BIOMINERALIZATION OF CALCIUM AND MAGNESIUM AS POTENTIAL PRETREATMENT TO IMPROVE THE QUALITY OF SEAWATER FOR MINING PROCESSES
Biómineralizatión of calcium and magnesium as potential pretreatment to improve the quality of seawater for mining processes
| dc.contributor | Cisternas Arapio, Luis | |
| dc.contributor | UNIVERSIDAD DE ANTOFAGASTA | |
| dc.creator | Arias Tranquilo, Dayana Nathaly | |
| dc.date | 2018-05-08T14:59:18Z | |
| dc.date | 2022-08-17T18:35:48Z | |
| dc.date | 2018-05-08T14:59:18Z | |
| dc.date | 2022-08-17T18:35:48Z | |
| dc.date | 2017 | |
| dc.date.accessioned | 2023-08-22T06:50:08Z | |
| dc.date.available | 2023-08-22T06:50:08Z | |
| dc.identifier | 21130712 | |
| dc.identifier | https://hdl.handle.net/10533/211000 | |
| dc.identifier.uri | https://repositorioslatinoamericanos.uchile.cl/handle/2250/8329469 | |
| dc.description | Seawater (SW) in mining is used in a desalinated or non-desalinated mode and it is presented as a favorable alternative to supply the lack of water in this industry. The first option means high investment costs and energy consumption translated into greater pollution, either by the emission of greenhouse gases or an impact not quantified yet to the marine ecosystem due to the spillage of brines into the sea. The second option refers to adapt the processes to the characteristics of the SW and to face the problems generated by corrosion. No mining companies carry out a partial desalination of the SW in order to leave the harmless elements for the processes and eliminating destructive ones. For this reason, this research studies the elimination of some of the harmful ions, specifically Ca2+ and Mg2+, through the application of biological precipitation or biomineralization mediated by halotolerant ureolytic bacteria. The contribution of this thesis is based on three pillars which are: 1) Isolation, selection and identification of biomineralizing bacteria from the Salar de Atacama, 2) Evaluation of the capacity of these bacteria to precipitate Ca2+ and Mg2+ from SW and the selection of that bacterial strain that precipitates the highest concentration of ions, and 3) Experiments aimed to establish a method for immobilization of biomass for the selected bacterial strain, as well as the determination of the parameters that influence the precipitation of ions from SW. The most remarkable results of this work respond to the objectives set. Thirty-six ureolytic halotolerant bacterial strains belonging to the genera Salinivibrio, Halomonas, Pseudomonas, Bacillus, Shewanella, Porphyrobacter, Marinilactobacillus and Rhodococcus were isolated. All bacterial strains precipitate calcium carbonate crystals and two bacterial strains are capable to remove Ca2+ and Mg2+ from SW. Free cells of Rhodococcus erythropolis TN24F removed in just 7 days ~95% of soluble calcium and within 14 days of bioassay the ~8% magnesium ion. Better results were obtained with free cells of B. subtilis strain LN8B which removed ~97% of the Ca2+ in 5 days and, ~67% of Mg2+ in 14 days. X-ray diffraction analysis of the precipitated originated from both bacterial strains indicated that the precipitates formed correspond mainly to halite (NaCl), monohydrocalcite (CaCO3H2O), anhydrite (CaSO4), and struvite (NH4MgPO46H2O). It was determined that the optimal matrix for immobilizing B. subtilis LN8B corresponded to polyvinyl alcohol with sodium alginate. Response Surface Methodology (RSM) and Artificial Neural Networks (ANNs) were applied for modeling Ca2+ and Mg2+ removal behavior. The input variables considered were the concentration of urea (20-40 g/L), number of cells in the immobilization matrix (pC, 1109, 11010 and 11011 cells/mL), and SW to spheres ratio (SW:S, 1-3). It was found that all variables considered had important effects on both of calcium and magnesium removal from SW, and several interactions of variables were also important. ANNs gave better modeling capability than RSM. Under these antecedents, it is proposed that a good removal of both ions is obtained when 30 g/L of urea, 11011 cells / mL in the immobilization matrix, and an SW: S ratio of 2 is used. Additionally, for the incorporation of the spheres with immobilized biomass of B. subtilis LN8B a laboratory scale bubble column reactor was built. The operation parameters have been established and preliminary results of ion removal have been obtained. Finally, this study reinforces the application of biomineralization mediated by halotolerant ureolytic bacteria as a biotechnological tool to improve the SW quality for industrial processes and alternatively as a reverse osmosis pretreatment. | |
| dc.description | PFCHA-Becas | |
| dc.description | PFCHA-Becas | |
| dc.format | application/pdf | |
| dc.relation | instname: Conicyt | |
| dc.relation | reponame: Repositorio Digital RI2.0 | |
| dc.relation | info:eu-repo/grantAgreement//21130712 | |
| dc.relation | info:eu-repo/semantics/dataset/hdl.handle.net/10533/93488 | |
| dc.rights | info:eu-repo/semantics/openAccess | |
| dc.rights | CC0 1.0 Universal | |
| dc.rights | info:eu-repo/semantics/openAccess | |
| dc.rights | http://creativecommons.org/publicdomain/zero/1.0/ | |
| dc.subject | Ingeniería y Tecnología | |
| dc.subject | Biotecnología Industrial | |
| dc.subject | Biotecnología Industrial | |
| dc.title | BIOMINERALIZATION OF CALCIUM AND MAGNESIUM AS POTENTIAL PRETREATMENT TO IMPROVE THE QUALITY OF SEAWATER FOR MINING PROCESSES | |
| dc.title | Biómineralizatión of calcium and magnesium as potential pretreatment to improve the quality of seawater for mining processes | |
| dc.type | Tesis Doctorado | |
| dc.type | info:eu-repo/semantics/doctoralThesis | |
| dc.type | info:eu-repo/semantics/publishedVersion | |
| dc.type | Tesis |