Adsorption of Arsenate and Arsenite by Iron-Treated Activated Carbon and Zeolites: Effects of pH, Temperature, and Ionic Strength

2005 ◽  
Vol 40 (4) ◽  
pp. 723-749 ◽  
Author(s):  
Kelly Payne ◽  
Tarek Abdel-Fattah
Keyword(s):  
Activated Carbon ◽  
Ionic Strength ◽  
Effects Of Ph

Effects of pH and ionic strength on the cation exchange capacity of soils with variable charge

Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 93 ◽  
Author(s):  
GP Gillman
Keyword(s):  
Ionic Strength ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Surface Soils ◽  
Ph Values ◽  
Variable Charge ◽  
Effects Of Ph ◽  
Variable Charge Soils

The cation exchange capacity of six surface soils from north Queensland and Hawaii has been measured over a range of pH values (4-6) and ionic strength values (0.003-0.05). The results show that for variable charge soils, modest changes in electrolyte ionic strength are as important in their effect on caton exchange capacity as are changes in pH values.

Evaluation of effects of pH and ionic strength on colloidal stability of IgG solutions by PEG-induced liquid-liquid phase separation

2016 ◽  
Vol 145 (18) ◽  
pp. 185101 ◽  
Author(s):  
Ronald W. Thompson ◽  
Ramil F. Latypov ◽  
Ying Wang ◽  
Aleksey Lomakin ◽  
Julie A. Meyer ◽  
...  
Keyword(s):  
Phase Separation ◽  
Ionic Strength ◽  
Liquid Phase ◽  
Colloidal Stability ◽  
Liquid Phase Separation ◽  
Effects Of Ph ◽  
Liquid Liquid Phase Separation

Effects of pH, aluminium, and soft water on larvae of the amphibians Bufo bufo and Triturus vulgaris

2006 ◽  
Vol 84 (11) ◽  
pp. 1668-1677 ◽  
Author(s):  
Jon K. Skei ◽  
Dag Dolmen
Keyword(s):  
Ionic Strength ◽  
High Mortality ◽  
Bufo Bufo ◽  
Soft Water ◽  
Internal Environment ◽  
Triturus Vulgaris ◽  
Effects Of Ph ◽  
Low Ionic Strength

Larval Bufo bufo (L., 1758) and Triturus vulgaris (L., 1758) were exposed to soft water (0.5 mg·L–1 Ca2+) experimentally acidified to pH 3.9 to 5.9 and total aluminium concentrations of <10, 150, and 300 µg·L–1. Below pH 4.5 both species experienced increased mortality. The LC50 (168 h) for <10 and 150 µg·L–1 Al was pH 4.3 and 4.1 for B. bufo and 4.2 and 4.1 for T. vulgaris. However, Al3+ increased the survival of both species, which may be due to the contribution of Al3+ to the ionic strength. No B. bufo larvae died at pH >4.5, whereas T. vulgaris at higher Al concentrations suffered relatively high mortality at pH 5.1–5.9, where Al occurs mainly as Al(OH)2+ and Al(OH)2+. Unlike external gills (T. vulgaris), internal gills (B. bufo) have their own internal environment and are probably better protected against the presence of these toxic Al species in the water. These Al species thus seem to be toxic to T. vulgaris larvae but not to B. bufo. Chloride was seen to be important for survival in water of low ionic strength, since the survival of T. vulgaris larvae, particularly at low Al concentration, increased at pH levels down to pH 4.3 when the water was acidified with HCl.

Effects of pH, ionic strength, and solutes on DNA adsorption by andosols

2010 ◽  
Vol 46 (5) ◽  
pp. 531-535 ◽  
Author(s):  
Kazutoshi Saeki ◽  
Takashi Kunito ◽  
Masao Sakai
Keyword(s):  
Ionic Strength ◽  
Dna Adsorption ◽  
Effects Of Ph

Importance of site-specific factors for the immobilization of contaminants using biochar and wood-based activated carbon

2021 ◽  
Author(s):  
Sampriti Chaudhuri ◽  
Gabriel Sigmund ◽  
Hary von Rautenkranz ◽  
Thorsten Hueffer ◽  
Thilo Hofmann
Keyword(s):  
Activated Carbon ◽  
Ionic Strength ◽  
Water Chemistry ◽  
Pore Water ◽  
Electrostatic Attraction ◽  
Inorganic Contaminants ◽  
Diverse Range ◽  
Pore Water Chemistry ◽  
Specific Factors ◽  
Carbonaceous Sorbents

&lt;p&gt;The use of environmentally friendly low-cost sorbents such as biochar and wood-based activated carbon as soil amendment has shown promising results in immobilizing organic and inorganic contaminants. They can be suitable soil remediation options at sites with residual contamination, where the contaminated hotspot has been removed. The effectiveness of biochar and activated carbon application is site dependent. Specifically, dissolved organic carbon (DOC), pH, and ionic strength in the pore water are important factors which can influence the extent of contaminant immobilization. Although there has been significant progress in developing alternative carbonaceous sorbents, the efficiency of these materials in a diverse range of soil and pore water conditions remains an open question. To address this knowledge gap, the present study investigates the influence of pore water chemistry on sorption of organic and inorganic contaminants to biochar and wood-based activated carbon. Sorption of selected non-polar, polar and ionizable polycyclic aromatic compounds (PACs) and inorganic Cadmium (Cd) to biochar and a wood-based activated carbon was studied under different pore water chemistry conditions. Batch sorption experiments were conducted using an experimental design approach (Box Behnken Design) with three different levels of DOC, pH, and ionic strength, yielding background solutions mimicking a wide spectrum of pore water chemistries. Sorption K&lt;sub&gt;D&lt;/sub&gt; values [L/kg] were calculated from aqueous contaminant concentrations after equilibration. Results were analyzed using a response surface methodology (RSM) approach on Minitab 19 and fitted to a model equation using linear, squared and two-way interactions terms.&lt;/p&gt;&lt;p&gt;Our results show that the ionizable PAC (phenyl phenol) and Cd were most affected by changes in pore water chemistries. For phenyl phenol, the presence of a phenolic group can cause H-bonding and electrostatic attraction and repulsion, while pH-dependent changes in speciation, precipitation and electrostatic attraction can occur for Cd. Sorption of all PACs negatively correlated with DOC, indicating competition of DOC with PACs for sorption sites. Sorption of non-polar (acenaphthene), polar N substituted (carbazole) and ionizable (phenyl phenol) PACs was hindered under acidic conditions, due to precipitation of DOC. For Cd, higher pH and low DOC levels favored sorption. This can be attributed to a lower Cd solubility in the presence of leached phosphate at higher pH, and a predominance of Cd(OH)&lt;sub&gt;2&lt;/sub&gt; in the neutral to alkaline regime. Our findings highlight the importance of considering a combination of site- and contaminant-specific factors when planning to apply carbonaceous sorbents for contaminant immobilization, with pH and DOC generally being more important than ionic strength.&lt;/p&gt;

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