نتایج جستجو برای: surface complexation

تعداد نتایج: 641070  

2014
Petri M. S. Pulkkinen Jukka Hassinen Robin H. A. Ras Heikki Tenhu

This paper describes a detailed study on the complexation of pyridinium derivatives with calixarenes bound to gold nanoparticles (AuNPs). The studied calixarene derivatives are mixed with alkanethiols to formmixed monolayers on AuNP surfaces. The key findings are: (i) even a small amount (less than 11 mol%) of calixarenes can retain their complexation abilities among a majority of alkanethiols ...

Journal: :Environmental geochemistry and health 2011
Jihoon Cha Mingcan Cui Min Jang Sang-Hyun Cho Deok Hyun Moon Jeehyeong Khim

This study examines the adsorption isotherms, kinetics and mechanisms of Pb²(+) sorption onto waste cow bone powder (WCBP) surfaces. The concentrations of Pb²(+) in the study range from 10 to 90 mg/L. Although the sorption data follow the Langmuir and Freundlich isotherm, a detailed examination reveals that surface sorption or complexation and co-precipitation are the most important mechanisms,...

1996
Carol J. Bruton Brian E. Viani

The observed variability of fluid chemistry at the Äspö Hard Rock Laboratory is not fully described by conservative fluid mixing models. Ion exchange may account for some of the observed discrepancies. It is also possible that variably charged solids such as oxyhydroxides of Fe can serve as sources and sinks of anions and cations through surface complexation. Surface complexation reactions on h...

2012
Hanna Nelson Andrey Shchukarev Staffan Sjöberg Lars Lövgren

The aqueous solubility of oxyanion (e.g. phosphates and arsenates), and thereby their mobility, bioavailability (phosphates) and toxicity (arsenates), in soils and sediments is dependent upon their chemical speciation. In complex, multicomponent systems, equilibrium modelling can be a useful tool to predict chemical speciation. When establishing a model, it is essential to understand the intera...

Journal: :journal of nanostructures 2012
m. masteri-farahani p. eghbali f. salimi

covalent grafting of mcm-41 with 3-chloropropyl trimethoxysilane and subsequent reaction respectively with acacdien and complexation with moo2(acac)2 afforded moo2acacdien@mcm-41. x-ray diffraction and nitrogen sorption analyses revealed the preservation of the textural properties of the support as well as accessibility of the channel system despite sequential reduction in surface area, pore vo...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

in this thesis protic and aprotic ammonium-based ionic liquids were synthesized and their surface tensions were measured in the range of 298-373k. the protics are alkyl ammonium-based ils with the carboxylate (formate, acetate, propionate) anion and aprotics are quaternary ammonium-based ils with bis(trifluoromethylsulfonyl)imide anion. capillary rise method was used for surface tension measure...

2011
ANPALAKI J. RAGAVAN

Simulation of chemical element adsorption, release, and transport is possible without the need to perform time consuming, detailed adsorption studies on multiple samples by incorporating prediction equations into chemical speciation–transport models before simulating. Adsorption models also assume that the chemical species in a mixture is at chemical equilibrium which is the state in which the ...

1998

Surface complexation models (SCMs) have been successfully used to describe metal ion adsorption on pure mineral materials. However, such models have rarely been applied to model adsorption on natural materials. In this study, the surface complexation model approach was used to describe the surface properties and adsorption behavior of natural aquatic sediment. Three typical versions of the surf...

2016
Janek Greskowiak Michael Hay Henning Prommer Chongxuan Liu Vincent Post Rui Ma James Davis Chunmiao Zheng John M. Zachara Michael B. Hay Vincent E. A. Post James A. Davis

Simulating adsorption of U(VI) under transient groundwater flow and hydrochemistry: Physical versus chemical nonequilibrium model" (2011). [1] Coupled intragrain diffusional mass transfer and nonlinear surface complexation processes play an important role in the transport behavior of U(VI) in contaminated aquifers. Two alternative model approaches for simulating these coupled processes were ana...

2014
Youchi Zhang

In this study, the adsorptive characteristics of biochar generated from anaerobically digested garden wastes (AD-char) were investigated. Metal adsorption onto AD-chars reached equilibrium in 48 h; the adsorption capacity of Cu by AD-char was 182 μmol g, which was higher than that of Zn (35.3 μmol g) and Mn (60.7 μmol g). The metal adsorption was well described by the pseudo second-order kineti...

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