Fe-Trimesic Acid/Melamine Gel-Derived Fe/N-Doped Carbon Nanotubes as Catalyst of Peroxymonosulfate to Remove Sulfamethazine

Abstract

The conventional precursor preparation of metal–organic frameworks (MOFs) for nitrogen-doping carbon materials is divided into the preparation of MOFs and the mixing of the nitrogen source, which is a complex and time-consuming step. In this study, Fe-BTC gel/nitrogen source-derived carbon materials were synthesized using one or more of the following raw ingredients: Fe(NO3)3·9H2O, FeCl3·6H2O, Fe2(SO4)3, trimesic acid, melamine and dicyandiamide. The influence of different raw ingredients on the preparation and performance of catalysts was investigated. Fe(NO3)3·9H2O can react with trimesic acid to form a gel with ethanol as solvent, and the gel helped the homogeneous dispersion of the added melamine and did not precipitate. Fe-C-N(M), synthesized from the three materials mentioned, was identified as the optimal catalyst; the removal rate of 5 mg/L sulfadimethoxine (SMZ) reached 100% at 15 min when the Fe-C-N(M) dosage was 50 mg/L, PMS concentration was 0.5 mM, and the pH was 5.78 (initial pH of the solution). The removal of SMZ was not significantly inhibited by the pH (3–9) and 0–10 mM inorganic anions (Cl−, NO3−, HCO3− and H2PO42−). Through quenching tests, electron paramagnetic resonance and probe experiments, 1O2 and a small amount of free radicals (•OH and SO4•−) bound on the catalyst surface are discovered to be the primary active ingredients that activate PMS to degrade SMZ.

Optimization of Adsorption Conditions Using Response Surface Methodology for Tetracycline Removal by MnFe2O4/Multi-Wall Carbon Nanotubes

“…The researchers proposed that adsorption by magnetic multi-walled carbon nanotubes (MMWCNTs) was a highly practical process due to the simplicity of design, excellent contaminant adsorption performance, and low environmental impact [24][25][26][27][28]. Previous studies have indicated that the adsorption process by MMWCNTs was capable of highly efficient removal of antibiotics [29][30][31]. Although MMWCNTs could effectively remove TC, the optimization of the adsorption effect of MMWCNTs on TC and the interaction of various factors on treatment efficiency have not been documented [32,33].…”

“…Compared with CCD, BBD is more inclined to solve the local optimal solution (the level of BBD factors is generally less than 5) [20,49,50]. As one of the most commonly used response surface methods, the BBD avoided extreme conditions, and it had a moderate number of experiments, simple and efficient software operation, and high reliability and accuracy of optimization results, without massive training data for the simulation [25,29,[51][52][53]. The removal rate of TC in this study was affected by three factors (pH, time, and adsorbent dosage).…”

Decolorization of Textile Azo Dye via Solid-State Fermented Wheat Bran by Lasiodiplodia sp. YZH1

“…The Box-Behnken design (BBD) is one of the most commonly used RSM methods. It allows the modeler to explore the relationships between the design variables and the response variables without having to conduct a large number of experiments, which is the main advantage of this analysis; it also has simple and efficient software operation, and high reliability and accuracy of optimization results [30,31]. BBD has been successfully used for the optimization of process parameters in dye decolorization [32,33], heavy metal biosorption [34,35], and a wide range of other field applications [36,37].…”