https://hdl.handle.net/10680/1322 2023-02-26T03:13:50Z 2023-02-26T03:13:50Z Indraratne, Srimathie P. Attanayake, Chammi P. Kumaragamage, Darshani Amarawansha, Geethani Goltz, Douglas M. Applin, Daniel M. https://hdl.handle.net/10680/2033 2023-02-14T09:00:46Z 2023-01-17T00:00:00Z

Mobility of arsenic and vanadium in waterlogged calcareous soils due to addition of zeolite and manganese oxide amendments Indraratne, Srimathie P.; Attanayake, Chammi P.; Kumaragamage, Darshani; Amarawansha, Geethani; Goltz, Douglas M.; Applin, Daniel M. Addition of manganese(IV) oxides (MnO2) and zeolite can affect the mobility of As and V in soils due to geochemical changes that have not been studied well in calcareous, flooded soils. This study evaluated the mobility of As and V in flooded soils surface-amended with MnO2 or zeolite. A simulated summer flooding study was conducted for 8 weeks using intact soil columns from four calcareous soils. Redox potential was measured in soils, whereas pH, major cations, and As and V concentrations were measured biweekly in pore water and floodwater. Aqueous As and V species were modeled at 0, 4, and 8 weeks after flooding (WAF) using Visual MINTEQ modeling software with input parameters of redox potential, temperature, pH, total alkalinity, and concentrations of major cations and anions. Aqueous As concentrations were below the critical thresholds (<100 μg L−1), whereas aqueous V concentrations exceeded the threshold for sensitive aquatic species (2–80 μg L−1). MnO2-amended soils were reduced to sub-oxic levels, whereas zeolite-amended and unamended soils were reduced to anoxic levels by 8 WAF. MnO2 decreased As and V mobilities, whereas zeolite had no effect on As but increased V mobility, compared to unamended soils. Arsenic mobility increased under anoxic conditions, and V mobility increased under oxic and alkaline pH conditions. Conversion of As(V) to As(III) and V(V) to V(IV) was regulated by MnO2 in flooded soils. MnO2 can be used as an amendment in immobilizing As and V, whereas the use of zeolite in flooded calcareous soils should be done cautiously.

2023-01-17T00:00:00Z Bloomfield, Hannah R. Hollett, Joshua W. Ritch, Jamie S. https://hdl.handle.net/10680/1955 2021-07-01T07:00:35Z 2021-06-01T00:00:00Z

一头牛的晶体结构和计算研究o-bridged bis-titanium(III) complex Bloomfield, Hannah R.; Hollett, Joshua W.; Ritch, Jamie S. The solid-state structure of the new compound mu-oxido-bis[dichloridotris(tetrahydrofuran-kappa-O)titanium(III)], [Ti2Cl4O(C4H8O)6], at 150 K has been determined. The crystal has monoclinic (C2/c) symmetry and the complex features C2 symmetry about the bridging O atom. Positional disorder is evident in one of the three tetrahydrofuran environments. A post-Hartree–Fock computational analysis indicates that the complex has nearly degenerate triplet and singlet spin states, with the former favoured slightly by ca 2 kJ mol-1.

2021-06-01T00:00:00Z Ritch, Jamie S. https://hdl.handle.net/10680/1943 2021-05-22T07:00:41Z 2018-07-01T00:00:00Z

Synthesis and coordination chemistry of cyclic seleno- and telluroureas Ritch, Jamie S. Chalcogenated derivatives of N-heterocyclic carbene ligands have received increasing attention due to their diverse chemical reactivity and potential applications in fields such as medicine and materials chemistry. This chapter summarizes the synthetic methods for the preparation of cyclic heavy chalcogenoureas featuring heterocyclic cores and explores their diverse coordination chemistry with p- and d-block metals.

2018-07-01T00:00:00Z Perras, Justin H. Mezibroski, Stephan M. J. Wiebe, Matthew A. Ritch, Jamie S. https://hdl.handle.net/10680/1942 2021-05-22T07:01:08Z 2018-01-30T00:00:00Z

不同的银(I)配位化学循环ic selenourea ligands Perras, Justin H.; Mezibroski, Stephan M. J.; Wiebe, Matthew A.; Ritch, Jamie S. The coordination chemistry of two selenourea ligands (SeIMes and SeIPr) towards silver(I) triflate and silver(I) nitrate was investigated. Two aggregation modes were observed in the solid state, strongly influenced by the size of the aromatic substituents on the ligand. With mesityl groups, selenium-bridged bimetallic motifs [AgX(SeIMes)]2 were obtained, while for the bulkier diisopropylphenyl groups ion-separated species of formulae [Ag(SeIPr)2]+[X]− were obtained. Recrystallization of [Ag(NO3)(SeIMes)]2 from hot methanol resulted in the formation of a unique coordination polymer featuring three silver environments. Characterization of the complexes by NMR spectroscopy and mass spectrometry suggested all complexes adopt the ionic aggregation mode in methanol solution.

2018-01-30T00:00:00Z