LaCuMnOx (LCMO) perovskite was designed as an effective catalyst to activate peroxydisulfate (PDS) to remove bisphenol A (BPA) in hypersaline wastewater.
Results
In the LCMO/PDS system, BPA (10 mg/L) was removed completely and the mineralization degree reached 74.9% in the presence of 0.12 g/L catalyst and 1.2 mM PDS. The BPA removal efficiency was still almost 100% even after five cycles. Metal ion leakage also indicated the stability of the catalytic system. •OH, SO4•−, 1O2, and O2•− all contributed to BPA removal, and O2•− accounted for the greatest contribution. The presence of oxygen vacancies (Vo··) on the surface of the catalyst was important for PDS activation and the formation of active species. In addition, the system could still maintain outstanding performance even when [Cl−] and [SO42−] were 100 g/L. CO32− and HCO3− inhibited BPA degradation greatly, even at very low concentrations. The inhibitory effect was related to changes in the pH of the solution caused by the addition of CO32− and HCO3−. This effect could be eliminated by adjusting the pH.
Jun Chen, Xue Li, Xiaohong Yang, Yutong Wang, Zongsheng Zhan, Dawei Teng, Mingxia Du, Dong Lv, Kaiqi Yao, Chunnian Da, Mengqiu Xu
BACKGROUND
Piezoelectric catalysis using perovskite-type barium titanate (BaTiO3) has been applied to the decomposition of refractory organic pollutants through piezoelectric catalytic persulfate (PS). Nevertheless, challenges such as a limited specific surface area, poor electrical conductivity and a tendency towards agglomeration in BaTiO3 necessitate the exploration of novel methods to enhance its piezoelectric efficiency.
RESULTS
Sludge carbon (SC) from sewage treatment and BaTiO3 was utilized to develop a novel piezoelectric catalytic material (BaTiO3/SC). The specific surface area of BaTiO3/SC reached 67.92 m2 g−1, which is nine times larger than that of BaTiO3 alone. The inclusion of SC in the composite enhanced the number of active sites and contributed to a higher degree of graphitization, improved electrical conductivity, and provided a more stable structure for BaTiO3/SC. This material was capable of harvesting mechanical vibration energy from ultrasound, thereby generating piezoelectric catalytic properties and activating PS to achieve a 93% decomposition ratio of enrofloxacin (ENR) in water within 80 min. The activation of PS by BaTiO3/SC piezocatalysis led to the production of reactive oxygen species (ROS), such as •OH and SO4−•. These ROS attack the quinolone ring of ENR, which is susceptible to cleavage, resulting in the decomposition of ENR into intermediates of lower toxicity.
Yongming Wang, Qiang Chen, Yuezong Su, Yuxuan He, Jin Qian, Kailin Xu
BACKGROUND
The increasing presence of antibiotics in aquatic environments poses significant ecological risks, with sulfamethoxazole (SMX) being a prominent example due to its persistence and widespread use in medical and veterinary practices. Advanced oxidation processes, particularly those based on peroxymonosulfate (PMS), have shown promise in degrading such contaminants. This work explored the efficacy of a bimetallic selenide catalyst, FeSe2/MoSe2 (FM), synthesized via a hydrothermal method, for the rapid activation of PMS and subsequent degradation of SMX.
RESULTS
Over 95% SMX degradation was achieved with a 0.25 g/L catalyst dosage and 1.5 g/L PMS dosage, demonstrating that FM was an effective PMS activator capable of efficiently oxidizing SMX. The EPR tests and quenching experiments confirmed the presence of 1O2, SO4•– and •OH in the degradation system, with SO4•- predominating. The redox cycling of Mo with Fe was involved in the activation of PMS. Moreover, the DFT calculations of the SMX molecule revealed that the vulnerable sites were mainly in the vicinity of the sulfonamide group and the oxygen-containing group. The toxicity assessment disclosed that most of the primary degradation intermediates of SMX were toxic, while the further small molecule products were non-toxic.
Within the scope of this study, bismuth oxide (Bi2O3) nanoparticles have been synthesized by a simple method, and the usability of these nanoparticles as adsorbents has been investigated. For this purpose, Bi2O3 nanoparticles were synthesized by a chemical method. These particles were characterized by various methods such as Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface area, scanning electron microscopy, and X-ray diffraction. The nature of the synthesized nanoparticles was confirmed by characterization results and the synthesized particles were found to be nanoscale. As a result of the characterization, the average particle diameters and surface areas were found to be 22.24, 32.24 and 49.98 nm, and 5.95, 3.54 and 0.75 m2 g−1 for different calcination temperatures of 105, 250 and 600 °C, respectively. Adsorption parameters such as initial quetiapine concentration, bismuth oxide nanoparticle dosage, temperature, equilibrium contact time, and pH were also studied. Moreover, kinetic, isotherm, and thermodynamics modeling of adsorption have been performed to account for the adsorption mechanism of quetiapine by Bi2O3 nanoparticles.
RESULTS
The thermodynamic study has specified that adsorption has been spontaneous and exothermic. The kinetic study has pointed out that a pseudo-second-order model (R2 = 0.9853) has been favorable to the data. Furthermore, a Freundlich isotherm model (R2 = 0.8258) has been better fitted to the experimental adsorption results. The maximum adsorption capacity and percentage of adsorption values were 27.38 mg g−1 and 76.81%, respectively.
Dmitry Girenko, Bohdan Murashevych, Pavlo Demchenko, Alexander Velichenko
BACKGROUND
The synthesis of sodium hypochlorite (NaClO) by classical electrolysis of NaCl solutions on a Ti/Pt anode is characterized by parallel formation of undesirable sodium chlorate (NaClO3) impurities. Oxidation of hypochlorite to chlorate with high current efficiency (CE) is realized on the oxidized, passivated Pt surface. On a Pt surface reduced by cathodic polarization, NaClO synthesis can be realized with the CE close to 90% almost without chlorate accumulation. Long-term electrolysis leads to passivation of the Pt surface.
RESULTS
Electrolysis while periodically changing the polarity of the electrodes (current reverse mode) increases the time the Pt surface remains in the activated state. Carrying out electrolysis in this way makes it possible to increase CE(NaClO) 1.5–2.0-fold while simultaneously reducing CE(NaClO3) (sodium chlorate) by ≤10-fold. This study additionally determined the optimal parameters of reverse electrolysis, examined the effect of changing polarity on the state of the Ti/Pt electrode surface and studied the kinetic patterns of active platinum coating dissolution.
Tobacco stalk, the main waste from tobacco planting, was used as raw material to produce levulinic acid, one of the most important platform chemicals. It was reported that steam explosion was an efficient method to treat lignocellulose to hydrolyze the hemicellulose component. Oxidation treatment combined with catalysis of Al2(SO4)3 proved to be efficient for the conversion of cellulose to levulinic acid in our recent report. Here, tobacco stalk was first treated by steam explosion, and then the solid residue was oxidized and converted to levulinic acid in the presence of Al2(SO4)3.
RESULTS
A xylo-oligosaccharide yield of 6.6 g 100 g−1 was obtained from tobacco stalk via steam explosion. 15.4 g 100 g−1 (39.6 mol%) yield of levulinic acid was obtained from oxidized tobacco stalk in water at 180 °C in 5 h using Al2(SO4)3 as a catalyst. As high as 20.8 g 100 g−1 (53.5 mol%) yield of levulinic acid can be obtained using NaCl as a co-catalyst.
Jessica San Martín-Davison, Raquel Lebrero, Christian Vergara-Ojeda, Felipe Scott, Cesar Huiliñir, Alberto Vergara-Fernández
Background
Naphthalene is a polycyclic aromatic hydrocarbon, highly dangerous for human health. It is produced as a byproduct of incomplete combustion of organic material and is frequently present in the air. Biofilters offer an effective alternative for its treatment. The aim of this work was to study the treatment of naphthalene vapors through biofiltration using two biofilters: one inoculated with a consortium composed of Fusarium solani and Rhodococcus erythropolis (BF1), and the other inoculated with a consortium of microbial isolates obtained from a previous biofilter eliminating naphthalene vapors.
Results
The results demonstrate that inoculating a biofilter with a reconstructed consortium of microbial isolates from a naphthalene vapor-eliminating biofilter allowed a reduction of the startup time from 35 to 5 days, while maintaining a consistent removal capacity (6 g m−3 h−1, equivalent to 80% removal efficiency). It was also observed that the biofilter inoculated with the reconstructed consortium exhibited comparable robustness to a biofilter previously operated for 4 months with naphthalene, with a maximum removal capacity of 14 g m−3 h−1 for a naphthalene inlet load of 17 g m−3 h−1. The study of microbial communities indicates an increase in the bacterial variability, while fungal variability remains low, with Fusarium solani being predominant at 97%.
Chemical pollutants, such as nitroaromatic compounds, have been a significant challenge in recent decades of human societies as they contribute to environmental pollution and pose serious health risks due to their high toxicity. One promising and green method to address this issue is the photocatalytic reduction of nitroaromatic compounds to their corresponding amino aromatic compounds. In this study, an rGO/CuBi2O4 nanocomposite was synthesized using the hydrothermal method, involving the simultaneous reduction of graphene oxide and the coupling of CuBi2O4 nanoparticles in its layers. The resulting heterogeneous structure was characterized using various techniques including FTIR, Raman, XPS, XRD, FESEM, TEM, EDAX, UV–Vis DRS, BET, PL spectroscopy, and EIS. Subsequently, the photocatalytic efficiency of the nanocomposite in reducing nitroaromatic compounds to the corresponding aromatic amines under visible light was evaluated.
RESULTS
The results indicated that graphene oxide was effectively reduced and coupled with CuBi2O4 nanoparticles in the reduced graphene oxide sheets. The rGO/CuBi2O4 heterogeneous nanocomposite successfully reduced nitroaromatic compounds to the corresponding aromatic amines under visible light. Hydrazine monohydrate was used to supply the necessary hydrogen for the reaction.
Murad Shafiyev, Elif Erçarıkcı, Kader Dağcı Kıranşan, Ezgi Topçu
BACKGROUND
The design of new-generation flexible sensors for medical applications has gained considerable interest in the research community in recent past years. Herein, a free-standing flexible electrode was developed for the electrochemical determination of Paracetamol (PC). This graphene-based paper electrode was prepared using graphene and MnCo2O4 dispersion with a mold-casting method followed by chemical reduction. The morphology and structure of our flexible paper electrode (MnCo2O4/GP) were characterized by scanning electron microscopy, energy-dispersive, X-ray diffraction, X-ray photoelectron, and Raman spectroscopy.
RESULTS
The as-prepared flexible MnCo2O4/GP showed outstanding sensing performance for PC, as compared to GP, due to the excellent electrochemical properties of MnCo2O4. The proposed sensor exhibited a wide linear range of 4.64–1000 μM for electrochemical determination of PC with a low detection limit of 1.39 μM. Furthermore, MnCo2O4/GP was successfully applied for PC syrup and tablets with good accuracy results.
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号