Iron-Loaded Carbon Aerogels Derived from Bamboo Cellulose Fibers as Efficient Adsorbents for Cr(VI) Removal

A unique iron/carbon aerogel (Fe/CA) was prepared via pyrolysis using ferric nitrate and bamboo cellulose fibers as the precursors, which could be used for high-efficiency removal of toxic Cr(VI) from wastewaters. Its composition and crystalline structures were characterized by FTIR, XPS, and XRD. In SEM images, the aerogel was highly porous with abundant interconnected pores, and its carbon-fiber skeleton was evenly covered by iron particles. Such structures greatly promoted both adsorption and redox reaction of Cr(VI) and endowed Fe/CA with a superb adsorption capacity of Cr(VI) (182 mg/g) with a fast adsorption rate (only 8 min to reach adsorption equilibrium), which outperformed many other adsorbents. Furthermore, the adsorption kinetics and isotherms were also investigated. The experiment data could be much better fitted by the pseudo-second-order kinetics model with a high correlating coefficient, suggesting that the Cr(VI) adsorption of Fe/CA was a chemical adsorption process. Meanwhile, the Langmuir model was found to better describe the isotherm curves, which implied the possible monolayer adsorption mechanism. It is noteworthy that the aerogel adsorbent as a bulk material could be easily separated from the water after adsorption, showing high potential in real-world water treatment.

Facile Synthesis of Iron-Based MOFs MIL-100(Fe) as Heterogeneous Catalyst in Kabachnick Reaction

An effective technique was proposed for the synthesis of novel α-aminophosphonates: a three-component one-pot condensation reaction of aniline, aromatic aldehydes, and triphenyl phosphite in the presence of (MIL-100(Fe)) as a heterogeneous catalyst. Initially, MIL-100(Fe) was synthesized using H3BTC and ferric nitrate at low temperature and atmospheric pressure. Further, MIL-100(Fe) was characterized using various techniques such as XRD, BET surface area, scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR), and thermogravimetric analysis (TGA). Herein, MIL-100(Fe) showed exceptional catalytic performance for the synthesis of α-aminophosphonate and its derivatives compared with conventional solid catalysts, and even homogeneous catalysts. The study demonstrated that MIL-100(Fe) is an ecofriendly and easily recyclable heterogeneous catalyst in Kabachnick reactions for α-aminophosphonate synthesis, with high yield (98%) and turnover frequency (TOF ~ 3.60 min−1) at room temperature and a short reaction time (30 min).

Synthesis and Characterization of New Ferrite-Lignin Hybrids

The paper presents the synthesis and characterization of new cobalt ferrite-lignin hybrids. The hybrids were obtained through the combustion of cobalt nitrate and ferric nitrate, two kinds of lignin being used as combustion agents. The temperatures of calcination were 500 °C and 900 °C, respectively. The hybrids were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). The magnetic properties were also assessed by vibrating sample magnetometer system (VSM). This facile synthesis method made it possible to obtain cobalt ferrite-lignin hybrids with a spinel structure. Their particle sizes and crystallite sizes have increased with an increment in the calcination temperature. A different occupancy of cations at octahedral and tetrahedral sites also occurred upon the increase in temperature. The hybrids comprising organic lignin presented the best magnetic properties.

Iron Modified Titanate Nanotube Arrays for Photoelectrochemical Removal of E. coli

This study used iron modified titanate nanotube arrays (Fe/TNAs) to remove E. coli in a photoelectrochemical system. The Fe/TNAs was synthesized by the anodization method and followed by the square wave voltammetry electrochemical deposition (SWVE) method with ferric nitrate as the precursor. Fe/TNAs were characterized by SEM, XRD, XPS, and UV-vis DRS to investigate the surface properties and light absorption. As a result, the iron nanoparticles (NPs) were successfully deposited on the tubular structure of the TNAs, which showed the best light utilization. Moreover, the photoelectrochemical (PEC) properties of the Fe/TNAs were measured by current-light response and electrochemical impedance spectroscopy. The photocurrent of the Fe/TNAs-0.5 (3.5 mA/cm2) was higher than TNAs (2.0 mA/cm2) and electron lifetime of Fe/TNAs-0.5 (433.3 ms) were also longer than TNAs (290.3 ms). Compared to the photolytic (P), photocatalytic (PC), and electrochemical (EC) method, Fe/TNAs PEC showed the best removal efficiency for methyl orange degradation. Furthermore, the Fe/TNAs PEC system also performed better removal efficiency than that of photolysis method in E. coli degradation experiments.

Highly Active Fischer-Tropsch Synthesis Fe-BDC MOF-Derived Catalyst Prepared by Modified Solvothermal Method

Fe-MIL-88B was prepared by a method that utilizes ferric nitrate and terephthalic acid (TPA or H2BDC) as precursors. The catalyst was characterized by TEM, SEM, FTIR, XRD, BET, and TGA. The pyrolyzed MOF (Fe-MIL-88B/C) was then tested for FTS at 300 psi, 300/340°C and H2/CO=1 after reduction under flow of hydrogen at 400°C for 4 hours. GC product results show promising FTS performance and stability compared to previously reported Fe-MOF derived catalysts with CO conversion of 96.90% at 340°C for 40 hours and 97.45% at 300°C for 26 hours.

Synthesis of Fe-doped TiO2 nanotubes by hydrothermal method for photodegradation of methylene blue from aqueous solutions

Fe-doped TiO2 nanotubes were prepared by hydrothermal method using ferric nitrate and commercial TiO2 powder. The obtained materials were characterized by means of XRD, TEM, BET, FT-IR and UV-Vis-DRS. The photocatalytic activity was evaluated based on photodegradation of methylene blue under visible light irradiation. The results show that Fe3+ ions might incorporate into the lattice of TiO2 nanotubes. Fe-doped TiO2 materials showed narrower band gap energies, higher specific surface areas, more hydroxyl groups on the surface and significantly improved photocatalytic activity. The optimum Fe doping at the molar ratios of Fe/Ti = 0.5% showed the highest photocatalytic activity and was 3.08 times higher than that of undoped TiO2. The kinetic studies showed the decomposition of MB followed pseudo first-order kinetics with the rate constant were determined kapp = 5.64×10-2 min−1.