• 2020

In this study, extraction of uranium(VI) from an aqueous nitric acid solution was investigated using tri-n-butyl phosphate (TBP) as an extractant in an ionic liquid, 1-alkyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ([Cnmim][Tf2N]). The distribution ratio of U(VI) in 1.1 M TBP/[Cnmim][Tf2N] was significantly high when the concentration of nitric acid was low. The value of the distribution ratio decreased as the concentration of the nitric acid increased at lower acidities, and then increased with a nitric acid concentration of up to 8 M. This can be attributed to the different extraction mechanisms of U(VI) based on nitric acid concentrations. Thus, a cation exchange at low acidity levels and an ion-pair extraction at high acidity levels were suggested as the extraction mechanism of U(VI) in the TBP/[Cnmim][Tf2N] system.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.223-235
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• 2006

Soil testing laboratories unfamiliar with turfgrasses will often overestimate the plant's need for phosphorus and underestimate the need for potassium. This is partly due to differences in rooting between grasses and many garden plants and crops. The grasses are generally more efficient in extracting phosphorus from the soil, reducing their need for phosphorus fertilizer. The fact that crop yield is often the primary objective in field crop production, and is usually of little interest in turfgrass management, may affect soil test interpretation for potassium. Potassium levels above those required for maximum tissue yield of grasses may improve stress tolerance and turfgrasses will usually benefit from higher applications of this element. There are also diffrrences in soil testing philosophies. Some laboratories use the sufficiency level of available nutrients(SLAN) approach, whereas others prefer the basic cation saturation ratio(BCSR) approach. Some will use a combination of the two methods. The use of the BCSR theory easily lends itself to abuse and questionable fertilizer applications and products are sometimes recommended citing imbalances in cation ratios. The usefulness of the BCSR ratio theory of soil testing varies with soil texture and interpretations on tests performed on sand-based media are particularly a problem. Other soil testing problems occur when sand-based media used on sports fields and golf greens contain free calcium carbonate. The ammonium acetate extractant at pH 7.0 dissolves excessive amounts of calcium that can bias cation exchange capacity measurements and measurements of cation ratios. Adjusting the pH of the extractant to 8.1 can improve the accuracy of the testing procedure for calcareous media.

• Resources Recycling
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• v.12 no.1
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• pp.25-32
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• 2003

A study on the separation of heavy metals such as iron, copper, zinc and nickel from electroplating waste water has been investigated. The results showed that the PC-88A was more effective extractant for the extraction of zinc and the efficiency of zinc was to be about 100% at pH 2.5. And copper and nickel were extracted about 100% at pH 2 and more than 90% at pH 4～5 with LIX 84, respectively. On the other hand, in the case of solvent extraction of electroplating waste water(Acid-Alkali type) containing heavy metals, the ferric ion was first extracted at pH 2∼2.5 with 20% Naphthenic acid or 10% Versatic acid-10. And then, copper and zinc were extracted at pH 2 with 3% LIX 84 and at pH 2.5∼3 with 20% PC-88A respectively, remaining nickel in the raffinate. In this manner, the heavy metals in electroplating waste water could be effectively separated with solvent extraction method.