No abstract

This study proposes a miniaturized fluorimetric device to determine caffeine in an energy drink and medicines by digital image using a smartphone.

Emerging contaminants are substances found in the environment whose concentrations vary from µg to ng L-1 and whose presence in wastewater has gained popularity in the scientific community due to the potential impacts these compounds can cause to the environment. This designation concerns the lack of legislation to regulate their discharge or even to monitor these compounds. Moreover, emerging contaminants are capable of causing harmful effects to nontarget organisms and therefore affect the ecosystem balance. There are several compounds classified as emerging contaminants such as pharmaceuticals, illicit drugs, hormones, pesticides, among others. And among them, caffeine is considered an emerging contaminant and can be highlighted due its presence in medicines, beverages, foodstuff and several other products. In addition, it is a compound used worldwide recognized as a marker of anthropogenic activity. In this review, we present a discussion about emerging contaminants, focusing on caffeine, regulatory aspects that involve the theme, as well as effects on organisms, removal technologies and techniques for analyzing these compounds in environmental matrices.

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This work investigates the physicochemical properties of a biochar obtained from sugarcane bagasse by torrefaction at four different temperatures (260, 270, 280, and 290 �C), without chemical or physical activation. The biochar was characterized by thermogravimetric and proximate analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, together with measurements of point of zero charge, pH, elemental composition, and surface area. Evaluation regarding the efficiency of the biochar employed as an adsorbent for the removal of caffeine, ciprofloxacin, and norfloxacin in wastewater samples. The assays were performed in batch vessels filled with lab-made sewage spiked with caffeine at 5.00 �g L�1 and with ciprofloxacin and norfloxacin at 10.0 �g L�1. These compounds were studied separately. The thermogravimetry data demonstrated that increasing the torrefaction temperature led to generation of a greater amount of fixed carbon, as well as loss of volatile materials and removal of non-condensable compounds. This was corroborated by the FTIR analyses, where a higher temperature led to higher intensity of bands corresponding to methyl, methylene, and C=C bonds. The biochar produced at 280��C presented the best stability, with adsorption efficiencies for removal from the lab-made sewage of 91% (norfloxacin), 81% (ciprofloxacin), and 58% (caffeine).