Organocation speciation. I. A comparison of the interactions of methylene blue and paraquat with bentonite and humic acid

1980 ◽  
Vol 58 (6) ◽  
pp. 547-554 ◽  
Author(s):  
R. D. Guy ◽  
D. R. Narine ◽  
S. deSilva
Keyword(s):  
Methylene Blue ◽  
Humic Acid ◽  
Ionic Strength ◽  
Alkaline Earth ◽  
Natural Waters ◽  
Exchange Capacity ◽  
Model System ◽  
Spectrophotometric Analysis ◽  
Clay Surface ◽  
Alkaline Earth Cations

A model System composed of bentonite, humic acid (HA), polystyrene sulphonic acid (PSSA), methylene blue (MB), and paraquat was used to characterize the possible interactions of organocations in natural waters. The adsorption and desorption studies with bentonite indicated that the clay had a strong preference for the organocations over alkali and alkaline earth cations. Paraquat saturated the bentonite up to the cation exchange capacity whereas methylene blue did not completely saturate the clay but did form methylene blue aggregates on the clay surface. The aggregates could be readily removed by washing with distilled water. The organocation interactions with the anionic polyelectrolytes were more susceptible to changes in pH or ionic strength. Paraquat could be completely desorbed from HA and PSSA by raising the solution ionic strength to 0.1. Methylene blue could not be completely removed from the humic acid but could be removed from PSSA by raising the ionic strength to 0.1. The studies indicate that a combination of dialysis separations, variation of ionic strength, and spectrophotometric analysis could be used to determine the free paraquat and the bound paraquat susceptible to changes in environmental levels of pH and ionic strength.

A contribution to the electrochemiluminiscence determination of cobalt with luminol

1984 ◽  
Vol 49 (7) ◽  
pp. 1635-1641 ◽  
Author(s):  
Jiří Herejk ◽  
Záviš Holzbecher
Keyword(s):  
Ionic Strength ◽  
Alkaline Earth ◽  
Supply Voltage ◽  
Alkaline Solutions ◽  
Appreciable Effect ◽  
Concentration Region ◽  
Experimental Conditions ◽  
Limit Of Determination ◽  
Alkaline Earth Cations

The effect was studied of experimental conditions (pH, ionic strength, supply voltage, and type of electrodes) and of the presence of some cations and anions on the luminiscence of aqueous solutions of luminol generated by alternating current. Of the ions studied, Co2+ and Br- affected the electrochemiluminiscence (ECL) of luminol to the highest extent. Co2+ ions increase the ECL of luminol in alkaline solutions in concentrations cCo2+ = 10-3-6.10-6 mol l-1, the limit of determination of cobalt is 0.13 μg ml-1. In the presence of bromide in concentrations higher than 0.2 mol l-1, however, Co2+ lowers the ECL intensity over the concentration region of cCo2+ = 10-2-2.10-4 mol l-1. Alkali metal and alkaline earth cations as well as small amount of Pb2+, Zn2+, Cu2+, Cr3+, and Fe3+ have no appreciable effect on the ECL of luminol.

Investigation of V(V) interaction with Humic Acid in aqueous solution using anion-exchange Ion Chromatography

2021 ◽  
Author(s):  
Lucija Knežević ◽  
Elvira Bura-Nakić
Keyword(s):  
Humic Acid ◽  
Ionic Strength ◽  
Anion Exchange ◽  
Ion Chromatography ◽  
Natural Waters ◽  
Detection System ◽  
Chemical Species ◽  
Research Report ◽  
Complexing Agent ◽  
Model Solutions

<p>The distribution of V chemical species in natural waters has been scarcely studied mainly due to its high reactivity and wide variety of co-existing forms depending on number of factors including metal concentration, pH, Eh, ionic strength, the presence of complexing ligands etc. <sup>1</sup> Importance of V speciation studies lies in the dependence of toxicity and bioavailability upon different chemical species that V takes form of in natural waters, with V(V) being most toxic and soluble <sup>4</sup>. Although thermodynamic calculations predict V(V) as dominant species in well oxidized marine environments, V(IV) is also reported to be present due to its ability to form stable complexes with Dissolved Organic Matter (DOM) related ligands found in natural waters <sup>2–6</sup>. Furthermore, previous research report that Humic Acid (HA) acts as an adsorbent and complexing agent for many trace metals (Cu<sup>2+</sup>, Zn<sup>2+</sup>, Cd<sup>2+</sup>, Fe<sup>2+</sup>). However, HA impact on V speciation and potential removal from the water column of natural aquatic systems is still unclear <sup>7</sup>.</p><p>Interaction of V(V) with HA was investigated in model solutions under different conditions using anion-exchange based Ion Chromatography with UV/Vis detection system. The goal of the research was to mimic natural conditions, as experimentally possible, in order to assess likely contribution of HA to changes in V speciation and potential removal from the solution by adsorption on HA colloids. Temporal study on V(V) reduction kinetics was conducted using strong chelator (EDTA) which was added in the filtrated solution prior to measurement in order to stabilize distribution of V species in the model solutions. Removal of V(V) from the solution on HA particles was quantified using calibration curves. Desorption experiments were performed with the addition of EDTA in un-filtrated solutions 24 hours before measurement.</p><p>Research showed that V interaction with HA is highly dependant on ionic strength of solution as well as ratios between V(V) and HA present in the solution. Desorption experiments showed almost complete recovery of V in the solutions with higher ionic strength, mainly in the form of V(IV). Observed reduction and removal of V(V) from the solution on the pH of natural waters suggest high impact of DOM on V speciation and consequently its toxicity and bioavailability.  </p><p><strong>References:</strong></p><p>1           P. N. Linnik and R. P. Linnik, Russ. J. Gen. Chem., 2018, <strong>88</strong>, 2997–3007.</p><p>2           J. P. Gustafsson, Appl. Geochemistry, 2019, <strong>102</strong>, 1–25.</p><p>3           P. Bernárdez, N. Ospina-Alvarez, M. Caetano and R. Prego, Environ. Chem., 2013, <strong>10</strong>, 42–53.</p><p>4           D. Wang and S. A. Sañudo Wilhelmy, Mar. Chem., 2009, <strong>117</strong>, 52–58.</p><p>5           K. Hirayama, S. Kageyama and N. Unohara, Analyst, 1992, <strong>117</strong>, 13–17.</p><p>6           D. Wang and S. A. Sañudo-Wilhelmy, Mar. Chem., 2008, <strong>112</strong>, 72–80.</p><p>7           Y. Yu, M. Liu and J. Yang, Chem. Ecol., 2018, <strong>34</strong>, 548–564.</p>

Factors Affecting the Adsorption of Complexed Heavy Metals on Hydrous Al2O3

1985 ◽  
Vol 17 (6-7) ◽  
pp. 1017-1028 ◽  
Author(s):  
H. A. Elliott ◽  
C. P. Huang
Keyword(s):  
Heavy Metals ◽  
Ionic Strength ◽  
Activity Coefficient ◽  
Alkaline Earth ◽  
Metal Adsorption ◽  
Alumina Surface ◽  
Factors Affecting ◽  
Factors Influencing ◽  
System Temperature ◽  
Alkaline Earth Cations

Factors influencing the adsorption behavior of heavy metals, viz Cu(II), Zn(II), Cd(II), Pb(II) and Ni(II), onto Al2O3 from aqueous solutions containing complexing ligands were investigated using batch adsoption experiments. For the Cu(II)/NTA/ γ-Al2O3, system, increasing the system ionic strength reduced Cu adsorption through activity coefficient and surface electrical double layer effects. The presence of alkaline earth cations (Ca(II) and Mg(II)) also reduced Cu removal from solution by lowering the ability of NTA to prevent Cu(OH)2 precipitation and through specific adsorption to the alumina surface. The adsorption of the heavy metals on Al2O3 from solutions containing NTA followed the sequence: Cu >Zn > Cd > Pb ≈ Ni. Increase in system temperature tended to decrease metal adsorption.

Sorption of Cadmium and Lead by Chelating Ion Exchangers Ostsorb OXIN, Ostsorb DETA, and Ostsorb DTTA

1994 ◽  
Vol 59 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
Ladislav Svoboda ◽  
Petr Vořechovský
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Sodium Perchlorate ◽  
Exchange Capacity ◽  
Chloride Ions ◽  
Point Of View ◽  
Alkaline Media ◽  
Ion Exchangers ◽  
Acidic Media ◽  
Cadmium And Lead

The properties of cellulose chelating ion exchangers Ostsorb have been studied in the sorption of cadmium and lead from aqueous solutions. The Cd(II) and Pb(II) ions are trapped by the Ostsorb OXIN and Ostsorb DETA ion exchangers most effectively in neutral and alkaline media but at these conditions formation of stable hydrolytic products of both metals competes with the exchange equilibria. From this point of view, Ostsorb DTTA appears to be a more suitable sorbent since it traps the Pb(II) and Cd(II) ions in acidic media already. Chloride ions interfere with the sorption of the two metals by Ostsorb DTTA whereas the ionic strength adjusted by the addition of sodium perchlorate does not affect the exchange capacity of this ion exchanger.

Corrigendum to: Effect of humic acid, fulvic acid, pH, ionic strength and temperature on 63Ni(II) sorption to MnO2

2020 ◽  
Vol 108 (7) ◽  
pp. 591
Author(s):  
Guodong Sheng ◽  
Jun Hu ◽  
Han Jing ◽  
Shitong Yang ◽  
Xuemei Ren ◽  
...  
Keyword(s):  
Humic Acid ◽  
Ionic Strength ◽  
Fulvic Acid ◽  
Acid Ph
Sign in / Sign up

Export Citation Format

Share Document