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Graphene quantum dots (GQDs) were synthesized by a facile one-step wet chemically derived from carbon fibers. A novel, sensitive, simple, and convenient method for the detection of tert-butylhydroquinone (TBHQ) was established based on GQDs and silver nanoparticle (AgNP) modified electrode. The modified electrode exhibited excellent electrocatalytic performance toward the electrochemical detection of TBHQ. Meanwhile, a possible reaction mechanism related to the oxidation of TBHQ was proposed. The electron transfer number and electron transfer coefficient were found to be 3.05 and 0.40. The surface concentration of TBHQon GQD/AgNP-modified electrode was calculated as 2.62 x [10.sup.-10] mol [cm.sup.-2]. Under the optimum conditions, a good linear relationship between peak current and the concentration of TBHQ was obtained in the range of 0.15-300 [micro]mol [L.sup.-1] with a detection limit of 0.07 [micro]mol [L.sup.-1] (S/N =3). The proposed method was successfully applied for the detection of TBHQin edible vegetable oil. Key words: graphene quantum dots, silver nanoparticles, tert-butylhydroquinone, modified electrode, edible vegetable oil. Nous avons synthetise des boites quantiques de graphene a partir de fibres de carbone par un procede chimique humide en une etape facile. Nous avons etabli une nouvelle methode sensible, simple et pratique pour la detection de la tert-butylhydroquinone (TBHQ) au moyen d'une electrode modifiee a base de boites quantiques de graphene et de nanoparticules d'argent. Nous avons observe que la performance electrocatalytique de l'electrode modifiee pour la detection electrochimique de la TBHQ etait excellente. Parallelement, nous avons propose un mecanisme de reaction possible pour l'oxydation de la TBHQ. Nous avons obtenu un nombre de transferts d'electrons de 3,05 et un coefficient de transfert d'electrons de 0,40. La concentration de TBHQ a la surface de l'electrode modifiee a base de boites quantiques de graphene et de nanoparticules d'argent a ete calculee a 2,62 x [10.sup.-10] mol [cm.sup.-2]. En conditions optimales, nous avons obtenu une bonne linearite entre le courant de pic et la concentration de TBHQ dans l'intervalle de 0,15 a 300 [micro]mol [L.sup.-1], avec une limite de detection de 0,07 [micro]mol [L.sup.-1] (rapport signal/bruit = 3). La methode proposee a ete appliquee avec succes a la detection de la TBHQ dans l'huile vegetale comestible. [Traduit par la Redaction] Mots-cles: boites quantiques de graphene, nanoparticules d'argent, tert-butylhydroquinone, electrode modifiee, huile vegetale comestible., Introduction Graphene quantum dots (GQDs), graphene sheets with lateral sizes less than 100 nm, have several unique properties over micrometre-sized graphene and graphene oxide sheets. (1) As a new type [...]

We load the natural active molecules onto the spin film in an array using electrospinning techniques. The electrospun active molecular membranes we obtain in optimal parameters exhibit excellent capacity for scavenging radical. The reaction capacity of three different membranes for free radicals are shown as follow, glycyrrhizin acid membrane > quercetin membrane > α-mangostin membrane. The prepared active molecular electrospun membranes with a large specific surface area and high porosity could increase the interaction area between active molecules and free radicals. Additionally, it also has improved anti-airflow impact strength, anti-contaminant air molecular interference ability, and the ability to capture free radicals. [ABSTRACT FROM AUTHOR]

In the troposphere, the knowledge about nitrous acid (HONO) sources is incomplete. The missing source of sulfate and fine particles cannot be explained during haze events. Air quality models cannot predict high levels of secondary fine-particle pollution. Despite extensive studies, one challenging issue in atmospheric chemistry is identifying the source of HONO. Here, we present direct ab initio molecular dynamics simulation evidence and typical air pollution events of the formation of gaseous HONO, nitrogen dioxide/hydrogen sulfite (HOS(O)2-NO 2 or NO 2 -HSO 3 ) from nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), water (H 2 O), and ammonia (NH 3 ) molecules in a proportion of 2:1:3:3. The reactions show a new mechanism for the formation of HONO and NO 2 -HSO 3 in the troposphere, especially when the concentration of NO 2 , SO 2 , H 2 O, and NH 3 is high (e.g., 2:1:3:3 or higher) in the air. Contrary to the proportion NO 2 , SO 2 , H 2 O, and NH 3 equaling to 1:1:3:1 and 1:1:3:2, the proportion (2:1:3:3) enables barrierless reactions and weak interactions between molecules via the formation of HONO, NO 2 -HSO 3 , and NH 3 /H 2 O. In addition, field observations are carried out, and the measured data are summarized. Correlation analysis supported the conversion of NO 2 to HONO during observational studies. The weak interactions promote proton transfer, resulting in the generation of HONO, NO 2 -HSO 3 , and NH 3 /H 2 O pairs.