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Fe-based MOFs (Fe-MOFs) are excellent photocatalysts and have synergy well with Fenton reagents relative to other MOFs. In this work, a series of uniformly covered NH2-Fe-MIL-88B@TpPa-1-COF composites were synthesized using an in-situ anchoring growth strategy, which used F127 as functional molecule to decorate NH2-Fe-MIL-88B nanoparticles to eliminate their surface electrostatic repulsion with Tp molecules during the subsequent coating procedure. Meanwhile, the -NH2 groups in the skeleton of NH2-Fe-MIL-88B could also be used as anchors to covalently connect TpPa-1-COF shell and migration channels for effective charge transfer. This uniformly covered core–shell structure would endow these composites with much more contact area and imine bond linkage between the Fe-MOFs core and COFs shell. Compared with the random packing structure, the uniformly covered Fe-MOF@COF-3 composite possessed a higher proportion of Fe2+ to Fe3+. As a result, the optimized Fe-MOF@COF-3 catalyst could achieve the highest photo-Fenton degradation efficiency of 93.9% for tetracycline hydrochloride (TC⋅HCl), which was much higher than 54.8% of pure NH2-Fe-MIL-88B. In addition, the uniform TpPa-1-COF shell could further effectively enhance the stability of NH2-Fe-MIL-88B by protecting Fe ions from leaching, and the toxicity of the water samples treated with our photo-Fenton degradation process declined obviously. All these merits will endow Fe-MOF@COF-3 photo-Fenton catalyst great potential application value as in the field of environmental governance. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysis is a promising method to solve the problem of antibiotic pollution in water. A series of Bi2SiO5/BiVO4 composite photocatalysts for tetracycline and levofloxacin degradation are prepared by a two-step hydrothermal method. Analysis results show that the as-prepared Bi2SiO5/BiVO4 (2:3) hybrid exhibits better photocatalytic activity than pure samples under visible light illumination. The photocatalytic degradation efficiency of the as-prepared composite shows the maximum of 72.2% within 120 min for tetracycline, which is higher than 43.5% of pure Bi2SiO5 and 67.2% of pure BiVO4, respectively. Furthermore, it is 80.3% within 120 min for levofloxacin, which is higher than 7.6% of pure Bi2SiO5 and 69.7% of pure BiVO4, respectively. The formation of n–n isotype heterojunction at the interface of Bi2SiO5 and BiVO4 in the as-prepared composites causes to the improvement of the transport rate and separation efficiency of the photogenerated electron and hole pairs. In addition, the holes play a dominant role in the photocatalytic degradation process. This work will provide a reference for the study of visible light driven photocatalysts to solve antibiotics pollution in water. [ABSTRACT FROM AUTHOR]

Recently, the problem of water pollution, caused by antibiotics, is becoming more and more serious. Photocatalysis is one of the promising technologies for removing antibiotics from water. Herein, the In2.77S4/Ti3C2 composites were prepared by an in-situ hydrothermal growth method for photocatalytic degradation of tetracycline (TC). The as-developed composites were characterized by various methods. The UV–Vis DRS spectra reveals that the introduction of Ti3C2 makes the bandgap of the as-prepared composites smaller and the visible light absorption ability improved. The photocatalytic degradation efficiency of the as-prepared composite is enhanced under visible light illumination. It is shown as first increasing and then decreasing with increasing the content of Ti3C2 in the composite and reaches to the maximum of 89.3% in 90 min, which is higher than 75.1% of In2.77S4 and 6.7% of Ti3C2. The reason of improvement is the interface between In2.77S4 and Ti3C2 is tightly combined to form a heterojunction. Moreover, the photocurrent intensity of the as-obtained composite is improved, while its Nyquist arc radius is decreased. In addition, holes are the main active species and ·OH and ·O2− play an auxiliary role during the degradation of TC. [ABSTRACT FROM AUTHOR]

A cauliflower-like In2.77S4 has been synthesized using polyvinylpyrrolidone (PVP) as a surfactant, and the In2.77S4/BiVO4 composite photocatalysts were further prepared via a hydrothermal method. The photocatalytic activity of the samples was evaluated using tetracycline (TC) dilute solution. The photocatalytic degradation mechanism of the as-prepared composites was also discussed. Moreover, the state density and electron transfer of as-constructed composites were investigated through density-functional theory (DFT). Analysis results show that the as-hybridized products have higher photocatalytic activity than pure samples. With increasing the amount of BiVO4, the photocatalytic activity of the as-constructed In2.77S4/BiVO4 composites is firstly increased and then decreased. The best photocatalytic degradation efficiency of the as-prepared composite for TC is 89.9% in 90 min, which is higher than 61% of In2.77S4 and 51% of BiVO4, respectively. The reason of photocatalytic property enhancement is that there are chemical bonds between the interface of In2.77S4 and BiVO4, and it is confirmed that h+ plays a leading role during the photocatalytic degradation process. This work can provide a reference for the treatment of antibiotics pollution in water under solar light. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysis technology is a promising method to solve the antibiotics pollution in water. Herein, a series of Sn-doped In2.77S4 (Sn-In2.77S4) hybrid photocatalysts for tetracycline degradation have been fabricated via a one-step hydrothermal process. The analytic results exhibit that doping Sn can improve the photocatalytic performance of In2.77S4 nanosheets under the visible light illumination and the doping amount obviously affects the photocatalytic performance of the samples. When the theoretical molar ratio of Sn4+ to In3+ is 0.04:1 (4%), the photocatalytic efficiency of the Sn-In2.77S4 photocatalyst exhibits the highest of 87.4% in comparison with 39.2% of pure In2.77S4 in 20 min. Moreover, its band gap energy has been reduced to 1.56 eV from 1.75 eV and the light absorption range has been broadened. The transfer rate and separation efficiency of photo-generated electron and hole pairs of the samples have also been enhanced. In addition, the holes play a leading role in the photocatalytic degradation process. [ABSTRACT FROM AUTHOR]

Ag2WO4 is a typically noble metal based photocatalyst with highly efficient photocatalytic activity. However, due to photocorrosion, the pristine Ag2WO4 is prone to inactivation during illumination. Constructing composite photocatalyst may be a useful method to promote the stability of Ag2WO4. In this work, Ag2WO4/graphitic carbon nitride nanotubes (g-C3N4 NTs) composite photocatalyst was prepared by adopting an in-situ composite strategy. The photocatalytic performance of the samples was discussed by the degradation of rhodamine B under visible light, and the catalytic mechanism was also analyzed. The characterization results show that the photocatalytic efficiency of the as-prepared Ag2WO4/g-C3N4 NTs composite increases firstly and then decreases along with the increase of the Ag2WO4 content. When the theoretical molar ratio of Ag2WO4:g-C3N4 NTs reaches 3:2, the photocatalytic degradation efficiency achieves the optimal value, that is 92.4% within 20 min, which obviously exceeds 2.8% of pure Ag2WO4 and 48.9% of pure g-C3N4 NTs. Moreover, the separation and migration efficiency of photoelectron–hole pairs of the composites can be accelerated in comparison with pure samples. In addition, superoxide radicals and hydroxyl radicals play major roles in the photocatalytic degradation process. [ABSTRACT FROM AUTHOR]

The Zn0.5Cd0.5S/SnO2 composite photocatalyst was synthesized via a hydrothermal method. The crystal phase, micromorphology, optical and photoelectric property as well as surface elements valence were characterized using X-ray diffraction, field emission scanning electron microscope, transmission electrical microscope, UV–Vis diffuse reflectance spectrometer, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy, respectively. Tetracycline was used to discuss the photocatalytic properties of the samples under visible light irradiation. Research results indicate that the as-synthesized Zn0.5Cd0.5S/SnO2 composite photocatalysts show better photocatalytic performance than that of pure samples. Moreover, the photocatalytic activity of the as-synthesized composites presents first increased and then decreased with increasing the amount of SnO2 in the composites. When the quality ratio of SnO2 to Zn0.5Cd0.5S is 7%, in 60 min, the as-synthesized composites reveal the best photocatalytic degradation efficiency of 92.9%, which is high than 85% of Zn0.5Cd0.5S and 0% of SnO2. This is ascribed of the improvement of the separation efficiency of photo-generated electron–hole pairs and the transmission rate of electrons. Furthermore, the decomposition mechanism of as-synthesized composites for tetracycline was also provided. The holes and superoxide radicals play crucial species in the photocatalytic degradation process. [ABSTRACT FROM AUTHOR]

The yolk–shell Bi@void@SnO2 photocatalyst was synthesized via a step-by-step process. The composition, morphology, optical and photoelectrochemical properties as well as the surface chemical composition and states of the samples were characterized by X-ray diffraction, transmission electron microscopy, UV–Vis diffuse reflectance spectra, electrochemical impedance spectra and X-ray photoelectron spectrometer, respectively. The tetracycline has been used to evaluate the photocatalytic activities of the as-synthesized samples. Compared with the degradation efficiency of 16.33% for pure Bi and almost nothing for SnO2 under visible light irradiation, the as-developed Bi@void@SnO2 photocatalyst possesses 81.81% of degradation efficiency. Meanwhile, the light absorption of the as-developed yolk–shell composites is broadened from ultraviolet to visible light comparing to pure SnO2 due to the surface plasmon resonance effect of Bi spheres. Moreover, the superoxide radicals, especially in holes, play leading roles during the photocatalytic degradation process. In addition, the decomposition mechanism of the as-fabricated composites for tetracycline is analyzed in detail. [ABSTRACT FROM AUTHOR]

The AgI/2D-La2Ti2O7 hybrids were obtained via a facile method at room temperature. Rhodamine B, as an organic dye, was used to determine the photocatalytic activity of the samples. The photocatalytic degradation mechanism was also analyzed. Experimental results display that AgI can broaden the light absorption of La2Ti2O7 under the visible light irradiation. The photocatalytic degradation efficiency of the as-synthesized hybrids appears the tendency of first increasing and then decreasing with increasing the usage of La2Ti2O7. When the usage of La2Ti2O7 is 10%, within 60 min, the as-synthesized hybrids possess the maximum of 93.1%. This is higher than 2.1% of La2Ti2O7 and 80.9% of AgI. Moreover, the improved photocatalytic activity can be attributed to AgI particles conjugating with 2D-La2Ti2O7 nanosheets via chemical-bonds, which can enhance the separation and transformation of the photo-generated holes and electrons. In addition, the dominating role is superoxide radicals during the photocatalytic process. [ABSTRACT FROM AUTHOR]

Alkaline anions, include CO32-, HCO3-, Al(OH)4-, OH-, continuously released from bauxite residue (BR), will cause a potential disastrous impact on surrounding environment. The composition variation of alkaline anions, alkaline phase transformation pathway, and micro-morphological transition characteristics during the gypsum addition were investigated in an attempt to understand alkalinity stabilization behavior. Results demonstrated that alkaline anions stabilization degree in leachates can reach approximately 96.29%, whilst pH and alkalinity were reduced from 10.47 to 8.15, 47.39 mmol/L to 2 mmol/L, respectively. During the alkalinity stabilization, chemical regulation behavior plays significant role in driving the co-precipitation reaction among the critical alkaline anions (CO32-, HCO3-, Al(OH)4-, OH-), with calcium carbonate (CaCO3)) being the most prevalent among the transformed alkaline phases. In addition, XRD and SEM-EDX analyses of the solid phase revealed that physical immobilization behavior would also influence the stability of soluble alkali and chemical bonded alkali due to released Ca2+ from gypsum which aggregated the clay particles and stabilized them into coarse particles with a blocky structure. These findings will be beneficial for effectively regulating strong alkalinity of BR. [ABSTRACT FROM AUTHOR]

A feasible approach to selectively recover iron and rare earth elements (REEs) from red mud through acid leaching-coordination-solvent extraction was proposed. The leaching efficiencies of Fe, Al, Ti, Sc, La, Ce, Nd and Y can reach up to 95.9%, 82.1%, 68.3%, 93.3%, 82.3%, 96.9%, 98.3% and 95.6%, respectively, under the optimal condition in the leaching process. Aliquat 336 showed excellent extraction performance of iron in chloride-rich solution, and the maximum extraction efficiency can reach over 96% in one time extraction while the loss of other metals was less than 10%, under the condition of Aliquat 336 concentration (v/v) of 30%, aqueous-organic ratio of 1.0 and extraction time of 20 min. Furthermore, P204 can effectively extract the scandium while Al and most other REEs remain in the aqueous phase. This approach may provide a new insight for the recovery of valuable resources from red mud. [ABSTRACT FROM AUTHOR]

The absorbent composing of Bayer red mud and water was prepared and applied to removing SO2 from flue gas. Effects of the ratio of liquid to solid (L/S), the absorption temperature, the inlet SO2 concentration, the O2 concentration, SO42- and other different components of Bayer red mud on desulfurization were conducted. The mechanism of flue gas desulfurization was also established. The results indicated that L/S was the prominent factor, followed by the inlet SO2 concentration and the temperature was the least among them. The optimum condition was as follows: L/S, the temperature and the SO2 concentration were 20:1, 25 °C and 1000 mg/m3, respectively, under the gas flow of 1.5 L/min. The desulfurization efficiency was not significantly influenced when O2 concentration was above 7%. The accumulation of SO42- inhibited the desulfurization efficiency. The alkali absorption and metal ions liquid catalytic oxidation were involved in the process, which accounted for 98.61%. [ABSTRACT FROM AUTHOR]

Vegetation encroachment occurred in bauxite residue disposal area (BRDA) following natural weathering processes, whilst the typical indicators of soil formation are still uncertain. Residue samples were collected from the BRDA in Central China, and related physical, chemical and biological indicators of bauxite residue with different storage years were determined. The indicators of soil formation in bauxite residue were selected using principal component analysis, factor analysis, and comprehensive evaluation to establish soil quality diagnostic index model on disposal areas. Following natural weathering processes, the texture of bauxite residue changed from silty loam to sandy loam. The pH and EC decreased, whilst porosity, nutrient element content and microbial biomass increased. The identified minimum data set (MDS) included available phosphorus (AP), moisture content (MC), C/N, sand content, total nitrogen (TN), microbial biomass carbon (MBC), and pH. The soil quality index of bauxite residue increased, and the relative soil quality index decreased from 1.89 to 0.15, which indicated that natural weathering had a significant effect on improveing the quality of bauxite residue and forming a new soil-like matrix. The diagnostic model of bauxite residue was established to provide data support for the regeneration on disposal area. [ABSTRACT FROM AUTHOR]

Bauxite residue deposit area (BRDA) is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity. Microbially-driven neutralization of bauxite residue, based on the microbial acid producing metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving its environmental outcomes. The hypothesis was that these extreme conditions promote microbial communities which are capable of novel ecologically relevant functions. Several alkaliphilic acid producing bacteria were isolated in this study. One strain was selected for its superior growth pattern and acid metabolism (termed EEEL02). Based on the phylogenetic analysis, this strain was identified as Bacillus thuringiensis. The optimized fermentation conditions were as follows: pH 10; NaCl concentration 5%; temperature 25 °C; EEEL02 preferred glucose and peptone as carbon and nitrogen sources, respectively. Based on optimal fermentation conditions, EEEL02 induced a significant pH reduction from 10.26 to 5.62 in 5-day incubation test. Acetic acid, propionic acid and CO2 (g) were the major acid metabolites of fermentation, suggesting that the pH reduction in bauxite residue may be caused by acid neutralization derived from microbial metabolism. This finding provided the basis of a novel strategy for achieving rapid pH neutralization of bauxite residue. [ABSTRACT FROM AUTHOR]

Rehabilitation (amendment and vegetation establishment) on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development. However, such approaches are inhibited by high pH, high exchangeable sodium (ESP) and poor nutrient status. Amendment with gypsum is effective in improving residue physical and chemical properties and promoting seed establishment and growth. Application of organics (e.g. compost) can address nutrient deficiencies but supplemental fertilizer additions may be required. A series of germination bioassays were performed on residue to determine candidate species and optimum rehabilitation application rates. Subsequent field trials assessed establishment of grassland species Holcus lanatus and Trifolium pratense as well as physical and chemical properties of amended residue. Follow up monitoring over five years assessed elemental content in grassland and species dynamics. With co-application of the amendments several grassland species can grow on the residue. Over time other plant species can invade the restored area and fast growing nutrient demanding grasses are replaced. Scrub species can establish within a 5 Yr period and there is evidence of nutrient cycling. High pH, sodicity and nutrient deficiencies are the major limiting factors to establishing grassland on residue. Following restoration several plant species can grow on amended residue. [ABSTRACT FROM AUTHOR]

Bauxite residue is a highly alkaline waste product from refining bauxite ore. Bioremediation driven by microbial activities has been evidently effective in lowering the alkalinity of bauxite residues, which is critical to the initiation of pedogenesis under engineered conditions. The present study investigated the changes of alkalinity and aggregation of bauxite residue at different depth in response to the colonization of Penicillium oxalicum in columns. The results demonstrated that the inoculation of P. oxalicum decreased the residue's pH to about 7 after 30 d only at the surface layer, which was exposed to aerobic conditions. The formation of aggregates was improved overall in the organic matter treated bauxite residue. However, the EC of bauxite residue increased with time under the incubation condition, probably due to accelerated hydrolysis of sodium-rich minerals. The inoculation of P. oxalicum had no effects on urease activity, but increased cellulose enzyme activity at surface layer only. [ABSTRACT FROM AUTHOR]

Aiming at alkaline problem of bauxite residue, this work focused variation of alkaline characteristics in bauxite residue through phosphogypsum treatment. The results demonstrated that the pH of bauxite residue reduced from initial 10.83 to 8.70 when 1.50 wt% phosphogypsum was added for 91 d. The removal rates of free alkali and exchangeable sodium were 97.94% and 75.87%, respectively. Meanwhile, significant positive correlations (P<0.05) existed between pH and free alkali, exchangeable sodium. The effect of free alkali composition was CO32->OH-> AlO2->HCO3-. In addition, alkaline phase decreased from 52.81% to 48.58% and gypsum stably presented in bauxite residue which continuously provided Ca2+ to inhibit dissolution of combined alkali. Furthermore, phosphogypsum promoted formation of macroaggregate structure, increased Ca2+, decreased Na+ and Al3+ on the surface of bauxite residue significantly, ultimately promoting soil formation in bauxite residue. [ABSTRACT FROM AUTHOR]

Bauxite residue disposal areas (BRDAs) are physically degraded and hostile to plant growth. Nevertheless, natural plant colonization was observed in an abandoned BRDA in Central China. The pioneer plant species at the disposal area were identified, whilst distribution characteristics of salt ions such as Na+, K+, and Ca2+ in plant tissues and rhizosphere residues were investigated. The mean concentration of exchangeable Na+ in the rhizosphere soils was 19.5 cmol/kg, which suggested that these pioneer plants had relatively high salinity resistance. Sodium content varied from 0.84 cmol/kg (Digitaria sanguinalis) to 39.7 cmol/kg (Kochia scoparia), whilst K to Na ratio varied from 0.71 (Myricaria bracteata) to 32.39 (Digitaria sanguinalis) in the shoots, which demonstrated that the salinity tolerance mechanisms of these pioneer species differed significantly. Accumulation factors of Na+ in local plant species ranged from 0.04 (D. sanguinalis) to 3.29 (M. bracteata), whilst the translocation factor varied from 0.13 (D. sanguinalis) to 2.92 (M. bracteata). The results suggested that four pioneer plant species including K. scoparia, M. bracteate, Cynodon dactylon and D. sanguinalis could be suitable for revegetation at other disposal areas. [ABSTRACT FROM AUTHOR]

Excess lithium in alumina is significantly bad for aluminum reduction. In this study, the concentration variation of lithium ion in sodium aluminate solution with addition of synthetic lithium aluminate was investigated. Elevating temperature, increasing caustic soda concentration, reducing alumina concentration or raising molar ratio α k improved equilibrium concentration of lithium ion in sodium aluminate solution. Agitation speed had a minimal effect on lithium ion concentration. Over 0.65 g/L lithium ion equilibrium concentration was observed in digestion process, whereas 35 mg/L lithium ion concentration remained in solution after precipitation time of 9 h. Moreover, equilibrium concentration decreased sharply from digestion of boehmite or diaspore to seed precipitation, about 95% lithium was precipitated into red mud (bauxite residue) and aluminum hydroxide. This study provides a valuable perspective in removal or extraction of lithium from sodium aluminate solution in alumina refineries. [ABSTRACT FROM AUTHOR]

The processes involved in the major steps of successful revegetation of bauxite residues are examined. The first phase is the natural physical, chemical and microbial ripening of the profile. This involves allowing the profile to drain, dry, shrink and crack to depth, leaching of soluble salts, alkalinity and Na down out of the surface layers, acidification by direct carbonation and natural seeding of tolerant vegetation with an accumulation of organic matter near the surface and an attendant development of an active microbial community. Following ripening, the surface layer can be tilled and gypsum and organic matter (e.g. manures, composts, biosolids) incorporated. These amendments result in a further decrease in pH, increase in Ca and other exchangeable cations, increased leaching of Na (with a reduction in exchangeable Na and ESP), improved physical properties, particularly aggregation, and a large increase in microbial activity. Other important considerations include the choice of suitable plant species tolerant to salinity/sodicity and local environmental conditions and the addition of balanced fertilizer applications. [ABSTRACT FROM AUTHOR]

Bauxite residue is a highly alkaline material generated from the production of alumina in which bauxite is dissolved in caustic soda. Approximately 4.4 billion tons of bauxite residues are either stockpiled or landfilled, creating environmental risks either from the generation of dust or migration of filtrates. High alkalinity is the critical factor restricting complete utilization of bauxite residues, whilst the application of alkaline regulation agents is costly and difficult to apply widely. For now, current industrial wastes, such as waste acid, ammonia nitrogen wastewater, waste gypsum and biomass, have become major problems restricting the development of the social economy. Regulation of bauxite residues alkalinity by industrial waste was proposed to achieve 'waste control by waste' with good economic and ecological benefits. This review will focus on the origin and transformation of alkalinity in bauxite residues using typical industrial waste. It will propose key research directions with an emphasis on alkaline regulation by industrial waste, whilst also providing a scientific reference point for their potential use as amendments to enhance soil formation and establish vegetation on bauxite residue disposal areas (BRDAs) following large-scale disposal. [ABSTRACT FROM AUTHOR]

The Ag2CrO4/SnO2 n-n type heterojunction has been fabricated by coupling Ag2CrO4 particles with SnO2 nanorods via an in situ synthetic method. The photocatalytic degradation mechanism of the as-prepared heterojunction has also been discussed. Characterization results revealed that the as-fabricated Ag2CrO4/SnO2 composites could reinforce the photo-degradation competencies for rhodamine B dilute solution compared to pure Ag2CrO4 and SnO2 samples. As the increase in the molar ratios of Ag2CrO4-SnO2, the photocatalytic degradation efficiency appeared to the tendency of first increasing and then decreasing. When it was 4:10, in 90 min, the as-obtained samples possessed the vintage photocatalytic degradation efficiency of 95.8% among of pure SnO2, Ag2CrO4 and the as-prepared composites with various molar ratios, respectively. Furthermore, the Ag2CrO4 and SnO2 were connected via chemical bonds to form the homogenous heterojunction. It could boost the separation and transfer of the photogenerated holes and electrons. In addition, the holes, hydroxyl and superoxide radicals played a major role during the photodegradation process. [ABSTRACT FROM AUTHOR]

The direct Z-scheme Ag2WO4/WS2 photocatalysts had been fabricated by using a deposition method. Experimental results indicated that WS2 nanosheets could improve the photocatalytic activity, light absorption and recyclability of Ag2WO4 under the visible light irradiation. The degradation efficiency of the as-obtained Ag2WO4/WS2 hybrids for rhodamine B displayed first increasing and then decreasing with increasing the usage of WS2 nanosheets. When the usage of WS2 was 15 wt%, in 120 min, it reached the maximum of 97.8%, which was higher than 17.8% of pure Ag2WO4. Moreover, after three cycles of the degradation, the as-prepared hybrids still possessed 94.4% of the degradation efficiency, which increased by 1211.1% compared with pure Ag2WO4. Moreover, superoxide and hydroxyl radicals played major role during the process of photocatalytic degradation. The enhanced photocatalytic activity could be ascribed to the formation of direct Z-scheme photocatalytic system between Ag2WO4 and WS2. [ABSTRACT FROM AUTHOR]

SnS/few layer boron nitride nanosheets composites were synthesized via a one-step hydrothermal method. The as-prepared samples were characterized by X-ray diffraction, transmission electrical microscopy, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, photoluminescence emission spectra and electrochemical impedance spectroscopy, respectively. Rhodamine B was adopted to evaluate the degradation efficiency of the as-prepared samples under visible light irradiation. Experimental results showed that, compared to pure SnS, the few layer boron nitride nanosheets could improve photocatalytic activities of the samples for the degradation of Rhodamine B. With increasing the usage amount of the few layer boron nitride nanosheets, the degradation efficiency was first increased and then decreased. When the usage amount of the few layer boron nitride nanosheets was 10 wt%, it exhibited the highest degradation efficiency of 93.7% in 210 min, which was higher than 50% of pure SnS. After it was recycled for four times, it still possessed 88.7% of degradation efficiency. This was increased by 1008.7% than pure SnS. Moreover, it had band gap energy of 1.78 eV, obviously smaller than 2.06 eV of pure SnS. In addition, a possible photocatalytic mechanism was also presented. [ABSTRACT FROM AUTHOR]

Boron nitride nanoparticles were prepared in a muffle furnace at 1000 °C by using commercial available boron nitride flakes and sodium chloride as raw materials. The structure, functional groups, morphology and specific surface area of the as-prepared samples were characterized by X-ray diffracmeter, fourier-transform infrared spectrometer, transmission electron microscope and accelerated surface area/porosimetry system, respectively. In order to evaluate the properties of the as-prepared products, they were mixed with epoxy resin to fabricate polymer-based composites. Experimental results showed that the average size and specific surface area of the as-prepared nanoparticles were about 20 nm and 895.7 m/g. Moreover, the as-prepared nanoparticles could improve the tensile strength and elongation at break of the epoxy matrix. Both of them were first increased and then decreased with increasing the usage amount of the as-prepared nanoparticles. When the usage amount of the boron nitride nanoparticles was 0.4 wt%, the tensile strength and elongation at break of the composites reached to 71.4 MPa and 22.1%, which were the maximum values of the composites, respectivley. They were increased by 137 and 146% more than those of pure epoxy resin. In addition, the as-prepared fillers could accelerate the solidification of the matrix. [ABSTRACT FROM AUTHOR]

Graphene nanomesh was prepared via one-step hydrothermal process in a teflon-lined autoclave. The graphite flakes were used as the raw materials and no templates were adopted during the preparation. Experiment results showed that as the hydrothermal temperature increased, there was an obvious transition in the structure and morphology of the final products. When the temperature was set at 95 °C, the graphite was oxidized to graphite oxide. The structural transition of the sample could be observed at 115 °C, part of the sample was reduced during the hydrothermal treatment. When the temperature reached to 135 or 155 °C, there appeared signals related to graphene; no obvious information about graphene oxide could be detected. Some holes were discovered in the samples. These structural changes were confirmed by X-ray diffraction, thermo-gravimetric analysis, and Fourier transform infrared spectroscopy and laser Raman spectroscopy. Moreover, atomic force microscope and transmission electron microscope revealed the as-prepared graphene was monolayer or few-layer nanomesh. [ABSTRACT FROM AUTHOR]

A comparative study of submicro-crystalline spinel LiMnO powders prepared by two different soft chemical routes such as hydrothermal and sol-gel methods is made. The dependence of the physicochemical properties of the spinel LiMnO powder has been extensively investigated by using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope, cyclic voltammogram, charge-discharge test, and electrochemical impedance spectroscopy (EIS). The results show that the electrochemical performances of spinel LiMnO depend strongly upon the synthesis method. The LiMnO powder prepared by hydrothermal route has higher specific capacity and better cycling performance than the one synthesized from sol-gel method. The former has the max discharge capacity of 114.36 and 99.78 mAh g at the 100th cycle, while the latter has the max discharge capacity of 98.67 and 60.25 mAh g at the 100th cycle. The selected equivalent circuit can fit well the EIS results of synthesized LiMnO. For spinel LiMnO from sol-gel method and hydrothermal route in the first charge process R remain almost invariable, R and R first decreasing and then increasing with the increase of polarization potential. [ABSTRACT FROM AUTHOR]

The Zn2+ doped In2.77S4 (Zn–In2.77S4) photocatalyst has been synthesized via a one-step hydrothermal method. The tetracycline was adopted to measure the photocatalytic performance of the as-fabricated Zn–In2.77S4 composites. The probable photocatalytic degradation mechanism of the as-prepared composites was also discussed. Experimental results reveal that doping Zn2+ into In2.77S4 can broaden the light absorption range and improve the recycle ability as well as the separation efficiency of photo-generated electron–hole pairs of pure In2.77S4. Moreover, as the doping amount of Zn2+ increased the photocatalytic efficiency of the as-obtained Zn–In2.77S4 composites appears the tendency of firstly increasing and then decreasing. When the molar ratio of Zn2+ to In3+ is 0.04:1 (4%), in 15 min, the photocatalytic efficiency of the as-developed Zn–In2.77S4 photocatalyst reaches to the maximum of 90.0%. It is higher than 31.8% of pure In2.77S4. Furthermore, superoxide radicals and holes play major roles in the process of photodegradation tetracycline. This research can supply a promising guide to solve antibiotics pollution in water under sunlight. [ABSTRACT FROM AUTHOR]

The In2.77S4/SrCO3 heterojunction photocatalyst had been prepared by one-step hydrothermal method. X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectrometry, UV-Vis diffuse reflectance spectroscopy and electrochemical impedance spectroscopy were used to analyze the structure, morphology, chemical compositions, optical properties and charge carrier behaviors of the as-prepared In2.77S4/SrCO3 hybrids, respectively. Experimental results revealed the SrCO3 could obviously improve the recyclability and photocatalytic activities of In2.77S4 nanosheets for both methyl orange and tetracycline oxidation under visible light. The photocatalytic degradation efficiency of the as-obtained In2.77S4/SrCO3 hybrids was first increased and then decreased with increasing the molar ratio of Sr(NO3)2 to In(NO3)3·4.5H2O. When it was 0.4:1, that of the as-prepared hybrids with the band gap of 1.63 eV reached the maximum of 96.0% in 30 min for methyl orange and 82.7% in 20 min for tetracycline. These were higher than 88.0% and 40.0% of In2.77S4 nanosheets as well as 0.8 and 1.8% of SrCO3 particles, respectively. After three cycles, its photocatalytic efficiency still possessed 92.7% for methyl orange and 80.3% for tetracycline, which were much higher than 35.3% and 11.3% of In2.77S4 nanosheets. Moreover, the possible photocatalytic degradation mechanism of the In2.77S4/SrCO3 hybrids was also proposed. [ABSTRACT FROM AUTHOR]

The In2.77S4 microspheres had been firstly fabricated by using polyethylene glycol (PEG) as the morphological modifier and then used to hybridize with In(OH)3 nanocubes by a simply depositional method. The structure, optical properties, morphology, chemical compositions, and charge carrier behaviors of the as-prepared In2.77S4/In(OH)3 composites were characterized, respectively. The methyl orange, tetracycline, rhodamine B, and Cr(VI) dilute solution were selected to evaluate their photocatalytic activities. Experimental results showed that In(OH)3 nanocubes could improve the photocatalytic activity and recyclability of the In2.77S4 microspheres under the visible light irradiation. With the usage of In(OH)3 increased, the photocatalytic efficiency of the hybrids was firstly increased and then decreased. When the mass ratios of In2.77S4 to In(OH)3 were 6:2, it reached the maximum of 100% in 15 min for methyl orange, obviously higher than 67.4% of In2.77S4 and 1.1% of In(OH)3. Meanwhile, it could also oxidize 85.6% of tetracycline in 20 min, 97.8% of rhodamine B in 7.5 min, and reduce 92.9% of Cr(VI) in 30 min under the visible light irradiation. Moreover, it could still degrade 91.7% of methyl orange solution after 3 cycles, which was much higher than 40.7% of In2.77S4 microspheres. In addition, the possible mechanism of enhancing photocatalytic properties was proposed. [ABSTRACT FROM AUTHOR]