Removal of diclofenac from aqueous solutions by adsorption on thermo-plasma expanded graphite

The adsorption of diclofenac on thermo-plasma expanded graphite (a commercial product) from water solutions was investigated. The adsorbent material was characterized by SEM, TEM, BET, Raman and X-ray diffraction analyses. Typical diffractogram and Raman spectrum of graphitic material, dimension of 24.02 nm as crystallite dimension and a surface area of 47 m2 g−1 were obtained. The effect of pH on the adsorption capacity was evaluated in the range 1–7 and the adsorption mechanism was described by kinetic and isothermal studies. Pseudo-second order and Dubinin–Radushkevich models agreed with theoretical values of adsorption capacity (i.e. 400 and 433 mg g−1, respectively) and resulted to be the best fit for kinetics and isothermal experimental data. The thermodynamics of the process was evaluated by plotting the adsorption capacity/concentration ratio at the equilibrium as a function of different values of the multiplicative inverse of temperature. Moreover, the adsorbent regeneration was also investigated, comparing two different remediation techniques. Solvent washing performed with NaOH 0.2 M and thermo-treatment carried out by heating in an oven at 105 °C for 2 h and then at 200 °C for 4 h. The thermo-treatment was the best technique to regenerate the adsorbent, ensuring same performance after 4 cycles of use and regeneration.

Abordagem qualitativa na avaliação de risco químico em atividade de lavagem de peças de impressão gráfica com solvente orgânico

The printing industry is diverse and serves all the economic sectors. In the graphic industry it is common to use paints and solvents that have risky chemical substances in their composition which may cause damage to the central nervous system, euphoria, dizziness, drowsiness, irritations in the eyes, in the skin and respiratory tract. This research uses a qualitative chemical risk database from the International Chemical Control Toolkit (ICCT), adapted from COSHH Essentials published in 1998 by Healthy and Safety Executive (HSE), in the United Kingdom. A qualitative methodology, simple and practical, was applied to solvent washing activities of the graphic printing industry of a flexible plastic packaging company in Campina Grande-PB. A qualitative methodology was used to determine preventive actions and control measures for ethyl acetate solvent exposure. From simple information contained in the MSDS of chemical substance, such as safety phrases and boiling temperature, together with the amount handled by the worker and the operating temperature of the activity, it was possible to establish adequate control measures to be implemented in the areas with chemical hazard.

Photo-Induced Black Phase Stabilization of CsPbI3 QDs Films

α-CsPbI3 quantum dots (QDs) show outstanding photoelectrical properties that had been harnessed in the fabrication of perovskite QDs solar cells. Nevertheless, the stabilization of the CsPbI3 perovskite cubic phase remains a challenge due to its own thermodynamic and the presence of surface defects. Herein, we report the optimization of the CsPbI3 QDs solar cells, by monitoring the structure, the morphology and the optoelectronic properties after a precise treatment, consisting of the conventional solvent washing with a time limited ultraviolet (UV) exposure combination, during the layer-by-layer deposition. The UV treatment compensates the defects coming from the essential but deleterious washing treatment. The material is stable for 200 h and the PCE improved by the 25% compared with that of the device without UV treatment. The photo-enhanced ion mobility mechanism is discussed as the main process for the CsPbI3 QDs and solar cell stability.

Review and reproducibility of forming adsorbed layers from solvent washing of melt annealed films

Efforts to reproduce the “Guiselin’s experiment” procedure finds hads(t) curves to be far less reliable than implied in the literature, being strongly dependent on solvent washing conditions, consistent with how adsorption in solution is understood.

Preparation of Micro-Patterned CaMn7O12 Ceramic Films via a Photosensitive Sol-Gel Method

Mn/acetylacetone chelate was synthesized using Mn(CH3COO)2·4H2O as raw material, methanol as the solvent, and acetylacetone as the chelating agent. The ultraviolet (UV)-absorption peak of the synthesized chelate was found around 298 nm. CaMn7O12 sol was subsequently prepared using the Mn/AcAc chelate as the Mn source and calcium nitrate as the calcium source. The UV test indicates that the CaMn7O12 sol has the UV-sensitive characteristics. Owing to its photo-sensitivity, micro-patterned CaMn7O12 ceramic film can be prepared without photoresist, only through dip-coating, drying, UV-irradiation, solvent-washing, and heat treatment. The magnetic test result indicates that the micro-patterned CaMn7O12 ceramic film has a saturation magnetization of 112.8 emu/cm3, which is close to that of non-patterned CaMn7O12 ceramic film.