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Francic N.,University of Maribor | Nedeljko P.,Institute for Environmental Protection and Sensors Ltd. | Lobnik A.,University of Maribor
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

In the past decade, interest in mesoporous materials has developed dramatically since they can be useful in a number of applications, including adsorption and sensor technology. Mesoporous materials are a class of nanostrustures with well-defined mesoscale (2-50 nm) pores, surface areas up to 1000 m2/g and large pore volumes (~1.0 mL/g). In general, ordered mesoporous materials are formed from solution by co-assembly and cross-linking of network-forming inorganic species (typically oxides) in the presence of structure-directing agents (SDAs) [1]. The SDAs are typically surfactants or blockcopolymers that self-organize into mesoscale (2-50 nm) structures, according to the solution composition and processing conditions used [2]. Owing to their structural properties and regular morphology, mesoporous silicas (MPS) are promising materials for applications in the immobilization processes or as supports for bulky bio-molecules, such as enzymes. We report on the synthesis of mesoporous silica (MPS) particles and their potential use for immobilization of the enzyme hexahistidine tagged OPH (His6-OPH). Particle characterization points out a strong influence of the synthesis parameters (addition of ethyl acetate). BET results show a high specific surface area (300-450 m2/g) and an appropriate pore size distribution ranging from 10 to 40 nm. Immobilization of the enzyme His6-OPH, with the size of 72 kDa and isoelectric point (pI) of 8.5, was carried out in MPS particles of spherical morphology. Preliminary results indicate significant potential in use of encapsulated enzyme His6-OPH for the purpose of bio-sensing or in the detoxification processes of organophosphates. © 2013 SPIE. Source


Bauman M.,Institute for Environmental Protection and Sensors Ltd. | Poberznik M.,Institute for Environmental Protection and Sensors Ltd. | Kolar M.,University of Maribor | Lobnik A.,University of Maribor
Tekstil | Year: 2014

The oxidation of the often used oxazine direct dye C.I. Direct Blue 106 (Direct Dye 106) in an aqueous solution (600 mg I-1) by ozonation was investigated. VIS spectra showed degradation of the oxazine groups in the initial Direct Dye 106 structure. The oxidation by-products, such as sulphate, nitrate, nitrite, chloride ions and phenolic compounds, were identified by MS-MS and the LC-MS analyses. After ozonation the wastewater containing the Direct Dye 106 showed no toxic characteristics, according to Daphnia magna test (24 h-EC50 > 75%). Source


Bauman M.,Institute for Environmental Protection and Sensors Ltd. | Poberznik M.,Institute for Environmental Protection and Sensors Ltd. | Kolar M.,University of Maribor | Lobnik A.,University of Maribor
Tekstil | Year: 2014

The oxidation of the often used oxazine direct dye C.I. Direct Blue 106 (Direct Dye 106) in an aqueous solution (600 mg L-1) by ozonation was investigated. VIS spectra showed degradation of the oxazine groups in the initial Direct Dye 106 structure. The oxidation by-products, such as sulphate, nitrate, nitrite, chloride ions and phenolic compounds, were identified by MS-MS and the LC-MS analyses. After ozonation the wastewater containing the Direct Dye 106 showed no toxic characteristics, according to Daphnia magna test (24 h-EC50>75%). Source

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