Microalgae have high potential to remove inorganic nutrients from wastewater and to produce biodiesel. Effects of nitrogen and phosphorus concentrations on growth, nutrient uptake, and lipid ...accumulation of a freshwater microalga
Scenedesmus sp. LX1 were studied.
Scenedesmus sp. LX1’s growth was in accordance with the Monod model. The following Monod parameters were obtained: the N- and P-saturated maximum growth rate was 2.21
×
10
6
cells
mL
−1
d
−1, and the half-saturation constants of N and P uptake were 12.1
mg
L
−1 and 0.27
mg
L
−1, respectively. In the nitrogen/phosphorus ratio of 5:1–12:1, 83–99% nitrogen and 99% phosphorus could be removed. In conditions of nitrogen (2.5
mg
L
−1) or phosphorus (0.1
mg
L
−1) limitation,
Scenedesmus sp. LX1 could accumulate lipids to as high as 30% and 53%, respectively, of its algal biomass. The lipid productivity/unit volume of culture, however, was not enhanced. Further research should be made on how to enhance both lipid content and lipid productivity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Fabricating proton exchange membranes (PEMs) with high ionic conductivity and ideal mechanical robustness through regulation of the membrane microstructures achieved by molecular‐level hybridization ...remains essential but challenging for the further development of high‐performance PEM fuel cells. In this work, by precisely hybridizing nano‐scaled bismuth oxide clusters into Nafion, we have fabricated the high‐performance hybrid membrane, Nafion‐Bi12‐3 %, which showed a proton conductivity of 386 mS cm−1 at 80 °C in aqueous solution with low methanol permeability, and conserved the ideal mechanical and chemical stabilities as PEMs. Moreover, molecular dynamics (MD) simulation was employed to clarify the structural properties and the assembly mechanisms of the hybrid membrane on the molecular level. The maximum current density and power density of Nafion‐Bi12‐3 % for direct methanol fuel cells reached to 432.7 mA cm−2 and 110.2 mW cm−2, respectively. This work provides new insights into the design of versatile functional polymer electrolyte membranes through polyoxometalate hybridization.
A hybrid membrane (Nafion‐Bi12‐3 %) used as a high‐performance proton exchange membrane (PEM) is fabricated through molecular‐level doping of {H6Bi12O16} clusters into ionic phase of Nafion. The clusters combine with anionic side chains of Nafion and optimize the hydrophilic/hydrophobic nano‐phases, resulting in hybrid membranes with high proton conductivity, ideal mechanical and chemical stability, and low methanol permeability.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Summarized the over-growth risks of non-pathogenic CRB.•Presented the genus, sources and chlorine resistance of all the isolated CRB strains.•Demonstrated the lack of widely-accepted method to ...evaluate chlorine resistance.•Proposed a recommended evaluating method for chlorine resistance.•Proposed a quantitative definition of chlorine-resistant bacteria.
Chlorine-resistant bacteria (CRB) are commonly defined as bacteria with high resistance to chlorine disinfection or bacteria which can survive or even regrow in the residual chlorine. Chlorine disinfection cannot completely control the risks of CRB, such as risks of pathogenicity, antibiotic resistance and microbial growth. Currently, researchers pay more attention to CRB with pathogenicity or antibiotic resistance. The microbial growth risks of non-pathogenic CRB in water treatment and reclamation systems have been neglected to some extent. In this review, these three kinds of risks are all analyzed, and the last one is also highlighted. In order to study CRB, various methods are used to evaluate chlorine resistance. This review summarizes the evaluating methods for chlorine resistance reported in the literatures, and collects the important information about the typical isolated CRB strains including their genera, sources and levels of chlorine resistance. To our knowledge, few review papers have provided such systematic information about CRB. Among 44 typical CRB strains from 17 genera isolated by researchers, Mycobacterium, Bacillus, Legionella, Pseudomonas and Sphingomonas were the five genera with the highest frequency of occurrence in literatures. They are all pathogenic or opportunistic pathogenic bacteria. In addition, although there are many studies on CRB, information about chlorine resistance level is still limited to specie level or strain level. The difference in chlorine resistance level among different bacterial genera is less well understood. An inconvenient truth is that there is still no widely-accepted method to evaluate chlorine resistance and to identify CRB. Due to the lack of a unified method, it is difficult to compare the results about chlorine resistance level of bacterial strains in different literatures. A recommended evaluating method using logarithmic removal rate as an index and E. coli as a reference strain is proposed in this review based on the summary of the current evaluating methods. This method can provide common range of chlorine resistance of each genus and it is conducive to analyzing the distribution and abundance of CRB in the environment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
For successful wastewater reclamation, advanced oxidation processes have attracted attention for elimination of emerging contaminants. In this study, the synergistic treatment with UV irradiation and ...chlorine (UV/chlorine) was used to degrade carbamazepine (CBZ). Neither UV irradiation alone nor chlorination alone could efficiently degraded CBZ. UV/chlorine oxidation showed a significant synergistic effect on CBZ degradation through generation of radical species (OH and Cl), and this process could be well depicted by pseudo first order kinetic. The degradation rate constants (kobs,CBZ) of CBZ increased linearly with increasing UV irradiance and chlorine dosage. The degradation of CBZ by UV/chlorine in acidic solutions was more efficient than that in basic solutions mainly due to the effect of pH on the dissociation of HOCl and OCl− and then on the quantum yields and radical species quenching of UV/chlorine. When pH was increased from 5.5 to 9.5, the rate constants of degradation of CBZ by OH decreased from 0.65 to 0.14 min−1 and that by Cl decreased from 0.40 to 0.11 min−1. The rate constant for the reaction between Cl and CBZ was 5.6 ± 1.6 × 1010 M−1 s−1. Anions of HCO3− (1–50 mM) showed moderate inhibition of CBZ degradation by UV/chlorine, while Cl− did not. UV/chlorine could efficiently degrade CBZ in wastewater treatment plant effluent, although the degradation was inhibited by about 30% compared with that in ultrapure water with chlorine dosage of 0.14–0.56 mM. Nine main oxidation products of the CBZ degradation by UV/chlorine were identified using the HPLC-QToF MS/MS. Initial oxidation products arose from hydroxylation, carboxylation and hydrogen atom abstraction of CBZ by OH and Cl, and were then further oxidized to generate acylamino cleavage and decarboxylation products of acridine and acridione.
•UV/chlorine showed synergistic degradation of carbamazepine than UV and chlorination.•Carbamazepine degraded through both OH and Cl ways during UV/chlorine oxidation•Carbamazepine could be efficiently degraded by UV/chlorine in UPW and WWTP effluent.•The second order rate constant between carbamazepine and Cl were examined
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Tumor‐associated neutrophils (TANs) play a crucial role in tumor development and progression in the cancer microenvironment. Despite increased understanding of TAN contributions to hepatocellular ...carcinoma (HCC) progression and prognosis, the direct interaction between TANs and HCC cells is not fully understood. In this study, we tested the effect of TANs on HCC cells in vitro and in vivo and investigated the mechanism of interaction between them. Our results showed that TANs secreted bone morphogenetic protein 2 and transforming growth factor beta 2 and triggered microRNA 301b‐3p (miR‐301‐3p) expression in HCC cells, subsequently suppressed gene expression of limbic system–associated membrane protein (LSAMP) and CYLD lysine 63 deubiquitinase (CYLD), and increased stem cell characteristics in HCC cells. These TAN‐induced HCC stem‐like cells were hyperactive in nuclear factor kappa B signaling, secreted higher levels of chemokine (C‐X‐C motif) ligand 5 (CXCL5), and recruited more TAN infiltration, suggesting a positive feedback loop. In clinical HCC samples, increased TANs correlated with elevated miR‐301b‐3p, decreased LSAMP and CYLD expression, and increased nuclear p65 accumulation and CXCL5 expression, all of which predicted patient outcome. Conclusion: Our work identified a positive feedback loop governing cancer stem‐like cells and TANs in HCC that controls tumor progression and patient outcome.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In reverse osmosis (RO) system for wastewater reclamation, biofouling is an inevitable issue. Chlorine disinfection is commonly used in pretreatment to control biofouling. Some chlorine-resistant ...bacteria could survive after chlorine disinfection and the microbial community structure in feed water changes significantly, thus leading to the change of biofouling potential. In this study, the effect of chlorine disinfection on the biofouling of RO membrane was investigated using a laboratory cross-flow RO system. Chlorine disinfection inactivated most bacteria in feed water. However, during the operation of RO system, with the increase of chlorine dosage the flux decline became more severe after a period of operation. The final normalized flux after 21 days was 0.27, 0.26, 0.20, and 0.21 with 0, 1, 5, and 15 mg-Cl2/L chlorine as pretreatment, respectively. After the operation, the numbers of active bacteria in the foulants on the fouled membrane were on the same level regardless of the chlorine dosage, whereas the thickness of the foulants increased with the chlorine dosage significantly. Additionally, the higher total organic carbon concentration indicated more extracellular polymeric substances (EPS) in foulants. Microbial community structure analysis showed that the abundance and the species number of chlorine-resistant bacteria increased significantly with the chlorine dosage. Typical chlorine-resistant bacteria, including Methylobacterium, Pseudomonas, Sphingomonas, and Acinetobacter, were identified as significantly distinctive genera in the foulants after the pretreatment by 15 mg-Cl2/L chlorine. Compared with the bacteria without chlorine disinfection, these remaining bacteria produced more EPS with higher molecular weight, which could be the major contribution to more severe RO membrane fouling after chlorine disinfection.
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•Studied effect of chlorine disinfection on biofouling of reverse osmosis (RO) system.•Applied lab RO systems, multiple microscopy, gene sequencing and organic analysis.•Chlorine disinfection changed the microbial community structure in foulants.•Four dominant chlorine-resistant strains were found in foulants with 15 mg-Cl2/L.•Extracellular polymeric substance produced by these strains caused severe biofouling.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Studies on ultraviolet light-emitting diode (UV-LED) water disinfection have shown advantages, such as safety, flexible design, and lower starting voltages. However, information about reactivation ...after UV-LED disinfection is limited, which is an important issue of UV light-based technology. In this study, the photoreactivation and dark repair of Escherichia coli after UV-LEDs and low pressure (LP) UV disinfection were compared. Four UV-LED units, 265 nm, 280 nm, the combination of 265 + 280 (50%), and 265 + 280 (75%) were tested. 265 nm LEDs was more effective than 280 nm LEDs and LP UV lamps for E. coli inactivation. No synergic effect for disinfection was observed from the combination of 265 and 280 nm LEDs. 265 nm LEDs had no different reactivation performances with that of LP UV, while 280 nm LEDs could significantly repress photoreactivation and dark repair at a low irradiation intensity of 6.9 mJ/cm2. Furthermore, the UV-induced damage of 280 nm LEDs was less repaired which was determined by endonuclease sensitive site (ESS) assay. The impaired protein activities by 280 nm LEDs might be one of the reasons that inhibited reactivation. A new reactivation rate constant, Kmax, was introduced into the logistic model to simulate the reactivation data, which showed positive relationship with the maximum survival ratio and was more reasonable to interpret the results of photoreactivation and dark repair. This study revealed the distinct roles of different UV lights in disinfection and reactivation, which is helpful for the future design of UV-LED equipment.
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•265 nm LEDs was more effective for E. coli disinfection.•No synergic effect for disinfection from the combination of 265 and 280 nm LEDs.•280 nm LEDs significantly reduced the reactivation processes.•Protein-damaging may be one reason that inhibited the reactivation.•New reactivation rate constant with clear physical meaning was introduced.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This study provided an overview of established and emerging nanomaterial (NM)-enabled processes and devices for water disinfection for both centralized and decentralized systems. In addition to a ...discussion of major disinfection mechanisms, data on disinfection performance (shortest contact time for complete disinfection) and energy efficiency (electrical energy per order; EEO) were collected enabling assessments firstly for disinfection processes and then for disinfection devices. The NM-enabled electro-based disinfection process gained the highest disinfection efficiency with the lowest energy consumption compared with physical-based, peroxy-based, and photo-based disinfection processes owing to the unique disinfection mechanism and the direct mean of translating energy input to microbes. Among the established disinfection devices (e.g., the stirred, the plug-flow, and the flow-through reactor), the flow-through reactor with mesh/membrane or 3-dimensional porous electrodes showed the highest disinfection performance and energy efficiency attributed to its highest mass transfer efficiency. Additionally, we also summarized recent knowledge about current and potential NMs separation and recovery methods as well as electrode strengthening and optimization strategies. Magnetic separation and robust immobilization (anchoring and coating) are feasible strategies to prompt the practical application of NM-enabled disinfection devices. Magnetic separation effectively solved the problem for the separation of evenly distributed particle-sized NMs from microbial solution and robust immobilization increased the stability of NM-modified electrodes and prevented these electrodes from degradation by hydraulic detachment and/or electrochemical dissolution. Furthermore, the study of computational fluid dynamics (CFD) was capable of simulating NM-enabled devices, which showed great potential for system optimization and reactor expansion. In this overview, we stressed the need to concern not only the treatment performance and energy efficiency of NM-enabled disinfection processes and devices but also the overall feasibility of system construction and operation for practical application.
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•Brief overview of NM-enabled processes and devices for water disinfection.•Evaluation of NM-enabled processes/devices based on performance and energy efficiency.•Applying contact time and electrical energy per order (EEO) for assessment of processes and devices.•Discussion of influencing factors on contact time and EEO for NM-enabled disinfection.•Summary of NMs recovery and electrode strengthening methods for practical application.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Influent and effluent quality of municipal wastewater treatment plants plays significant roles in selecting the appropriate treatment technologies and influencing the ecology of receiving water ...bodies. The quality of reclaimed water sources for water reuse can also be determined based on the influent wastewater and treated effluent information. Comprehensive analyses based on statistical data collected from 3340 Chinese municipal wastewater treatment plants were performed so as to better understand the effects of influent and effluent wastewater quality on the treatment performance, environmental concerns and resources utilization. Provincial characteristics of wastewater quality both in quantity and quality were identified, providing valuable information for the proposal of targeted management strategies in pollution control, water reuse and resources recovery. The influents of municipal wastewater treatment plants in north China had high wastewater pollutant loadings, but the effluent was of high quality due to the wide implementation of water reuse strategies in northern water scarcity regions. The potentials for organic and nutrient recovery from the influents were brought forward based on the mass balance. The importance of wastewater as a resource, and the adoption of advanced treatment and resources utilization in the long-term should be highlighted for sustainable water management.
•Statistical data on influent and effluent wastewater quality of China were analysed.•Provincial and regional characteristics of wastewater quality were identified.•The potentials for water reuse and organic and nutrient recovery were calculated.•The importance of wastewater as a resource was highlighted for sustainability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Prevention and management of lung cancer in China Hong, Qun‐Ying; Wu, Guo-Ming; Qian, Gui‐Sheng ...
Cancer,
September 1, 2015, 2015-Sep-01, 2015-09-00, 20150901, Volume:
121, Issue:
S17
Journal Article
PDF
