Thermoluminescent properties of ZnS:Mn nanocrystalline powders.

Thermoluminescent ZnS nanocrystals doped with Mn(2+) ions were synthesized by chemical co-precipitation method. From X-ray diffraction studies it was observed that the synthesized nanoparticles have cubic zinc blende structure with average sizes of about 40-50nm. Morphology was analyzed by TEM. Photoluminescence studies showed two transitions, one of them close to 396nm and other close to 598nm, which is enhanced with increasing dopant concentration, this behavior was also observed in the cathodoluminescence spectrum. The thermoluminescence gamma dose-response has linear behavior over dose range 5-100mGy, the glow curve structure shows two glow peaks at 436K and at 518K that were taken into account to calculate the kinetic parameters using the Computerized Glow Curve Deconvolution procedure.

Desarrollo de un bioadsorbente laminar con Phanerochaete chrysosporium hipertolerante al cadmio, al níquel y al plomo para el tratamiento de aguas / Development of a laminar bioadsorbent with hypertolerant Phanerochaete chrysosporium to Cd, Ni and Pb for wastewater treatment

Antecedentes. El uso de basidiomicetes para la remoción de metales es una alternativa con respecto a los métodos tradicionales, básicamente porque la biomasa actúa como un intercambiador natural al remover metales en solución. Objetivo. Desarrollar un bioadsorbente laminar empleando el hongo basidiomicete con mayor resistencia al cadmio (Cd), al níquel (Ni) y al plomo (Pb). Métodos. Se valoró la tolerancia de Trametes versicolor, Pleurotus ostreatus y Phanerochaete chrysosporium frente a concentraciones ascendentes de sulfato de sulfato de cadmio, acetato de plomo y cloruro de níquel. Se desarrolló un bioadsorbente a base de láminas de polietileno con biomasa fúngica, que se evaluó en columnas de burbujeo empleando agua residual sintética con los 3 metales con una concentración final de 300mg/l. Finalmente, con un experimento complementario en matraces Erlenmeyer, se valoró el efecto de mayor cantidad de biomasa sobre la eficiencia de remoción. Resultados. El hongo P. chrysosporium fue la cepa más tolerante a C4H6O4Pb (10.000mg/l), a Cl2Ni (300mg/l) y CdSO4·8H2O (1.500mg/l). En el reactor y bajo condiciones no ligninolíticas, el hongo removió el 69% de la demanda química de oxígeno, produjo enzimas como lignino peroxidasa (0,01U/l) y manganeso peroxidasa (0,6U/l) y se observó la acumulación de los metales en la pared. Al incrementar la biomasa a 1,6 (p/v) se favoreció la bioadsorción de los metales en la mezcla (el 57% para el Pb, el 74% para el Cd y el 98% para el Ni) y por separado (el 95% para el Pb, el 60% para el Cd y el 56% para el Ni). Se observó una competencia entre el Ni y el Pb por los ligandos de la pared. Conclusión. Se desarrolló un novedoso sistema laminar a base de biomasa viable de P. chrysosporium que posee gran área superficial y tolera elevadas concentraciones de Cd, Ni y Pb, como alternativa para la remoción de metales en aguas(AU)

Background. The use of basidiomycetes for metal removal is an alternative to traditional methods. In this, the biomass acts as a natural ionic exchanger removing metals from solution. Objective. To develop a laminar biosorbent using a basidiomycete fungus resistant to high Cd, Ni and Pb concentrations. Methods. The tolerance of Trametes versicolor, Pleurotus ostreatus and Phanerochaete chrysosporium was evaluated using increasing concentrations of the heavy metal salts, cadmium sulphate, lead acetate and nickel chloride. A biosorbent system was developed based on polyethylene sheets with a fungal biomass. It was evaluated in bubble columns using synthetic wastewater with the 3 metal salts at a rate of 300mg/l. Finally, in a complementary experiment using shake flasks, the effect of a higher amount of biomass related to the metal removal efficiency was evaluated. Results. P. chrysosporium strain was more tolerant to C4H6O4Pb (10,000mg/l), Cl2Ni (300mg/l) and CdSO4·8H2O (1,500mg/l). In a reactor, under non-ligninolytic conditions, the fungus removed 69% of the chemical oxygen demand and produced enzymes such as LiP (0.01U/l) and MnP (0.6U/l.). An accumulation of metals in the wall was observed. By increasing the biomass to 1.6 (w/v), the metal biosorption was favored in the mixture (57% Pb, 74% Cd, and 98% Ni) and separately (95% Pb, 60% Cd, and 56% Ni). Competition between Ni and Pb by ligands of the wall was observed. Conclusion. A novel laminar system based on P. chrysosporium viable biomass was developed. It has a large surface area and tolerance to high concentrations of Cd, Ni and Pb. It seems to be an alternative for the removal of metals from water(AU)

[Development of a laminar bioadsorbent with hypertolerant Phanerochaete chrysosporium to Cd, Ni and Pb for wastewater treatment]. / Desarrollo de un bioadsorbente laminar con Phanerochaete chrysosporium hipertolerante al cadmio, al níquel y al plomo para el tratamiento de aguas.

BACKGROUND: The use of basidiomycetes for metal removal is an alternative to traditional methods. In this, the biomass acts as a natural ionic exchanger removing metals from solution. OBJECTIVE: To develop a laminar biosorbent using a basidiomycete fungus resistant to high Cd, Ni and Pb concentrations. METHODS: The tolerance of Trametes versicolor, Pleurotus ostreatus and Phanerochaete chrysosporium was evaluated using increasing concentrations of the heavy metal salts, cadmium sulphate, lead acetate and nickel chloride. A biosorbent system was developed based on polyethylene sheets with a fungal biomass. It was evaluated in bubble columns using synthetic wastewater with the 3 metal salts at a rate of 300 mg/l. Finally, in a complementary experiment using shake flasks, the effect of a higher amount of biomass related to the metal removal efficiency was evaluated. RESULTS: P. chrysosporium strain was more tolerant to C4H6O4Pb (10,000mg/l), Cl2Ni (300mg/l) and CdSO4·8H2O (1,500 mg/l). In a reactor, under non-ligninolytic conditions, the fungus removed 69% of the chemical oxygen demand and produced enzymes such as LiP (0.01 U/l) and MnP (0.6 U/l.). An accumulation of metals in the wall was observed. By increasing the biomass to 1.6 (w/v), the metal biosorption was favored in the mixture (57% Pb, 74% Cd, and 98% Ni) and separately (95% Pb, 60% Cd, and 56% Ni). Competition between Ni and Pb by ligands of the wall was observed. CONCLUSION: A novel laminar system based on P. chrysosporium viable biomass was developed. It has a large surface area and tolerance to high concentrations of Cd, Ni and Pb. It seems to be an alternative for the removal of metals from water.