Determination of the aluminium complexing capacity of fulvic acids and natural waters, with examples from five New Zealand rivers

1996 ◽  
Vol 47 (1) ◽  
pp. 11 ◽  
Author(s):  
DJ Hawke ◽  
KJ Powell ◽  
JE Gregor
Keyword(s):  
Reaction Time ◽  
Natural Waters ◽  
Fulvic Acids ◽  
Operational Definition ◽  
Experimental Conditions ◽  
River Waters ◽  
Complexation Capacity ◽  
Complexing Capacity ◽  
Definition Of

An FIA technique with 7 s reaction time was used to analyse free plus labile Al in fulvic acid (FA) solutions and natural waters at pH 4.7, without the need for separation procedures. Titrations of these solutions using incremental pH or total Al were used to determine pH binding curves or estimates of the 'kinetic' Al complexation capacity (Al-CCk) respectively. The operational definition of Al-CCk relates to the capacity of a humic substance or natural water to bind Al through a 7-s FIA reaction time under defined experimental conditions of chromophore (CAS) concentration, ionic strength, and pH. Both Al binding strength and complexation capacity were greater than the corresponding Cu-CC (ISE) values. The Al-CCk measurements at pH 4.7 were 710 μmol Al g-1 v. 590 μmol Cu g-1. Al-CCk results (pH 4.7) were higher for soil FA (710 μmol g-1) than for aquatic FA (390 μmol g-1). Al-CCk results (pH 4.7) for five unfiltered river waters from different catchments gave results in the range 6.5-9.8 μmol Al L-1. The differences between total (natural) Al in the samples and Al-CCk were between 2.7 μM and 8.6 μM. Filtration experiments identified fractionation patterns between total (natural) Al and the fraction of Al-CCk not utilized. The Al titration of alginate, another component of natural organic matter, is reported.

Assessment of the Effect of Acidic Deposition on Canadian Lakes: Determination of Critical Loads for Sulphate Deposition

1993 ◽  
Vol 28 (3-5) ◽  
pp. 183-187 ◽  
Author(s):  
D. S. Jeffries ◽  
D. C. L. Lam
Keyword(s):  
Critical Load ◽  
Critical Loads ◽  
Acidic Deposition ◽  
Operational Definition ◽  
Eastern Canada ◽  
Wide Range ◽  
Sulphate Deposition ◽  
Definition Of ◽  
Terrain Characteristics

The operational definition of the “critical” load for wet SO4 deposition is that which does not increase the regional percent of lakes having pH≤6 for the portion of the population that historically had pH>6. Reviews of the effects of acidic deposition on aquatic biota show that the pH=6 threshold used to determine the critical load is sufficient to protect most organisms. It is inappropriate to specify a single critical load for the whole of eastern Canada due to variability in terrain sensitivity. The Atlantic provinces and easterr Quebec generally have very low critical loads (<8 kg. ha−1.yr−1). The terrain characteristics of this area dictate a critical load very close to background deposition. Lakes in southwestern Quebec and Ontario have critical loads of <8 to >20 kg.ha−1.yr−1 reflecting the wide range in terrain sensitivities that exist in each province.

scholarly journals Determination of humic and fulvic acids in river waters by concentration with anion exchanger followed by centrifugation.

1989 ◽  
Vol 5 (3) ◽  
pp. 363-365 ◽  
Author(s):  
Tsutomu NOMIZU ◽  
Masaki SANJI ◽  
Masataka HIRAIDE ◽  
Atsushi MIZUIKE
Keyword(s):  
Anion Exchanger ◽  
Fulvic Acids ◽  
Humic And Fulvic Acids ◽  
River Waters

Critical evaluation of the copper(II) solubilization method for the determination of the complexation capacity of natural waters

1977 ◽  
Vol 49 (14) ◽  
pp. 2358-2363 ◽  
Author(s):  
P. G. C. Campbell ◽  
Marc. Bisson ◽  
Robert. Gagne ◽  
Andre. Tessier
Keyword(s):  
Natural Waters ◽  
Critical Evaluation ◽  
Complexation Capacity

scholarly journals Performance determination of high-purity N2-PSA-plants

Adsorption ◽  
2020 ◽  
Vol 26 (7) ◽  
pp. 1215-1226
Author(s):  
A. Marcinek ◽  
J. Guderian ◽  
D. Bathen
Keyword(s):  
Performance Indicators ◽  
Molecular Sieves ◽  
Separation Processes ◽  
Experimental Conditions ◽  
Reference Process ◽  
Pressure Swing ◽  
Set Up ◽  
Definition Of ◽  
Experimental Findings

Abstract The global demand on highly purified gases provided by energy-efficient separation processes grows steadily since decades. An example of particular industrial relevance is nitrogen generated by pressure swing adsorption from compressed air. A kinetically based separation of oxygen from nitrogen is possible by means of carbon molecular sieves (CMS) since oxygen adsorbs remarkably faster in CMS than nitrogen. Even high product purities (5–1000 ppm O2) are easily achievable in commercial generators. However, only a few studies present experimental findings in this purity range. That comes as no surprise, since experimental conditions are not standardised and the determination of N2-PSA performance indicators still creates an experimental challenge. Moreover, the design of the set-up remarkably influences the experimental results. Thus it is the motivation of this study to develop a multi-step strategy, comprising the definition of a reference process, the derivation of explicit and implicit performance indicators based on either flow meter readings or macroscopic material balances, a verification strategy for experimentally obtained data, and an error consideration, which advices accuracy requirements for analysers and flow meters. The effect of cycle time and operating temperature on the performance indicators is exemplarily studied at high purities by means of the proposed strategy.

scholarly journals The use of ultra-violet visible spectroscopy to determination some antibiotics beta-lactam in some drugs

2010 ◽  
Vol 7 (1) ◽  
pp. 444-553
Author(s):  
Baghdad Science Journal
Keyword(s):  
Reaction Time ◽  
Pharmaceutical Preparations ◽  
Ultra Violet ◽  
Beta Lactam ◽  
Visible Spectroscopy ◽  
Experimental Conditions ◽  
Acid Media ◽  
Beta Lactam Antibiotics ◽  
Standard Additions

This research aims to use chemical reaction to determine some of beta lactam antibiotics which include cephalexin and ceftriaxone in some pharmaceuticals by formation Prussian Blue complexes and using them for the UV-Vis., determination of drugs at wavelengths range (700- 720)nm by reaction them with FeCl3 in the presence of reagent K3[Fe(CN)6] in acid media . The optimal experimental conditions for the complex formation have been studied such as volume of HCl , K3[Fe(CN)6] , FeCl3 ,temperature and reaction time .Analytical figures of merits obtained on applying the developed procedure for cephalexin and ceftriaxone resp. are Linearity,(2-10),(1-7)?g.ml-1 LOD(0.0601,0.0330) ?g.ml-1. The developed procedure has been successfully applied to the determination of the antibiotics Cephalexin and Ceftriaxone in pharmaceutical preparations , Cephalexin and Gramocef using direct and standard additions method. The analytical results match well with the drug contents as indicated by recovery percent had been found as follows (103.50%,93.27%.) for cephalexin, and ceftriaxone resp..

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