Energy-transfer-mediated oxygen activation in carbonyl functionalized carbon nitride nanosheets for high-efficient photocatalytic water disinfection and organic pollutants degradation.

Polymeric photocatalysts are promising candidates for water purification, however their catalytic performance are still unsatisfactory due to the fast charge recombination that leads to low reactive oxygen radicals production. In this study, a conceptual energy-transfer-mediated photocatalytic oxygen activation system over polymeric carbon nitride without the need of electron-hole separation is proposed, exhibiting remarkable singlet oxygen triggered bacteria inactivation performance as well as organic pollutants degradation. By structure and excitonic effect modulation, the oxygen activation process changes from the traditional electron-transfer mechanism to the final energy-transfer pathway, leading to the selective generation of singlet oxygen with high efficiency. The generated singlet oxygen is found to fervently attack the bacteria membrane, creating irreparable pores or holes on the cell membrane for cytoplasmic contents leaking out to accelerate bacteria destruction. The work demonstrated here offers a new photocatalytic oxygen activation pathway for achieving high-efficient reactive oxygen species generation performance without the need of charge separation.

Efficient electrochemical reduction of nitrobenzene by nitrogen doped porous carbon.

Electrochemical reduction process is a promising method for wastewater treatment, and its performance is determined by cathode material. Nitrogen doped carbon is a kind of favorable cathode material for electrochemical reduction, but deep understanding for the effect of nitrogen concentration and reduction pathway is still needed. In this paper, nitrogen doped porous carbon (NPC) with different nitrogen concentration were fabricated by directly carbonization of ZIF-8 under various temperatures. The electrochemical reduction performance of NPCs was evaluated by reducing nitrobenzene (NB), and the effects of nitrogen concentration were discussed. NPC with 22.7% nitrogen concentration exhibited the best NB reduction performance with the NB removal constant about 1.0 h-1 under optimal conditions; the NB removal rate and aniline (AN) production on this NPC are 4.2 and 8.5 times higher than graphite electrode. Further H* quenching experiment indicates the NPC electrochemical reduction process mainly following an indirect hydrogenation reduction pathway. These results offer some insights into the electrochemical reduction process on nitrogen doped carbon, which may facilitate the design of efficient metal free carbon based catalyst for wastewater electrochemical pretreatment.

Evaluation on the risk controlling value of urban soil organic pollutants based on land-use planning in China.

Land left after urban industrial enterprises relocate is usually planned for various land-use types that can influence human health risks. In China, urban development consists of at least eight land uses: urban residential (UR), public administration/service (PA/S), commercial/service (C/S), industrial, logistics storage, transportation (TR), public utility, and park green space. The (PA/S) type has two classes: PA/S1 includes administrative, cultural relics and historic, foreign affairs, and religious facility lands, with adults the sensitive recipients. Class PA/S2 includes lands related to cultural facilities, education and scientific research, sports, medical, and social welfare facilities, in which children are the sensitive recipients. The UR type has UR 1 and UR 2 classes with and without underground space, respectively. The C/S type has C/S1 and C/S2 classes with and without underground space, respectively. The TR type has TR1, TR2, and TR3 classes which indicate urban road, subway, and traffic hub land, respectively. To the above, we applied conceptual models and exposure pathways of volatile organic compounds and semi-volatile organic compounds. Exposure parameters were investigated for six regions and above eight land uses featuring different soil, climate, and population behavior characteristics: north, east, south, northwest, northeast, and southwest (covering China entirely). Risk controlling values (RCVs) corresponding to a lifetime cancer risk of 10-6 in this paper were calculated using the C-GAC model introduced by 'Chinese Technical Guidelines for Risk Assessment of Contaminated Sites' with above exposure parameters to determine whether it has potentially significant levels of contamination that may warrant further investigation. Our results revealed two main patterns: (1) our soil risk controlling values for the six regions-north, east, south, northwest, northeast, and southwest-revealed some between-region variability (up to 28%). Hence, for urban contaminated sites in different regions of China, different RCVs should be considered when evaluating possible health risks. (2) The results for the organic pollutants tested across the eight types of land use showed maximum values up to 90 times the minimum value. The greater the risk controlling value of the same pollutant, the less sensitive the site is to that pollutant. Urban road land, traffic hub land, and park green space land are not sensitive to volatile organic pollutants.

Climatic burden of eating at home against away-from-home: A novel Bayesian Belief Network model for the mechanism of eating-out in urban China.

Dietary patterns of eating away-from-home (AFH) considerably differ from those of eating at home in urban China, thus generating varied carbon footprints. However, few studies have investigated the effect of eating places on diet-related climatic burden, and few have modelled the mechanism under the condition of eating-out because the decision of consumers on whether to eat AFH or at home is determined by multiple non-linear socioeconomic factors. Here, we compared the carbon footprints of eating at home and AFH using household survey data from 12 Chinese provinces, and developed a Bayesian Belief Network (BBN) model to identify key factors of eating AFH. Our findings show that eating AFH leads to higher climatic burdens though respondents consume less food on average than when eating at home. However, in urban areas, the carbon footprint generated increases more rapidly from eating at-home than when eating AFH. The BBN model was found to have strong capability to predict the possibility of eating out with an accuracy of 89%. Although diet patterns and embedded carbon footprint vary considerably across provinces from northeastern to southwestern China, sufficient evidence could not be found to support the influence of geographic factors on the decision of respondents to eat AFH at large scale. Instead, individual occupation and income were found to be the two key contributors. Thus, merely estimating the carbon footprint of food consumption is currently not sufficient, but social and economic elements need to be quantitatively considered to differentiate the eating-place effect on diet-related climatic burden.

Achieving efficient nitrogen removal and nutrient recovery from wastewater in a combining simultaneous partial nitrification, anammox and denitrification (SNAD) process with a photobioreactor (PBR) for biomass production and generated dissolved oxygen (DO) recycling.

This study presents a new way to achieve energy neutral wastewater treatment based on a combined nitrification, anammox, and denitrification (SNAD) process and photobioreactor (PBR) configuration with external recycling instead of aeration, and without an additional carbon source, using fixed-film-activated sludge technology (IFAS). The SNAD-PBR process achieved total nitrogen (TN) and phosphorus removal efficiencies of 90 and 100%, respectively. In addition, dissolved oxygen (DO) was controlled in the range 0.4-1.2 mg/L by the introduction of an external recycling system. The presence of microalgae to serve as a carbon source in the SNAD reactor enabled the denitrifiers to survive. When the reflux ratio was 1:3, the lower COD/N protected the activity of the anammox bacteria, not suppressed by the heterotrophic denitrifiers. Microbial community analysis by Illumina MiSeq sequencing revealed that the new environment was more suitable for Candidatus Brocadia when a reflux system was introduced.

Enhancing methane production from U. lactuca using combined anaerobically digested sludge (ADS) and rumen fluid pre-treatment and the effect on the solubilization of microbial community structures.

Methane production by the anaerobic digestion of seaweed is restricted by the slow degradation caused by the influence of the rigid algal cell wall. At the present time, there has been no study focusing on the anaerobic digestion of U. lactuca by co-fermentation and pre-treatment with rumen fluid. Rumen fluid can favor methane production from algal biomass by utilizing the diversity and quantity of bacterial and archaeal communities in the rumen fluid. This research presents a novel method based on combined ADS and rumen fluid pre-treatment to improve the production of methane from seaweed. Biochemical methane potential (BMP) tests were performed to investigate the biogas production using combined ADS and rumen fluid pre-treatment at varied inoculum ratios on the performance of methane production from U. lactuca biomass. Compared to the control (no rumen fluid pre-treatment), the highest BMP yields of U. lactuca increased from 3%, 27.5% and 39.5% to 31.1%, 73% and 85.6%, respectively, for three different types of treatment. Microbial community analysis revealed that the Methanobrevibacter species, known to accept electrons to form methane, were only detected when rumen fluid was added. Together with the significant increase in species of Methanoculleus, Methanospirillum and Methanosaeta, rumen fluid improved the fermentation and degradation of the microalgae biomass not only by pre-treatment to foster cell-wall degradation but also by relying on methane production within itself during anaerobic processes. Batch experiments further indicated that rumen fluid applied to the co-fermentation and pre-treatment could increase the economic value and hold promise for enhancing biogas production from different seaweed species.

Health risk assessment of an abandoned herbicide factory site for transportation use in Dalian, China.

An abandoned herbicide factory site was used as an example of how planning should be considered for development of the site for transportation use in Dalian, China. Exposure pathways and parameters for three types of transportation use (land for a traffic hub, land for an urban road, and land for a subway) were developed. Twenty-five sampling sites were selected and 38 soil samples were collected in March 2015. Hexachlorobenzene and benzo(a)pyrene which were extracted by Soxhlet extraction and detected by gas chromatography mass spectrometry were the most significant pollutants detected. The maximum concentration of the two pollutants in the surface layer (0-0.5 m) were 0.57 and 3.10 mg/kg, and in the bottom layer (1.0 m) were 2.57 and 3.72 mg/kg, respectively. In this study, risk assessment results based on the established exposure scenario and parameters showed that there was a significant difference in traffic hub land use under specific exposure pathway and common insensitive land use exposure pathways (direct ingestion of soil, dermal contact with soil, and inhalation of soil-derived dust). Commonly considered hexachlorobenzene and benzo(a)pyrene carcinogenic risk values exceeded the maximum acceptable level (10-6) and were found to be 23.9-fold and 189-fold higher than the carcinogenic risk values, respectively. Parameter sensitivity analysis data showed that for transportation use, the two parameters "EFOa" and "OSIRa" were the most significant factors associated with variation of the carcinogenic risk value. For traffic hub land use, urban road land use, and subway land use, the main exposure pathways were through "inhalation of soil vapors outdoors (from surface soil)," "direct ingestion of soil," and "inhalation of soil vapors indoors (from bottom soil)," which contributed 84.75, 73.00, and 100.00% to the total risk value, respectively.

Food consumption and waste and the embedded carbon, water and ecological footprints of households in China.

Strategies for reducing food waste and developing sustainable diets require information about the impacts of consumption behavior and waste generation on climatic, water, and land resources. We quantified the carbon, water, and ecological footprints of 17,110 family members of Chinese households, covering 1935 types of foods, by combining survey data with available life-cycle assessment data sets. We also summarized the patterns of both food consumption and waste generation and analyzed the factors influencing the observed trends. The average person wasted (consumed) 16 (415) kg of food at home annually, equivalent to 40 (1080) kg CO2e, 18 (673) m(3), and 173 (4956) gm(2) for the carbon, water and ecological footprints, respectively. The generation of food waste was highly correlated with consumption for various food groups. For example, vegetables, rice, and wheat were consumed the most and accounted for the most waste. In addition to the three plant-derived food groups, pork and aquatic products also contributed greatly to embedded footprints. The data obtained in this study could be used for assessing national food security or the carrying capacity of resources.

Assessing Major Accident Risks to Support Land-Use Planning Using a Severity-Vulnerability Combination Method: A Case Study in Dagushan Peninsula, China.

Major accident risks posed by chemical hazards have raised major social concerns in today's China. Land-use planning has been adopted by many countries as one of the essential elements for accident prevention. This article aims at proposing a method to assess major accident risks to support land-use planning in the vicinity of chemical installations. This method is based on the definition of risk by the Accidental Risk Assessment Methodology for IndustrieS (ARAMIS) project and it is an expansion application of severity and vulnerability assessment tools. The severity and vulnerability indexes from the ARAMIS methodology are employed to assess both the severity and vulnerability levels, respectively. A risk matrix is devised to support risk ranking and compatibility checking. The method consists of four main steps and is presented in geographical information-system-based maps. As an illustration, the proposed method is applied in Dagushan Peninsula, China. The case study indicated that the method could not only aid risk regulations on existing land-use planning, but also support future land-use planning by offering alternatives or influencing the plans at the development stage, and thus further enhance the roles and influence of land-use planning in the accident prevention activities in China.

Prediction of hydrolysis pathways and kinetics for antibiotics under environmental pH conditions: a quantum chemical study on cephradine.

Understanding hydrolysis pathways and kinetics of many antibiotics that have multiple hydrolyzable functional groups is important for their fate assessment. However, experimental determination of hydrolysis encounters difficulties due to time and cost restraint. We employed the density functional theory and transition state theory to predict the hydrolysis pathways and kinetics of cephradine, a model of cephalosporin with two hydrolyzable groups, two ionization states, two isomers and two nucleophilic attack directions. Results showed that the hydrolysis of cephradine at pH = 8.0 proceeds via opening of the ß-lactam ring followed by intramolecular amidation. The predicted rate constants at different pH conditions are of the same order of magnitude as the experimental values, and the predicted products are confirmed by experiment. This study identified a catalytic role of the carboxyl group in the hydrolysis, and implies that the carboxyl group also plays a catalytic role in the hydrolysis of other cephalosporin and penicillin antibiotics. This is a first attempt to quantum chemically predict hydrolysis of an antibiotic with complex pathways, and indicates that to predict hydrolysis products under the environmental pH conditions, the variation of the rate constants for different pathways with pH should be evaluated.

Potential of household environmental resources and practices in eliminating residual malaria transmission: a case study of Tanzania, Burundi, Malawi and Liberia.

BACKGROUND: The increasing protection gaps of insecticide-treated nets and indoor-residual spraying methods against malaria have led to an emergence of residual transmission in sub-Saharan Africa and thus, supplementary strategies to control mosquitoes are urgently required. OBJECTIVE: To assess household environmental resources and practices that increase or reduce malaria risk among children under-five years of age in order to identify those aspects that can be adopted to control residual transmission. METHODS: Household environmental resources, practices and malaria test results were extracted from Malaria Indicators Survey datasets for Tanzania, Burundi, Malawi and Liberia with 16,747 children from 11,469 households utilised in the analysis. Logistic regressions were performed to quantify the contribution of each factor to malaria occurrence. RESULTS: Cattle rearing reduced malaria risk between 26%-49% while rearing goats increased the risk between 26%-32%. All piped-water systems reduced malaria risk between 30%-87% (Tanzania), 48%-95% (Burundi), 67%-77% (Malawi) and 58%-73 (Liberia). Flush toilets reduced malaria risk between 47%-96%. Protected-wells increased malaria risk between 19%-44%. Interestingly, boreholes increased malaria risk between 19%-75%. Charcoal use reduced malaria risk between 11%-49%. CONCLUSION: Vector control options for tackling mosquitoes were revealed based on their risk levels. These included cattle rearing, installation of piped-water systems and flush toilets as well as use of smokeless fuels.

Fluorescent carbon nanoparticles for the fluorescent detection of metal ions.

Fluorescent carbon nanoparticles (F-CNPs) as a new kind of fluorescent nanoparticles, have recently attracted considerable research interest in a wide range of applications due to their low-cost and good biocompatibility. The fluorescent detection of metal ions is one of the most important applications. In this review, we first present the general detection mechanism of F-CNPs for the fluorescent detection of metal ions, including fluorescence turn-off, fluorescence turn-on, fluorescence resonance energy transfer (FRET) and ratiometric response. We then focus on the recent advances of F-CNPs in the fluorescent detection of metal ions, including Hg(2+), Cu(2+), Fe(3+), and other metal ions. Further, we discuss the research trends and future prospects of F-CNPs. We envision that more novel F-CNPs-based nanosensors with more accuracy and robustness will be widely used to assay and remove various metal ions, and there will be more practical applications in coming years.

Sustainable operation of submerged Anammox membrane bioreactor with recycling biogas sparging for alleviating membrane fouling.

A submerged anaerobic ammonium oxidizing (Anammox) membrane bioreactor with recycling biogas sparging for alleviating membrane fouling has been successfully operated for 100d. Based on the batch tests, a recycling biogas sparging rate at 0.2m(3)h(-1) was fixed as an ultimate value for the sustainable operation. The mixed liquor volatile suspended solid (VSS) of the inoculum for the long operation was around 3000mgL(-1). With recycling biogas sparging rate increasing stepwise from 0 to 0.2m(3)h(-1), the reactor reached an influent total nitrogen (TN) up to 1.7gL(-1), a stable TN removal efficiency of 83% and a maximum specific Anammox activity (SAA) of 0.56kg TNkg(-1) VSSd(-1). With recycling biogas sparging rate at 0.2 m(3) h(-1) (corresponding to an aeration intensity of 118m(3)m(-2)h(-1)), the membrane operation circle could prolong by around 20 times compared to that without gas sparging. Furthermore, mechanism of membrane fouling was proposed. And with recycling biogas sparging, the VSS and EPS content increasing rate in cake layer were far less than the ones without biogas sparging. The TN removal performance and sustainable membrane operation of this system showed the appealing potential of the submerged Anammox MBR with recycling biogas sparging in treating high-strength nitrogen-containing wastewaters.

[Land use pattern of Dalian City, Liaoning Province of Northeast China based on CA-Markov model and multi-objective optimization].

Based on the land use/cover maps of 1990, 2000, and 2010, topographic factors, and geographic elements, a CA-Markov model consisting of Markov transition matrix, multi-criteria evaluation, and cellular automata was developed to simulate the change trends of the future land use and landscape patterns of Dalian, Liaoning Province. The future land use pattern of Dalian was optimally allocated by the method of fuzzy multi-objective programming, based on the characters of land use structure, society, economy, and natural environment. The results indicated that in 1990-2010, the rapid development of Dalian showed the characteristics of the continued expansion of urban area and the reduction of cropland and woodland area. With the present speed of urban development, the landscape pattern and land use cover would have a great change, and the landscape fragmentation would be exacerbated. To optimize the land use structure could meet the demand of the future sustainable development of Dalian.

Management of occupational exposure to engineered nanoparticles through a chance-constrained nonlinear programming approach.

Critical environmental and human health concerns are associated with the rapidly growing fields of nanotechnology and manufactured nanomaterials (MNMs). The main risk arises from occupational exposure via chronic inhalation of nanoparticles. This research presents a chance-constrained nonlinear programming (CCNLP) optimization approach, which is developed to maximize the nanaomaterial production and minimize the risks of workplace exposure to MNMs. The CCNLP method integrates nonlinear programming (NLP) and chance-constrained programming (CCP), and handles uncertainties associated with both the nanomaterial production and workplace exposure control. The CCNLP method was examined through a single-walled carbon nanotube (SWNT) manufacturing process. The study results provide optimal production strategies and alternatives. It reveal that a high control measure guarantees that environmental health and safety (EHS) standards regulations are met, while a lower control level leads to increased risk of violating EHS regulations. The CCNLP optimization approach is a decision support tool for the optimization of the increasing MNMS manufacturing with workplace safety constraints under uncertainties.

Risk assessment and hierarchical risk management of enterprises in chemical industrial parks based on catastrophe theory.

According to risk systems theory and the characteristics of the chemical industry, an index system was established for risk assessment of enterprises in chemical industrial parks (CIPs) based on the inherent risk of the source, effectiveness of the prevention and control mechanism, and vulnerability of the receptor. A comprehensive risk assessment method based on catastrophe theory was then proposed and used to analyze the risk levels of ten major chemical enterprises in the Songmu Island CIP, China. According to the principle of equal distribution function, the chemical enterprise risk level was divided into the following five levels: 1.0 (very safe), 0.8 (safe), 0.6 (generally recognized as safe, GRAS), 0.4 (unsafe), 0.2 (very unsafe). The results revealed five enterprises (50%) with an unsafe risk level, and another five enterprises (50%) at the generally recognized as safe risk level. This method solves the multi-objective evaluation and decision-making problem. Additionally, this method involves simple calculations and provides an effective technique for risk assessment and hierarchical risk management of enterprises in CIPs.

Aqua-chlorido(3,5-dinitro-2-oxidobenzo-ato-κ(2)O(1),O(2))(1,10-phenanthroline-κ(2)N,N')chromium(III).

In the title compound, [Cr(C(7)H(2)N(2)O(7))Cl(C(12)H(8)N(2))(H(2)O)], the Cr(III) atom displays a distorted octa-hedral coordination geometry, with the chelating phenantroline and 3,5-dinitro-salicylate ligands in trans positions. In the crystal, mol-ecules are connected via O-H⋯O hydrogen bonds into a two-dimensional framework parallel to (100). In addition, there are π-π stacking inter-actions between phenanthroline ligands along the c axis, with a mean inter-planar distance of 3.456 (4) Å.

Research on the alternatives in a strategic environmental assessment based on the extension theory.

The main purpose of a strategic environmental assessment (SEA) is to facilitate the early consideration of potential environmental impacts in decision-making processes. SEA alternative identification is a core issue within the SEA framework. However, the current methods of SEA alternative formulation and selection are constrained by the limited setting range and lack of scientific evaluation. Thus, the current paper attempts to provide a new methodology based on the extension theory to identify a range of alternatives and screen the best one. Extension planning is applied to formulate a set of alternatives that satisfy the reasonable interests of the stakeholders. Extension priority evaluation is used to assess and optimize the alternatives and present a scientific methodology for the SEA alternative study. Thereafter, the urban traffic plan of Dalian City is used as an example to demonstrate the feasibility of the new method. The traffic planning scheme and the environmental protection scheme are organically combined based on the extension theory, and the reliability and practicality of this approach are examined.

2-(2-Pyrid-yl)pyridinium (2,2'-bipyridine-κN,N')tetra-kis-(nitrato-κO,O')bis-muthate(III).

The structure of the title compound, (C(10)H(9)N(2))[Bi(NO(3))(4)(C(10)H(8)N(2))], consists of 2-(2-pyrid-yl)pyridinium cations and anions [Bi(NO(3))(4)(C(10)H(8)N(2))](-). The Bi(3+) ion lies on the twofold axis. It is coordinated by two nitro-gen atoms from one 2,2'-bipyridine ligand and eight oxygen atoms from four NO(3) (-) anions. The disordered cation is positioned at the inversion centre. The [Bi(NO(3))(4)(C(10)H(8)N(2))](-) anions and 2-(2-pyrid-yl)pyridinium cations are connected via N-H⋯O hydrogen bonds into chains. Moreover, these chains are further linked into a two-dimensional layered structure through π-π stacking inter-actions between bipyridine ligands along the c axis [centroid-centroid distance = 2.868 (4) Å].