Salinity Mitigation for Potash Mine Sites: Synergistic Cation and Anion Removal Using a Dual-Adsorbent
| dc.contributor.advisor | Chang, Wonjae | |
| dc.contributor.committeeMember | Barbour, Lee | |
| dc.contributor.committeeMember | Lindsay, Matt | |
| dc.contributor.committeeMember | Soltan, Jafar | |
| dc.creator | Gibb, Nicholas P 1992- | |
| dc.creator.orcid | 0000-0003-0156-9197 | |
| dc.date.accessioned | 2017-01-12T22:24:20Z | |
| dc.date.available | 2018-10-16T17:31:19Z | |
| dc.date.created | 2016-12 | |
| dc.date.issued | 2017-01-12 | |
| dc.date.submitted | December 2016 | |
| dc.date.updated | 2017-01-12T22:24:20Z | |
| dc.description.abstract | Potash (KCl) mining generates large quantities of tailings and brine which can impact proximate aquifers, elevating the concentrations of Na+, K+, and Cl-. To desalinate brine-impacted groundwater near potash mines and other inland locations, two adsorbents were sequentially applied: (1) calcined layered double hydroxide (CLDH), to adsorb anions, divalent cations, and transiently raise the pH; and (2) acid-treated clinoptilolite zeolite, to adsorb monovalent cations and neutralize the effluent pH. To evaluate this dual-adsorbent process, equilibrium adsorption experiments were conducted and the adsorbents were characterized through X-ray diffraction, X-ray florescence, porosimetry, scanning electron microscopy, and synchrotron-based scanning transmission X-ray microscopy. Using synthetic NaCl solution, the Langmuir maximum adsorption capacity for Cl- onto CLDH and Na+ onto acid-treated zeolite was 116.3 and 28.4 mg/g, respectively. The Na+ uptake was greatly enhanced by solution pre-treatment (dechlorination) using CLDH, and also by zeolite acid treatment (with 1M = 2 M > 0.1 M > untreated, irrespective of acid type). Pre-conditioning the zeolite with Na+ prior to acid treatment also improved the adsorption capacity and promoted crystallinity. Desalination of potash brine-impacted groundwater was systematically investigated. Under the optimal conditions, the dual-adsorbent reduced the concentration of Cl- by 95.8%, Ca2+ by 89.8%, Mg2+ by 92.3%, Na+ by 91.9%, K+ by 96.5%, preserved a neutral pH (7.72), and lowered the sodium adsorption ratio (36.5 to 12.5) and the hardness (574 to 56.3 mg/L as CaCO3). In contrast, natural zeolite alone only removed 51.2% of the Na+ and 79.6% of the K+, and also generated extremely hard water (3620 mg/L as CaCO3) due to Ca2+ and Mg2+ exchange. Finally, zeolite regeneration studies were conducted using 0.1 M HCl. The Na+ was efficiently desorbed, but K+ remained. Over four consecutive adsorption–desorption cycles, the net K+ loading increased from 4.8 to 21.2 mg/g. This K-form zeolite could potentially be applied as a slow-release fertilizer, thereby transforming a potash mining waste material into a valuable resource. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/10388/7686 | |
| dc.subject | Zeolite | |
| dc.subject | Layered double hydroxide | |
| dc.subject | Desalination | |
| dc.subject | Sodium adsorption | |
| dc.subject | Potassium adsorption | |
| dc.subject | Chloride adsorption | |
| dc.subject | Regeneration | |
| dc.title | Salinity Mitigation for Potash Mine Sites: Synergistic Cation and Anion Removal Using a Dual-Adsorbent | |
| dc.type | Thesis | |
| dc.type.material | text | |
| local.embargo.terms | 2018-01-12 | |
| thesis.degree.department | Civil and Geological Engineering | |
| thesis.degree.discipline | Environmental Engineering | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Masters | |
| thesis.degree.name | Master of Science (M.Sc.) |