RESUMO
Wet flue gas denitrification offers a new route to convert industrial nitrogen oxides (NOx) into highly concentrated nitrate wastewater, from which the nitrogen resource can be recovered to ammonia (NH3) via electrochemical nitrate reduction reactions (NITRRs). Low-cost, scalable, and efficient cathodic materials need to be developed to enhance the NH3 production rate. Here, in situ electrodeposition was adopted to fabricate a foamy Cu-based heterojunction electrode containing both Cu-defects and oxygen vacancy loaded Cu2O (OVs-Cu2O), which achieved an NH3 yield rate of 3.59 mmol h-1 cm-2, NH3 Faradaic efficiency of 99.5%, and NH3 selectivity of 100%. Characterizations and theoretical calculations unveiled that the Cu-defects and OVs-Cu2O heterojunction boosted the H* yield, suppressed the hydrogen evolution reaction (HER), and served as dual reaction sites to coherently match the tandem reactions kinetics of NO3-to-NO2 and NO2-to-NH3. An integrated system was further built to combine wet flue gas denitrification and desulfurization, simultaneously converting NO and SO2 to produce the (NH4)2SO4 fertilizer. This study offers new insights into the application of low-cost Cu-based cathode for electrochemically driven wet denitrification wastewater valorization.
Assuntos
Amônia , Águas Residuárias , Nitratos/química , Dióxido de Nitrogênio , Desnitrificação , EletrodosRESUMO
In this study, high-performance liquid chromatography was used to determine four components of Shaoyao Gancao Decoction (SGD), and the effect of purification was evaluated using fingerprints, similarity analysis and cell experiments. An effective method for isolation and purification of SGD was established. The adsorption/desorption properties of SGD were evaluated using resin screening, isothermal analysis, adsorption kinetics, and dynamic adsorption-desorption experiments. It was shown that the Langmuir equation fitted the isotherm data well and that a pseudo-second-order model accurately described kinetic adsorption on AB-8 resin. Analysis of thermodynamic parameters showed that the adsorption process was exothermic. Under the optimal process conditions, the concentrations of albiflorin, paeoniflorin, liquiritin and ammonium glycyrrhizinate in the product were 73.05, 134.04, 45.04 and 75.00 mg/g, respectively. The yields of the four components were 71.89 %-86.19 %. Cell experiments showed that the purified SGD retained anti-inflammatory activity. This research lays the foundation for the separation and purification of SGD and subsequent preparation research.
Assuntos
Medicamentos de Ervas Chinesas , Glucosídeos , Monoterpenos , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Glucosídeos/isolamento & purificação , Glucosídeos/química , Monoterpenos/isolamento & purificação , Monoterpenos/química , Adsorção , Flavanonas/isolamento & purificação , Flavanonas/química , Flavanonas/análise , Animais , Ácido Glicirrízico/isolamento & purificação , Ácido Glicirrízico/química , Ácido Glicirrízico/análise , Hidrocarbonetos Aromáticos com Pontes/química , Hidrocarbonetos Aromáticos com Pontes/isolamento & purificação , Camundongos , Resinas Sintéticas/química , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/química , Humanos , Células RAW 264.7RESUMO
Toluene, a prominent member of volatile organic compounds (VOCs), exerts a substantial adverse influence on both human life and the environment. In the context of advanced oxidation processes, the ·OH radical emerges as a highly efficient oxidant, pivotal in the elimination of VOCs. This study employs computational quantum chemistry methods (G4MP2//B3LYP/6-311++G(d,p)) to systematically investigate the degradation of toluene by ·OH radicals in an implicit solvent model, and validates the rationale of choosing a single-reference method using T1 diagnostics. Our results suggest three possible reaction mechanisms for the oxidation of toluene by ·OH: firstly, the phenyl ring undergoes a hydrogen abstraction reaction followed by direct combination with ·OH to form cresol; secondly, ·OH directly adds to the phenyl ring, leading to ring opening; thirdly, oxidation of sidechain to benzoic acid followed by further addition and ring opening. The last two oxidation pathways involve the ring opening of toluene via the addition of ·OH, significantly facilitating the process. Therefore, both pathways are considered feasible for the degradation of toluene. Subsequently, the UV-H2O2 system was designed to induce the formation of ·OH for toluene degradation and to identify the optimal reaction conditions. It was demonstrated that ·OH and 1O2 are the primary active species for degrading toluene, with their contribution ranking as ·OH > 1O2. The intermediates in the mixture solution after reactions were characterized using GC-MS, demonstrating the validity of theoretical predictions. A comparative study of the toluene consumption rate revealed an experimental comprehensive activation energy of 10.33 kJ/mol, which is consistent with the preliminary activation energies obtained via theoretical analysis of these three mechanisms (0.56 kJ/mol to 13.66 kJ/mol), indicating that this theoretical method can provide a theoretical basis for experimental studies on the oxidation of toluene by ·OH.
RESUMO
This study employs five UV-AOPs (PMS, PDS, H2O2, NaClO and NaClO2) to produce radicals (â¢OH, SO4â¢-, ClOâ¢, O2â¢- and 1O2) and further comparatively studies their activity sequence and activity difference cause in toluene degradation. The toluene mineralization efficiency as a descending order is 73 % (UV-PMS) > 71 % (UV-PDS) > 70 % (acidified-UV-NaClO) > 55 % (UV-H2O2) > 36 % (UV-NaClO) > 35 % (UV-NaClO2); that of conversion efficiency is 99 % (acidified-UV-NaClO) > 95 % (UV-PMS) > 90 % (UV-PDS) > 74 % (UV-H2O2) > 44 % (UV-NaClO) > 41 % (UV-NaClO2). Acidic pretreatment significantly boosts the reactivity of UV-NaClO. ESR combined with radical quenching tests reveals the radicals' generation and evolution, and their contribution rates to toluene conversion, i.e. ClO⢠> SO4â¢- > O2â¢- > 1O2 > â¢OH. Theoretical calculations further unveil the ring-opening reaction routes and the nature of the activity difference of different radicals. The minimum energy required for ring-opening reaction is 116.77, 150.63, 168.29 and 191.92 kJ/mol with respect to ClOâ¢, SO4â¢-, 1O2 and â¢OH, and finding that the ClOâ¢-HO⢠pair is the best for toluene mineralization. The difficulty for eliminating typical VOCs by using UV-AOPs method is determined as toluene > chlorobenzene > benzene > ethyl acetate.
RESUMO
The computer-aided drug design (CADD) course that spans biochemistry, computational chemistry, medicinal chemistry, and other cutting-edge sciences is considered an important course by pharmaceutical universities in China. The course teaches students how drugs bind to protein targets and exert their biological activities using computer tools, and covers the basic principles of drug development and optimization. Due to the lockdown and social distancing measures adopted during the coronavirus disease 2019 (COVID-19) pandemic, the CADD course in Shenyang Pharmaceutical University was briefly suspended. Thereafter, it was taught in the online mode by adopting a novel blended teaching method. Through a questionnaire survey and final report assessment, we found that blended teaching might provide an opportunity to stimulate greater motivation and interest in students as well as improve teaching effectiveness and learning outcomes of the course. This study describes how we conducted the CADD course during the COVID-19 period with the intention of providing a reference for other teachers to conduct similar courses.
Assuntos
COVID-19 , Farmácia , Humanos , Pandemias , Universidades , COVID-19/epidemiologia , Controle de Doenças Transmissíveis , Desenho de Fármacos , Estudantes , Preparações FarmacêuticasRESUMO
Chromium poisoning has become one of the most common heavy metal poisoning occupational diseases with high morbidity and mortality. However, most antidotes detoxify the whole body and are highly toxic. To achieve hepato-targeted chromium poisoning detoxification, a novel hepato-targeted strategy was developed using aging erythrocyte membranes (AEMs) as biomimetic material coated with a dimercaptosuccinic acid (DMSA) nanostructured lipid carrier to construct a biomimetic nano-drug delivery system. The particle size, potential, drug loading, encapsulation rate, in vitro release, and stability of the nanoparticles (NPs) were characterized. Confocal microscopy and flow cytometry showed that the prepared NPs could be phagocytized by RAW264.7 macrophage cells. The efficacy of AEM-DMSA-NPs for targeted liver detoxification was evaluated by in vitro MTT analysis and an in vivo model of chromium poisoning. The results showed that the NPs could safely and efficiently achieve targeted liver chromium poisoning detoxification. All the results indicated that the biomimetic nano-drug delivery system mediated by aging erythrocyte membranes and containing DMSA nanoparticles could be used as a novel therapeutic drug delivery system potentially targeting liver detoxification.
Assuntos
Antídotos/farmacologia , Materiais Biomiméticos/metabolismo , Cromo/intoxicação , Membrana Eritrocítica/metabolismo , Nanopartículas/química , Succímero/farmacologia , Animais , Antídotos/administração & dosagem , Antídotos/farmacocinética , Química Farmacêutica , Portadores de Fármacos , Liberação Controlada de Fármacos , Fígado/efeitos dos fármacos , Masculino , Camundongos , Tamanho da Partícula , Células RAW 264.7 , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Succímero/administração & dosagem , Succímero/farmacocinéticaRESUMO
The hydrolytic kinetics of lithospermic acid B (LAB) extracted from the roots of Salvia miltiorrhiza (Chinese herb: danshen) was investigated by using reversed-phase high-performance liquid chromatography (HPLC) with UV-vis detection. The influences of initial drug concentration, pH and temperature on hydrolysis of LAB were studied in aqueous solutions. The results showed that initial concentration of LAB has no effect on the degradation rate at pH 2.0. The hydrolysis followed pseudo-first-order kinetics at 90 degrees C. The log k(obs)-pH profile indicated that the optimal stability range was at pH 2.0-5.0. The rate constant of overall hydrolysis as a function of temperature under the given conditions obeyed the Arrhenius equation. Analysis of the acid-induced degraded solution of LAB by liquid chromatography-mass spectrometry (LC-MS) revealed at least four degradation products [M-H](-) ion at m/z 197, 137, 537 and 537, respectively. Three of these degradation products, i.e. danshensu (DSU), protocatechuic aldehyde (PRO), and lithospermic acid, were further identified by comparing the retention times with standard samples. According to the structure of LAB and its hydrolysis behavior in solution, the other product was proposed to be the isomer of lithospermic acid.
Assuntos
Benzofuranos/química , Depsídeos/química , Medicamentos de Ervas Chinesas/química , Salvia miltiorrhiza/química , Benzaldeídos/química , Benzofuranos/isolamento & purificação , Catecóis/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida de Alta Pressão/normas , Depsídeos/isolamento & purificação , Estabilidade de Medicamentos , Medicamentos de Ervas Chinesas/isolamento & purificação , Meia-Vida , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Lactatos/química , Espectrometria de Massas/métodos , Espectrometria de Massas/normas , Modelos Químicos , Estrutura Molecular , Raízes de Plantas , Padrões de Referência , Soluções , Espectrofotometria Ultravioleta/métodos , Espectrofotometria Ultravioleta/normas , TemperaturaRESUMO
The degradation of lithospermic acid B (LAB) was investigated as a function of buffer concentration, pH and temperature. Stability tests were performed using a stability-indicating high-performance liquid chromatography (HPLC) with UV-vis detection. The degradation followed pseudo-first-order kinetics under all experimental conditions. The maximum stability of LAB was observed at pH 2.0. The logk(pH)-pH profile described by specific acid-base catalysis and water molecules agreed with the experimental results. The overall degradation rate constant as a function of the temperature under the given conditions obeyed the Arrhenius equation. The chemical fate of LAB in mild acidic solution was investigated, and nine degradation products were detected and tentatively identified by LC-MS analysis. The primary degradation pathway involving the cleavage of ester bond and ring-opened of benzofuran in the LAB are proposed.