The present paper should be considered as a review of the application of Fourier Transform Infra-Red for surface clay characterization. The application of surface clay materials for water treatment, oil adsorption, ex...The present paper should be considered as a review of the application of Fourier Transform Infra-Red for surface clay characterization. The application of surface clay materials for water treatment, oil adsorption, excipients or as active in drugs has largely increased these recent years. The surface clay material presents hydroxyl groups, which can link very easily water molecules. These hydroxyl groups can react with organic groups and by their vibration in the infra-red region, FT-IR can be easily used as a technical method for surface clay characterization. In this paper, we focus on the determination of Lewis and Bronsted acid sites on the clay surface, a critical review of the sample preparation, the surface characterization of bulk clay and the modified surface clay samples using FT-IR spectroscopy.展开更多
In this study, a low-cost and sensitive voltammetric method was developed for the determination of paraquat (PQ2+). This was achieved by coating a glassy carbon electrode with a purified fraction of a smectite-type cl...In this study, a low-cost and sensitive voltammetric method was developed for the determination of paraquat (PQ2+). This was achieved by coating a glassy carbon electrode with a purified fraction of a smectite-type clay, which was then used to accumulate paraquat by an ion exchange process. The electronanalytical procedure involves two steps: the chemical preconcentration of paraquat under open-circuit conditions in an aqueous medium, followed by the voltammetric detection of the preconcentrated pollutant in a medium containing permanganate ions which significantly improved through its catalytic action the electrode response. A systematic study of the experimental conditions (pH of the accumulation and detection media, permanganate concentration in the detection medium, clay content of the coating, potential and duration of the electrolysis step) on the stripping response were examined in detail. After optimization, a linear calibration curve for paraquat was obtained in the concentration range from 1.6 to 2.8 μM, leading to a detection limit of 3.8 × 10–9 mol·L–1 (S/N = 3). The proposed method was successfully applied to the determination of paraquat in spring water.展开更多
文摘The present paper should be considered as a review of the application of Fourier Transform Infra-Red for surface clay characterization. The application of surface clay materials for water treatment, oil adsorption, excipients or as active in drugs has largely increased these recent years. The surface clay material presents hydroxyl groups, which can link very easily water molecules. These hydroxyl groups can react with organic groups and by their vibration in the infra-red region, FT-IR can be easily used as a technical method for surface clay characterization. In this paper, we focus on the determination of Lewis and Bronsted acid sites on the clay surface, a critical review of the sample preparation, the surface characterization of bulk clay and the modified surface clay samples using FT-IR spectroscopy.
文摘In this study, a low-cost and sensitive voltammetric method was developed for the determination of paraquat (PQ2+). This was achieved by coating a glassy carbon electrode with a purified fraction of a smectite-type clay, which was then used to accumulate paraquat by an ion exchange process. The electronanalytical procedure involves two steps: the chemical preconcentration of paraquat under open-circuit conditions in an aqueous medium, followed by the voltammetric detection of the preconcentrated pollutant in a medium containing permanganate ions which significantly improved through its catalytic action the electrode response. A systematic study of the experimental conditions (pH of the accumulation and detection media, permanganate concentration in the detection medium, clay content of the coating, potential and duration of the electrolysis step) on the stripping response were examined in detail. After optimization, a linear calibration curve for paraquat was obtained in the concentration range from 1.6 to 2.8 μM, leading to a detection limit of 3.8 × 10–9 mol·L–1 (S/N = 3). The proposed method was successfully applied to the determination of paraquat in spring water.
