Inverse micelle fabrication of ordered mesoporous manganese oxide and degradation of tetracycline hydrochloride.

Ordered mesoporous manganese oxides (MnOx) were synthesized using the modified inverse micelle method. The crystal structure and surface morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The element content and changes in surface valence of catalysts were analyzed by X-ray photoelectron spectroscopy (XPS). The MnOx were used to activate peroxymonosulfate (PMS) to degrade tetracycline hydrochloride (TCH). The catalytic activity of MnOx was enhanced at a calcination temperature of 350 °C (MM-3). The degradation efficiency of TCH in MM-3/PMS system was 87.89% in 180 min. Appropriate dosages of catalyst and PMS improve the degradation efficiency of TCH. This system showed a wide range of pH application (3-9). In the presence of coexisting ions and humic acid, the degradation efficiency of TCH was still above 80%. The results of free radical capture experiment and electron paramagnetic resonance (EPR) test proved that the system activates PMS to produce three types of free radicals: SO4-, OH and 1O2. Therefore, MM-3 is a promising catalyst for the degradation of TCH in practical wastewater treatment.

Highly efficient Cr(VI) removal from industrial electroplating wastewater over Bi2S3 nanostructures prepared by dual sulfur-precursors: Insights on the promotion effect of sulfate ions.

In this work, different Bi2S3 nanostructures were prepared from various single and dual sulfide precursors via a solvothermal method. It was found that Bi2S3 nanostructures prepared from dual sulfur precursors of L-cysteine and ammonium sulfide exhibited highest Cr(VI) removal ability with maximum Cr(VI) removal capacity of 148.95 mg/g in Cr(VI) solution (pH = 2). More importantly, the removal capacity strikingly increased to 223.33 and 240.25 mg/g in two kinds of actual industrial electroplating wastewater. By analyzing the components of actual electroplating wastewater and the results of control experiments in the absence and presence of different ions in Cr(VI) solution, it was found that SO42- played a critical role in the Cr(VI) removal over Bi2S3. The addition of SO42- could promote the conversion of Cr(VI) to Cr(III) on the surface of Bi2S3, thus leading to the enhanced Cr(VI) removal ability in actual electroplating wastewater. The Bi2S3 maintained its original Cr(VI) removal ability after four cycles in the electroplating wastewater, indicating the moderate reuse ability of the sample. This work not only demonstrated an highly efficient nanomaterials for the Cr(VI) removal in industrial electroplating wastewater, but also provided an insight on the influence of the components in wastewater on Cr(VI) removal.

Facile inverse micelle fabrication of magnetic ordered mesoporous iron cerium bimetal oxides with excellent performance for arsenic removal from water.

In this study, magnetic ordered mesoporous Fe/Ce bimetal oxides (OMICs) were successfully synthesized via the modified sol-gel-based inverse micelle method. The textural/structure properties, surface chemistry and adsorption behavior of OMICs could be easily adjusted by using the calcination temperature. The sintering of samples would decrease the surface area, while expand the pore and crystallite size, which resulted in the formation of highly ordered inner-connected structure. Compared with pure mesoporous iron oxides (MI) and mesoporous cerium oxides (MC), this ordered mesoporous iron-cerium bimetal oxides (OMIC-3, 450 °C) exhibited remarkable arsenic adsorption performance. The maximum adsorption capacities of As(III) and As(V) for OMIC-3 were 281.34 and 216.72 mg/g, respectively, and both As(III)/As(V) adsorption kinetics were well described by the pseudo-second order. The ionic strength and coexisting ions (except SiO32- and PO43-) did not affect arsenic removal, while humic acid (HA) significantly influenced on the arsenic removal even at a lower concentration. The adsorption mechanism study revealed that both the surface charge and surface M-OH groups of OMIC-3 were played the key roles in arsenic removal. The reusable property suggested that this magnetic OMIC-3 was a promising excellent adsorbent for decontamination of arsenic-polluted (especially As(III)-polluted) wastewater.

Fabrication uniform hollow Bi2S3 nanospheres via Kirkendall effect for photocatalytic reduction of Cr(VI) in electroplating industry wastewater.

Hazardous hexavalent chromium removal from wastewater is an urgent issue in industry environmental pollution. In this work, hollow Bi2S3 nanospheres have been successfully synthesized from unique Bi2O3 porous nanospheres via Kirkendall effect through hydrothermal process. It was found that the sulfur source and the initial Bi2O3 templates played key roles in the formation of the uniform morphologies and structures through an anion exchange process. Compared with other Bi2S3 samples, the synthesized hollow Bi2S3 nanospheres exhibited much enhanced photocatalytic ability for Cr(VI) photoreduction. XPS analysis demonstrated that Cr(VI) was reduced to less harmful Cr(III) species over hollow Bi2S3 nanospheres under visible-light irradiation. More importantly, the hollow Bi2S3 nanospheres remained high efficiency and good stability in the recycling Cr(VI) photoreduction, and exhibited remarkable Cr(VI) removal ability in actual electroplating industry wastewater treatment.

Study on the Effect of the Three-Dimensional Electrode in Degradation of Methylene Blue by Lithium Modified Rectorite.

This study presents the electrochemical degradation of methylene blue (MB) wastewater in a synthetic solution using three-dimensional particle electrodes. The novel particle electrodes were fabricated in this work using the lithium modified rectorite (Li-REC). The adsorption property of the fabricated particle electrodes was studied in a series of experiments. The optimum electrochemical operating conditions of plate distance, cell voltage, and concentration of electrolyte were 2 cm, 9 V, and 0.06 mol L-1, respectively. It was also found that microwave irradiation can effectively improve the adsorption property and electrical property of the fabricated electrodes. In addition, the scanning electron microscope (SEM) of the fabricated electrodes was investigated. The experimental results revealed the order of adsorption property and electrical property of the fabricated electrodes. So, fabricated electrodes are not only of low cost and mass produced, but also efficient to achieve decolorization of MB solution.