scholarly journals Effects of exogenous addition of cadmium on cadmium speciation in hyperaccumulator of Sedum alfredii Hance

2021 ◽  
Vol 245 ◽  
pp. 03016
Author(s):  
Jiawei Yang ◽  
Lin Sun ◽  
Xing Shen ◽  
Changsheng Peng
Keyword(s):  
Extraction Method ◽  
Extraction Rate ◽  
Chemical Extraction ◽  
Sedum Alfredii ◽  
Continuous Extraction ◽  
Exogenous Addition ◽  
Cadmium Speciation ◽  
Continuous Chemical ◽  
Extraction Agent ◽  
Rate Of Extraction

Continuous chemical extraction is considered to be one of the most common methods for the extraction of heavy metals speciations in plants. However, the basis for the extraction order of this method is not explained and has been rarely studied. In this paper, we analyzed the speciations of cadmium in plants by a four-step continuous extraction method. The extraction sequence of ethanol and water was studied to study the effect of extraction sequence on the extraction rate of extraction agent. The results showed that cadmium exists mostly in NaCl extraction state and the extraction rate of the two kinds of extraction agents decreased when the order of ethanol and water was changed.

Study on Pure Aqueous Extraction Method of PHB/Ectoine Co-Products Based on Osmotic Downshock

2014 ◽  
Vol 955-959 ◽  
pp. 3377-3380 ◽  
Author(s):  
Qing Chen ◽  
Te Wang ◽  
Jin Dan Zhao ◽  
Fu Hui Kang ◽  
Yi Ming Zhang ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Hollow Fiber ◽  
Extraction Method ◽  
Pure Water ◽  
Aqueous Extraction ◽  
Extraction Rate ◽  
Extraction Temperature ◽  
Optimal Conditions ◽  
Pressure Extraction ◽  
Osmotic Downshock

The simultaneously co-production of Poly-β-hydroxybutyrate (PHB) and ectoine in a process (PHB/Ect co-production) and co-products extraction have great significant for reducing the manufacture cost and promoting industrialization of PHB and ectoine. The pure aqueous extraction method based on osmotic downshock was used for the extraction of PHB/Ect co-products byH. salina. The effects of osmotic pressure, extraction temperature and extraction time on the extraction rate of PHB were investigated. The ectoine was extracted and purified by the techniques of hollow fiber and ion exchange. The optimal conditions for PHB extraction were osmotic downshock in pure water, extraction temperature at 60 °C and extraction for 4 h. The extraction rate of PHB was 87.5%. The extraction rate of ectoine was 84.2%.

Development of a Soil Bioassay for Triclopyr Residues and Comparison with a Laboratory Extraction

2010 ◽  
Vol 24 (4) ◽  
pp. 538-543 ◽  
Author(s):  
R. D. Ranft ◽  
S. S. Seefeldt ◽  
M. Zhang ◽  
D. L. Barnes
Keyword(s):  
Standard Deviation ◽  
Field Trial ◽  
Extraction Method ◽  
Response Curve ◽  
The Other ◽  
Chemical Extraction ◽  
Plant Soil ◽  
Broad Leaf ◽  
Soil Bioassays ◽  
Residual Herbicide

The use of triclopyr for the removal of woody and broad-leaf vegetation in right-of-ways and agricultural settings has been proposed for Alaska. Triclopyr concentrations in soil after application are of concern because residual herbicide may affect growth of subsequent vegetation. In order to measure triclopyr residues in soil and determine the amount of herbicide taken up by the plant, soil bioassays were developed. Four agricultural species, turnip, lettuce, mustard, and radish, were tested to determine sensitivity to triclopyr in a 1-wk bioassay. The sensitivity (I50) of turnip, lettuce, mustard, and radish was 0.33 ± 0.05 kg ai ha−1, 0.78 ± 0.11 kg ai ha−1, 0.78 ± 0.07 kg ai ha−1, and 0.85 ± 0.10 kg ai ha−1 (mean ± SE), respectively. Mustard was the most consistent crop in the bioassay with a midrange response to triclopyr and lowest standard deviation for germination as compared to the other species. Thus, it was used in a bioassay to determine triclopyr concentrations in a field trial. The bioassay of mustard closely matched residual amounts of triclopyr in a field trial determined by chemical extraction. Estimates of residual triclopyr concentrations using the bioassay method were sometimes less than the triclopyr concentration determined using a chemical extraction. These differences in concentrations were most evident after spring thaw when the chemical extraction determined there was enough triclopyr in the soil to reduce mustard growth over 60%, yet the bioassay measured only a 10% reduction. The chemical extraction method may have identified nonphototoxic metabolites of triclopyr to be the herbicidal triclopyr acid. These methods, when analyzed together with a dose–response curve, offer a more complete picture of triclopyr residues and the potential for carryover injury to other plant species.

Odour, covering and ventilation

2009 ◽  
Vol 59 (7) ◽  
pp. 1377-1384 ◽  
Author(s):  
D. Sivil ◽  
J. A. Hobson
Keyword(s):  
Mass Transfer ◽  
Emission Rate ◽  
Extraction Rate ◽  
Critical Flow ◽  
Residence Times ◽  
Minimum Rate ◽  
Maximum Value ◽  
Odour Concentration ◽  
Rate Of Extraction ◽  
Concentration Limits

A technique is described based on the decay in concentration of added SF6 to measure L0, the rate of leakage from an enclosure with no extraction of air. It is believed this measurement is much more precise than measurements of E0, the minimum rate of extraction which just prevents leakage. Three out of four enclosures studied had L0 values equating to residence times of air that were well under one hour. Relationships were developed between extraction rate and concentration and emission rate for enclosed odour sources based on mass transfer from water to air. These could be used to assess the benefits of minimising extraction rates while remaining within concentration limits set on the grounds of corrosion or toxicity. From these relationships a critical flow can be identified, termed Q50, at which both the emission rate and concentration of a particular species are at 50% of their maximum value. In any particular system, Q50 for one species, such as H2S, will in general not be the same as for another species, nor for odour concentration. As a consequence the benefit of reducing extraction rates based on H2S may not appear as good as it would based on an assessment of odour concentration. A second consequence is that as the rate of air extraction is varied, the ratio between two species or between H2S and odour concentration, is likely to vary.

scholarly journals Enhanced lipid extraction from microalgae in biodiesel production

2017 ◽  
Vol 71 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Myung-Gyun Kim ◽  
Hyun-Wook Hwang ◽  
Antony Nzioka ◽  
Young-Ju Kim
Keyword(s):  
Conversion Rate ◽  
Extraction Method ◽  
Extraction Efficiency ◽  
Fatty Acid Content ◽  
Lipid Extraction ◽  
Microwave Treatment ◽  
Extraction Process ◽  
Biodiesel Production ◽  
Chemical Extraction ◽  
Operation Control

In order to secure more effective lipid extraction method, this research investigated new lipid extraction method using laser with absorbent and sought its optimum operation control. In addition, this study compared lipid extraction efficiency and FAME conversion rate between laser extraction method at optimum condition and existing extraction method. Results from experiments for optimizing lipid extraction method using laser showed that the maximum extraction efficiency (81.8%) was attained when using laser with an output capacity of 75Wh/L. Extraction efficiency increased up to 90.8% when microwave treatment as pretreatment process was conducted. Addition of absorbents during lipid extraction process with laser showed higher extraction efficiency than laser and chemical method. It was also found that laser extraction method with absorbent had higher total fatty acid content (853.7 mg/g oil) in extracted lipid than chemical extraction method (825.4 mg/g oil). Furthermore, it had the highest FAME conversion rate (94.2%).

The Extraction of Metal Contaminants Using Supercritical Carbon Dioxide

2018 ◽  
Vol 7 (1) ◽  
pp. 52-60
Author(s):  
Sesik Kang ◽  
Minsu Ju ◽  
Junghoon Kim
Keyword(s):  
Supercritical Co2 ◽  
Extraction Method ◽  
Solution Process ◽  
Extraction Rate ◽  
Waste Reduction ◽  
Environmentally Benign ◽  
Sample Matrix ◽  
Water Based ◽  
Maximum Extraction ◽  
Static Extraction

Conventional decontamination methods utilize water-based systems, which generate high amounts of secondary wastes. Herein, the authors describe an environmentally benign decontamination method using liquid and supercritical CO2. The use of CO2 as a solvent affords effective waste reduction by its ability to be recycled, thereby leaving behind only the contaminants upon its evaporation. In this study, a CO2 solution process was assessed using t-butyl salen (t-salen), dicyclohexano-18Crown6 (DC18C6), 8-hydroxyquinoline (8-HQN), perfluoro-1-octanesulfonic acid tetra-ethylammonium salt (NEt4PFOSA), and pentadecafluorooctanoic acid ammonium salt (NEt4PFOA) to extract spiked radioactive contaminants (Nb, Zr, Co, Sr) from an inert sample matrix, namely with filter paper. With the static extraction method, Sr was extracted with a maximum extraction rate of 97%, and Nb was extracted with a maximum extraction rate of 75%. Additionally, the authors were also able to extract Co and Zr with maximum extraction rates of 73% and 64%, respectively.

PREPARATION OF ω-BROMOALKAN-1-OLS FROM α,ω-ALKANEDIOLS BY THE CONTINUOUS EXTRACTION METHOD

1983 ◽  
Vol 15 (1-2) ◽  
pp. 63-67 ◽  
Author(s):  
F. Camps ◽  
J. M. Casamor ◽  
J. Coll ◽  
A. Guerrero ◽  
M. Riba
Keyword(s):  
Extraction Method ◽  
Continuous Extraction

scholarly journals Estimation of Spiecies of Zinc, Lead, Copper and Cadmium in Fly Ash by a Sequencial Chemical Extraction Method.

2001 ◽  
pp. 79-90 ◽  
Author(s):  
Masaki TAKAOKA ◽  
Yasuhiro KURAMOTO ◽  
Nobuo TAKEDA ◽  
Takeshi FUJIWARA
Keyword(s):  
Fly Ash ◽  
Extraction Method ◽  
Chemical Extraction

Extraction of Admixed Polymers from Natural Rubber Vulcanizates

1967 ◽  
Vol 40 (5) ◽  
pp. 1553-1559 ◽  
Author(s):  
W. Cooper ◽  
R. K. Smith
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Continuous Extraction ◽  
High Molecular Weight Polymer ◽  
Molecular Weight Polymer ◽  
Considerable Uncertainty ◽  
Consequence Analysis ◽  
Natural Rubber Vulcanizates ◽  
Rate Of Extraction

Abstract Extraction by solvent of admixed poly(methyl methacrylate) or polystyrene from natural rubber vulcanizates is dependent on the crosslink density, the solvent, the molecular weight of the polymer, and the size of sample extracted. High molecular weight polymer is extracted very slowly, and in some cases several weeks of continuous extraction have been found necessary. The rate of extraction is increased, as would be expected, by solvents which swell the rubber strongly, and by increase in temperature of extraction. In some cases the vulcanization procedure degrades the polymer, while in others there is a possibility of cocrosslinking the rubber and polymer. Graft copolymers from rubber and methyl methacrylate or styrene possess similar characteristics when vulcanized. In consequence, analysis of the content of free homopolymer is subject to considerable uncertainty. In the analysis of these rubber and polystyrene mixtures by ozonolysis, polystyrene was found to be very susceptible to attack by ozone.

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