Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Engineering
Sorption Of Binary Mixtures Of Aromatic Nitrogen Heterocyclic Compounds On Subsurface Materials, John M. Zachara, Calvin C. Ainsworth, Christina E. Cowan, Berta L. Thomas
Sorption Of Binary Mixtures Of Aromatic Nitrogen Heterocyclic Compounds On Subsurface Materials, John M. Zachara, Calvin C. Ainsworth, Christina E. Cowan, Berta L. Thomas
US Department of Energy Publications
Single and binary solute sorption of pyridine, quinoline, and acridine has been investigated on two low organic carbon subsurface materials with similar properties but different equilibrium pH when saturated with water. Single solute sorption for all compounds is higher in the acidic soil as compared to the basic soil, reflecting stronger sorption of the protonated organic cations. The protonated species exhibit high selectivity for the exchange complex at low aqueous concentration with selectivity increasing with ring number. Binary sorption experiments with quinoline/pyridine and quinoline/acridine demonstrate that competitive sorption occurs between compounds in the acidic subsoil where the protonated compound species …
Quinoline Sorption On Na-Montmorillonite: Contributions Of The Protonated And Neutral Species, Calvin C. Ainsworth, John M. Zachara, Ron L. Schmidt
Quinoline Sorption On Na-Montmorillonite: Contributions Of The Protonated And Neutral Species, Calvin C. Ainsworth, John M. Zachara, Ron L. Schmidt
US Department of Energy Publications
Dilute aqueous solutions of quinoline were contacted with Na-montmorillonite to elucidate the sorption process of the neutral and protonated species. Sorption occurs via a combination of ion exchange and molecular adsorption and yields S-type isotherms. Exchange between the quinolinium ion (QH+ and Na can be described by means of Vanselow selectivity coefficients and a thermodynamic exchange constant (Kex). Due to the apparent adsorption of the neutral species at high mole fractions (x) of the solid phase, the thermodynamic standard state was defined as 0.5 mole fraction. The selectivity at pH ~4.95 of the QH+ species over …
Chromate Adsorption On Amorphous Iron Oxyhydroxide In The Presence Of Major Groundwater Ions, John M. Zachara, Donald Girvln, Ronald Schmidt, C. Thomas Resch
Chromate Adsorption On Amorphous Iron Oxyhydroxide In The Presence Of Major Groundwater Ions, John M. Zachara, Donald Girvln, Ronald Schmidt, C. Thomas Resch
US Department of Energy Publications
Chromate adsorption on amorphous iron oxyhydroxide was investigated in dilute iron suspensions as a single solute and in solutions of increasing complexity containing CO2 (g), SO42-(aq), H4Si04(aq), and cations [K+, Mg2+, Ca2+(aq)]. In paired-solute systems (e.g., CrO42- =H2CO3*), anionic cosolutes markedly reduce CrO42- adsorption through a combination of competitive and electrostatic effects, but cations exert no appreciable influence. Additionally, H4Si04 exhibits a strong time-dependent effect: CrO42- adsorption is greatly decreased with increasing H4SiO4 …
Applications Of The Semiclassical Spectral Method To Nuclear, Atomic, Molecular, And Polymeric Dynamics, M. L. Koszykowski, G. A. Pfeffer, D. W. Noid
Applications Of The Semiclassical Spectral Method To Nuclear, Atomic, Molecular, And Polymeric Dynamics, M. L. Koszykowski, G. A. Pfeffer, D. W. Noid
US Department of Energy Publications
Nonlinear dynamics plays a dominant role in a variety of important problems in chemical physics. Examples are unimolecular reactions, infrared multiphoton decomposition of molecules, the pumping process of the gamma ray laser, dissociation of vibrationally excited state-selected van der Waals’s complexes, and many other chemical and atomic processes. The present article discusses recent theoretical studies on the quasi-periodic and chaotic dynamical aspects of vibrational-rotational states of atomic, nuclear, and molecular systems using the semiclassical spectral method (SSM). We note that the coordinates, momenta, and so on, are found using classical mechanics in the studies included in this review. Consequently, certain …