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Síntesis y caracterización de silicatos de calcio nano-estructurados modificados con Mg(II) y su aplicación en la remoción de fosfatos y metales pesados desde aguas ácidas contaminadas
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hidalgo, López Isabel, Alicia |
| Copyright Year | 2014 |
| Abstract | Synthesis and characterization of nano-structured calcium silicates modified with magnesium and their application on the removal of phosphate and metallic ions from polluted acid solutions In this work was studied the removal of phosphate ions from aqueous solutions that simulate acidic industrial waste waters that also contain other pollutants as NH4 + , Cu(II), Cd(II) y Zn(II), by means of an adsorption process onto nano-structured calcium silicates modified or not with magnesium. The magnesium-modified nano-structured calcium silicates were synthesized following a route based on the reaction of a sodium silicate solution and calcium and magnesium hydroxides, respectively. Sorbents were physically and chemically characterized using diverse methodologies, among them, scanning electron microscopy, porosimetry analysis and X-ray diffraction. They resulted be amorphous having a rough surface. BET analysis indicated a surface area of 86 m 2 /g and an average pore diameter around 20 nm for calcium silicate modified with 30% of Mg. A highly efficient sorption of phosphate ions onto nano-structured calcium silicates modified or not with magnesium throughout the revised acidity range due likely to the generation of insoluble and stable calcium and magnesium phosphates. A 280-300 mg PO4 3/g n-silicate phosphate loading capacity was measured. Removal of PO4 3ions was enhanced by the presence of NH4 + ions in the treated solution due the production of very insoluble double-magnesium and ammonium phosphate. The existence of PO4 3and ammonium ions did not affected the sorption of metallic ions Cu(II), Cd(II) y Zn(II), which would occur through the formation of hydroxides and stable and granular basic silicates salts. However, the experimentally observed results indicate that is no possible modifying the calcium silicates by replacement of calcium atoms by magnesium atoms beyond 30 % (molar) since the nano-structure of silicates is affected being reduced they sorption capacity. Finally, the experimental results of sorption kinetics were analyzed by using a pseudosecond-order model based more in the sorption capacity of solids than in the concentration of pollutants in solution. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://repositorio.uchile.cl/bitstream/handle/2250/129966/Sintesis-y-caracterizacion-de-silicatos-de-calcio-nano-estructurados.pdf;jsessionid=24D3DE72E76D18428A62EA420C2C6F74?sequence=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
