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Journal ArticleDOI: 10.1016/J.JHAZMAT.2021.125578

Simultaneous removal of nitrate and diethyl phthalate using a novel sponge-based biocarrier combined modified walnut shell biochar with Fe3O4 in the immobilized bioreactor.

04 Mar 2021-Journal of Hazardous Materials (Elsevier)-Vol. 414, pp 125578-125578
Abstract: A novel biological carrier combining sponge and modified walnut shell biochar with Fe3O4 (MWSB@Fe3O4) was fabricated to achieve simultaneous removal of nitrate and diethyl phthalate (DEP). The optimal reaction conditions of the immobilized bioreactor were: carbon to nitrogen (C/N) ratio of 1.5, Fe2+ concentration of 20 mg L−1, and hydraulic retention time (HRT) of 8 h. Under the optimal conditions and DEP concentration of 800 μg L−1, the highest removal efficiency of DEP and nitrate in the immobilized bioreactor with the novel biological carrier were 67.87% and 83.97% (68.43 μg L−1 h−1 and 1.71 mg L−1 h−1), respectively. Scanning electron microscopy (SEM) showed that the novel biological carrier in this study carried more bio–sediments which is closely related to the denitrification efficiency. The gas chromatography (GC) data showed that the nitrogen production of the immobilized bioreactor (99.85%) was higher than that of another experimental group (97.84%). Fluorescence excitation–emission matrix (EEM) and Fourier transform infrared spectrometer (FTIR) indicated the immobilized bioreactor emerged more extracellular polymeric substances (EPS) which was related to favourable biological stability under the DEP environment. Moreover, according to high–throughput sequencing data, the Zoogloea sp. L2 responsible for iron–reduction and denitrification was the main strain in this immobilized bioreactor.

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Topics: Bioreactor (55%), Diethyl phthalate (53%), Denitrification (52%)

6 results found

Journal ArticleDOI: 10.1016/J.BIORTECH.2021.125065
Qiao Chang1, Amjad Ali1, Junfeng Su1, Qiong Wen1  +3 moreInstitutions (1)
Abstract: The co-existence of nitrate, manganese (Mn), and antibiotics are of a wide concern. In this study, a denitrifying and manganese-oxidizing Zoogloea Q7 bacterium was immobilized using polyvinyl alcohol/sodium alginate with sponge cube (PVA/SA@sponge cube) in the reactor. The optimal operation parameters of the bioreactor were explored. Maximum nitrate, Mn(II), and tetracycline (TC) removal efficiencies of 93.00, 72.34, and 57.32% were achieved with HRT of 10 h, pH of 6.5, Mn(II) concentration of 20 mg L−1, and TC of 1 mg L−1, respectively. Fluorescence excitation-emission matrix (EEM) proved that the microorganism in the bioreactor was greatly active. Scanning electron microscope (SEM) images demonstrated that Zoogloea Q7 was commendably immobilized on the novel material. X-ray diffraction (XRD) analysis suggested that the bioprecipitate was mainly composed of MnO2 and MnCO3. Through high-throughput analysis, Zoogloea sp. Q7 was considered to be the dominant bacteria present in the bioreactor.

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Topics: Zoogloea (58%), Bioreactor (52%)

4 Citations

Journal ArticleDOI: 10.1016/J.BIORTECH.2021.125326
Liang Xu1, Amjad Ali1, Junfeng Su1, Tingling Huang1  +2 moreInstitutions (1)
Abstract: A kind of gel beads loaded with iron–carbon powder (Fe–C), Zoogloea sp. L2, and riboflavin (VB2) were prepared through cross–linking of sodium alginate (SA) to establish an immobilized bioreactor. The optimal ratio of SA beads was adjusted by orthogonal experiment. The change of oxidation–reduction potential (ORP) and the concentration of Fe2+ and Fe3+ showed that the addition of VB2 as a redox mediator can promote denitrification. Under the optimal conditions (carbon to nitrogen (C/N) ratio = 2.0, pH = 7.0, and hydraulic retention time (HRT) = 8 h), the nitrate removal efficiency (NRE) of bioreactor reached 98.48% (1.99 mg L–1h−1). Furthermore, Fourier transform infrared spectrometer (FTIR), Fluorescence excitation–emission matrix (EEM), X–ray diffraction (XRD), and gas chromatography (GC) analysis revealed that the immobilization and denitrification of the immobilized bioreactor were excellent. High throughput sequencing also showed that Zoogloea played a vital role in nitrate removal.

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Topics: Zoogloea (57%), Denitrification (53%), Bioreactor (50%)

2 Citations

Journal ArticleDOI: 10.1016/J.BIORTECH.2021.125690
Qiao Chang1, Amjad Ali1, Junfeng Su1, Qiong Wen1  +2 moreInstitutions (1)
Abstract: A Mn(II) oxidizing-denitrifying and tetracycline (TC) removal bacterium Zoogloea sp. MFQ7 was isolated in this study. Nitrogen removal was 83.49% by nitrogen balance experiment. The maximum removal efficiencies of nitrate, Mn(II), and TC by strain MFQ7 within 96 h was 100.00, 74.56, and 63.59% at C/N of 2.0, pH of 7.0, Mn(II) of 20 mg L−1, temperature of 30.0 °C, and TC of 0.2 mg L−1. SEM illustrated that biogenic manganese oxides (BMO) was petal-like, XRD and XPS analyses confirmed that MnO2 was the main component of BMO. Besides, the maximum adsorption capacity of BMO for TC was 52.21 mg g−1. FTIR detected the changes in TC adsorption by BMO. Pseudo-second-order model (R2 = 0.994) explained the adsorption kinetics of TC on BMO and Langmuir isotherm model (R2 = 0.983) suggested that it was homogeneous adsorption, thermodynamics data (ΔG

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Topics: Adsorption (53%), Langmuir adsorption model (51%)

1 Citations

Open accessJournal ArticleDOI: 10.1016/J.JHAZMAT.2021.127918
Liang Xu1, Junfeng Su1, Amjad Ali1, Qiao Chang1  +2 moreInstitutions (1)
Abstract: In this study, a nitrate–dependent ferrous (Fe2+) oxidizing strain under anaerobic conditions was selected and identified as XL4, which belongs to Aquabacterium. The Box–Behnken design (BBD) was used to optimize the growth conditions of strain XL4, and the nitrate removal efficiency of strain XL4 (with 10% inoculation dosage, v/v) could reach 91.41% under the conditions of 30.34 ℃, pH of 6.91, and Fe2+ concentration of 19.69 mg L–1. The results of Fluorescence excitation–emission matrix spectra (EEM) revealed that the intensity of soluble microbial products (SMP), aromatic proteins and the fulvic–like materials were obvious difference under different Fe2+ concentration, pH, and temperature. X–ray diffraction (XRD) data confirmed that the main components of bio–precipitation were Fe3O4 and FeO(OH), which were believed to be responsible for the adsorption of phenol and estradiol. Furthermore, the maximum adsorption capacity of bio–precipitation for phenol and estradiol under the optimal conditions were 192.6 and 65.4 mg g–1, respectively. On the other hand, the adsorption process of phenol and estradiol by bio–precipitation confirmed to the pseudo–second–order and Langmuir model, which shows that the adsorption process is chemical adsorption and occurs on the uniform surface.

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Topics: Aquabacterium (58%), Adsorption (56%), Langmuir adsorption model (54%) ... show more

Journal ArticleDOI: 10.1016/J.BIORTECH.2021.126249
Huu-Tuan Tran, Chitsan Lin, Xuan-Thanh Bui1, Minh Ky Nguyen  +6 moreInstitutions (3)
Abstract: Phthalates are well-known emerging contaminants that harm human health and the environment. Therefore, this review aims to discuss about the occurrence, fate, and phthalates concentration in the various environmental matrices (e.g., aquatic, sediment, soil, and sewage sludge). Hence, it is necessary to treat sources containing phthalates before discharging them to aqueous environment. Various advanced wastewater treatments including adsorption process (e.g., biochar, activated carbon), advanced oxidation processes (e.g., photo-fenton, ozonation, photocatalysis), and biological treatment (membrane bioreactor) have been successfully to address this issue with high removal efficiencies (70–95%). Also, the degradation mechanism was discussed to provide a comprehensive understanding of the phthalate removal for the reader. Additionally, key factors that influenced the phthalates removal efficiency of these technologies were identified and summarized with a view towards pilot-scale and industrial applications.

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Topics: Sewage treatment (54%)


62 results found

Open accessBook
01 Jan 1992-
Abstract: Set your standards with these standard methods. This is it: the most widely read publication in the water industry, your all-inclusive reference tool. This comprehensive reference covers all aspects of USEPA-approved water analysis methods. More than 400 methods - all detailed step-by-step; 8 vibrant, full-color pages of aquatic algae illustrations; Never-before-seen figures that will help users with toxicity testing and the identification of apparatus used in the methods; Over 300 superbly illustrated figures; A new analytical tool for a number of inorganic nonmetals; Improved coverage of data evaluation, sample preservation, and reagant water; And much more!

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78,276 Citations

Journal ArticleDOI: 10.1038/NRMICRO.2018.9
Abstract: Nitrogen is an essential component of all living organisms and the main nutrient limiting life on our planet By far, the largest inventory of freely accessible nitrogen is atmospheric dinitrogen, but most organisms rely on more bioavailable forms of nitrogen, such as ammonium and nitrate, for growth The availability of these substrates depends on diverse nitrogen-transforming reactions that are carried out by complex networks of metabolically versatile microorganisms In this Review, we summarize our current understanding of the microbial nitrogen-cycling network, including novel processes, their underlying biochemical pathways, the involved microorganisms, their environmental importance and industrial applications

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Topics: Nitrogen cycle (55%), Microbial ecology (51%), Comammox (51%)

861 Citations

Open accessJournal ArticleDOI: 10.1128/AEM.65.8.3697-3704.1999
Ana Fernández1, Suiying Huang, Sherry L. Seston, Jian Xing2  +3 moreInstitutions (2)
Abstract: The microbial community dynamics of a functionally stable, well-mixed, methanogenic reactor fed with glucose were analyzed over a 605-day period. The reactor maintained constant pH and chemical oxygen demand removal during this period. Thirty-six rrn clones from each of seven sampling events were analyzed by amplified ribosomal DNA restriction analysis (ARDRA) for the Bacteria and Archaea domains and by sequence analysis of dominant members of the community. Operational taxonomic units (OTUs), distinguished as unique ARDRA patterns, showed reproducible distribution for three sample replicates. The highest diversity was observed in the Bacteria domain. The 16S ribosomal DNA Bacteria clone library contained 75 OTUs, with the dominant OTU accounting for 13% of the total clones, but just 21 Archaea OTUs were found, and the most prominent OTU represented 50% of the clones from the respective library. Succession in methanogenic populations was observed, and two periods were distinguished: in the first, Methanobacterium formicicum was dominant, and in the second, Methanosarcina mazei and a Methanobacterium bryantii-related organism were dominant. Higher variability in Bacteria populations was detected, and the temporal OTU distribution suggested a chaotic pattern. Although dominant OTUs were constantly replaced from one sampling point to the next, phylogenetic analysis indicated that inferred physiologic changes in the community were not as dramatic as were genetic changes. Seven of eight dominant OTUs during the first period clustered with the spirochete group, although a cyclic pattern of substitution occurred among members within this order. A more flexible community structure characterized the second period, since a sequential replacement of a Eubacterium-related organism by an unrelated deep-branched organism and finally by a Propionibacterium-like species was observed. Metabolic differences among the dominant fermenters detected suggest that changes in carbon and electron flow occurred during the stable performance and indicate that an extremely dynamic community can maintain a stable ecosystem function.

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502 Citations

Journal ArticleDOI: 10.1021/ES00009A036
Abstract: The kinetics of the reduction of 10 monosubstituted nitrobenzenes (NBs) by Fe(II) has been investigated under various experimental conditions in aqueous suspensions of minerals commonly present in soils and sediments. Aqueous solutions of Fe(II) were unreactive. In suspensions of Fe(III)-containing minerals (magnetite, goethite, and lepidocrocite), Fe(II) readily reduced the NBs to the corresponding anilines in a strongly pH-dependent reaction. Our results suggest that on other mineral surfaces (γ-aluminum oxide, amorphous silica, titanium dioxide, and kaolinite) iron (hydr)oxide coatings are indispensable to promote the reduction of NBs by adsorbed Fe(ll). Apparent pseudo-first-order rate constants, k obs , were used to describe the initial kinetics of the NB reduction, covering several half-lives of the compounds. The distinct effect of substituents on k obs and the observed pronounced competition between different NBs indicate that precursor complex formation as well as the (re)generation of reactive surface sites are rate-determining steps in the overall reduction of the NBs. The results of this study demonstrate that Fe(ll) adsorbed on iron (hydr)oxide surfaces or surface coatings may play an important role in the reductive transformation of organic pollutants in subsurface environments. Our findings may also contribute to a better understanding of the various redox processes involved in groundwater remediation techniques based on Fe(0) as the bulk reductant.

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Topics: Lepidocrocite (54%), Oxide (51%), Goethite (51%)

436 Citations

Journal ArticleDOI: 10.1016/S0045-6535(02)00616-1
Jie Chen1, Eugene J. LeBoeuf2, Sheng Dai1, Baohua Gu1Institutions (2)
01 Feb 2003-Chemosphere
Abstract: Because of the well-known molecular complexity and heterogeneity of natural organic matter (NOM), an aquatic bulk NOM was fractionated into well-defined polyphenolic-rich and carbohydrate-rich subfractions. These fractions were systematically characterized by fluorescence emission, three dimensional excitation-emission matrices, and synchronous-scan excitation spectroscopy in comparison with those of the reference International Humic Substances Society soil humic acid and Suwannee River fulvic acid. Results indicate that fluorescence spectroscopy can be useful to qualitatively differentiate not only NOM compounds from varying origins but also NOM subcomponents with varying compositions and functional properties. The polyphenolic-rich NOM-PP fraction exhibited a much more intense fluorescence and a red shift of peak position in comparison with the carbohydrate-rich NOM-CH fraction. Results also indicate that synchronous excitation spectra were able to provide improved peak resolution and structural signatures such as peak positioning, shift, and intensity among various NOM components as compared with those of the emission and excitation spectra. In particular, the synchronous spectral peak intensity and its red shift in the region of about 450-480 nm may be used to indicate the presence or absence of high molecular weight and polycondensed humic organic components, or the multicomponent nature of NOM or NOM subcomponents.

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Topics: Humic acid (54%), Fluorescence spectroscopy (52%)

379 Citations