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020 ▼a 9781085642798
035 ▼a (MiAaPQ)AAI13883845
040 ▼a MiAaPQ ▼c MiAaPQ ▼d 247004
0820 ▼a 628
1001 ▼a Zhang, Yilun.
24513 ▼a An Experimental and Modeling Study of Silicate Dissolution Kinetics Near Equilibrium.
260 ▼a [S.l.]: ▼b Indiana University., ▼c 2019.
260 1 ▼a Ann Arbor: ▼b ProQuest Dissertations & Theses, ▼c 2019.
300 ▼a 186 p.
500 ▼a Source: Dissertations Abstracts International, Volume: 81-03, Section: B.
500 ▼a Advisor: Zhu, Chen.
5021 ▼a Thesis (Ph.D.)--Indiana University, 2019.
506 ▼a This item must not be sold to any third party vendors.
506 ▼a This item must not be added to any third party search indexes.
520 ▼a Near-equilibrium dissolution rates of silicate minerals are critical for assessing the safe geological storage of CO2 and high-level nuclear wastes. Therefore, assessing the dissolution behavior of those substances is also of critical importance. As one of the most widely occurring and abundant silicate minerals, feldspars have long been the subject of such dissolution studies. Unfortunately, dissolution behavior at environmentally relevant conditions is still poorly understood due to the difficulties involved in experiments at circumneutral pH and near-equilibrium conditions. These difficulties include secondary phase precipitation and low reaction rates.The isotope doping method is a promising technique which can decouple simultaneous dissolution-precipitation reactions at circumneutral pH and near-equilibrium conditions. My study used this method to analyze the dissolution of albite at 50 째C and pH=5-6. The initial solution was doped with 29Si and solutes were added to set the initial solution at near-equilibrium conditions. The results of my experiments showed that even though the system seemed to be in equilibrium with albite, albite dissolution was coupled to multiple other secondary phase precipitation reactions was, which led to a net change in solution chemistry. Further analysis indicated that this evolution in solution chemistry was consistent with coupled dissolution-precipitation reactions between albite and analcime, or between albite and an analcime-like phase. Furthermore, contrary to the commonly assumed transition state theory (TST) rate equations, my results also suggested that the feldspar precipitation reaction may not occur at a significant level.In addition to my work on albite dissolution, I also conducted experiments on the kinetics of the kyanite dissolution reaction. The results of these experiments showed that the dissolution rate of kyanite can be described by the rate equation (n/a) where the rate constant, k = 5.08x10-13 mol m-2 s-1, and the activation energy, Ea = 73.5 kJ/mol.The dissolution rate of kyanite is pH-independent at near-neutral conditions (pH = 3.5-7.5) and at temperatures between 0 째C and 22 째C. This phenomenon can be attributed to the surface speciation of kyanite, which has a wide pH range under which the neutral surface species (>SOH) dominates.
590 ▼a School code: 0093.
650 4 ▼a Environmental science.
690 ▼a 0768
71020 ▼a Indiana University. ▼b Environmental Science.
7730 ▼t Dissertations Abstracts International ▼g 81-03B.
773 ▼t Dissertation Abstract International
790 ▼a 0093
791 ▼a Ph.D.
792 ▼a 2019
793 ▼a English
85640 ▼u http://www.riss.kr/pdu/ddodLink.do?id=T15491327 ▼n KERIS ▼z 이 자료의 원문은 한국교육학술정보원에서 제공합니다.
980 ▼a 202002 ▼f 2020
990 ▼a ***1816162
991 ▼a E-BOOK