Some plants do not grow due to the high pH levels of ecological concrete pore solutions. In this paper, we design and build an integrated device featuring a combined microbial film and a transverse/U-shaped grouting film. We have applied to the China Intellectual Property Office for an invention patent on this device. The device overcomes the blockage of the grouting port caused by microbial and vertical grouting. The vertical grouting tube leaves holes inside a specimen, reducing the compressive strength, while the integrated device optimizes and decreases variation in the recycling of microbial bacteria. The reduction in the pore alkalinity of porous ecological concrete resulting from the microbial grouting film of this device is larger than that resulting from a microbial sprayed film. The pH values of porous ecological concrete with microbial grouting films and microbial sprayed films are obtained by the pure slurry soaking method and solid–liquid extraction method, respectively. The pH value is lower for the film obtained by the pure slurry soaking method than for that obtained by the solid–liquid extraction method. Conversely, the pH value of porous ecological concrete with a microbial grouting film is reduced to approximately 8 at an age of 56 days. The compressive strengths of the porous ecological concrete specimens with the two films are almost the same. The results of this study provide the necessary theoretical basis for developing alkali reduction technology for porous ecological concrete with environmental and economic benefits.

The abuse of antibiotics has caused serious harm to the ecological environment and human health. Fenton-like advanced oxidation technology is a green and effective treatment means, but how to improve the Fenton reaction efficiency and wide pH adaptability is still a big challenge. Herein, we designed and developed a single-atom catalyst Cu-1-CN with graphite-phase carbon nitride as the carrier by loading a low amount of metal Cu. The N atom anchors the copper atom in the form of a coordination bond, and the single atom Cu site has excellent performance in activating H2O2. Not only a short period of time (10 min) oxidation degradation of tetracycline (degradation rate 80 %), and in a broad range of pH (3.2 similar to 9.5) still maintaining high removal performance (efficiency more than 70 %). Combined with X-ray absorption fine structure characterization and density functional theory (DFT) calculations, it is considered that isolated Cu atom and N atom cooperate to construct highly reactive Cu-N-4 active centre, which completes the task of H2O2 activation. This study provides a new theoretical basis and technical support for the degradation of antibiotic pollutants by single-atom Fenton-like reaction.

Due to their non-specific toxicity, environmentally discharged anticancer drugs can significantly threaten aquatic organisms and human health. This study prepared highly stable magnetic composites with a multicore-shell structure, Fe3O4 @EDTA@UiO-66-NH2 (FEU), and their adsorption behaviour towards methotrexate (MTX, a typical anticancer drug in water) was investigated. The highest adsorption capacity of FEU for MTX reached 262.5 mg.g(-1), much higher than most reported magnetic adsorbents. FEU showed excellent selectivity for MTX, four and nine times that of ibuprofen and sulphadiazine, respectively. Zeta potential and X-ray photoelectron spectroscopic analyses and GCMC simulations revealed that the MTX adsorption mechanism on FEU was primarily through hydrogen bonding and electrostatic interactions. Also, pH significantly affected the adsorption, guiding the study of the reversible adsorption-desorption performance of FEU. In addition, FEU exhibits good cycling performance, with only a 10% decrease in adsorption capacity after five regeneration cycles. Moreover, the composite exhibited excellent magnetic properties, allowing for rapid recovery by magnets after adsorption. This study provides new ideas for preparing materials with high adsorption performance of MTX for material recycling and sustainable use.

The electro-peroxone (E-peroxone) process combines ozone (O3) and hydrogen peroxide (H2O2) produced by an oxygen reduction reaction (ORR) pathway to generate super-active hydroxyl radical (·OH), which is considered to be a promising new advanced oxidation technology. Here, a N/Co-co-doped graphite gas diffusion electrode (Co-NG GDE) has been prepared by a simple mixed calcination method and applied in the E-peroxone system. Somewhat surprisingly, the Co-NG GDE exhibited the highest degradation efficiency for phenol and oxalate, though it performed the worst in the ORR to H2O2. The characterization test and experimental results have shown that Co-NG GDE produces abundant O2.– that can replace H2O2 to react with O3 to form super-active ·OH, which is due to the higher pyridine-N content of it. This work circumvents the limitation of H2O2 as the main intermediate in the traditional E-peroxone process by altering the main reaction pathway of the E-peroxone process and brings some new enlightenment to the research and development of this methodology.

This paper proposes a simple, direct, and fast method for the quantitative detection of oxygen in reduced graphene oxide (r-GO) by femtosecond laser-induced breakdown spectroscopy (fs-LIBS). First, GO was reduced by continuous-wave (CW) laser beams with different powers; subsequently, the oxygen content in the r-GO was detected through the intensity of oxygen obtained by fs-LIBS. The fit of the observed data and errors by LIBS was compared with the results of x-ray photoelectron spectroscopy (XPS), and the fs-LIBS results correlate well with the XPS results; it indicated that fs-LIBS can realize quantitative analysis of the GO-reduction degree. The method provides a convenient and time-efficient way for detecting the reduction degree of r-GO and can extend the applications of r-GO with different reduction degrees.

A multifunctional magnetic core–shell Fe3O4@SiO2nanoparticle decorated with rhodamine-based receptor has been successfully synthesized, aiming to detect and remove Hg2+from aqueous media.

Poly(m-phenylenediamine)-coated Fe3O4/o-MWCNTs nanoparticles (PmPD/Fe3O4/o-MWCNTs) were synthesized by one-step chemical oxidation polymerization.

A one-step solvothermal method was developed to prepare nearly cubic ZnFe2O4 nanoparticles loaded on 1,6-hexanediamine-functionalized reduced graphene oxide (HDA–RGO–ZnFe2O4) for fast removal of Cr(vi).

A multifunctional organic-inorganic hybrid sensing material (RB-KCC-1) was prepared by the immobilization of a rhodamine-based receptor (RB-Si) within the channels of fibrous silica spheres (KCC-1), and characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, N2 adsorption-desorption, and UV-vis absorption and fluorescence spectroscopy. This multifunctional sensor exhibits high surface area, large open pores and a flexible fibrous structure, and excellent optical sensing properties that allow for highly selective, sensitive and "naked eye" Hg2+ detection. The fluorescence enhancement responses of RB-KCC-1 are associated with the spirolactam ring opening of the rhodamine group, and a detection limit of 9.05 × 10-7 M is obtained. In additional, it is also an excellent adsorbent for the removal of Hg2+ from aqueous solution. The adsorption process of Hg2+ on RB-KCC-1 is well described by the Langmuir isotherm equation, and the equilibrium adsorption capacity is 115.47 mg g-1. These results indicate that these multifunctional composites may have good potential as favorable materials for the facile detection and effective removal of Hg2+ in biological, environmental, and industrial fields.

Well-characterized Fe3O4/hierarchical Mn3O4/rGO composites exhibited high catalytic ability towards the degradation of MB using PMS as an oxidant.

Highly effective nanoscale zero valent iron (nZVI) immobilized on magnetic Fe3O4-reduced graphene oxide (Fe0–Fe3O4–RGO) was successfully fabricated and firstly proposed as a heterogeneous Fenton catalyst for the removal of Methylene Blue (MB). The characterization of the hybrids revealed that Fe3O4 were distributed on RGO nanosheets evenly, the nZVI were wrapped by Fe3O4 assembled on the RGO nanosheets. The effects of pH value, initial concentration of MB, catalyst dosage, and hydrogen peroxide (H2O2) concentration on the degradation of MB were systematically investigated. Typically, 98.0% removal of 50mg/L MB could be achieved within 60min with the initial pH value of 3.00, H2O2 concentration 0.8mmol/L, catalyst dose 0.10g/L. The analysis of kinetics showed that the removal of MB followed the pseudo-second-order kinetics better than the pseudo-first-order kinetics. In addition to its high catalytic activity, the reusability and superparamagnetism make it a promising candidate as heterogeneous Fenton catalyst to remove organic contaminants in water.

A novel TiO2/ZnO–NH2–reduced graphene oxide (TZ-a-RGO) nanocomposite was successfully prepared using a facile one-step hydrothermal method. The TZ-a-RGO was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area analysis and UV-vis absorption spectrophotometry to investigate its structural features. The TZ-a-RGO was used as a catalyst to remove methyl orange (MO) from wastewater, and the results indicated that this catalytic system has a good performance in terms of removal of MO. The adsorption experiments of the TZ-a-RGO followed the pseudo-second-order kinetic model, and the adsorption isotherms were accurately represented by the Langmuir model. The degradation of methyl orange (MO) by TZ-a-RGO fitted well with the Langmuir–Hinshelwood model, and MO removal was obtained through a synergistic effect of adsorption and photocatalysis. The photocatalytic rate of MO over the composites was as high as 8.2 and 3.2 times that over commercial P25 (Degussa) and TiO2/ZnO, respectively. The potential photocatalytic mechanism for the TZ-a-RGO nanocomposite under UV was discussed.

A cellulose-based paper chemodosimeter was designed and prepared by reactions of Rhodamine B with natural cellulose paper. Its sensing property to Hg2+ was investigated by fluorescence spectroscopies. While the Hg2+-indicating paper was immersed into the Hg2+ solution, the ring of the rhodamine spirolactam opened and the thiosemicarbazide moiety would undergo an irreversible desulfurization reaction to form its corresponding oxadiazole structure, a colorful and fluorescent product. The color change can be discerned by a naked eye under the irradiation of 365nm UV light. The Hg2+-indicating paper displayed excellent selective toward Hg2+ over other commonly metal ions and the sensitive detection of Hg2+ was not interfered by other heavy metal ions. The results suggested that the Hg2+-indicating paper would serve as a practical fluorescent chemodosimeter for rapid and convenience detection of Hg2+.

Based on the Hg2+-induced ring-open characteristic of spirolactam in Rhodamine derivatives,and followed by the fluorescenceturn-oneffect,novel fluorescent chemosensors 2-Thenaldehydealdehyde rhodamine B hydrazone(RhBTh)and Benzaldehyde rhodamine B hydrazone(RhBAr)had been designed and synthesized,and their application in the detection of Hg2+were carried out.The results showed that both RhBTh and RhBAr exhibited good fluorescent enhancement toward Hg2+,and other metal ions showed no significant interference during the detection process.The detection limits were determined to be 7.8nmol/L and 12.5nmol/L,respectively.As a result,RhBTh and RhBAr showed good sensitivity and selectivity toward Hg2+.

We have designed and synthesized a spirobifluorene–tetrrhodamine fluorescent probe 2 based on the through-bond energy transfer (TBET) system for the “off–on” detection of Hg2+. As compared with fluorescence resonance energy transfer (FRET) strategy, the TBET system did not need spectral overlap between the donor emission and the acceptor absorption, therefore, the choice of dye pairs for the probe design was wide. The Stokes shift was larger and the energy transfer efficiency was higher than that of the FRET system. The probe 2 showed exclusive response toward Hg2+ by the fluorescence enhancement and the color changed from colorless to pink. Other metal ions showed no significant variation to Hg2+. The energy-transfer efficiency was calculated to be 99.6%, and the detection limit was determined to be 3 ppb. Thus, probe 2 could be used as a fluorescent and colorimetric chemosensor for the detection of Hg2+.

This study presents a simple route for the fabrication of manganese dioxide/iron oxide/acid oxidized multi-walled carbon nanotube magnetic nanocomposites (MnO2/Fe3O4/o-MWCNTs). The materials were characterized by transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometry, and Brunauer, Emmett, and Teller surface area measurement. MnO2/Fe3O4/o-MWCNTs are more effective for hexavalent chromium ion adsorption compared with other materials. Hexavalent chromium adsorption by MnO2/Fe3O4/o-MWCNTs is strongly pH dependent. The Langmuir isotherm model is consistent with the experimental data at different temperatures. The maximum adsorption capacity was determined to be q(max) = 186.9 mg g(-1). A contact time of different initial concentrations was about 150 min to attain adsorption equilibrium. The kinetic adsorption of different initial concentrations can be described by the pseudo-second-order rate equation. The overall rate process was apparently influenced by external mass transfer and intraparticle diffusion. Moreover, the thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic, and that the adsorption mechanism included both the physical and the chemical adsorption mechanisms. After adsorption, MnO2/Fe3O4/o-MWCNTs can be conveniently and quickly separated from the media by an external magnetic field, and adsorption capacity can remain up to 85% after five times of usage. Thus, MnO2/Fe3O4/o-MWCNTs are good candidate for efficient hexavalent chromium removal from wastewater and for the deep-purification of polluted water. (C) 2013 Elsevier B.V. All rights reserved.