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Forty strains of Mn-oxidizing microalgae (MnOMs) with different Mn2+ oxidation mechanisms were identified from two aquatic environments. Among them, three strains of isolates (Chlamydomonas sp. WH1–1, Chlamydomonas sp. WH1–4, and Chlorella sp. WH2–5) oxidize Mn2+ by increasing the ambient pH and by secreting Mn oxidation factors (e.g., superoxide-production enzymes and/or other Mn oxidases) into the extracellular environment at the same time. In carbamazepine (CBZ) removal by MnOMs and/or Bio-MnOx, the combination of MnOMs and Bio-MnOx significantly increased the CBZ (1 mg/L) removal efficiency from 36.05% (by MnOMs alone) and 20.11% (by Bio-MnOx alone) to 80.13% by two synergistic mechanisms. One of the synergistic mechanisms was confirmed as that the Mn2+ was re-oxidized by MnOMs to Bio-MnOx, which can promote the CBZ removal, and another was the mutual exchange of degradation products of CBZ as shared reactants between MnOMs and Bio-MnOx. The degradation intermediates of CBZ were analyzed using high-performance liquid chromatography-tandem mass spectrometry, based on which the CBZ degradation pathway by MnOMs and Bio-MnOx was proposed. These findings expand existing knowledge on the Mn2+ oxidation mechanisms of MnOMs, and indicate that MnOMs and their generated Bio-MnOx are promising for the removal of CBZ or other pharmaceutical contaminants from wastewater.
Quanfeng Wang; Haoxuan Wei; Wenbo Liu; Jun Zhai. Carbamazepine removal by the synergistic effect of manganese-oxidizing microalgae and biogenic manganese oxides. Journal of Hazardous Materials 2021, 419, 126530 .
AMA StyleQuanfeng Wang, Haoxuan Wei, Wenbo Liu, Jun Zhai. Carbamazepine removal by the synergistic effect of manganese-oxidizing microalgae and biogenic manganese oxides. Journal of Hazardous Materials. 2021; 419 ():126530.
Chicago/Turabian StyleQuanfeng Wang; Haoxuan Wei; Wenbo Liu; Jun Zhai. 2021. "Carbamazepine removal by the synergistic effect of manganese-oxidizing microalgae and biogenic manganese oxides." Journal of Hazardous Materials 419, no. : 126530.
BACKGROUND Sonophotocatalysis has gained great attention for researches and practical applications to treat refractory organic dye from wastewater. However, its degradation efficiency needs to be improved further. To further enhance the sonophotocatalytic performance, here we report a novel H2O2 assisted TiO2 based sonophotocatalyic system (H2O2-US-UV/TiO2) for degradation of acid orange 7 (AO7). RESULTS Effects of operating parameters including the catalysts dosage, concentration of the oxidative agents, and initial pH were analyzed through response surfaced method coupled with Box–Behnken experimental design (RSM-BBD) and experiments. Introducing H2O2 into the US-UV/TiO2 system can significantly enhance the AO7 removal. A quadratic model was proposed for predicting AO7 degradation using the RSM-BBD method, and the statistical significance of the model was confirmed by the analysis of variance (ANOVA). The real AO7 removal efficiency (95.8%) at experimental condition of 0.5g/L TiO2, 4mM H2O2, and initial pH of 3 was comparable with the predicated value (98.6%) obtained from this model. Quenching tests revealed that the ·OH was the key reactive species in the sonophotocatalytic system. The degradation products including 2-naphthol, 4-carboxylphenylglycine, cinnamic acid and 1,10-Decanediol were identified. CONCLUSION Adding H2O2 has improved the degradation performance of AO7 in US-UV/TiO2 system, the H2O2 concentration was the more significant experimental factor than initial pH and TiO2 dosage. A degradation pathway of AO7 removal was suggested according to the result of LC-MS. The novel hybrid H2O2-US-UV/TiO2 system can be utilized as an efficient process for recalcitrant dye wastewater treatment.
Haoxuan Wei; Hasibur Rahaman; Jujiao Zhao; Dayan Li; Jun Zhai. Hydrogen peroxide enhanced sonophotocatalytic degradation of acid orange 7 in aqueous solution: optimization by B ox– B ehnken design. Journal of Chemical Technology & Biotechnology 2021, 96, 2647 -2658.
AMA StyleHaoxuan Wei, Hasibur Rahaman, Jujiao Zhao, Dayan Li, Jun Zhai. Hydrogen peroxide enhanced sonophotocatalytic degradation of acid orange 7 in aqueous solution: optimization by B ox– B ehnken design. Journal of Chemical Technology & Biotechnology. 2021; 96 (9):2647-2658.
Chicago/Turabian StyleHaoxuan Wei; Hasibur Rahaman; Jujiao Zhao; Dayan Li; Jun Zhai. 2021. "Hydrogen peroxide enhanced sonophotocatalytic degradation of acid orange 7 in aqueous solution: optimization by B ox– B ehnken design." Journal of Chemical Technology & Biotechnology 96, no. 9: 2647-2658.
The assessment of the impacts of climate change on hydrology is important for better water resources management. However, few studies have been conducted in semi-arid Africa, even less in Madagascar. Here we report, climate-induced future hydrological prediction in Mangoky river, Madagascar using an artificial neural network (ANN) and the soil and water assessment tool (SWAT). The current study downscaled two global climate models on the mid-term, noted the 2040s (2041–2050) and long-term, noted 2090s (2091–2099) under two shared socioeconomic pathways (SSP) scenarios, SSP 3–7.0 and SSP 5–8.5. Statistical indices of both ANN and SWAT showed good performance (R2 > 0.65) of the models. Our results revealed a rise in maximum temperature (4.26–4.69 °C) and minimum temperature (2.74–3.01 °C) in the 2040s and 2090s. Under SSP 3–7.0 and SSP 5–8.5, a decline in the annual precipitation is projected in the 2040s and increased the 2090s. This study found that future precipitation and temperature could significantly decrease annual runoff by 60.59% and 73.77% in the 2040s; and 25.18% and 23.45% in the 2090s under SSP 3–7.0 and SSP 5–8.5, respectively. Our findings could be useful for the adaptation to climate change, managing water resources, and water engineering.
Mirindra Rabezanahary Tanteliniaina; Hasibur Rahaman; Jun Zhai. Assessment of the Future Impact of Climate Change on the Hydrology of the Mangoky River, Madagascar Using ANN and SWAT. Water 2021, 13, 1239 .
AMA StyleMirindra Rabezanahary Tanteliniaina, Hasibur Rahaman, Jun Zhai. Assessment of the Future Impact of Climate Change on the Hydrology of the Mangoky River, Madagascar Using ANN and SWAT. Water. 2021; 13 (9):1239.
Chicago/Turabian StyleMirindra Rabezanahary Tanteliniaina; Hasibur Rahaman; Jun Zhai. 2021. "Assessment of the Future Impact of Climate Change on the Hydrology of the Mangoky River, Madagascar Using ANN and SWAT." Water 13, no. 9: 1239.
Wastewater treatment plants (WWTPs) are now facing the challenges of high cost, high energy consumption, while effluent quality is relatively poor with total nitrogen concentration exceeding the requirement of reuse. This study investigated the performance of contaminants removal, especially nitrogen (N) by a hybrid oxidation ditch (H-OD) which is based on the theory of integrated fixed-film activated sludge (IFAS) under different control factors. The aeration rate, return ratio and hydraulic loading were controlled at 0.4 m3/h, 100% and 0.55 m3/m3·h respectively as the optimized control parameter values. Under the optimized conditions, the effluent concentration of COD and NH4+-N were 35.8 mg/L, 1.04 mg/L, respectively, while the suspended solid (SS) was below 10 mg/L. The average removal rate of TN was 72.8%, and simultaneous nitrification and denitrification (SND) was achieved at 42.7%. Besides, when the C/N ratio was maintained from 2.12 to 5.56, the complete nitrification and denitrification was obtained. The results showed that the H-OD was suitable for nitrogen removal and SND was very attractive for practical engineering applications.
Kwami Coco Dzidula Agbewornu; Tanveer M. Adyel; Jun Zhai. Optimizing nitrogen removal in a hybrid oxidation ditch. Journal of Environmental Chemical Engineering 2021, 9, 105443 .
AMA StyleKwami Coco Dzidula Agbewornu, Tanveer M. Adyel, Jun Zhai. Optimizing nitrogen removal in a hybrid oxidation ditch. Journal of Environmental Chemical Engineering. 2021; 9 (4):105443.
Chicago/Turabian StyleKwami Coco Dzidula Agbewornu; Tanveer M. Adyel; Jun Zhai. 2021. "Optimizing nitrogen removal in a hybrid oxidation ditch." Journal of Environmental Chemical Engineering 9, no. 4: 105443.
Organotrophic anammox is a promising process for treating both nitrogen and organic containing wastewater than that of the traditional autotrophic anammox for sole nitrogen removal. However pathways of nitrogen removal particularly at metagenomic level in both processes are still unknown. Here we report, metabolic pathways of nitrogen removal in two lab-scale sequencing batch reactors (SBR), one autotrophic and another organotrophic (TOC/TN = 0.1) anammox bacteria incubated over 220 days. Both reactors showed satisfactory nitrogen removal with 840.31 mg N/L.d and 786.81 mg N/L.d for autotrophic and organotrophic anammox reactors respectively. Four anammox species namely Candidatus B. fulgida, B. sinica, J. caeni and Candidatus K. stuttgartiensis were identified in both reactors. The Candidatus K. stuttgartiensis (4%) was dominant in autotrophic reactor whereas Candidatus J. caeni (10%) in the organotrophic reactor. The supply of organic promoted the growth of anammox bacteria more than three times higher than that of the autotrophic anammox reactor. The functional genes related to the DNRA pathway was obtained in all anammox species except for Candidatus K. stuttgartiensis. The co-existence of other DNRA (Armatimonadetes and Thauera) and partial denitrifying bacteria (Chloroflexi) was also found in both reactors. Moreover, functional genes related to acetate metabolism by acetyl-CoA way were obtained in all anammox bacteria except Candidatus B. fulgida which showed alternative ackA/Pac-t pathways in organic anammox reactor. Overall current results suggest that the anammox, DNRA and partial denitrification were the key nitrogen transformation pathways, particularly in organotrophic anammox reactor. Our findings will improve understanding of the practical application of organotrophic anammox for wider wastewater treatment.
Xuejiao Yin; Hasibur Rahaman; Wenbo Liu; Jacek Mąkinia; Jun Zhai. Comparison of nitrogen and VFA removal pathways in autotrophic and organotrophic anammox reactors. Environmental Research 2021, 197, 111065 .
AMA StyleXuejiao Yin, Hasibur Rahaman, Wenbo Liu, Jacek Mąkinia, Jun Zhai. Comparison of nitrogen and VFA removal pathways in autotrophic and organotrophic anammox reactors. Environmental Research. 2021; 197 ():111065.
Chicago/Turabian StyleXuejiao Yin; Hasibur Rahaman; Wenbo Liu; Jacek Mąkinia; Jun Zhai. 2021. "Comparison of nitrogen and VFA removal pathways in autotrophic and organotrophic anammox reactors." Environmental Research 197, no. : 111065.
Metal–organic frameworks (MOFs) derived CoFe2O4 is regarded as a promising catalyst in pollutants control due to its good performance for peroxymonosulfate (PMS) activation. However, the study towards organic dyes degradation is rare and the mechanism of the synergy effect of Co and Fe is not clarified. Herein, the MOFs derived M-Co1+xFe2-xO4 with more Co(III) in octahedral sites was prepared and used to degrade organic dyes by activating PMS. Under optimized conditions, the Rhodamine B (RhB) degradation kinetics rate of M-Co1+xFe2-xO4 is 0.260 min-1, which is 20 times higher than the commercial Co3O4 (0.013 min-1). SO4•- plays the vital role in RhB degradation and the contribution of Co(III) in octahedral sites is greater than that of Fe for PMS activation. Under weak acidic condition (pH 5), the effect of surface adsorbed OH- on PMS activation is negligible meanwhile the valence conversion of Fe is absent, implying the mechanism of synergy effect of Co and Fe under such condition is different from what previously reported. This work would shed lights on understanding the origin of the activity of CoFe2O4 in PMS activation and developing PMS-based technologies for organic dyes wastewater treatment.
Jujiao Zhao; Haoxuan Wei; Peisong Liu; Anran Zhou; Xia Lin; Jun Zhai. Activation of peroxymonosulfate by metal–organic frameworks derived Co1+xFe2−xO4 for organic dyes degradation: A new insight into the synergy effect of Co and Fe. Journal of Environmental Chemical Engineering 2021, 9, 105412 .
AMA StyleJujiao Zhao, Haoxuan Wei, Peisong Liu, Anran Zhou, Xia Lin, Jun Zhai. Activation of peroxymonosulfate by metal–organic frameworks derived Co1+xFe2−xO4 for organic dyes degradation: A new insight into the synergy effect of Co and Fe. Journal of Environmental Chemical Engineering. 2021; 9 (4):105412.
Chicago/Turabian StyleJujiao Zhao; Haoxuan Wei; Peisong Liu; Anran Zhou; Xia Lin; Jun Zhai. 2021. "Activation of peroxymonosulfate by metal–organic frameworks derived Co1+xFe2−xO4 for organic dyes degradation: A new insight into the synergy effect of Co and Fe." Journal of Environmental Chemical Engineering 9, no. 4: 105412.
The coupling transformation of carbon, nitrogen and sulfur compounds has been studied in lab-scale and pilot-scale constructed wetlands (CWs), but few studies investigated full-scale CW. In this study, we used batch experiments to investigate the potentials of carbon, nitrogen and sulfur transformation in a long-term operated, full-scale horizontal subsurface flow wetland. The sediments collected from the HSFW were incubated for 48 h in the laboratory with supplying various dosages of carbon, nitrogen and sulfur compounds. The results showed that heterotrophic denitrification was the main pathway. At the same time, the sulfide (S2−)-based autotrophic denitrification was also present. Increasing TOC concentration or NO3− concentration could promote heterotrophic denitrification but did not inhibit the sulfide-based autotrophic denitrification. In our experiment, the highest NO3− removal via autotrophic denitrification was 25.23% while that via heterotrophic denitrification was 73.66%, leading to the total NO3− removal of 98.89%. The results also demonstrated that NO3− rather than NO2− was the preferable electron acceptor for both heterotrophic and sulfide-based autotrophic denitrification in the CW. Increasing S2− concentrations promote NO3− removal from 12.99% to 25.23% without organic carbon, but varying NO3− or NO2− has no effects. These results indicated that concentrations of S2−, instead of NO3− or NO2−, was the limiting factor for sulfide-based autotrophic denitrification in the studied CW. The microbial community analysis and correlation analysis between the transformation of carbon, nitrogen and sulfur compounds and relative abundance of bacteria further confirmed that in the CW, the key pathways coupling transformation were heterotrophic denitrification and sulfide-based autotrophic denitrification. Overall, the current study will enhance understanding of carbon, nitrogen, and sulfur transformation in CW and support better design and treatment efficiency.
Wenbo Liu; Hasibur Rahaman; Jacek Mąkinia; Jun Zhai. Coupling transformation of carbon, nitrogen and sulfur in a long-term operated full-scale constructed wetland. Science of The Total Environment 2021, 777, 146016 .
AMA StyleWenbo Liu, Hasibur Rahaman, Jacek Mąkinia, Jun Zhai. Coupling transformation of carbon, nitrogen and sulfur in a long-term operated full-scale constructed wetland. Science of The Total Environment. 2021; 777 ():146016.
Chicago/Turabian StyleWenbo Liu; Hasibur Rahaman; Jacek Mąkinia; Jun Zhai. 2021. "Coupling transformation of carbon, nitrogen and sulfur in a long-term operated full-scale constructed wetland." Science of The Total Environment 777, no. : 146016.
Due to their vulnerability, understanding the impacts of global warming on rainfall is important for a tropical country and islands. This research aimed to assess the impact of global warming on rainfall in Madagascar, using the Mann-Kendall test, continuous wavelet transform, and polynomial regression. The result showed that the annual, seasonal maximum, and minimum temperature increased, while elevation amplified the increase of maximum temperature. Different trends in rainfall were found in the 22 regions of Madagascar but in general, the increasing trend in rainfall was prominent at a higher elevation than lower elevation. The annual rainfall decreased up to −5 mm per year for the regions located below 450 m of altitude while increased up to +5 mm per year above 500 m. We found that the wet becomes wetter with an important increase in rainfall in summer and the increase in temperature influenced the rainfall. The annual rainfall increased with temperature and elevation. However, if the increase in temperature was more than 0.03 °C per year, the annual rainfall increased regardless of elevation. The knowledge of the elevation dependence of the impact of warming on rainfall is important for water resources management and climate change adaptation strategies, especially for island nations and African countries.
Mirindra Finaritra Rabezanahary Tanteliniaina; Jia Chen; Tanveer M. Adyel; Jun Zhai. Elevation Dependence of the Impact of Global Warming on Rainfall Variations in a Tropical Island. Water 2020, 12, 3582 .
AMA StyleMirindra Finaritra Rabezanahary Tanteliniaina, Jia Chen, Tanveer M. Adyel, Jun Zhai. Elevation Dependence of the Impact of Global Warming on Rainfall Variations in a Tropical Island. Water. 2020; 12 (12):3582.
Chicago/Turabian StyleMirindra Finaritra Rabezanahary Tanteliniaina; Jia Chen; Tanveer M. Adyel; Jun Zhai. 2020. "Elevation Dependence of the Impact of Global Warming on Rainfall Variations in a Tropical Island." Water 12, no. 12: 3582.
Combination of sulfate radical (SO4−) and singlet oxygen (1O2) could enhance the removal of organic pollutants in PMS activation because of the high-selective oxidation of electrophilic compounds by 1O2. Co oxides are highly active towards PMS activation, but improving the generation of 1O2 in PMS activation with Co oxides as catalysts remains a great challenge. Herein, the Zn doped Co oxides (ZnCoOx) was prepared by calcining Zn doped ZIF-67 in air. The oxygen vacancies content of ZnCoOx could be adjusted by controlling Zn doping level and the presence of oxygen vacancies leads to the generation of 1O2 in ZnCoOx/PMS system. The optimized ZnCoOx-2 presents the kinetic constant of 0.538 min−1 for Rhodamine B removal, which is 14.2 times higher than that of undoped sample and 38.4 times higher than that of commercial Co3O4. 1O2 and SO4− exist in ZnCoOx/PMS system while 1O2 plays the dominant role for pollutants removal. The oxygen vacancies of ZnCoOx are demonstrated to be responsible for the generation of 1O2 and the mechanism is further investigated. This study provided an efficient catalyst to combine the advantages of 1O2 and SO4− for pollutants removal by PMS activation, and the results could open a new avenue for development of heterogeneous catalysts for PMS activation.
Jujiao Zhao; Fengchao Li; Haoxuan Wei; Hainan Ai; Li Gu; Jia Chen; Lei Zhang; Minghui Chi; Jun Zhai. Superior performance of ZnCoOx/peroxymonosulfate system for organic pollutants removal by enhancing singlet oxygen generation: The effect of oxygen vacancies. Chemical Engineering Journal 2020, 409, 128150 .
AMA StyleJujiao Zhao, Fengchao Li, Haoxuan Wei, Hainan Ai, Li Gu, Jia Chen, Lei Zhang, Minghui Chi, Jun Zhai. Superior performance of ZnCoOx/peroxymonosulfate system for organic pollutants removal by enhancing singlet oxygen generation: The effect of oxygen vacancies. Chemical Engineering Journal. 2020; 409 ():128150.
Chicago/Turabian StyleJujiao Zhao; Fengchao Li; Haoxuan Wei; Hainan Ai; Li Gu; Jia Chen; Lei Zhang; Minghui Chi; Jun Zhai. 2020. "Superior performance of ZnCoOx/peroxymonosulfate system for organic pollutants removal by enhancing singlet oxygen generation: The effect of oxygen vacancies." Chemical Engineering Journal 409, no. : 128150.
Mn(III) has been regarded as the origin of oxidative reactivity of MnO2 recently, however this remains controvertible. Herein, carbamazepine (CBZ), a typical refractory pharmaceutical, was treated by δ-, α-, β-, and γ-MnO2 and the role of Mn(III) was investigated. After the removal of Mn(III) by pyrophosphate washing, the δ-MnO2 exhibited a higher kinetics rate (0.180 min−1) than the sample before washing (0.075 min−1). Dissolved Mn(III) in the forms of acetate-complex Mn(III), newly acid-dissolved Mn(III) from MnO2 solid, and in-situ generated Mn(III) showed negligible oxidative reactivity towards the oxidation of CBZ. These evidenced that Mn(III) did not play a critical role in the oxidation of CBZ. The oxidative reactivity of MnO2 with different structures for the oxidation of CBZ followed the order: δ-MnO2 >> > α-MnO2 ≈ γ-MnO2 > β-MnO2. Density functional theory calculations suggested that the crystalline plane of δ-MnO2 significantly contributed to the oxidation of CBZ, thus leading to the superior performance of δ-MnO2. A new surface reaction dominated mechanism was proposed, which implies that the oxidative reactivity of MnO2 may not result from Mn(III) as previously believed. These findings could shed light on the understanding of MnO2-involved oxidation in water treatment and natural processes.
Jujiao Zhao; Ruihan Liao; Quanfeng Wang; Yixuan Chen; Wenbo Liu; Bo Shang; Jun Zhai. A new insight into the mechanism of carbamazepine oxidation by MnO2: Crystalline structure versus Mn(III). Science of The Total Environment 2020, 753, 141835 .
AMA StyleJujiao Zhao, Ruihan Liao, Quanfeng Wang, Yixuan Chen, Wenbo Liu, Bo Shang, Jun Zhai. A new insight into the mechanism of carbamazepine oxidation by MnO2: Crystalline structure versus Mn(III). Science of The Total Environment. 2020; 753 ():141835.
Chicago/Turabian StyleJujiao Zhao; Ruihan Liao; Quanfeng Wang; Yixuan Chen; Wenbo Liu; Bo Shang; Jun Zhai. 2020. "A new insight into the mechanism of carbamazepine oxidation by MnO2: Crystalline structure versus Mn(III)." Science of The Total Environment 753, no. : 141835.
The processes of (n)ZVI/AC((nano)zero valent iron/activated carbon)micro-electrolysis were applied for nitrate removal from groundwater, aiming to reduce nitrate to N2, an environmentally friendly end product. (n)ZVI was utilized and combined with selected commercial AC to form the micro-electrolysis. Effect of different operational parameters, including reductant dosage, (n)ZVI/AC ratios, and reaction pH, on nitrate and TN removal were cleared. The results showed that nZVI presents higher reaction activities than ZVI in micro-electrolysis. With the increase of the (n)ZVI/AC mass ration from 1:2 to 2:1, the TN removal increased from 16.8% to 38.9%, then declined with the further increase of the ratio. The nitrate removal was negatively correlated with the initial pH of the solution. Compared to ZVI particles, even with a lower dosage, nZVI presented 100% nitrate removal at acidic and neutral pH conditions, and TN removal could maintain higher than 35% with pH lower than 9.0. A kinetic model was also established to explain the pathways of nitrate removal, and the results indicated that AC not only enriched nitrate as an adsorbent but also present highly potential in catalytic converting nitrate to N2. The technique presented great potentials in removing nitrate from water and a promising application prospect.
Ningfan Song; Jian Xu; Yunpeng Cao; Fan Xia; Jun Zhai; Hainan Ai; Dezhi Shi; Li Gu; Qiang He. Chemical removal and selectivity reduction of nitrate from water by (nano) zero-valent iron/activated carbon micro-electrolysis. Chemosphere 2020, 248, 125986 .
AMA StyleNingfan Song, Jian Xu, Yunpeng Cao, Fan Xia, Jun Zhai, Hainan Ai, Dezhi Shi, Li Gu, Qiang He. Chemical removal and selectivity reduction of nitrate from water by (nano) zero-valent iron/activated carbon micro-electrolysis. Chemosphere. 2020; 248 ():125986.
Chicago/Turabian StyleNingfan Song; Jian Xu; Yunpeng Cao; Fan Xia; Jun Zhai; Hainan Ai; Dezhi Shi; Li Gu; Qiang He. 2020. "Chemical removal and selectivity reduction of nitrate from water by (nano) zero-valent iron/activated carbon micro-electrolysis." Chemosphere 248, no. : 125986.
Bioremediation of pharmaceutical-contaminated wastewater using microalgae has attracted increasing attention. Cyanobacteria, which are important prokaryotic microalgae, are widely distributed in different water environments, and have the advantages of simple culture and a fast growth rate. However, studies on either the toxicity of pharmaceutical contaminants (PhCs) to cyanobacteria or the removal of PhCs by cyanobacteria are scarce. In this study, carbamazepine (CBZ) and Spirulina platensis were selected as model PhCs and cyanobacteria, respectively. CBZ (>1 mg/L) had toxicity effects on S. platensis, showing maximal growth inhibition (34.0%) at 100 mg/L after 10 days of cultivation. At CBZ < 25 mg/L, S. platensis showed a trend similar to that of eukaryotic microalgae in increasing superoxide dismutase and catalase activities and content of chlorophylls, carotenoids, carbohydrates, and lipids. These results indicated that S. platensis had a similar protective mechanism to CBZ toxicity as that of the eukaryotic microalgae. Increasing CBZ concentration (50–100 mg/L) significantly decreased these biochemical characteristics and photosynthetic activity owing to the serious damage of the structure and function of S. platensis. However, with increasing cultivation time, the growth and photosynthetic activity of S. platensis recovered from the toxicity of CBZ. S. platensis showed a maximum of 30.97 ± 1.30% removal of CBZ (1 mg/L), mainly through biodegradation. Addition of 0.3 mg/L glucose enhanced this removal efficiency to 50.13 ± 2.51% via co-metabolism. These findings indicated that S. platensis can be used for the removal of CBZ or other PhCs from wastewater.
Quanfeng Wang; Wenbo Liu; Xiaoting Li; Rong Wang; Jun Zhai. Carbamazepine toxicity and its co-metabolic removal by the cyanobacteria Spirulina platensis. Science of The Total Environment 2019, 706, 135686 .
AMA StyleQuanfeng Wang, Wenbo Liu, Xiaoting Li, Rong Wang, Jun Zhai. Carbamazepine toxicity and its co-metabolic removal by the cyanobacteria Spirulina platensis. Science of The Total Environment. 2019; 706 ():135686.
Chicago/Turabian StyleQuanfeng Wang; Wenbo Liu; Xiaoting Li; Rong Wang; Jun Zhai. 2019. "Carbamazepine toxicity and its co-metabolic removal by the cyanobacteria Spirulina platensis." Science of The Total Environment 706, no. : 135686.
This study aims to enhance hydrolysis and anaerobic digestion of corn cob (CC) by using food waste (FW) pretreatment. FW, which tends to be acidification in fermentation, was applied in this process as an acid-like agent to accelerate lignocellulose hydrolysis, aiming to promote methane yield in further digestion process. The effect of FW pretreatment on pH, soluble chemical oxygen demand (SCOD), volatile fatty acids (VFAs), cellulose/hemicellulose contents and cellulose crystallinity are specially focused. FW:CC = 1:3 based on volatile solid (VS) was found to be the optimal mixing ratio in pretreatment and its hydrolysis efficiency was 28% higher than the control group. An increase of 13.2% in cellulose reduction and a decrease of 6.7% in cellulose crystallinity was achieved at this ratio. Supplementation of FW increased VFA concentrations in slurry mixture that directly change the activities of enzymes and microorganisms. In the stage of methane production, the digester A3 (FW:CC = 1:6 based on VS) with higher hydrolysis efficiency presented the best performance in methane production with a specific methane yield of 401.6 mL/g·VS, due to the recovery of the pH in this digester to the optimal pH range for methanogens’ metabolism (pH 6.3–7.2). Kinetics studies of cellulose/hemicellulose degradation indicated that the pretreatment of FW could improve the degradation of cellulose. Three-dimensional excitation emission matrix (3DEEM) results further confirmed that FW play an important role in lignocellulose hydrolysis. In addition, variations of lignocellulosic textures during the pretreatment were also cleared by using field emission-scanning electron microscopy (FE-SEM) analysis.
Huijing Zou; Qin Jiang; Ruilin Zhu; Yongdong Chen; Tong Sun; Mingxing Li; Jun Zhai; Dezhi Shi; Hainan Ai; Li Gu; Qiang He. Enhanced hydrolysis of lignocellulose in corn cob by using food waste pretreatment to improve anaerobic digestion performance. Journal of Environmental Management 2019, 254, 109830 .
AMA StyleHuijing Zou, Qin Jiang, Ruilin Zhu, Yongdong Chen, Tong Sun, Mingxing Li, Jun Zhai, Dezhi Shi, Hainan Ai, Li Gu, Qiang He. Enhanced hydrolysis of lignocellulose in corn cob by using food waste pretreatment to improve anaerobic digestion performance. Journal of Environmental Management. 2019; 254 ():109830.
Chicago/Turabian StyleHuijing Zou; Qin Jiang; Ruilin Zhu; Yongdong Chen; Tong Sun; Mingxing Li; Jun Zhai; Dezhi Shi; Hainan Ai; Li Gu; Qiang He. 2019. "Enhanced hydrolysis of lignocellulose in corn cob by using food waste pretreatment to improve anaerobic digestion performance." Journal of Environmental Management 254, no. : 109830.
The considerable amount of methane (CH4) emitted from constructed wetlands (CWs) during wastewater treatment has the potential to intensify global climate change. Reducing CH4 emissions from CWs is, therefore, an important step in mitigating global warming. In this study, we compared CH4 emission fluxes from long-term operated pilot-scale vertical-flow CWs with natural manganese ore (Mn-CW) and gravel (Gr-CW, control) as a substrate without any seeding sludge or sediment added. The CH4 emission from the Mn-CW (3.01 ± 0.38 g C/m2/day) was significantly lower than the emission from the Gr-CW (5.50 ± 0.24 g C/m2/day). Mn(IV)-dependent anaerobic oxidation of CH4 (Mn-AOM) occurred in the Mn-CW, and was estimated to account for 66% of the total CH4 emissions reduction. The anaerobic methanotrophic archaea lineage ANME-2d present in the Mn-CW was considered the likely methanotroph that mediated Mn-AOM. Anaerobic fermentation, dissimilatory Mn reduction, and hydrogenotrophic methanogenesis were the main processes responsible for the degradation of organics in the Mn-CW. The acetoclastic methanogen archaea were suppressed in the Mn-CW. For the first time, Mn-AOM was demonstrated to be spontaneously present in the freshwater CWs. Our findings also demonstrated a novel approach to mitigate CH4 emissions from CWs, and indicate potential strategies against global climate change.
Wenbo Liu; Haiwen Xiao; Hongpu Ma; Yuanyuan Li; Tanveer M. Adyel; Jun Zhai. Reduction of methane emissions from manganese-rich constructed wetlands: Role of manganese-dependent anaerobic methane oxidation. Chemical Engineering Journal 2019, 387, 123402 .
AMA StyleWenbo Liu, Haiwen Xiao, Hongpu Ma, Yuanyuan Li, Tanveer M. Adyel, Jun Zhai. Reduction of methane emissions from manganese-rich constructed wetlands: Role of manganese-dependent anaerobic methane oxidation. Chemical Engineering Journal. 2019; 387 ():123402.
Chicago/Turabian StyleWenbo Liu; Haiwen Xiao; Hongpu Ma; Yuanyuan Li; Tanveer M. Adyel; Jun Zhai. 2019. "Reduction of methane emissions from manganese-rich constructed wetlands: Role of manganese-dependent anaerobic methane oxidation." Chemical Engineering Journal 387, no. : 123402.
Organotrophic anaerobic ammonium oxidation (anammox) bacteria can utilize small volatile fatty acids with nitrate as electron acceptors with less energy consumption and no biomass production. To achieve a faster and stable start-up of organotrophic anammox process, in this study, the growth of organotrophic anammox bacteria seeded from hybrid constructed wetland (CW) sediment under different TOC/TN ratios and different chloramphenicol concentrations were investigated. The incubation study was conducted at the TOC/TN ratio = 0.0375–0.1 or 0.1–0.2 for the period of over five months by using serum bottles. The anammox bacteria revealed a higher activity when the TOC/TN ratio was 0.1, with the removal efficiency of NH4+-N (60–80%) and NO2−-N (~100%). The relative abundances of anammox in the incubated CW sediment were about 30% higher in comparison with the municipal waste water treatment plant sludge, suggesting the CW sediment could be a viable source for the enrichment of organotrophic anammox bacteria. On the contrary, the continuous addition of 50 mg/L chloramphenicol completely inhibited the anammox activity in our study. Following the results of the batch tests, Candidatus Brocadia caroliniensis was successfully enriched with the CW sediment in an auto-controlled SBR for the period of 40 days.
Xuejiao Yin; Jun Zhai; Wei Hu; Yue Li; Hasibur Rahaman; Jacek Mąkinia. A fast start-up of the organotrophic anammox process inoculated with constructed wetland sediment. Ecological Engineering 2019, 138, 454 -460.
AMA StyleXuejiao Yin, Jun Zhai, Wei Hu, Yue Li, Hasibur Rahaman, Jacek Mąkinia. A fast start-up of the organotrophic anammox process inoculated with constructed wetland sediment. Ecological Engineering. 2019; 138 ():454-460.
Chicago/Turabian StyleXuejiao Yin; Jun Zhai; Wei Hu; Yue Li; Hasibur Rahaman; Jacek Mąkinia. 2019. "A fast start-up of the organotrophic anammox process inoculated with constructed wetland sediment." Ecological Engineering 138, no. : 454-460.
To enhance microalgal growth and optimize ammonium utilization, the effect of ammonium on microalgal growth, biochemical composition and photosynthetic performance were investigated by mixotrophic cultivation of microalga Spirulina platensis comparing with autotrophic cultivation. The results indicated that elevated ammonium significantly affected the microalgal growth, but the microalga in mixotrophic cultivation showed better growth and stronger tolerance to higher ammonium. The microalgal proteins were increased by increasing nitrogen concentration. The synthesis of microalgal carbohydrates was inhibited by higher ammonium, especially in mixotrophic cultivation. The addition of ammonium decreased the microalgal lipids in autotrophic cultivation but increased microalgal lipids in mixotrophic cultivation. Ammonium negatively affected the microalgal photosynthetic performance. The inhibition was intensified by elevated ammonium, inducing stronger photosystem protection mechanism, particularly in mixotrophic cultivation. The rate of ammonium inhibition to the microalgal photosystem was quick in the early stage by decreasing electron transport rate of PS II.
Xiaoting Li; Wei Li; Jun Zhai; Haoxuan Wei; Quanfeng Wang. Effect of ammonium nitrogen on microalgal growth, biochemical composition and photosynthetic performance in mixotrophic cultivation. Bioresource Technology 2018, 273, 368 -376.
AMA StyleXiaoting Li, Wei Li, Jun Zhai, Haoxuan Wei, Quanfeng Wang. Effect of ammonium nitrogen on microalgal growth, biochemical composition and photosynthetic performance in mixotrophic cultivation. Bioresource Technology. 2018; 273 ():368-376.
Chicago/Turabian StyleXiaoting Li; Wei Li; Jun Zhai; Haoxuan Wei; Quanfeng Wang. 2018. "Effect of ammonium nitrogen on microalgal growth, biochemical composition and photosynthetic performance in mixotrophic cultivation." Bioresource Technology 273, no. : 368-376.
Carbamazepine (CBZ), a widely used antiepileptic drug, is refractory to biological wastewater treatment. Rapid removal of CBZ is possible using synthetic manganese oxide (δ-MnO2) but the removal mechanisms require further investigation. In this study, CBZ degradation by δ-MnO2 was carried out at different pH to further explore the degradation mechanisms. Results show that CBZ degradation by δ-MnO2 was highly pH dependent, and rapid degradation occurred when pH <2.8. Based on the density functional theory calculations, increasing [H+] not only increased the reactivity of δ-MnO2, but also enhanced the secondary reactions of the intermediates. During the degradation process, protonation of CBZ degradation intermediates, instead of CBZ, played an important role. The overall kinetics of CBZ degradation was then described by the retarded first-order model. The initial rate (rinit) in the model between pH 2.0 and 6.2 was determined to be rinit = (2.41 ± 0.51) × 10−3[CBZ]1.21[MnO2]1.07[H+]1.41. This is the first report revealing that protonation of intermediates from CBZ degradation can improve the CBZ oxidation by δ-MnO2. The pathways of CBZ degradation by δ-MnO2 were also proposed. The results of this study provide a new insight into the processing mechanism.
Jun Zhai; Quanfeng Wang; Qing Li; Bo Shang; Hasibur Rahaman; Jialiang Liang; Jiucui Ji; Wenbo Liu. Degradation mechanisms of carbamazepine by δ-MnO2: Role of protonation of degradation intermediates. Science of The Total Environment 2018, 640-641, 981 -988.
AMA StyleJun Zhai, Quanfeng Wang, Qing Li, Bo Shang, Hasibur Rahaman, Jialiang Liang, Jiucui Ji, Wenbo Liu. Degradation mechanisms of carbamazepine by δ-MnO2: Role of protonation of degradation intermediates. Science of The Total Environment. 2018; 640-641 ():981-988.
Chicago/Turabian StyleJun Zhai; Quanfeng Wang; Qing Li; Bo Shang; Hasibur Rahaman; Jialiang Liang; Jiucui Ji; Wenbo Liu. 2018. "Degradation mechanisms of carbamazepine by δ-MnO2: Role of protonation of degradation intermediates." Science of The Total Environment 640-641, no. : 981-988.
The extensive use of silver nanoparticles (Ag NPs) inevitably leads to their release into aquatic ecosystems through sewage discharge. Currently, the impact of Ag NPs on activated sludge has been widely reported, however little is known about how Ag NPs influence nitrogen transformation and metabolic pathways in biofilm systems. In this study, the effects of Ag NPs on nitrogen transformation in constructed wetlands (CWs) were studied using metagenomic analysis. Results showed that total nitrogen and ammonia-nitrogen removal rates were significantly lowered after short-term exposure (5 d) to 1 and 50 mg/L Ag NPs, and long-term exposure (60 d) to Ag NPs caused cumulatively inhibitory effects on nitrogen removal. In addition, the majority of Ag NPs were captured by the CW substrate, with minor amounts reaching plant tissues and effluent. Scanning electron microscopy images and lactate dehydrogenase release assays suggested that a large number of NPs were adsorbed onto the biofilms covering the gravel, which significantly inhibited microbial viability. Furthermore, metagenomic analysis revealed that, bacterial community structures were significantly altered by the presence of Ag NPs, especially those of nitrogen-transforming microorganisms. Clusters of Orthologous Groups annotation demonstrated that Ag NPs impacted metabolic functional potentials, especially for amino acid transport and metabolism. Kyoto Encyclopedia of Genes and Genomes annotation indicated that Ag NPs changed the nitrogen metabolic pathways. Overall, Ag NPs resulted in a decline in the nitrogen removal rate in CWs, which is likely to cause eutrophication of receiving waters.
Xiaobo Liu; Xiangyu Yang; Xuebin Hu; Qiang He; Jun Zhai; Yi Chen; Qing Xiong; Jan Vymazal. Comprehensive metagenomic analysis reveals the effects of silver nanoparticles on nitrogen transformation in constructed wetlands. Chemical Engineering Journal 2018, 358, 1552 -1560.
AMA StyleXiaobo Liu, Xiangyu Yang, Xuebin Hu, Qiang He, Jun Zhai, Yi Chen, Qing Xiong, Jan Vymazal. Comprehensive metagenomic analysis reveals the effects of silver nanoparticles on nitrogen transformation in constructed wetlands. Chemical Engineering Journal. 2018; 358 ():1552-1560.
Chicago/Turabian StyleXiaobo Liu; Xiangyu Yang; Xuebin Hu; Qiang He; Jun Zhai; Yi Chen; Qing Xiong; Jan Vymazal. 2018. "Comprehensive metagenomic analysis reveals the effects of silver nanoparticles on nitrogen transformation in constructed wetlands." Chemical Engineering Journal 358, no. : 1552-1560.
In this study, the effect of nitrogen limitation on microalgal growth, biochemical composition and photosynthetic performance was investigated in fed-batch mixotrophic cultivation of microalga Spirulina platensis, compared with that in autotrophic cultivation. The microalgal biomass productivity was greatly enhanced by mixotrophic cultivation. With nitrogen limitation, the mixotrophic culture accelerated the degradation of microalgal pigments and proteins to supply intracellular nitrogen for maintaining higher biomass productivity, simultaneously accumulating more carbohydrates. The mixotrophic cultivation amplified the adverse effect of nitrogen limitation on the microalgal photosynthetic performance in comparison with autotrophic cultivation. This fed-batch mixotrophic cultivation is an effective strategy for enhancing biomass productivity and total carbohydrates yield under nitrogen limited conditions.
Xiaoting Li; Wei Li; Jun Zhai; Haoxuan Wei. Effect of nitrogen limitation on biochemical composition and photosynthetic performance for fed-batch mixotrophic cultivation of microalga Spirulina platensis. Bioresource Technology 2018, 263, 555 -561.
AMA StyleXiaoting Li, Wei Li, Jun Zhai, Haoxuan Wei. Effect of nitrogen limitation on biochemical composition and photosynthetic performance for fed-batch mixotrophic cultivation of microalga Spirulina platensis. Bioresource Technology. 2018; 263 ():555-561.
Chicago/Turabian StyleXiaoting Li; Wei Li; Jun Zhai; Haoxuan Wei. 2018. "Effect of nitrogen limitation on biochemical composition and photosynthetic performance for fed-batch mixotrophic cultivation of microalga Spirulina platensis." Bioresource Technology 263, no. : 555-561.
Produced water (PW) from natural gas field, characterized with high organic contents, has brought high environmental concerns world widely. Fenton and enhanced Fenton technologies were considered as the potential methods to degrade the organic contaminates in the PW, but with very limited data or reference. Here, we examined the optimum conditions of Fenton on organics and colour removal from natural gas PW after coagulation pre-treatment. Simultaneously, the optimal Fenton process integrated with ultraviolet (UV) and ultrasonic (US) irradiation were applied to enhance pollutants removal efficiencies. The optimal Fenton conditions were found at 60 min with molar ratios of 6:1 and 25:1 for H2O2/COD and H2O2/Fe2+, respectively and the initial pH of 3. Among these the three treatment processes, chemical oxygen demand (COD), total organic carbon, 5-day biological oxygen demand (BOD5), and colour removal efficiencies were highest during UV–Fenton (82, 73, 68, and 95%,) followed by US–Fenton (79, 70, 66, and 95%) and Fenton treatment (70, 58, 51, and 92%), respectively. High biodegradability (BOD5/COD) was also observed after UV–Fenton process (0.76) than the others (both 0.73). The current study showed a satisfactory carbon and colour removal efficiencies from PW using different Fenton processes; however, there still is a need for final polishing such as biological treatment or low cost constructed wetland before discharge. This study can be a good reference for engineering application PW treatment.
J. Zhai; H. Ma; J. Liao; M. H. Rahaman; Zhongping Yang; Z. Chen. Comparison of Fenton, ultraviolet–Fenton and ultrasonic–Fenton processes on organics and colour removal from pre-treated natural gas produced water. International Journal of Environmental Science and Technology 2017, 15, 2411 -2422.
AMA StyleJ. Zhai, H. Ma, J. Liao, M. H. Rahaman, Zhongping Yang, Z. Chen. Comparison of Fenton, ultraviolet–Fenton and ultrasonic–Fenton processes on organics and colour removal from pre-treated natural gas produced water. International Journal of Environmental Science and Technology. 2017; 15 (11):2411-2422.
Chicago/Turabian StyleJ. Zhai; H. Ma; J. Liao; M. H. Rahaman; Zhongping Yang; Z. Chen. 2017. "Comparison of Fenton, ultraviolet–Fenton and ultrasonic–Fenton processes on organics and colour removal from pre-treated natural gas produced water." International Journal of Environmental Science and Technology 15, no. 11: 2411-2422.