Epithermal neutron activation analysis along with ICP-OES, LA ICP-MS, and XRF were used to determ... more Epithermal neutron activation analysis along with ICP-OES, LA ICP-MS, and XRF were used to determine the elemental composition of coal fly ash from the Malta coal power station in the Mpumalanga province of South Africa. A total of 54 major, trace and rare earth elements were obtained by the four analytical techniques. The results were compared and the discrepancies discussed to show the merits and drawbacks of each of the techniques. It was shown that the elemental content of this particular coal fly ash are of the same order as the NIST standard reference material Coal Fly Ash 1633b.
Mining of coal is very extensive and coal is mainly used to produce electricity. Coal power stati... more Mining of coal is very extensive and coal is mainly used to produce electricity. Coal power stations generate huge amounts of coal fly ash of which a small amount is used in the construction industry. Mining exposes pyrite containing rocks to H2O and O2. This results in the oxidation of FeS2 to form H2SO4. The acidic water, often termed acid mine drainage (AMD), causes dissolution of potentially toxic elements such as, Fe, Al, Mn and naturally occurring radioactive materials such as U and Th from the associated bedrock. This results in an outflow of AMD with high concentrations of sulphate ions, Fe, Al, Mn and naturally occurring radioactive materials. Treatment of AMD with coal fly ash has shown that good quality water can be produced which is suitable for irrigation purposes. Most of the potentially toxic elements (Fe, Al, Mn, etc) and substantial amounts of sulphate ions are removed during treatment with coal fly ash. This research endeavours to establish the fate of the radioactive materials in mine water with coal fly ash containing radioactive materials. It was established that coal fly ash treatment method was capable of removing radioactive materials from mine water to within the target water quality range for drinking water standards. The alpha and beta radioactivity of the mine water was reduced by 88% and 75% respectively. The reduced radioactivity in the mine water was due to greater than 90% removal of U and Th radioactive materials from the mine water after treatment with coal fly ash as ThO2 and UO2. No radioisotopes were found to leach from the coal fly ash into the mine water.
Madzivire. G., Petrik. L. F., Gitari. W. M., Balfour. G., Vadapalli. V. R. K., and Ojumu. T. V. (... more Madzivire. G., Petrik. L. F., Gitari. W. M., Balfour. G., Vadapalli. V. R. K., and Ojumu. T. V. (2009). Role of ph on sulphate removal from circumneutral mine water using coal fly ash. International Mine Water Conference, 19th – 23rd October 2009, Pretoria, South Africa.
Iron nanoparticles (nano Fe) were extracted from coal fly ash (CFA) or ferric chloride (FeCl3) an... more Iron nanoparticles (nano Fe) were extracted from coal fly ash (CFA) or ferric chloride (FeCl3) and used for acid mine drainage (AMD) remediation. Characterisation was achieved by X-ray diffraction (XRD), X-ray fluorescence, scanning electron microscopy-energy dispersive spectroscopy (SEM–EDX), high resolution transmission electron microscopy (HRTEM), and the Braunaer–Emmet–Teller (BET) surface area determination. The HRTEM indicated good dispersion of the characteristic bead-like structure of nano Fe. It was also observed that the nano Fe were mainly in the zero-valent oxidation state, as denoted by the characteristic peak at ≈ 44.7° in the XRD analysis; it was accompanied by the generally accepted oxide layer around the particles, which was confirmed by the appearance of a core–shell structure in the HRTEM micrographs. The BET surface areas of the nano Fe extracted from the CFA or FeCl3 were recorded to be 34.7 or 88.8 m2/g, respectively. The nano Fe lowered the concentration of most of the monitored contaminants, with the percentage removal ranging from 17 to 99%. The pH of the AMD after treatment with nano Fe obtained from CFA or FeCl3 increased to 5.74 or 6.01, respectively, from 3.49, the electrical conductivity decreased to 0.18 or 0.13 Ω/m, respectively from 0.57 Ω/m, while the total dissolved solids was decreased to 447 or 384 mg/L, respectively, from 1683 mg/L. The water quality of the treated AMD is suitable for Category 4 industrial use, per the Dept. of Water Affairs and Forestry’s limits.ZusammenfassungEisen-Nanopartikel (Nano-Fe) wurden aus Kohleflugaschen (CFA) bzw. Eisen(III)-chlorid (FeCl3) extrahiert und zur Behandlung von Sauerwasser (AMD) genutzt. Zur Phasenanalyse wurden eingesetzt Röntgenbeugung (XRD), Röntgenfluoreszenz, Rasterelektronenmikroskopie mit energiedispersiver Röntgenspektroskopie (SEM–EDX), hochauflösende Transmissionselektronenmikroskopie (HRTEM) sowie die Bestimmung der spezifischen Oberfläche nach der BET-Methode (Brunauer, Emmet und Teller). Die HRTEM-Untersuchungen deuteten auf eine gute Dispergierung der typischerweise tröpfchenartigen Nanoeisenstruktur hin. Das Nanoeisen lag überwiegend nullwertig vor, wie sich anhand des XRD-Peaks bei ≈ 44,7° feststellen ließ; es trat in Begleitung allgemein akzeptierter, partikelumschließender Oxidschichten auf, was durch den Nachweis einer Kern-Schalen-Struktur in den HRTEM-Abbildungen belegt wurde. Die BET-Oberflächen von aus CFA bzw. FeCl3 extrahiertem Nanoeisen betrugen 34,7 bzw. 88,8 m2/g. Das Nanoeisen führte zur Konzentrationsverringerung der meisten der kontrollierten Schadstoffe, mit Abtrennraten von 17…99%. Der pH-Wert des Sauerwassers stieg nach der Behandlung mit aus CFA bzw. FeCl3 extrahiertem Nanoeisen auf 5,74 bzw. 6,01, bei einem Ausgangswert von 3,49. Die elektrische Leitfähigkeit sank von 0,57 Ω/m auf 0,18 bzw. 0,13 Ω/m, während sich der Abdampfrückstand von 1683 mg/L auf 447 bzw. 384 mg/L verringerte. Das behandelte Sauerwasser erfüllt die Kriterien für eine industrielle Nutzung der Kategorie 4 gemäß den Grenzwerten der Abteilung für Wasserangelegenheiten und Forstwirtschaft.ResumenNanopartículas de hierro (nano Fe) fueron extraídas de cenizas de carbón (CFA) o de cloruro férrico (FeCl3) y se usaron para la remediación del drenaje ácido de minas (AMD). La caracterización se realizó mediante difracción de rayos X (XRD), fluorescencia de rayos X, microscopía electrónica de barrido-espectroscopia de energía (SEM–EDX), microscopía electrónica de transmisión de alta resolución (HRTEM) y la determinación del área superficial Braunaer-Emmet-Teller (BET). El HRTEM indicó una buena dispersión de la estructura tipo esférica de las de nano Fe. También se observó que los nano Fe estaban principalmente en el estado de oxidación cero, como se indica por el pico característico en ≈ 44.7° en el análisis de DRX; estuvo acompañado por la capa de óxido generalmente aceptada alrededor de las partículas, que se confirmó por la aparición de una estructura núcleo-cubierta en las micrografías HRTEM. Las áreas de superficie BET del nano Fe provenientes de CFA o FeCl3 fueron 34,7 y 88,8 m2/g, respectivamente. El nano Fe redujo la concentración de la mayoría de los contaminantes monitoreados, con un porcentaje de eliminación que oscila entre el 17 y el 99%. El pH de la AMD después del tratamiento con nano Fe obtenidas de CFA o FeCl3 aumentó a 5,74 y 6,01, respectivamente, desde un valor inicial de 3,49, la conductividad eléctrica disminuyó a 0,18 y 0,13 Ω/m, respectivamente, desde un valor inicial de 0,57 Ω/m, mientras que el total de sólidos disueltos se redujo a 447 o 384 mg/l, respectivamente, desde 1683 mg/l iniciales. La calidad del agua de la DMAE tratada es adecuada para el uso industrial de categoría 4, según los límites del Departamento de Asuntos Hídricos y Bosques.从粉煤灰或氯化铁中提取铁纳米颗粒处理矿山酸性废水的新方法利用粉煤灰(CFA)或氯化铁(FeCl3)提取铁纳米颗粒(nano…
Epithermal neutron activation analysis along with ICP-OES, LA ICP-MS, and XRF were used to determ... more Epithermal neutron activation analysis along with ICP-OES, LA ICP-MS, and XRF were used to determine the elemental composition of coal fly ash from the Malta coal power station in the Mpumalanga province of South Africa. A total of 54 major, trace and rare earth elements were obtained by the four analytical techniques. The results were compared and the discrepancies discussed to show the merits and drawbacks of each of the techniques. It was shown that the elemental content of this particular coal fly ash are of the same order as the NIST standard reference material Coal Fly Ash 1633b.
Mining of coal is very extensive and coal is mainly used to produce electricity. Coal power stati... more Mining of coal is very extensive and coal is mainly used to produce electricity. Coal power stations generate huge amounts of coal fly ash of which a small amount is used in the construction industry. Mining exposes pyrite containing rocks to H2O and O2. This results in the oxidation of FeS2 to form H2SO4. The acidic water, often termed acid mine drainage (AMD), causes dissolution of potentially toxic elements such as, Fe, Al, Mn and naturally occurring radioactive materials such as U and Th from the associated bedrock. This results in an outflow of AMD with high concentrations of sulphate ions, Fe, Al, Mn and naturally occurring radioactive materials. Treatment of AMD with coal fly ash has shown that good quality water can be produced which is suitable for irrigation purposes. Most of the potentially toxic elements (Fe, Al, Mn, etc) and substantial amounts of sulphate ions are removed during treatment with coal fly ash. This research endeavours to establish the fate of the radioactive materials in mine water with coal fly ash containing radioactive materials. It was established that coal fly ash treatment method was capable of removing radioactive materials from mine water to within the target water quality range for drinking water standards. The alpha and beta radioactivity of the mine water was reduced by 88% and 75% respectively. The reduced radioactivity in the mine water was due to greater than 90% removal of U and Th radioactive materials from the mine water after treatment with coal fly ash as ThO2 and UO2. No radioisotopes were found to leach from the coal fly ash into the mine water.
Madzivire. G., Petrik. L. F., Gitari. W. M., Balfour. G., Vadapalli. V. R. K., and Ojumu. T. V. (... more Madzivire. G., Petrik. L. F., Gitari. W. M., Balfour. G., Vadapalli. V. R. K., and Ojumu. T. V. (2009). Role of ph on sulphate removal from circumneutral mine water using coal fly ash. International Mine Water Conference, 19th – 23rd October 2009, Pretoria, South Africa.
Iron nanoparticles (nano Fe) were extracted from coal fly ash (CFA) or ferric chloride (FeCl3) an... more Iron nanoparticles (nano Fe) were extracted from coal fly ash (CFA) or ferric chloride (FeCl3) and used for acid mine drainage (AMD) remediation. Characterisation was achieved by X-ray diffraction (XRD), X-ray fluorescence, scanning electron microscopy-energy dispersive spectroscopy (SEM–EDX), high resolution transmission electron microscopy (HRTEM), and the Braunaer–Emmet–Teller (BET) surface area determination. The HRTEM indicated good dispersion of the characteristic bead-like structure of nano Fe. It was also observed that the nano Fe were mainly in the zero-valent oxidation state, as denoted by the characteristic peak at ≈ 44.7° in the XRD analysis; it was accompanied by the generally accepted oxide layer around the particles, which was confirmed by the appearance of a core–shell structure in the HRTEM micrographs. The BET surface areas of the nano Fe extracted from the CFA or FeCl3 were recorded to be 34.7 or 88.8 m2/g, respectively. The nano Fe lowered the concentration of most of the monitored contaminants, with the percentage removal ranging from 17 to 99%. The pH of the AMD after treatment with nano Fe obtained from CFA or FeCl3 increased to 5.74 or 6.01, respectively, from 3.49, the electrical conductivity decreased to 0.18 or 0.13 Ω/m, respectively from 0.57 Ω/m, while the total dissolved solids was decreased to 447 or 384 mg/L, respectively, from 1683 mg/L. The water quality of the treated AMD is suitable for Category 4 industrial use, per the Dept. of Water Affairs and Forestry’s limits.ZusammenfassungEisen-Nanopartikel (Nano-Fe) wurden aus Kohleflugaschen (CFA) bzw. Eisen(III)-chlorid (FeCl3) extrahiert und zur Behandlung von Sauerwasser (AMD) genutzt. Zur Phasenanalyse wurden eingesetzt Röntgenbeugung (XRD), Röntgenfluoreszenz, Rasterelektronenmikroskopie mit energiedispersiver Röntgenspektroskopie (SEM–EDX), hochauflösende Transmissionselektronenmikroskopie (HRTEM) sowie die Bestimmung der spezifischen Oberfläche nach der BET-Methode (Brunauer, Emmet und Teller). Die HRTEM-Untersuchungen deuteten auf eine gute Dispergierung der typischerweise tröpfchenartigen Nanoeisenstruktur hin. Das Nanoeisen lag überwiegend nullwertig vor, wie sich anhand des XRD-Peaks bei ≈ 44,7° feststellen ließ; es trat in Begleitung allgemein akzeptierter, partikelumschließender Oxidschichten auf, was durch den Nachweis einer Kern-Schalen-Struktur in den HRTEM-Abbildungen belegt wurde. Die BET-Oberflächen von aus CFA bzw. FeCl3 extrahiertem Nanoeisen betrugen 34,7 bzw. 88,8 m2/g. Das Nanoeisen führte zur Konzentrationsverringerung der meisten der kontrollierten Schadstoffe, mit Abtrennraten von 17…99%. Der pH-Wert des Sauerwassers stieg nach der Behandlung mit aus CFA bzw. FeCl3 extrahiertem Nanoeisen auf 5,74 bzw. 6,01, bei einem Ausgangswert von 3,49. Die elektrische Leitfähigkeit sank von 0,57 Ω/m auf 0,18 bzw. 0,13 Ω/m, während sich der Abdampfrückstand von 1683 mg/L auf 447 bzw. 384 mg/L verringerte. Das behandelte Sauerwasser erfüllt die Kriterien für eine industrielle Nutzung der Kategorie 4 gemäß den Grenzwerten der Abteilung für Wasserangelegenheiten und Forstwirtschaft.ResumenNanopartículas de hierro (nano Fe) fueron extraídas de cenizas de carbón (CFA) o de cloruro férrico (FeCl3) y se usaron para la remediación del drenaje ácido de minas (AMD). La caracterización se realizó mediante difracción de rayos X (XRD), fluorescencia de rayos X, microscopía electrónica de barrido-espectroscopia de energía (SEM–EDX), microscopía electrónica de transmisión de alta resolución (HRTEM) y la determinación del área superficial Braunaer-Emmet-Teller (BET). El HRTEM indicó una buena dispersión de la estructura tipo esférica de las de nano Fe. También se observó que los nano Fe estaban principalmente en el estado de oxidación cero, como se indica por el pico característico en ≈ 44.7° en el análisis de DRX; estuvo acompañado por la capa de óxido generalmente aceptada alrededor de las partículas, que se confirmó por la aparición de una estructura núcleo-cubierta en las micrografías HRTEM. Las áreas de superficie BET del nano Fe provenientes de CFA o FeCl3 fueron 34,7 y 88,8 m2/g, respectivamente. El nano Fe redujo la concentración de la mayoría de los contaminantes monitoreados, con un porcentaje de eliminación que oscila entre el 17 y el 99%. El pH de la AMD después del tratamiento con nano Fe obtenidas de CFA o FeCl3 aumentó a 5,74 y 6,01, respectivamente, desde un valor inicial de 3,49, la conductividad eléctrica disminuyó a 0,18 y 0,13 Ω/m, respectivamente, desde un valor inicial de 0,57 Ω/m, mientras que el total de sólidos disueltos se redujo a 447 o 384 mg/l, respectivamente, desde 1683 mg/l iniciales. La calidad del agua de la DMAE tratada es adecuada para el uso industrial de categoría 4, según los límites del Departamento de Asuntos Hídricos y Bosques.从粉煤灰或氯化铁中提取铁纳米颗粒处理矿山酸性废水的新方法利用粉煤灰(CFA)或氯化铁(FeCl3)提取铁纳米颗粒(nano…
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