In this work, three polymeric films derived from hydroxyphenylacetic acid isomers were electropolymerized onto the surfaces of graphite electrodes through cyclic voltammetry. Analysis of electrochemical behaviors and electrical properties of the three polymeric films were investigated and their probably structures were explored by molecular modeling. The best functionalization strategy for the incorporation and retention of adenine and guanine nitrogenous bases was the poly(3-hydroxyphenylacetic acid). It was applied for the immobilization of a nucleotide probe specific to DNA of the bacteria Neisseria meningitidis operated in amperometric and impedimetric indirect modes. The simple protocol of electrochemical detection of DNA by the bioelectrode, developed in this work, could be further enhanced and applied in a low-cost and pain-less platform to diagnose human meningitis infection.
The aim of the current study is to compare the chemical oxygen demand (COD) removal efficiency of a Venturi device to that of an orifice plate. The inlet pressure in the devices was optimized and the degradation kinetics was analyzed. In addition, the synergistic effect resulting from the combination between cavitation and H2O2 was investigated. An experimental apparatus was built to achieve these goals. A sucrose solution and an effluent from a sucrose-based soft drink industry were treated. Results showed that the Venturi device recorded 90% COD removal efficiency after three treatment minutes. On the other hand, the orifice plate recorded 90% COD removal efficiency after 9 min. The degradation kinetics-reaction order was 3.5, except for the highest Venturi inlet pressure (7.3 bar), which led to coalescence of cavities and to reduced degradation rate. The synergistic coefficient (Sc) was 185.20 and showed that the hybrid process (HC + H2O2) was much more efficient than the cavitation process applied alone. The high COD concentration in the effluent generated by the soft drink industry (2,512.8 mg L-1) was significantly decreased by 72%. The combined use of cavitation and Venturi has significant potential to remove high organic matter concentrations in short treatment periods.
Sanitization is a critical step for the reduction of microbial contaminants in fruits and vegetables in an effort to lessen the occurrence of foodborne diseases. The efficiency of different chemical compounds, either individually or combined with ultrasound treatment, in decontaminating fresh arugulas was evaluated here. The main physicochemical properties and the natural microbiota of arugulas were evaluated after sanitization for 5 min at 25 8C. The synergistic effect of ultrasound and sodium hypochlorite led to the best outcome. Ultrasound treatment improved the bactericidal effect of sodium hypochlorite (100 mg/L), leading to a reduction of 1.46 log cycles in relation to the non-sanitized samples, whereas sodium hypochlorite itself provided a 0.85 log cycle reduction. This synergism is due to the ability of ultrasound-induced cavitation to form oxidizing free radicals (e.g., ÁOH and ÁCl), in addition to its mechanical energy input that facilitates the permeation of hypochlorous acid molecules into microbial cells. It is noteworthy that this mechanical action also favors the removal of microbial biofilms and cell disintegration. The residual chlorine content was lower than that recommended by the current legislation for public water supply. The combined action did not significantly alter the physicochemical and colorimetric properties of the arugulas. Therefore, this sanitization protocol denotes a promising alternative for the decontamination of fruits and vegetables in the food industry and in food processing facilities.
Practical applicationsCurrently, there has been an increase in the demand for fresh food as well as an increase in the number of food outbreaks involving these products. In this context, to reduce microbial contamination, this research presents an alternative sanitization method that can be easily used in food processing units for decontamination of vegetables, increasing the microbiological safety of the final product to the consumer.
The efficiency of electrolysis (EC/Cl2) and photo-assisted electrolysis (EC/UV/Cl2) methods, in the presence of chloride, for the abatement of real dairy waste from a producer in the Triangulo Mineiro region of Brazil, was evaluated. A complete 23 factorial design was performed for the variables time, pH and current. After determining the ideal pH, a Central Compound Design (CCD) was performed, where the applied current (533.42 mA) and treatment time (60.45 minutes) were maximized. The effluent was subsequently submitted to prolonged EC/Cl2 and EC/UV/Cl2 treatment in order to evaluate the behaviour of specific environmental parameters over time. The EC/UV/Cl2 method was more efficient than simple EC/Cl2 treatment. The EC/UV/Cl2 method resulted in a reduction of all environmental parameters investigated to levels within legal standards for effluent discharge. A relatively low cost of treatment is obtained with Energy per Order (EEO) values of 0.89 and 1.22 kWh m−3 order−1 for the EC/UV/Cl2 and EC/Cl2 treatments, respectively. The electrochemical production of free chlorine species followed by subsequent photolysis and production of radical species can convert a simple electrochemical process into an advanced oxidation process (AOP).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.