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Ru-doped Co9S8 hollow porous polyhedrons (Ru–Co9S8 HPPs) derived from zeolitic-imidazolate-frameworks were synthesized through hydrothermal coprecipitation and thermal decomposition methods. The results indicate that Ru–Co9S8-500 HPPs possess a strong Ru–Co synergistic effect, large electrochemical surface area, and sufficient active sites, endowing them with excellent hydrogen evolution reaction performance. [ABSTRACT FROM AUTHOR]

The association between gallstone disease and coronary artery atherosclerotic disease (CAD) remains unclear. To clarify their relationship, patients with CAD newly diagnosed by coronary angiography were investigated in this cross-sectional study.The study cohort consisted of 1,270 patients undergoing coronary angiography for the first time between January 2007 and September 2011. Patients with ≥50% diameter stenosis in any major coronary artery on coronary angiography were defined as being CAD positive (n = 766) and those with no stenosis as CAD negative (n = 504). Multivariate logistic regression was used to investigate the relationship between gallstone disease and CAD. The odds ratios (OR) of factors associated with CAD were calculated. In addition, CAD-positive and CAD-negative patients were matched one-to-one by age, gender and metabolic syndrome (MetS), and the association between gallbladder disease and CAD was determined.The prevalence of gallstone disease was significantly higher in CAD-positive than in CAD negative patients (149/766 [19.5%] vs 57/504 [11.3%], P

MicroRNA (MiRNA) plays a crucial role in biological cells to enable assessment of a cancer's development stage. Increasing evidence has shown that the accurate and sensitive detection of miRNA holds the key toward correct disease diagnosis. However, some characteristics of miRNAs, such as their short chains, low concentration, and similar sequences, make it difficult to detect miRNA in biological samples. Nanomaterials usually have good optical, electronic, and mechanical properties and therefore provide new possibilities for improving the performance of miRNA assays. Many different sorts of nanomaterials, including metal nanomaterials, carbon nanomaterials, quantum dots, and transition-metal dichalcogenides, have been used to construct optical and electrochemical assays for miRNA and have shown attractive results. This review describes recent efforts in the application of nanomaterials as sensing elements in electrochemical and optical miRNA assays. The analytical figures of merit of various methods for the detection of miRNA are compared in the present article. The current capabilities, limitations, and future challenges in miRNA detection and analysis based on nanomaterials are also addressed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Se doping MWCNTs-graphene hybrids are prepared and used for supporting substrate. • Y-shaped DNA-aided target recycling signal amplification and hemin/G-quadruplex is used for signal amplification. • The biosensor used for PDGF-BB detection shows linear range of 0.1 pM-10 nM and detection limit of 27 fM. Abstract A highly sensitive electrochemical biosensor for detection of platelet-derived growth factor-BB (PDGF-BB) is developed by using Se-doped multi-walled carbon nanotubes (MWCNTs)-graphene hybrids as electrode supporting substrate, hemin/G-quadruplex as trace labels and Y-shaped DNA-aided target recycling as signal magnifier. The aptamer-containing hairpin probes were first immobilized on the electrode. When target PDGF-BB was added, the aptamer binded PDGF-BB to trigger catalytic assembly of two other hairpins to form many G-quadruplex Y-junction DNA structures, which released PDGF-BB to again bind the intact aptamer to initiate another assembly cycle. G-quadruplex/hemin complexes were produced when hemin was added to generate substantially amplified current output. The developed assay showed a linear range toward PDGF-BB from 0.1 pM to 10 nM with a detection limit of 27 fM (S/N = 3). The method showed excellent specificity and repeatability, and could be expediently applied for sensitive detection of other molecules by simply changing the aptamers. [ABSTRACT FROM AUTHOR]

In this work, a sandwich-type electrochemical biosensing platform is developed based on carbon sphere-MoS 2 (CS-MoS 2 ) and target recycling amplification of catalyzed hairpin assembly (CHA) strategy for ultrasensitive determination of microRNA (miRNA). The CS-MoS 2 is prepared and used as sensing substrate, which shows high specific surface area, enhanced stability and good dispersibility. The capture probe is first modified on Au nanoparticles/CS-MoS 2 modified glassy carbon electrode through Au-S band, and hairpin DNA1 (H1) then reacts with it and unfolds its loop domain by hybridizing with target miRNA-21. The opened H1 subsequently assembles with biotin labeled hairpin DNA 2 (H2) to displace the target. The liberated miRNA-21 is free and backs to the original solution to proceed next circulation, resulting in the generation of large amounts of H1–H2 duplex. Massive signal indicators horseradish peroxidase are then immobilized on electrode, and catalyze hydrogenperoxide + hydroquinone (H 2 O 2  + HQ) system to produce a strong electrochemical response. The proposed assay benefits from advantages of sandwich-type structure, favorable electrochemical properties of CS-MoS 2 and CHA target recycling amplification strategy. Therefore, it exhibits a wide linear relation between 1 × 10 −16 and 1 × 10 −10  M with a low detection limit of 1.6 × 10 −17  M for miRNA-21 detection. [ABSTRACT FROM AUTHOR]

In this work, we report an ultrasensitive electrochemical biosensor for microRNA-21 (miRNA-21) detection by using a competitive RNA–RNA hybridization configuration. A biotinylated miRNA of the self-same sequence with the target miRNA is mixed with the samples, and allowed competition with the target miRNA for a thiolated RNA probe immobilized onto a tungsten diselenide (WSe2) nanosheet modified electrode. Thereafter the current response is obtained by forming the hybridized biotinylated miRNA with streptavidin–horseradish peroxidase (HRP) conjugates to catalyze the H2O2 + hydroquinone (HQ) system. Benefiting from the high specific surface area of WSe2 nanosheets, the competitive hybridization configuration and the signal amplification of the H2O2 + HQ detection system, the proposed assay exhibits a wide linear range of 0.0001–100 pM towards target miRNA with a detection limit of 0.06 fM (S/N = 3), and shows excellent discrimination ability for base-mismatched miRNA sequences. Therefore, the designed platform has promising prospects for the detection of miRNA in biomedical research and early clinical diagnosis. [ABSTRACT FROM AUTHOR]

A 2-dimensional tungsten disulfide–acetylene black (WS2–AB) composite is synthesized by a simple hydrothermal method to achieve excellent electrochemical properties for applications as a DNA biosensor. The biosensor is fabricated based on the Au nanoparticles (AuNPs) and WS2–AB composite modified electrode, which subsequently is used to couple with a capture probe by an Au–S bond, then modified with target DNA, auxiliary DNA and bio-H1–bio-H2 (H1–H2) to perform hybridization chain reaction for signal amplification. Herein, two DNA hairpins H1 and H2 are opened by the recognition probe. The nicked double helices from hybridization chain reaction are used to immobilize horseradish peroxidase enzymes via biotin–avidin reaction, which produces signal-amplification detection of target DNA through the catalytic reaction of the hydrogenperoxide + hydroquinone system. Under optimum conditions, the as-prepared biosensor shows a good linear relationship between the current value and logarithm of the target DNA concentration ranging from 0.001 pM to 100 pM and a detection limit as low as 0.12 fM. Moreover, the fabricated biosensor exhibits good selectivity to differentiate the one-base mismatched DNA sequence. This work will open a pathway for ultrasensitive detection of other biorecognition events and gene-related diseases based on layered WS2–AB and hybridization chain reaction. [ABSTRACT FROM AUTHOR]

Background: Fatty liver index (FLI) was recently established to predict non-alcoholic fatty liver disease (NAFLD) in general population, which is known to be associated with coronary artery atherosclerotic disease (CAD).This study aims to investigate whether FLI correlates with NAFLD and with newly diagnosed CAD in a special Chinese population who underwent coronary angiography.Methods: Patients with CAD (n = 231) and without CAD (n = 482) as confirmed by coronary angiography were included. Among them, 574 patients underwent B-ultrosonography were divided into NAFLD group (n = 209) and non-NAFLD group (n = 365). Correlation between FLI and NAFLD was analyzed using pearson's correlation. The associations between FLI and NAFLD as well as CAD were assessed using logistic regression. The predictive accuracy of FLI for NAFLD was evaluated using receiver operating characteristics (ROC) curve analysis.Results: FLI was significantly higher in NAFLD group (37.10 ± 1.95) than in non-NAFLD group (17.70 ± 1.04), P < 0.01. FLI correlated with NAFLD (r = 0.372, P < 0.001). The algorithm for FLI had a ROC-AUC of 0.721 (95% CI: 0.678-0.764) in the prediction of NAFLD. Logistic regression analysis showed that FLI was associated with NAFLD (adjusted OR = 1.038, 95% CI: 1.029-1.047, P < 0.01). The proportion of patients with CAD did not differ among the groups of FLI ≤ 30 (32.3%), 30-60 (31.0%), and ≥60 (35.3%). No significant association was found between FLI and CAD (adjusted OR = 0.992, 95% CI: 0.981-1.003 in men and OR = 0.987, 95% CI: 0.963-1.012 in women, P > 0.05).Conclusions: FLI showed good correlation with NAFLD in patients who underwent coronary angiography, but not with newly diagnosed CAD. This might be underestimated because some patients in non-CAD group may have other underlying cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Anammox (anaerobic ammonium oxidation) is an important process of nitrogen cycle, with great potential for the practical use in removing nitrogen from the wastewater containing high concentration ammonium. However, the presence of high concentration organic carbon source is considered unfavorable to anammox. Coupling anammox and denitrification under the presence of organic carbon source could be a useful technique for removing both nitrogen and carbon. This pa- per reviewed the mechanisms of anammox-denitrification coupling process, functional microbial groups, initiation of the coupling process and its control, and related environmental affecting factors. The future research prospects and potential applications of anammox-denitrification coupling process in wastewater treatment were discussed. [ABSTRACT FROM AUTHOR]

In conventional wastewater bio-treatment, little attention has been paid on the bio-degradation of grease, causing low efficiency in the process, and thereby, further study should be made on the development and application of related mature and effective bio-treatment techniques. This paper summarized the pathways and mechanisms of grease bio-degradation in wastewater treatment, with the focus on the research progress in the functional microbes involved in lipid hydrolysis and long-chain fatty acid degradation, and briefly introduced a series of new treatment technologies based on the habitat differences of the functional microbes. The key breakthrough directions in the technological study of grease bio-degradation were prospected, expecting to provide theoretical guidance to the development of the related technologies. [ABSTRACT FROM AUTHOR]

In-situ ammonium removal from municipal solid waste (MSW) landfill is an attractive method due to its economic advantages. In this study, two simulated MSW bioreactors with different degrees of initial bio-stabilization were utilized to investigate the effects of intermittent aeration mode and the addition of activated sludge on the removal of ammonium. The results showed that up to 90% of ammonium could be removed and the amount of NOx—N produced was less than 1% of NH4+-N removed in both reactors. The pH values increased rapidly and finally arrived at a high level of 8.5—8.8. The efficiency of ammonium removal was improved by increasing the continuous aeration time, but it was not affected by the addition of activated sludge. A portion of liquid escaped from the reactors in the form of vapour, and as high as 195—258 mg L—1 of NH4 +-N was detected in the vapour collector. According to calculation, nitrification was inhibited by the high level of free ammonia in the bioreactors. As a result, air stripping was enhanced and became the primary pathway of ammonium removal. Therefore, controlling free ammonia concentration was essential in ammonium removal from the aerated MSW bioreactor. [ABSTRACT FROM AUTHOR]

Abstract: The current trend of global warming is expected to stimulate the expansion of harmful cyanobacteria blooms. Previously, the occidental type of barley straw has been used to control blooms in Europe and America, but very little is known about the antialgal abilities of its oriental relative. We tested the use of Tibetan hulless barley straw – the progenitor of oriental barley – to inhibit the growth of cyanobacterium Microcystis aeruginosa. Flow cytometry allowed assessment at single-cell level, with morphologic parameters (cell volume, cell membrane integrity) and physiological parameters (in vivo Chlorophyll a fluorescence, metabolic activity) used as endpoints. The reduction of cell densities together with integrated cell membranes suggests that Tibetan barley may act as an algistatic agent. Doses from 2.0 to 8.0gL−1 of Tibetan barley straw efficiently inhibited the alga, but these doses were much higher than those of occidental barley. Such a large dosage introduced additional nutrients, which stimulated the intracellular metabolic activity and induced two physiological subpopulations in the acute term. After mid and long-term exposure, the growth inhibition effect exceeded the stimulation effect, so that the cells’ metabolic activity and Chlorophyll a fluorescence decayed, simultaneously with shrinkage in the algal cell volume. [ABSTRACT FROM AUTHOR]

To study the oxidative stress and antioxidative response of Cinnamomum camphora seedlings exposed to nitrogen dioxide (NO2) fumigation. Measurements were made up of the growth, chlorophyll content, chlorophyll fluorescence, antioxidant system and lipid peroxidation of one-year-old C. camphora seedlings exposed to NO2 (0.1, 0.5, and 4 μl/L) fumigation in open top chambers over a period of 60 d. After the first 30 d, 0.5 and 4.0 μl/L NO2 showed insignificant effects on the growth of C. camphora seedlings. However, exposure to 0.5 and 4.0 μl/L NO2 for 15 d significantly reduced their chlorophyll content ( P<0.05), enhanced their malondialdehyde (MDA) content and superoxide dismutase (SOD) activity ( P<0.05), and also significantly reduced the maximal quantum yield of PSII in the dark [the ratio of variable fluorescence to maximal fluorescence ( Fv/ Fm)] ( P<0.05). In the latter 30 d, 0.5 μl/L NO2 showed a positive effect on the vitality of the seedlings, which was reflected by a recovery in the ratio of Fv/ Fm and chlorophyll content, and obviously enhanced growth, SOD activity, ascorbate (AsA) content and glutathione reductase (GR) activity ( P<0.05); 4.0 μl/L NO2 then showed a negative effect, indicated by significant reductions in chlorophyll content and the ratio of Fv/ Fm, and inhibited growth ( P<0.05). Conclusion: The results suggest adaptation of C. camphora seedlings to 60-d exposure to 0.1 and 0.5 μl/L NO2, but not to 60-d exposure to 4.0 μl/L NO2. C. camphora seedlings may protect themselves from injury by strengthening their antioxidant system in response to NO2-induced oxidative stress. [ABSTRACT FROM AUTHOR]

Abstract: Composting is an effective methodology for the treatment of organic waste like pig manure (PM) before land application. However, nitrogen loss through NH3 volatilization during the thermophilic phase is one of the major disadvantages of composting. The presence of Cu and Zn in compost arising from pig feed additives is also an issue. In this study the effects of bamboo charcoal (BC) and bamboo vinegar (BV) added to composting piles on nitrogen conservation and immobility of Cu and Zn during PM composting was investigated. Total Kjeldahl nitrogen (TKN) loss and mobility of Cu and Zn decreased with increased BC addition. TKN loss and mobility of Cu and Zn in the treatment with 9% BC at the end of composting significantly decreased by 65%, 35% and 39% respectively, as compared to the control. Addition of BV further decreased TKN loss. After composting, TKN loss in the treatment with 3% BC+0.4% BV was 23% lower than that in the treatment with 9% BC. The final results indicated that by adding BC or BC+BV into PM composting is an effective method to reduce TKN loss and control the mobility of Cu and Zn. [Copyright &y& Elsevier]

Objective: To investigate the struvite precipitation under constant and non-constant pH conditions and to test a stainless steel device under different operating regimes to maximize the recovery of struvite. Methods: The molar ratio of NH4 +: Mg2+: PO4 3− was adjusted to 1: 1.2: 1.2 and pH was elevated to 9.0. The absorbance measurement was used to trace the process of struvite crystallization. Wastewater and precipitate analysis was done by standard analytical methods. Results: The pH constant experiment reported a significantly higher struvite precipitation (24.6±0.86 g) than the non-constant pH experiment (19.8±1.86 g). The SAR ranged from 5.6 to 8.2 g m−2 h−1 to 3.6-4.8 g m−2 h−1 in pH constant and non-constant experiments, respectively. The highest struvite deposit on the device was found in regime 3 followed by in regimes 2 and 4. The highest PO4 3- (97.2%) and NH4 + (71%) removal was reported in the R1 regime. None of the influent Cu2+ or Zn2+ was precipitated on the device. Conclusion: A higher struvite yield is evident in pH constant experiments. Moreover, the stainless steel device facilitates the isolation of heavy metal free pure (around 96%) struvite from swine waste biogas digester effluent contaminated with cu2+ and Zn2+ and the highest yield is attainable with the device operating at 50 rpm with agitation by a magnetic stirrer. [Copyright &y& Elsevier]

Objective: To investigate the heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) in sludge of twelve wastewater treatment plants (WWTPs) in Zhejiang province of China, and to assess their potential for land application. Methods: Sludge was collected from 12 WWTPs within the province. gc-ms and aas were used to measure PAHs and HMs contents in sludge. Results: Concentrations of HMs in most of the sludge samples were below the regulatory limits for the sludge to be used in agriculture in China with the exception of Zn in 2 sludge samples and Cd in 1 sample. All 16 PAHs, targeted by the usepa agency, were found in the sludge from the twelve plants with a total concentration ranging from 33.73 mg kg-1 to 82.58 mg kg-1 (dry weight, d.w.). The levels of Σ9 PAHs varied from 13.87 mg kg-1 to 61.86 mg kg-1 (d.w.) in the sludge, far exceeding the limitation value recommended by the Europe Union. The concentration and composition of PAHs in sewage sludge varied and depended mainly on the quantity and type of industrial wastewater accepted by the WWTPs. a significant relationship between the proportion of industrial wastewater received by WWTPs and the total content of 16 PAHs in the sludge was observed. Conclusion: PAHs have become one of the primary pollutants in sludge of Zhejiang WWTPs instead of HMs. It is, therefore, essential to reduce the contents of PAHs before the sludge can be used in agriculture through proper treatment. [Copyright &y& Elsevier]

Abstract: A field experiment located in Taihu Lake Basin of China was conducted, by application of urea or a mixture of urea with manure, to elucidate the interception of nitrogen (N) export in a typical rice field through “zero-drainage water management” combined with sound irrigation, rainfall forecasting and field drying. N concentrations in floodwater rapidly declined before the first event of field drying after three split fertilizations, and subsequently tended to return to the background level. Before the first field drying, total particulate nitrogen (TPN) was the predominant N form in floodwater of plots with no N input, dissolved inorganic nitrogen (DIN) on plots that received urea only, and dissolved organic nitrogen (DON) on plots treated with the mixture of urea and manure. Thereafter TPN became the major form. No N export was found from the rice field, but total nitrogen (TN) of 15.8 kg/hm2 was remained, mainly due to soil N sorption. The results recommended the zero-drainage water management for full-scale areas for minimizing N export. [Copyright &y& Elsevier]

The application of nitrogen fertilizers leads to various ecological problems such as nitrate leaching. The use of nitrification inhibitors as nitrate leaching retardants is a proposal that has been suggested for inclusion in regulations in many countries. In this study, using a multi-layer soil column device, the influence of new nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) was studied for understanding the nitrogen vertical transformation and lowering the nitrate leaching at different soil profile depths. The results indicated that, within 60 d of experiment, the regular urea added 1.0% DMPP can effectively inhibit the ammonium oxidation in the soil, and improve the ammonium concentration in soil solution over the 20cm depths of soil profile, while decline the concentrations of nitrate and nitrite. No obvious difference was found on ammonium concentrations in soil solution collected from deep profile under 20cm depths between regular urea and the urea added 1.0% DMPP. There was also no significant difference for the nitrate, ammonium and nitrite concentrations in the soil solution under 40cm depths of soil profile with the increasing nitrogen application level, among the treatments of urea added 1.0% DMPP within 60 d. It is proposed that DMPP could be used as an effective nitrification inhibitor in some region to control ammonium oxidation and decline the ion-nitrogen leaching, minimizing the shallow groundwater pollution risk and being beneficial for the ecological environment. [Copyright &y& Elsevier]

Phytolacca acinosa Roxb. (P. acinosa) is a recently discovered manganese hyperaccumulator plant from southern China. It is a good candidate for phytoremediation of manganese(Mn) polluted soil for its high biomass and fast growth. Knowledge of the tissue localization and identification of heavy metals can provide essential information on metal toxicity and bioaccumulation mechanisms. Synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) microprobe was used in this study to investigate the cellular distributions of Mn and other elements in root, stem, leaf, petiole and midrib ofP. acinosa. The highest Mn content was found in the vascular tissues of root, stem, petiole and midrib. Cortex in root played a key role in Mn absorption and Mn was limited in the vascular bundle during the process of transportation in stem. Moreover, Mn content in leaf epidermis was higher than that in mesophyll, which suggested that the sequestration of Mn in leaf epidermis might be one of the detoxification mechanisms of P. acinosa. The significance of other elemental (such as P, S, K, Ca, Fe, Zn and Cu) distribution patterns and the correlation with Mn were also discussed. [ABSTRACT FROM AUTHOR]

For TiO_2 heterogeneous reaction, the reaction site and the detailed mechanism are interesting and controversy topics. In this paper, effects of surface fluorination of TiO_2 on the photocatalytic degradation of an azo dye, Orange G(OG) under UV or visible light irradiation were investigated, and the possible reaction site and mechanism were elucidated. The adsorption of OG on TiO_2 was nearly inhibited by fluoride but its UV light induced photodegradation rate was greatly increased by a factor of about 2.7, which was due to the more generated free hydroxyl radicals. It supported the views that fluoride could desorb the oxidant species from surface and that the reaction sites could move to the bulk solution. In TiO_2/Vis system, the observed inhibition effects of fluorination could be interpreted by the competitive adsorption, which provided additional evidences that the visible light sensitized photodegradation of dye pollutants on the catalyst surface. [ABSTRACT FROM AUTHOR]

Abstract: The role of rhizosphere bacteria in facilitating the solubility of copper (Cu) in contaminated soil and Cu accumulation in plant were studied. The bacteria strains were isolated from the rhizosphere of Elsholtzia splendens, a Cu accumulator growing on Tonglu Mountain copper mines. After the sandy soils containing 237 mg kg−1 were incubated with the bacteria strains, it was indicated that rhizosphere microbes played an important role in influencing the availability of water-soluble Cu in soils. Soils had greater concentrations of water-extractable Cu compared with axenic soils inoculated with different bacterial strains. Further evidence for bacterial facilitation of increased solubility of Cu in the soil was obtained using the antibiotic ampicillin (0.1 mg g− 1). There were 36% decreases in Cu concentration in the presence of bacterial strain MS12 and ampicillin together compared with bacterial inoculation alone. Different bacterial strains had different abilities on soil water-soluble Cu. To achieve the highest rates of plant Cu accumulation, it was necessary for bacteria to be present in the rhizosphere of E. splendens. Inoculated plants supplied with 20 μmol L− 1 CuSO4 had significantly greater concentrations of Cu in shoots and roots than uninoculated plants and bacterial strain MS2 was the most effective strain in promoting plant Cu uptake. There were 2.2-fold and 2.5-fold increases in Cu accumulation in the shoots and roots of plants inoculated with strain MS2 compared to axenic controls. Furthermore, when ampicillin and the bacterial strains were added together to the nutrient solution, the Cu concentrations in roots and shoots of ampicillin-treated plants were lower than those in inoculated plants. When ampicillin was added to the nutrient solution, Cu accumulation was inhibited by about 24–44% in shoots and 20–44% in roots. The above results provided a new insight into the phytoremediation of Cu-contaminated soil. [Copyright &y& Elsevier]

A greenhouse experiment was carried out to compare differences in potential activities of ammonification, nitrification and denitrification in rhizosphere and bulk soil in a heavy-metal-stressed system. Exchangeable fractions of Cd, Cu and Cr were all higher in the rhizosphere of maize than in bulk soil. Results showed that the mineralization of N in soil was stimulated by low concentration of Cd. Addition of Cd at low levels stimulated the ammonifying and nitrifying activity in soil, while inhibitory influences were shown at high levels. Nitrifying bacteria was proved to be the most sensitive one, whilst the effect on denitrifying bacteria was very limited. Comparing Cd, Cu and Cr(VI) at 20 mg/kg soil, Cd was the most effective inhibitor of ammonification and denitrification, while Cr(VI) had the strongest inhibitory influence on nitrifying activity. Root exudates played important roles on the different exchangeable metal fractions and bacterial activities between rhizosphere and non-rhizosphere. Nitrate was the main form of mineral N in soil, as well as the main form of N absorbed by plants, but the formation and relative absorption of ammonium were promoted in response to high Cd exposure. [ABSTRACT FROM AUTHOR]

Humic substrates are a major fraction of sediment organic matters, and the sorption of hydrophobic organic chemicals by humic substrates influences their behavior and fate in sediment. In this paper, organic matters were divided into non-humic substrates and humic substrates. Non-humic substrates include acid leaching fraction, acid extracted fraction, and lipid; humic substrates were fractionated into Ca-binding-FA (fulvic acid), Ca-binding-HA (humic acid), oxide-FA, oxide-HA, and humin. To study the effect of organic fractions on sorption properties, sorption kinetic and equilibrium sorption experiments of phenanthrene and pentachlorophenol (PCP) in five sediments were carried out. The results showed that the contents of acid leaching fraction and oxide-binding-HA were the main fractions to affect the sorption rate constant, and for the sorption capacity of phenanthrene, humin was the major fraction, followed by oxide-binding-HA, oxide-binding-FA, and so on. While for PCP, the factors of influence on sorption capacity were mainly CEC, Ca-binding-FA, and Ca-binding-HA. [ABSTRACT FROM AUTHOR]

Abstract: Biological removal of ammonia was investigated using two types of packing materials, compost and sludge in laboratory-scale biofilters (8l reactor volume). The aim of this study is to investigate the potential of unit systems packed with these supports in terms of ammonia emissions treatment. Experimental tests and measurements included analysis of removal efficiency, metabolic products, and results of long-term operation. The inlet concentration of ammonia applied was 20–200mgm−3. The ammonia loading rates of 24.9–566gNH3m−3d−1 to compost biofilter (BF3) and 24.9–472gNH3m−3d−1 to sludge biofilter (BF4) were applied for 210 days, respectively. Removal efficiencies of the compost and sludge biofilters were in the range of 97–99% and 95–99%, respectively when the inlet concentration of ammonia was below 110mgm−3, and the maximum elimination capacities were 288 and 243gNH3m−3d−1, respectively. However, removal efficiency and elimination capacity of both biofilters significantly decreased as the inlet concentration increased to above 110mgm−3. By using kinetic analysis, the maximum removal rate of ammonia, Vm, and the saturation constant, Ks, were determined for both packing materials and the value of Vm for compost was found to be larger. Periodic analysis of the biofilter packing materials showed the accumulation of the nitrification product in the operation. During the experiment, the pressure drops measured were very low. The use of both packing materials requires neither nutritive aqueous solution nor buffer solution. [Copyright &y& Elsevier]

The start-up and performance of the anaerobic attached film expanded bed (AAFEB) reactor with pre-aeration of carrier were investigated. The carriers of the reactors had been aerated for 10 days before they were put into the AAFEB reactors. The results indicated that the reactors advance the start-up by 15 days, and maintain higher efficiency when they were subjected to organic and hydraulic loading shock, but during steady-state operation, the reactors did not show better performance than the control reactors without pre-aeration of carrier. The thicker biofilm and higher biomass concentration of the reactors with pre-aeration were observed during the start-up period, but the difference between two types of reactors tapered with the time course, and at the steady-state operation, the difference between two types of reactors on these two parameters was not obvious. Maximum specific methane or acids production rates, dehydrogenase activity and coenzyme F420 content were continuously higher than those of the control reactors. After running 30 days, filamentous bacteria dominated in the reactors with pre-aeration, whereas the cocci were predominant species in the control reactors. It was suggested that the action of the biofilm is strongly dependent on the biofilm thickness or the biomass concentration in normal circumstances, but under adverse circumstances, such as organic or hydraulic loading shock, the characteristics and activity of the anaerobic granular sludge play key roles on the reactor performance. These results clearly indicated that pre-aeration of carrier favor to enhance the start-up and performance of AAFEB reactor. [Copyright &y& Elsevier]

To gain information on organic pollutants in water–sediment systems, a compartment model was applied to study the sorption course of phenanthrene and pentachlorophenol (PCP) in sediments. The model described the time-dependent interaction of phenanthrene and PCP with operationally defined reversible and irreversible (or slowly reversible) sediment fractions. The interactions between these fractions were described using first order differential equations. By fitting the models to the experimental data, apparent rate constants were obtained using numerical optimization software. The model optimizations showed that the amount of reversible phase increased rapidly in the first 10 d with the sorption time, then decreased after 10 d, while the amount of irreversible phase increased in the total sorption course. That suggested the mass transport between reversible phase and irreversible phase. The extraction efficiency with hot methanol ranged from 36% to 103% for phenanthrene and from 65% to 101% for PCP, with the trend of decreasing with sorption time. [Copyright &y& Elsevier]

The effect of elemental sulfur concentration on bioleaching of Cu, Zn and Pb and loss of fertilizer value from sewage sludge was investigated in flasks by batch experiments. The results showed that the ultimate pH of sludges with 3-5 g/L of sulfur added was about 1.3 and the production of SO42+ had good correlation with the elemental sulfur concentration. The sensitivity of removal efficiency of metals to sulfur concentration was: Pb > Cu > Zn. The sulfur concentration except for 3 - 5 g/L had significant effect on the solubilization of Cu, Pb and Zn. The highest solubilization efficiency for sludge with 3 g/L of sulfur was 87.86% for Cu, 32.72% for Pb and 92.14% for Zn which could make the treated sludge easily meet the metal limitations for land application. The sulfur concentration of 3 g/L was enough for the solubilization of all three heavy metals. The influence of sulfur concentration on solubilization of total nitrogen and potassium from sludge was negligible. but that on solublization of total phosphorus was of great importance. The loss of nitrogen phosphorus and potassium of sludge with 3 g/L of sulfur by bioleaching was 38.2%, 52.1% and 42.8% respectively, and the sludge still remained satisfactory fenilizer value after bioteaching. [ABSTRACT FROM AUTHOR]

A novel tri-primer polymerase chain reaction method (TP-PCR) was developed for the construction of a fused fpg gene, in which no endonuclease and ligase were used. Instead, two templates and three specifically designed primers were applied. Results showed that pheB and gfp genes, which encodes the catechol 2, 3-dioxygenase and the green fluorescent protein (GFP), respectively, were successfully fused into an fpg gene through the rapid TP-PCR system, indicating that TP-PCR method could be a useful tool for DNA fragment fusion in which no proper endonuclease sites were available. [Copyright &y& Elsevier]

The partitioning behavior of pentachlorophenol (PCP) in five sediments was studied using equilibrium sorption experiments and multiple cycles of sorption and desorption experiments. The results of the equilibrium sorption experiments showed that the isotherms of PCP on five sediments were linear and the partitioning coefficients (Kd) were proportional to the organic carbon content of the sediments. The average organic carbon content normalized partitioning coefficient (logKoc) of five sediments was 2.83±1.48. In multiple cycles of sorption and desorption experiments, the five sediments were found to exhibit statistically significant sorption–desorption hysteresis, and the hysteresis indices (HI) varied over a wide range (0.72–11.82). Correlations between the HI value and the percentage of lipid in the total organic matter in the sediment indicated that lipid was the main fraction to affect the hysteresis phenomenon, i.e., the higher the lipid percentage the greater the HI value. The hysteresis phenomenon was mostly caused by irreversible sorption of PCP on lipids, including entrapment by lipids, which induced the slow desorption rate from the sediment. Because of hysteresis in the sorption and desorption, the PCP ecological toxicity would be lower than expected. [Copyright &y& Elsevier]