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To study the influence of consolidation on the bearing capacity of the composite foundation in the process of caisson heightening, the consolidation characteristics of the sand pile composite foundation in the process of caisson heightening are discussed based on the sand pile composite foundation engineering of a large-scale onshore caisson foundation. The influence of loading duration and replacement rate of the sand pile are analyzed. Based on the area ratio method of pile-soil and the pile-soil stress ratio method, the formula of the ultimate bearing capacity of the sand pile composite foundation considering the consolidation effect is derived, which is compared with the measured value of the ultimate bearing capacity of the foundation. The results show that the time history curves of the bearing capacity of the composite foundation based on the two methods are close, and the initial bearing capacity is less than the measured value of bearing capacity, while the bearing capacity after consolidation is 68% and 80% higher than the natural strength of the composite foundation. This method considers the influence of consolidation on the bearing capacity of the foundation in the process of caisson heightening. It can avoid the problem of stagnant sinking of open caisson as it underestimates the actual bearing capacity of the foundation, and provides suggestions for calculation of ultimate bearing capacity of the composite foundation considering the influence of consolidation and formulating the reasonable construction scheme of open caisson.

In the study, a novel Fe–Mn oxide-modified cattail biochar was synthesised and Cr(VI) adsorption on Fe–Mn oxide-modified biochar in water was investigated. XRF, XRD and FTIR results indicated that ...

The rational design of a novel and environmentally friendly photocatalytic composite for persistent pollutant removal, energy production and catalytic applications have attracted widespread interest. In this study, the new composite composed of KOH-modified biochar and g-C

The development of novel and green photocatalysts have attracted considerable attentions due to their excellent performance for environmental remediation, especially for the degradation of persistent pollutants. In this work, the biochar-supported K-doped g-C3N4 composites with the high photocatalytic activity under visible light irradiation was prepared by the calcination-impregnation method. The crystal structure, apparent morphology and functional group composition of the as-prepared photocatalytic materials were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscope (FTIR). Moreover, the characterization of UV-Vis diffuse reflectance spectra (UV-Vis DRS) and photoluminescence technique (PL) verified the good optical properties of resultant samples. Naphthalene was selected as the representative compound to evaluate the photocatalytic performance of the prepared photocatalysts under visible light irradiation. The evaluation results showed that the biochar-supported K-doped g-C3N4 composites exhibited excellent photocatalytic activity (82.19%). Moreover, the photocatalytic degradation rate basically remained unchanged after five cycles, indicating the good stability of the prepared photocatalysts. In addition, a possible mechanism for the photodegradation process was proposed on the basis of the main intermediates detected by gas chromatography-mass spectrometer (GC-MS). This study may provide a promising approach for the polycyclic aromatic hydrocarbon degradation by waste utilization of agricultural biomass and increasing the photocatalytic performance of pure g-C3N4.

The rational design of a novel and environmentally friendly photocatalytic composite for persistent pollutant removal, energy production and catalytic applications have attracted widespread interest. In this study, the new composite composed of KOH-modified biochar and g-C3N4 with different morphologies was successfully prepared with facile supramolecular self-assembly and thermal poly-condensation method. The characterization results of the as-prepared composites suggested that KOH-modified biochar had been well combined with g-C3N4 with different morphologies. These synthesized catalysts were used to degrade phenanthrene under visible light radiation. A-BC/g-C3N4-D performed best and removed 76.72% phenanthrene. Its first-order reaction rate constant was 0.355 h-1, which was 3.7 times higher than that of g-C3N4. A-BC/g-C3N4-D still exhibited a high photocatalytic activity after four cycles. Radical quenching results showed that superoxide radical (·O2-), hydroxyl radical (·OH) and hole (h+) could be used as active species in the redox reaction with phenanthrene. Based on the exploration results of gas chromatography-mass spectrometer (GC-MS), a possible reaction pathway of phenanthrene degradation was also proposed. This study provides a novel strategy for fabricating various high-performance photocatalysts and the removal of persistent organic pollutants.

Three triphenylamine (TPA) substituted cyclometalated Ir(III) complexes IrA1, IrA2, and IrA3 based on Ir(ppy)3 were synthesized and applied as phosphorescent probes for the monitoring of molecular oxygen. The phosphorescence intensity of all the Ir(III) complexes in tetrahydrofuran (THF) was gradually quenched with an increase of oxygen concentration. The increase of TPA substituents on the meta-position of 2-phenylpyridine (IrA1-IrA3) gradually improved the oxygen sensitivity of cyclometalated Ir(III) complexes. IrA3 showed the highest oxygen sensitivity in THF with a KappSV of 204.8 bar−1 and a limit of detection (LOD) of 0.27 mbar. The relationship between molecular structure and the collision radiuses (σ) of all the Ir(III) complexes has been investigated on the basis of the Demas model and the fundamental expression of luminescence quenching systems by oxygen. The ratio of collision radiuses are σIrA1/σIr(ppy)3 = 1.27 ± 0.05, σIrA2/σIr(ppy)3 = 1.72 ± 0.10, and σIrA3/σIr(ppy)3 = 2.13 ± 0.07, respectively. The introduction and increase of TPA substituents can obviously increase the collision radiuses of cyclometalated Ir(III) complexes which leading to potential oxygen sensitivity. And the incremental effect of collision radiuses caused by the introduction of TPA substituents resulted in outstanding oxygen sensitivity of IrA3. The results demonstrate for the first time evidence between molecular structure and oxygen sensitivity of the emitters for optical sensing.

There are large amounts of dissolved organic matter (DOM) released into the soil during spring thaw, but its bioavailability and components are still unknown. The quantity, composition and stability of DOM in water extracts of forest soils during thaw were studied after two-month freezing with 9 levels of soil moisture ranging from 10% to 90% water-filled pore space (WFPS), by measuring soil carbon dioxide (CO2) flux, biodegradable dissolved organic carbon (BDOC) and nitrogen (BDON), ultraviolet absorbance and parallel factor analysis of fluorescence excitation-emission matrices. Concentrations of BDOC, BDON, DOC and DON were lowest around 30% WFPS and relatively higher and lower soil moisture both increased DOM and BDOM concentrations in thawing soil. With increasing WFPS, the dominant component of soil DOM changed from humic acid-like substances to fulvic acid-like substances and the biological origin of DOM increased gradually. The protein-like component accounted for 8–20% of soil DOM and was affected by vegetation type and WFPS singly and interactively. The results implied that forest soils with more than 50% WFPS before winter freezing could release large amounts of fulvic acid-like DOM, which would be easily biodegraded and emitted as CO2 or run off with ground water during spring snow thaw.

The aim of this study was to determine the remediation efficiency of petroleum-contaminated soil from an oilfield using different types of remediation treatments under laboratory conditions. Compared with unamended soil as the control treatment (T1), soil samples were amended with bulrush straw powder (T2), with biochar alone (T3) and in combination with nutrients (nitrogen and phosphorus) (T4). The remediation experiment was carried out for 8 weeks. The extent of hydrocarbon degradation was monitored gravimetrically, and the residual oil fractions were analyzed by gas chromatography. The characteristics of the polluted soil (water-holding capacity and nutrients) were improved significantly by biochar addition (p

The degradation performance of organic matters and microorganism abundance variations of two horizontal subsurface flow constructed wetlands (HSSFCWs) with different influent COD/N ratios and a spray aeration system were investigated. Oxygen-enriched influent water was beneficial to enhance the abilities of nitrification and biodegradation of organic matters. Due to the sufficient carbon source supply under influent COD/N ratio of 8.0, the high removal performances of COD (93%), NH4-N (85%) and total nitrogen (78%) were simultaneously obtained in HSSFCWs with a spray aeration system. The increase in nitrite and nitrate bacteria was beneficial to complete nitrification and improve NH4-N removal. The increase in denitrifying bacteria contributed to complete denitrification and guaranteed the high removal efficiency of NO3-N. The results suggested that the spray aeration combined with high influent COD/N ratios could achieve the high nitrogen removal in HSSFCWs.

Three Ir(III) complexes IrC1, IrC2, and IrC3 substituted with 4-(diphenylamino)phenyl (TPA), 4-(9H-carbazol-9-yl)phenyl (Cz1), and 9-phenyl-9H-carbazol-3-yl (Cz2) moieties were prepared and fully characterized as phosphorescent emitters. In comparison with Ir(ppy)3, introduction of TPA, Cz1, and Cz2 moieties strongly improved the oxygen sensitivities of IrC1–IrC3. Short-decayed IrC1 with I0/I100 of 168.6 and KappSV of 202.2 bar−1 in THF exhibited the highest sensitivity for oxygen. TPA and Cz moieties caused remarkable collision radius variations of the Ir(III) complexes with 2.13 ± 0.08 for σIrC1/σIr(ppy)3, 1.24 ± 0.06 for σIrC2/σIr(ppy)3, and 1.54 ± 0.08 for σIrC3/σIr(ppy)3. For demonstrating the dependence of oxygen sensitivity on the molecular structure of the oxygen-sensitive probes (OSPs), the delocalization of spin populations (DSPs) has been applied for the first time to confirm the collision radius variations of Ir(III) complexes. Remarkable DSPs were found on the TPA, Cz1, and Cz2 moieties with the spin population (percentage of the spin population) of 0.23210 (11.61%), 0.08862 (4.43%), and 0.13201 (6.60%), respectively. And strong linear correlations (R2 = 0.997) between the collision radius variations and spin population on TPA and Cz moieties were apparent. The DSPs could be used to describe the dependence of oxygen sensitivity on the molecular structure of the OSPs. For achieving real-time oxygen sensing, the photostability, oxygen sensing performance, and operational stability of IrC1–IrC3 and Ir(ppy)3 immobilized in ethyl cellulose (EC) were investigated. The IrC1-EC film demonstrated outstanding photostability after 60 min of irradiation and excellent operational stability for continuous oxygen monitoring with no attenuation of the original emission intensity in 4000 s. This study quantified and analyzed the dependence of oxygen sensitivity on the molecular structure of Ir(III) complexes for the first time and illustrated a feasible approach to achieve high-efficiency sensors for real-time monitoring of oxygen.

Honeycombed iron doped graphitic carbon nitride with outstanding N 2 photofixation ability is synthesized in this work. Characterization results indicate that Fe 3+ inserts at the interstitial position and is stabilized in the electron-rich g-C 3 N 4 through the coordinative Fe-N bonds. Fe 3+ sites can chemisorb and activate N 2 molecules, then transfer the photogenerated electrons from the g-C 3 N 4 to adsorbed N 2 molecules. Fe0.05-CN displays the highest NH 4 + generation rate, which is approximately 13.5-fold higher than that of neat g-C 3 N 4 . Density functional theory simulations prove the N 2 activation effect of Fe 3+ sites due to the high adsorption energy and prolonged N N bond. Charge density difference result confirms the electrons transfer process from the Fe 3+ doping sites to N 2 molecule. DOS results indicate that the electrons of σ g 2p orbital (HOMO) in nitrogen atom is delocalized significantly when N 2 adsorbed on Fe 3+ doping sites, leading to its orbital energy almost connects to that of π g * 2p orbital (LUMO), which confirming that Fe 3+ doping sites can activate the N 2 molecule effectively. The Mulliken charge of nitrogen is −3.1 when the N 2 adsorbed on Fe 3+ doping sites, indicating that N 2 molecule is enriched by large number of electrons, which is beneficial to the H + attack to form NH 4 + .

Nitrogen fixation is the second most important chemical process in nature next to photosynthesis. Herein, we report a novel g-C3N4/ZnSnCdS heterojunction photocatalyst prepared using the hydrothermal method that has an outstanding nitrogen photofixation ability under visible light. The as-prepared ZnSnCdS is the ternary metal sulfide Zn0.11Sn0.12Cd0.88S1.12 with many sulfur vacancies, not a mixture of ZnS, SnS2, and CdS. Strong electronic coupling, as evidenced by the ultraviolet–visible, X-ray photoelectron spectroscopy, photoluminescence, and electrochemical impedance spectra results, exists between two components in the g-C3N4/ZnSnCdS heterojunction photocatalysts, leading to more effective separation of photogenerated electron–hole pairs and faster interfacial charge transfer. The sulfur vacancies on ternary metal sulfide not only serve as active sites to adsorb and activate N2 molecules but also promote interfacial charge transfer from ZnSnCdS to N2 molecules, thus significantly improving the nitroge...

River ecosystem health assessments provide the foundation for river ecological protection and integrated management. To evaluate the aquatic ecosystem health of the Fan River basin, benthic macroinvertebrate indices (the Multimeric Macroinvertebrates Index Flanders (MMIF) and Family Biotic Index (FBI)), a habitat index (the river habitat quality Index (RHQI)) and a water quality index (the Improved Water Pollution Index (IWPI)) were selected. The entropy weighting method was used to calculate the RHQI and IWPI. A fuzzy comprehensive evaluation method was used to evaluate the aquatic ecosystem health. The evaluation results indicated that the aquatic ecosystem health of the Fan River basin was better in 2018 than in 2011, which respectively belonged to the ends of the 11th and 12th Five-Year Plans of the Major Science and Technology Programs for Water Pollution Control and Treatment in China. The proportions of sampling stations with good, moderate and poor grades in 2011 were 50.0%, 40.0% and 10.0%, respectively, and in 2018, the proportions of stations with excellent, good and moderate grades were 20.0%, 50.0% and 30.0%, respectively. A correlation analysis showed that the RHQI was significantly correlated with the MMIF, FBI and IWPI. The riparian land use pattern was an important factor that influenced changes in the aquatic ecosystem health grade. Of the water quality parameters, total phosphorous (TP) and potassium bichromate index (COD) were the main factors that affected the characteristics of benthic macroinvertebrates and the aquatic ecosystem health.

To understand the relative importance of plant community composition and plant-induced soil properties on N transformations, the soil N mineralization, ammonification and nitrification characteristics of natural secondary forests (Quercus mongolica-Juglans mandshurica forest: QJF, and Quercus mongolica-Populus davidiana forest: QPF) and the adjacent larch plantations (Larix kaempferi forest: LF1 and LF2) were studied during the growing season. All of the forest types showed seasonal dynamics of N mineralization rates. The total cumulative N mineralization was significantly higher in QPF (73.51 kg hm&minus, 2) than in LF1 (65.64 kg hm&minus, 2) and LF2 (67.51 kg hm&minus, 2) (p &lt, 0.05). The total cumulative nitrification from May to November was significantly higher in QJF (65.16 kg hm&minus, 2) and QPF (64.87 kg hm&minus, 2) than in LF1 (52.62 kg hm&minus, 2) and FL2 (54.17 kg hm&minus, 0.05). Based on the variation partitioning, independent soil properties were the primary determinants of the N transformations (13.5%). Independent climate conditions explained 5.6% of the variations, while plant variations explained 3.2% of the variations in N transformations. We concluded that different forest types with various plant community compositions have different influences on the litterfall quantity and quality and the nutrient availability, and these differences interact with seasonal climate conditions that in turn drive the differences in N mineralization.

A novel ternary metal sulfide photocatalyst Mo0.1Ni0.1Cd0.8S was prepared for photofixation of atmospheric nitrogen to ammonia under visible light. Characterization results indicate that the obtained catalyst is Mo and Ni co-doped CdS with many sulfur vacancies, not a mixture of MoS2, NiS and CdS. The sulfur vacancies on Mo0.1Ni0.1Cd0.8S not only serve as active sites to adsorb and activate N2 molecules but also promote interfacial charge transfer from Mo0.1Ni0.1Cd0.8S to N2 molecules, thus significantly improving the nitrogen photofixation ability. The concentration of sulfur vacancies plays a significantly important role in the N2 photofixation ability. A possible mechanism was proposed.

To improve the efficiency of the existing plant for refractory petrochemical dry-spun acrylic fiber (DAF) wastewater treatment, a pilot-scale hybrid anoxic/oxic-membrane bioreactor (A/O-MBR) system with multi-cell section was designed and tested. The operation parameters, alkalinity and carbon source demands in nitrification/denitrification and removal performance of typical pollutants were investigated, and the results were compared with those from the existing wastewater treatment plant (WWTP) of DAF factory. It showed that at hydraulic retention time >32 h, recycle ratio of 80 % and pH 7.2–7.8 in nitrification stage, the average removal efficiency of COD, NH4 +–N and TN in the hybrid A/O-MBR could reach 56.5, 86.6 and 45.9 %, respectively, which had been significantly higher than those of the existing WWTP. The deficiency of alkalinities and carbon sources hindered further nitrogen removal; therefore, Na2CO3 and NaAc were supplemented to improve the performance of nitrification and denitrification, and the recycle ratio was optimized from 80 to 200 %. Then, under the conditions of 200 % recycle ratio, 97.8–148.5 mg/L of alkalinity addition to oxic tank and 107.4–149.6 mg/L of carbon source addition to anoxic tank, the nitrification and denitrification performance in the hybrid A/O-MBR was clearly enhanced, and the NH4 +–N and TN removal efficiency could be improved from 64.3 and 45.9 to 86.9 and 60.5 %, respectively. Meanwhile, the removal efficiency of typical pollutants SO3 2−, CN−, AN, DMF, BOD and TOC reached 99.3, 91.3, 100, 100, 92.5 and 53.5 %, respectively. Compared with the existing WWPT, the tested hybrid A/O-MBR process had a better treatment performance for nitrification and denitrification, and the effluent could meet the Grade I requirements of the National Discharge Standard of Acrylic Fiber Industry.

Estimating regional nutrient criteria for streams and rivers is a key step toward protecting river water quality and restoring the health of aquatic ecosystems. Using a multivariable statistical analysis technique, nutrients were identified as the main factor influencing the degradation of the benthic macroinvertebrate community. Three chemical methods (the reference stream distribution approach, all-streams distribution approach and Y-intercept approach) and one biological method (the stress-response approach) were applied to evaluate the nutrient thresholds in the Qing River basin. The reference stream distribution approach and all-streams distribution approach were based on calculating a predetermined percentile of reference streams and all-streams water quality data set, respectively. The Y-intercept approach was based on determining the influence of human activity on water quality by linear regression models. The biological method was based on the response of the benthic macroinvertebrate community structure to changes in water quality. The chemical thresholds were 0.750–1.288 mg/L for total nitrogen (TN) and 0.035–0.046 mg/L for total phosphorus (TP); the biological thresholds were 1.050–1.655 for TN and 0.052–0.101 for TP. The results from the chemical approaches were verified using the biological method, resulting in preliminarily recommended thresholds of 1.000 mg/L TN and 0.040 mg/L TP in the Qing River system.

Direct hydroxylation of benzene to phenol using molecular oxygen is a green route with high atom economy but still a great challenge when compared with the existing method of production. The activation of oxygen is necessary and reductive agents were used to activate dioxygen in a so-called “reductive activation” process. Here, nano vanadium oxides that consist mainly of low valence vanadium to activate dioxygen were prepared under different conditions via a hydrothermal method. Under the optimized conditions, an excellent phenol selectivity of 96.3% with benzene conversion of 4.2% was achieved over the VOC2O4–N-5 without reductive agents. Characterizations revealed that VOC2O4–N-5 was composed of a mesoporous nanosphere structure with medium strong acid sites and low valence vanadium species. A mechanism was proposed as follows: dioxygen was activated by low valence vanadium in VOC2O4–N-5 to produce the active oxygen species which oxidized acetic acid to peracetic acid. Then the active oxygen species was subsequently transferred from peracetic acid to benzene and inserted into the C–H bond to give phenol.

In heterojunction catalysts, the potential difference is the main driving force for efficient charge separation and transfer. The slight difference in the electronic band structure of the isotype heterojunction catalysts causes a poor driving force, leading to a dissatisfactory charge separation efficiency. In this work, g-C3N4/S-g-C3N4 metal-free isotype heterojunction catalysts (GCN–SCN) with an enhanced charge driving force were prepared by a two step calcination method. Anoxic photocatalytic degradation of RhB under visible light was used to evaluate the performance of the as-prepared g-C3N4 catalysts. The results indicate that this two step calcination method can markedly improve the charge driving force of the as-prepared isotype heterojunctions, leading to a more efficient charge-carrier migration. GCN–SCN displays the highest reaction rate constant of 0.0228 min−1, which is 3.5 and 2.9 times higher than that of GCN/SCN(1) and GCN/SCN(2) prepared by a one step calcination method. A linear relationship is observed between the VB driving force and RhB degradation rate. This paper provides a new perspective to prepare isotype heterojunctions with an improved charge driving force and photocatalytic performance.

g-C 3 N 4 /WO 3 composites were prepared by three different methods: ultrasonic dispersion, calcination, and hydrothermal method. X-ray diffraction (XRD), UV–vis spectroscopy, nitrogen adsorption, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and Electrochemical impedance spectroscopy (EIS) were used to characterize the prepared catalysts. The results indicated that the preparation method significantly influenced the interaction between g-C 3 N 4 and WO 3 , leading to the obvious difference in separation rate of photogenerated electrons and holes. The activities were tested in photocatalytic Rhodamine B (RhB) degradation and H 2 production under visible light. The activities of g-C 3 N 4 /WO 3 composites were obviously higher than that of single g-C 3 N 4 or WO 3 . The composite prepared by the hydrothermal method exhibited the highest photocatalytic activity.

A series of visible light responsive Ni/NiO/N–TiO2−x heterojunction nanocomposites are prepared by nonthermal NH3 plasma treatment. X-ray diffraction, N2 adsorption, UV–Vis spectroscopy, Electrochemical impedance spectroscopy, Photoluminescence, and X-ray photoelectron spectroscopy are used to characterize the prepared nanocomposites. Ni species deposition decreases the surface free energy of nanocomposites, reduce the thermodynamic driving force for particle growth, thus leading to the smaller particle sizes. NH3 plasma treatment do not influence the crystal structure but shift its absorption edges to the visible light region, reduce partial NiO to metallic Ni, and form high concentration of oxygen vacancies. H2 production performances on prepared TiO2 nanocomposites are evaluated under visible light irradiation using CH3OH as scavenger. The results indicate that Ni0/Ni2+ ratio plays a significantly important role on the photocatalytic H2 production ability. Adequate oxygen vacancies concentration can improve the visible light utilization, leading to an enhanced photocatalytic performance. The prepared R–Ni(0.03)N(10)Ti exhibited the highest H2 production ability (1210 μmol h−1) and apparent quantum yield (7.5%), which is 250 times higher than that of neat TiO2. The possible mechanism is proposed.

Phosphorus doped g-C3N4 was prepared by a simple method using dicyandiamide monomer and diammonium hydrogen phosphate as precursors. X-ray diffraction (XRD), UV-Vis spectroscopy, Fourier transform infrared spectra (FT-IR), photoluminescence (PL), X-ray photoelectron spectroscopy (XPS) and photocurrent measurement were used to characterize the prepared catalysts. The results indicated that the introduction of phosphorus inhibited the crystal growth of graphitic carbon nitride, decreased the band gap energy and increased the separation efficiency of photogenerated electrons and holes. The P doping site is influenced by the phosphorus source. Interstitial P doping is more effective in improving the photocatalytic activity of Rhodamine B (RhB) degradation compared with substitutional P doping. A possible mechanism was proposed.

The effect of H 2 –CCl 4 mixture plasma treatment on TiO 2 photocatalytic oxidation of aromatic air contaminants under both UV and visible light was reported. X-ray diffraction (XRD), UV–Vis spectroscopy, photoluminescence (PL), Temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared TiO 2 nanoparticles. Carbon atoms were doped into TiO 2 by replacing titanium atoms whereas chlorine located on TiO 2 surface to form Ti–Cl bond via the coordination with Ti 4+ sites by plasma treatment. The carbon doping amount and surface chlorine content of TiO 2 under H 2 –CCl 4 mixture plasma treatment were obviously higher than that under single CCl 4 plasma treatment. H 2 –CCl 4 mixture plasma treated catalyst exhibited much higher photocatalytic oxidation performances of benzene and toluene than that of single CCl 4 plasma treated catalyst and P25 under both UV and visible light. Chlorine radicals formed under illumination are effective in oxidizing aromatic side groups, but ineffective in reactions with the aromatic ring, thus benzene conversions were lower than that of toluene under both UV and visible light. The possible mechanism was proposed.

and GR have many similar structure and electronicproperties in common. Therefore, it is reasonable to raise afundamental question: are they similar in promoting thephotocatalytic performance of semiconductors when we usethem to assemble carbon-semiconductor composite photo-catalysts? In this work, the CNT, C

A convenient N 2 –CCl 4 mixture plasma treatment to improve TiO 2 photocatalytic oxidation of aromatic air contaminants under both UV and visible light was reported. X-ray diffraction (XRD), N 2 adsorption, UV–vis spectroscopy, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared TiO 2 catalysts. The microstructures of the TiO 2 catalysts were preserved after plasma treatments. Chlorine ions did not doped into TiO 2 lattice but located on TiO 2 surface via the coordination with Ti 4+ sites. The doping N content of prepared TiO 2 catalyst increased obviously by using this N 2 –CCl 4 mixture plasma method. The activities were tested in the photocatalytic oxidation of benzene and toluene under both UV and visible light. Chlorine radicals which formed under illumination are effective in oxidizing aromatic side groups, but ineffective in reactions with the aromatic ring.

The dihydroxy naphthalene/ complexes with different substitution patterns were prepared by surface modification. X-ray diffraction, UV-Vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared composite materials. The results indicated that the surface modification did not influence the crystallization of . The visible-light absorbances of prepared dihydroxy naphthalene/ complexes could be assigned to the ligand-to-metal charge transfer. The obtained catalyst exhibited outstanding photocatalytic activity and stability under visible light. A linear relationship existed between the percentages of hydroxynaphthalenes coordinated on surface and production ability. The substitution pattern of dihydroxy naphthalene and content could also influence the photocatalytic performance remarkably. The photocatalytic production ability was further improved after loading with ultra low concentration of Pt, 0.02 wt %. The possible mechanism was proposed.

Stormwater draining from impervious surfaces in urban areas often contains readily soluble salts in runoff, which contribute dramatically to the degradation of aquatic ecosystem. The concentrations of potassium (K), cadmium (Ca), sodium (Na), magnesium (Mg), chloride (Cl) and sulfate (SO42-) in stormwater runoff in the urban areas of Shenyang city were measured in 4 rainfall events during July 2009 to June 2010. The results showed that there was an obvious increasing of salt ions concentrations in stormwater runoff samples, especially Na and Cl. It is also found that readily soluble salts ions in stormwater runoff peaked at the first storm event after winter. This study demonstrated that the applied deicing salts in winter significantly contributed to the increasing concentrations of K, Ca, Na, Mg, Cl, and SO42- in urban stormwater runoff. It is evident that the application of deicing salts in cold regions of China every year has had adverse impacts on the aquatic ecology through stormwater runoff.

The negative effect of deicing salt on surface water have been reported by a number of studies, but there is a lack of knowledge about the effects of deicing salt on the growth behavior and the change of biochemical composition of algal Chlorella vulgaris (C. vulgaris). Algal were cultured at different concentration of deicing salt, algal cell densities, chlorophyll (a), protein and polysaccharides contents were measured. The results of this work showed that deicing salt had statistically significant inhibitory effects (P

A novel ternary metal sulfide photocatalyst Mo0.1Ni0.1Cd0.8S was prepared for photofixation of atmospheric nitrogen to ammonia under visible light. Characterization results indicate that the obtained catalyst is Mo and Ni co-doped CdS with many sulfur vacancies, not a mixture of MoS2, NiS and CdS. The sulfur vacancies on Mo0.1Ni0.1Cd0.8S not only serve as active sites to adsorb and activate N2 molecules but also promote interfacial charge transfer from Mo0.1Ni0.1Cd0.8S to N2 molecules, thus significantly improving the nitrogen photofixation ability. The concentration of sulfur vacancies plays a significantly important role in the N2 photofixation ability. A possible mechanism was proposed.

The composite photocatalyst, N-TiO2 loaded with Ni2O3, was prepared by N2 plasma treatment. X-ray diffraction, X-ray fluorescence, N2 adsorption, UV-vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared TiO2 samples. The results indicated that the band gap energy was decreased obviously by nitrogen doping, whereas loading of Ni2O3 did not influence the band gap and visible light absorption. The photocatalytic activities were tested in the degradation of 2,4,6trichlorophenol (TCP) under visible light. The photocatalytic activity and stability of composite photocatalyst were much higher than that of catalyst modified with nitrogen or Ni2O3 alone. The synergistic effect of doping nitrogen and Ni2O3 over TiO2 was investigated.

Ag deposited N-TiO2 composite nanoparticles were prepared via NH3 plasma treatment. X-ray diffraction, UVvis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared TiO2 samples. The plasma treatment did not change the phase composition and particle sizes of TiO2 samples, but extended its absorption edges to the visible light region. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activities of Ag deposited N-TiO2 composite nanoparticles were much higher than Ag-TiO2, NTiO2, and P25. A possible mechanism for the photocatalysis was proposed.

coated composite materials with enhanced photocatalytic activity under UV light was prepared by a simple catalytic hydrolysis method. XRD, TEM, UV-vis spectroscopy, Photoluminescence, FT-IR and XP spectra were used to characterize the prepared samples. The obvious shell-core structure was shown for obtained @ sample. The average thickness of the coating layer was 2-3 nm. The interaction between and restrained the recombination of excited electrons and holes. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under UV light. The photocatalytic activity of @ was much higher than that of P25 and mechanical mixing sample . The possible mechanism for the photocatalysis was proposed.

A visible light responsive N, Mo co-doped were prepared by sol-gel method. X-ray diffraction, TEM, adsorption, UV-vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared samples. Doping restrained the phase transformation from anatase to rutile and reduced the particle sizes. The band gap was much narrowed after N, Mo co-doping. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activities of doped were much higher than that of neat . The photocatalytic stability of N, Mo co-doped was much better than that of N doped .

A modified sol-gel method and -plasma treatment were used to prepare bulk and surface doped N-, respectively. XRD, TEM, UV-vis spectroscopy, adsorption, Elemental Analyzer, Photoluminescence, and XP spectra were used to characterize the prepared samples. The N doping did not change the phase composition and particle sizes of samples, but increased the visible light absorption. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activity of surface doped N- prepared by -plasma was much higher than that of bulk doped N- prepared by sol-gel method. The possible mechanism for the photocatalysis was proposed.

A visible light responsive N-doped TiO 2 was prepared via a reduction–nitridation procedure by nonthermal plasma treatment. X-ray diffraction, N 2 adsorption, UV–vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared TiO 2 samples. The plasma treatment did not change the phase composition and particle sizes of TiO 2 samples, but extended its absorption edges to the visible light region. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activities of TiO 2 prepared by reduction–nitridation procedure were much higher than that of samples prepared by simple nitridation treatment. The enhanced activity was ascribed to the substitutional N-doping and appropriate concentration of oxygen vacancies. TOHN10 prepared by reduction–nitridation procedure exhibited excellent photocatalytic stability. A possible mechanism for the photocatalysis was proposed.

Titanium dioxide (TiO2) nanoparticles co-doped with N and Fe were prepared via modified sol–gel process. The products were characterized by transmission electron microscopy (TEM), N2 adsorption, X-ray diffraction (XRD), Raman spectroscopy, UV–vis spectroscopy, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS). It is shown that the prepared TiO2 particles were less than 10 nm with narrow particle size distribution. The addition of MCM-41 caused the formation of Ti–O–Si bond which fixed the TiO2 on MCM-41 surface, thus restricted the agglomeration and growth of TiO2 particles. The photocatalytic performance in the degradation of methylene blue showed that N, Fe co-doped TiO2 exhibited much higher photocatalytic activity than doped sample with nitrogen or Fe3+ alone under both UV and visible light. N, Fe co-doping decreased the loss of doping N during the degradation reaction, thus increased the photocatalytic stability. It was also found that the nitridation time had significant influence on the photocatalytic activity of prepared TiO2 catalysts.

Heavy metal pollution of soils has become a major concern in China as a consequence of rapid urbanization and industrialization in recent years. However, the evaluation on soil heavy metal pollution in Shenyang, the largest heavy industrial base city in China, has not yet been conducted. In this study, accumulation, chemical speciation, and vertical distribution Cu, Zn, Pb and Cd in soils were studied and pollution condition was assessed in Tiexi Industrial District of Shenyang, the largest and oldest industrial zone in Northeastern China. The results showed that in topsoil, the average concentration of total Cu, Zn, Pb, and Cd was 209.06, 599.92, 470.19 and 8.59 mg kg−1, respectively, much higher than the national threshold limit. The values of pollution index and integrated pollution index showed that the pollution level was Cd > Cu > Zn > Pb, and Cd, Cu and Zn belong to heavy pollution level. The residual, Fe and Mn oxide-bound, and organic-bound species accounted for about 90%, while carbonate-bound and exchangeable species accounted for about 10%. This study indicates that the soils in the industrial zone were widely and extremely polluted by multi-heavy metals as a result of long-term industrial activities.

Nitrogen fixation is the second most important chemical process in nature, next to photosynthesis. Herein, we report a novel g-C3N4/ZnMoCdS heterojunction photocatalyst with outstanding nitrogen photofixation ability under visible light prepared by hydrothermal post-treatment. The as-prepared ZnMoCdS is the ternary metal sulfide Zn(0.12)Mo(0.12)Cd(0.9)S(1.14) with many sulfur vacancies, not a mixture of ZnS, MoS2 and CdS. Strong electronic coupling, as evidenced by the UV-Vis, XPS and EIS results, exists between two components in g-C3N4/ZnMoCdS heterojunction photocatalysts, leading to more effective separation of photogenerated electron-hole pairs and faster interfacial charge transfer. The sulfur vacancies on ternary metal sulfides not only serve as active sites to adsorb and activate N2 molecules but also promote interfacial charge transfer from the catalyst to N2 molecules, thus significantly improving their nitrogen photofixation ability. With an optimal ZnMoCdS mass percentage of 80%, the as-prepared heterojunction photocatalyst exhibits the highest NH4(+) generation rate under visible light, which is 13.5-fold and 1.75-fold greater than those of individual g-C3N4 and ZnMoCdS, respectively.

Extending the application of photocatalytic oxidation technology to the anoxic removal of organic pollutants that exist under some oxygen-free conditions is attractive but challenging. In this study, oxygen functionalized S–P codoped g-C3N4 nanorods with outstanding visible light activity under anoxic conditions are synthesized using a hydrothermal post-treatment. S and P codoping inhibits the crystal growth of graphitic carbon nitride, enhances the SBET, decreases the band gap energy, and increases the separation efficiency of photogenerated electrons and holes, which increases the anoxic photocatalytic RhB degradation constant by approximately 6.5 times. Oxygen functionalization not only increases the adsorption ability of graphitic carbon nitride but also captures the photogenerated electrons to produce photogenerated holes for RhB degradation under anoxic conditions, leading to a doubling of the RhB degradation constant. This study provides new insight into the design and fabrication of anoxic photocatalysts.

An experiment with a D-optimum saturation design (D-312) of three factors (N, P fertilizers and irrigation water) and five levels was used to assess the combined effects of N, P fertilization and irrigation water on the grain yield of spring wheat grown in the semiarid area of West Liaoning province, P. R. China. Best-fit predictive model of spring wheat grain yield was constructed by simultaneously including these three factors. The effects of N, P fertilizers and irrigation water on spring wheat grain yield were highly statistically significant. Although a previous study in the same area had shown that water was the most important factor affecting spring wheat grain yield, principal factor analysis in this experimental case indicated that, under normal rainfall conditions when the amount of irrigation water ranged from 45 to 360 mm, N fertilizer was the most effective factor, while marginal effect analysis demonstrated that the spring wheat grain yield response to N, P fertilizers and irrigatio...

Expected changes in precipitation over large regions of the world under global climate change will have profound effects on terrestrial ecosystems in arid and semiarid regions. To explore how changes in the amount of precipitation in the growing season would affect soil nitrogen (N) availability in a semiarid ecosystem, we established rainout shelters and irrigation systems by simulating 30% reduced (DRY) and 30% increased precipitation (WET) relative to natural precipitation (Control) to measure some key soil process properties for two growing seasons in a nutrient-poor Mongolian pine (P. sylvestris var. mongolica) plantation. Both WET and DRY treatments significantly affected monthly soil inorganic nitrogen concentrations, which showed a higher inorganic N under DRY than Control in each month and lower in WET than Control. Monthly soil microbial biomass N content was reduced by DRY and raised by WET treatments. The results indicated the asynchrony of the availability of soil moisture and soil nutrients in Mongolian pine plantations at the Horqin Sandy Lands in Northeast China. Water limited plant growth in Mongolian pine plantations when precipitation decreased, and nitrogen limitation became increasingly important when precipitation increased. Accumulation of N in microbial biomass is an important mechanism for N cycling in this ecosystem. To effectively manage Mongolian pine plantations, it is advised that evapotranspiration is minimized when precipitation decreases and that there is an increase in soil N availability by protecting litterfall when precipitation increases.

Band gap-tunable potassium doped graphitic carbon nitride with enhanced mineralization ability was prepared using dicyandiamide monomer and potassium hydrate as precursors. X-ray diffraction (XRD), N2 adsorption, UV-Vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared catalysts. The CB and VB potentials of graphitic carbon nitride could be tuned from −1.09 and +1.56 eV to −0.31 and +2.21 eV by controlling the K concentration. Besides, the addition of potassium inhibited the crystal growth of graphitic carbon nitride, enhanced the surface area and increased the separation rate for photogenerated electrons and holes. The visible-light-driven Rhodamine B (RhB) photodegradation and mineralization performances were significantly improved after potassium doping. A possible influence mechanism of the potassium concentration on the photocatalytic performance was proposed.