Modeling ionic strength effects on anion adsorption at hydrous oxide/solution interfaces

Hayes, Kim F.; Papelis, Charalambos; Leckie, James O.

doi:10.1016/0021-9797(88)90039-2

Cited by 476 publications

(345 citation statements)

References 7 publications

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“…Despite the pH values which range between 6.78 and 7.22, the important value of T As in samples W 1 ,W 2 ,S P ,W 3 &W 4 could be explained by the dominance of the anoxic form arsenite, As(III), which has more affinity for solids above pH 7-8, and which its sorption decreases with increasing ionic strength. 37 These results appear to confirm the origin of these samples derived from recharge-transit conditions as reported by Tóth. 7,25 The concentration of Pb,Ni,Hg,Cd,Cu&Cr are below the proposed standard of the WHO (Table 2).…”

Section: Minor and Trace Constituents In Groundwatersupporting

confidence: 88%

“…In the study region, the origin of U in samples W 1 ,W 2 ,S P ,W 3 &W 4 could be related to the leaching of sediments derived from granodiorite-tonalite formations under acidic conditions; groundwater remaining in contact with rocks for a long period of time have higher U contents than those with short residence. 37 Consequently, this residence time proxy suggests that W 2 might be supplied with the oldest groundwater. Alike uranium, V concentrations in samples W 1 ,W 2 ,S P ,W 3 &W 4 (14.7-89.9 µg/l) appear to be correlated to the pH and the concentration of HCO 3 in the solution (Tables 1&2).…”

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confidence: 99%

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Investigating regional groundwater flow systems in baja california central desert region

Ouysse¹,

Wehncke²,

Rivera³

2018

IJH

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In Northern Baja California, environmental conservation may not be fully accomplished in the absence of a clear understanding of key factors controlling and protecting biodiversity. Groundwater is an environmental agent triggering the presence of a wide range of arid ecosystems; therefore, any sustainable development in the region has to maintain a balance between environmental, social and economical benefits. The present study has placed a great emphasis on the understanding and distribution of groundwater flow systems, and their environmental interactions in the protected area of the Valle de Los Círios, using physical-chemical and isotope methods. Results show the presence of three groundwater groups portraying contrasting flow systems conditions. Analyzed samples have been classified as fresh-brackish, and thermal alkaline groundwater as suggested by pH, temperature and TDS. The Br/Cl ratio in most samples was close to the ocean molar value (1.5x10 -3 ) indicating the importance of marine aerosol fraction in the recharged waters; however, Mg/Cl,Na/Cl,Ca/Cl,SO 4 / Cl and Cl/HCO 3 +Cl ratios were significantly different to those of seawater mixing conditions. Dominant ions (Na,Ca and Cl), chemical age proxies (Li), and δ 18 O suggest waters with long residence time, with the possibility of been recharge during the late glacial period. Thermal ground water shows low minor and trace element content and exhibits the dominance of Na-plagioclase hydrolysis; their low levels of Sr and Ba suggest negligible contact with calcareous rocks and their estimated temperature at depth (80to100°C) and TDS suggest groundwater has travelled through fractured media. This introduction study suggests that desertic species in Valle de Los Cirios are highly sustained by groundwater of local and intermediate flows.

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Section: Minor and Trace Constituents In Groundwatersupporting

confidence: 88%

mentioning

confidence: 99%

Investigating regional groundwater flow systems in baja california central desert region

Ouysse¹,

Wehncke²,

Rivera³

2018

IJH

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“…Earlier studies (Hayes et al, 1988;Persson et al, 1996a,b;Huang, 2004) reported that phosphate was strongly adsorbed on hematite through an inner-sphere ligand exchange mechanism. Calculation results of back-titration showed the phosphate binding on LT released more OH À than that on ST (Table 1).…”

Section: Surface Characteristic Changes As Affected By Phosphate Pretmentioning

confidence: 96%

“…5) indicated that the adsorption and desorption processes of Cu and Cd on hematite were irreversible, which was one of the characteristics of inner-sphere complex while outer-sphere complex was reversible (Sparks, 2002). Study of the ionic strength effects on adsorption was conducted consequently as another evidence to distinguish outer-sphere and innersphere complexes (Hayes et al, 1988). McBride (1997) indicated that ions forming inner-sphere surface complexes showed little ionic strength dependence and outer-sphere complexes would increase with increasing solution ionic strength.…”

Section: Effect Of Phosphate Pretreatment On the Cu And CD Adsorptionmentioning

confidence: 99%

Effect of phosphate on the adsorption of Cu and Cd on natural hematite

Zhang

Jiang

et al. 2006

Chemosphere

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Interactions between anions and cations are important to understand the chemical processes of pollutants in environment. In this study, batch experiments were carried out to investigate the simultaneous adsorption of Cu and Cd on hematite as affected by phosphate. Phosphate pretreatment suppressed the maximum adsorption of Cu and Cd on hematite and moved the adsorption pH edges to a higher pH range. Phosphate application time had a marked impact on Cu and Cd adsorption and longer contact time resulted in more reduction of Cu and Cd adsorption. Results of backtitration, Fourier transform infrared (FTIR) spectroscopy study and ionic strength effect on the adsorption revealed that Cu and Cd were adsorbed on hematite mainly through the inner-sphere complex formation mechanism and phosphate treatment reduced the inner-sphere adsorption sites, thus decreasing Cu and Cd adsorption on hematite.

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“…Alternatively, ions may retain their hydration sheath upon adsorption, thereby forming weaker ion-pair complexes, equivalent to outer-sphere solution complexes (Stumm, 1992;Hayes and Leckie, 1987;Hayes et al, 1988). In either case, sorption of cations is accompanied by release of protons in solution and sorption of anions is accompanied by consumption of protons.…”

Section: Factors Affecting Sorptionmentioning

confidence: 99%

Fate and transport processes controlling the migration of hazardous and radioactive materials from the Area 5 Radioactive Waste Management Site (RWMS)

Estrella¹

1994

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Modeling ionic strength effects on anion adsorption at hydrous oxide/solution interfaces

Cited by 476 publications

References 7 publications

Investigating regional groundwater flow systems in baja california central desert region

Investigating regional groundwater flow systems in baja california central desert region

Effect of phosphate on the adsorption of Cu and Cd on natural hematite

Fate and transport processes controlling the migration of hazardous and radioactive materials from the Area 5 Radioactive Waste Management Site (RWMS)

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