RESUMEN
Persulfate (PS) activated by Fe(ii) has been widely investigated for degradation of contaminants. However, the Fe(ii)/PS systems used for actual contaminated groundwater remediation have been restricted by circulation of Fe(iii)/Fe(ii). Herein, an ascorbic acid (AA) enhanced Fe(ii)/PS system was developed for degradation of tetracycline (TC) contaminated groundwater. The influence of Fe(ii), AA, PS dosage and pH on degradation of TC was investigated, the free radicals produced in the reaction were identified and the reusability of Fe(ii) in the Fe(ii)/PS/AA system for degradation of TC was also evaluated. The results showed that AA significantly promoted the degradation of TC in the Fe(ii)/PS system, and a degradation rate of 86% for TC was achieved at 60 min. The dominant oxidant species for contaminant degradation in the Fe(ii)/PS/AA system is ËOH. Appropriate Fe(ii), AA and PS dosage can improve the degradation rate of TC. Moreover, the degradation rate of TC in the Fe(ii)/PS/AA system under acidic conditions is higher than that under alkaline conditions. With the increase of reaction time, TC can also be completely degraded even with a little Fe(ii) or under alkaline conditions in the Fe(ii)/PS/AA system, and Fe(ii) showed a good reusability for the degradation of TC. Thus, the AA-enhanced Fe(ii)/PS system for the degradation of contaminants displays the advantages of less Fe(ii) consumption and a wide range of pH. This method provides a new strategy for in situ remediation of contaminated groundwater.
RESUMEN
Herein, a novel Ru-doped bimetal phosphide (Ru-NiCoP) heterostructure electrocatalyst on Ni foam is successfully synthesized through a multi-step hydrothermal reaction, ion exchange, and phosphorization method for efficient overall water splitting in alkaline media. The doping of Ru and P can effectively optimize the electronic structure and expose more active sites. The unique 3D interconnected nanowires not only ensures the uniform distribution of Ru coupled with NiCoP, but also endows the Ru-NiCoP/NF with the large ECSA, the fast electron transport and the favorable reaction kinetics attributes. Benefiting from the compositional and structural advantages, Ru-NiCoP/NF catalyst exhibits significantly enhancedcatalytic activities along with excellent stability, only needing 32.3 mV at 10 mA cm-2 for HER and 233.8 mV at 50 mA cm-2 for OER. In particular, when Ru-NiCoP/NF is employed as both cathode and anode electrodes,a small voltage of 1.50 V is required to reach 30 mA cm-2for overall water splittingwith an impressive stability. This study provides an alternative strategyon the design and development of high performance catalysts foroverall water splittingand other energy conversion fields.
RESUMEN
In this work, the feasibility of a novel sensitive electrochemiluminescence aptasensor for the detection of lysozyme using Ru(bpy)32+-Silica@Poly-L-lysine-Au (RuSiNPs@PLL-Au) nanocomposites labeling as an indicator was demonstrated. The substrate electrode of the aptasensor was prepared by depositing gold nanoparticles (AuNPs) on 3D graphene-modified electrode. The lysozyme binding aptamer (LBA) was attached to the 3D graphene/AuNPs electrode through gold-thiol affinity, hybridized with a complementary single-strand DNA (CDNA) of the lysozyme aptamer labeled by RuSiNPs@PLL-Au as an electrochemiluminescence intensity amplifier. Thanks to the synergistic amplification of the 3D graphene, the AuNPs and RuSiNPs@PLL-Au NPs linked to Ru(bpy)32+-ECL further enhanced the ECL intensity of the aptasensor. In presence of lysozyme, the CDNA segment of the self-assembled duplex was displaced by the lysozyme, resulting in decreased electrochemiluminescence signal. Under the optimized conditions, the decrease in electrochemiluminescence intensity varied proportionally with the logarithmic concentration of the lysozyme from 2.25 × 10-12 to 5.0 × 10-8 molâ¯L-1, and the detection limit was estimated to 7.5 × 10-13 molâ¯L-1. The aptasensor was further tested in real samples and found reliable for the detection of lysozyme, thus holding great potential application in food safety researches and bioassay analysis.