Search Results (5)

To degrade high-concentration and toxic organic effluents, we developed Fe-Cu active sites loaded on biomass-source carbon aerogel (CA) to produce a low-cost and high-efficiency magnetic Fenton-like catalyst for the catalytic oxidative decomposition of organic pollutants. It exhibits excellent performance in catalytic Fenton-like reactions for RhB removal at an ultrahigh initial concentration of up to 1000 ppm. To be specific, Fe₃O₄ and Cu nanoparticles are generated in situ on a mesoporous CA support, denoted as an Fe₃O₄-Cu/CA catalyst. Experimentally, factors including initial dye concentration, catalyst dosage, H₂O₂ dosage, pH, and temperature, which significantly influence the oxidative degradation rate of RhB, are carefully studied. The RhB (1000 ppm) degradation ratio reaches 93.7% within 60 min under low catalyst and H₂O₂ dosage. The catalyst also shows slight metal leaching (almost 1.4% of total Fe and 4.0% of total Cu leached after a complete degradation of 25 μmol RhB under conditions of 15 mg catalyst dosage, 20 mL RhB solution (600 ppm), and 200 μL 30 wt% H₂O₂ dosage, at pH of 2.5, at 40 °C), good catalytic activity for degrading organic pollutants, excellent reusability, and good catalytic stability (the degradation ratio is nearly 82.95% in the 8th cycle reaction). The synergistic effect between Fe and Cu species plays a vital role in promoting the redox cycle of Fe(III)/Fe(II) and enhancing the generation of ·OH. It is suitable for ultrahigh-concentration organic pollutant degradation in practical wastewater treatment applications. Full article

Removing high-concentration organic dye from wastewater is of great concern because the hazards can cause serious damage to the environment and human health. In this study, the hybrid dimensionally stable anode (DSA) with a Ce-doped and SnO₂-Sb₂O₅ intermediate layer was fabricated and used for the electro-catalytic oxidation of three kinds of ultra-high-concentration organic dyes. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) confirmed the denser surface structure and morphology of the composite Ti/SnO₂-Sb₂O₅/Ce-PbO₂ electrode. Moreover, the electrode exhibited an excellent oxygen evolution potential of 1.58 V. The effect on the removal efficiencies of high concentrations of up to 1 g/L of methyl orange, methylene blue, and neutral red solutions with the above composite electrode was investigated. The research results illustrated that target molecules in the three different dye solutions were rapidly decolorized and decomposed by electro-catalytic oxidation in less than 35 min. Additionally, the degradation process still followed pseudo-first-order kinetics for high-concentration dye solutions. The removal efficiency of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) for the three dye solutions was more than 98%, and the results of the gas chromatography–mass spectrometry (GC-MS) analysis showed that it had the best degradation effects for neutral red, which decomposed more thoroughly. More than 80 h of accelerated life also revealed excellent performance of the composite electrode in the face of high-concentration dye solution degradation. Considering these results, the Ti/SnO₂-Sb₂O₅/Ce-PbO₂ anode could be utilized to treat wastewater containing high-concentration dyes with high efficiency. Full article

Covalent organic frameworks (COFs), as a novel crystalline porous adsorbent, have been attracting significant attention for their synthesis and application exploration due to the advantages of designability, stability, and functionalization. Herein, through increasing the concentration of the acid catalyst, a facile solution-refluxing synthesis method was developed for the preparation of a three-dimensional dynamic COF material, COF-300, with high yields (>90%) and high space–time yields (>28 kg m^–3 day^–1). This synthesis method not only permits gram-scale synthesis, but also yields products that well maintain porosity and unique guest-dependent dynamic behavior. Moreover, the catalytic activity of COF-300 as a metal-free photocatalyst was explored for the first time. Under 365 nm ultra-violet light irradiation, COF-300 can effectively catalyze the dye degradation (>99%) in wastewater with good recyclability. By adding magnetic Fe₃O₄ nanoparticles into the solution-refluxing synthesis of COF-300, Fe₃O₄/COF-300 nanocomposites can be obtained and used as magnetically recyclable photocatalysts, demonstrating the superiority of this facile synthesis procedure. Our study provides new insights for the preparation of COF materials and a constructive exploration for their water treatment application. Full article

In the present study, methylene blue (MB) removal from aqueous solutions via the photocatalytic process using TiO₂ as a catalyst in the presence of external ultra-violet light (UV) was investigated. The results of adsorption in the absence of UV radiation showed that adsorption reached an equilibrium state at 60 min. The experimental kinetic data were found to be well fitted by the pseudo-second-order model. Furthermore, the isotherm study suggested that dye uptake by TiO₂ is a chemisorption process with a maximum retention capacity of 34.0 mg/g. The photodegradation of MB was then assessed under various experimental conditions. The related data showed that dye mineralization decreased when dye concentrations were increased and was favored at high pH values and low salt concentrations. The simultaneous presence of organic and inorganic pollution (Zinc) was also evaluated. The effect of the molar ratio Zn²⁺/MB⁺ in the solution at different pH values and NaCl concentrations was also monitored. The corresponding experimental results showed that at low values of Zn²⁺ in the solution (30 mg/L), the kinetic of the MB removal became faster until reaching an optimum at Zn²⁺/MB⁺ concentrations of 60/60 mg/L; it then slowed down for higher concentrations. The solutions’ carbon contents were measured during the degradation process and showed total mineralization after about 5 h for the optimal Zn²⁺/MB⁺ condition. Full article

The synthesis of interconnected nanoporous carbon (NPC) material from direct annealing of ultra-small Al-based metal–organic complex (Al-MOC) has been demonstrated. NPC presents a large accessible area of 1054 m²/g, through the Methylene Blue (MB) adsorption method, which is comparable to the high specific surface area (SSA) of 1593 m²/g, through an N₂ adsorption/desorption analysis. The adsorption properties and mechanisms were tested by various dye concentrations, pH, and temperature conditions. The high MB accessible area and the good electrical conductivity of the interconnected NPC, led to a large specific capacitance of 205 F/g, with a potential window from 0 to 1.2 V, in a symmetric supercapacitor, and a large energy density of 10.25 Wh/kg, in an aqueous electrolyte, suggesting a large potential in supercapacitors. Full article