ULTRASONICS SONOCHEMISTRY
·
2019
·
IF 7.279
Yitao Li,Xingdong Shi,Zhi Zhang,Yazhou Peng
Ultrasonic treatment has attracted much attention because of its physical and chemical effects that are distinct from those of chemical agents. In particularly, high-frequency ultrasound is known as an effective method because the theoretical resonance frequency of the gas vesicles in Microcystis aeruginosa is in the high frequency range (>100 kHz), which causes gas vesicles collapse and changes the settleability of the algal cells. In this work, the effects of the ultrasonic frequency, acoustic power density and duration on enhancing coagulation to remove turbidity in algae-laden water were studied. In order to explain the mechanism, the morphology of algae cells, the changes in extracellular organic substances, the zeta potential and the formation of hydroxyl radicals were analyzed systematically. Finally, Zeta potentials and flocs morphology after adding PAC were investigated to verify the mechanism. The results showed that the frequency exhibited fewer effects than power and duration on coagulation. SEM images showed that there were more severe cellular damages at 430 and 740 kHz than other frequencies. Sonication could cause the collapse of gas vesicle inside the cell, which was due to the instantaneous high pressure generated by the ultrasonic cavitation instead of the resonance. Furthermore, sonication would result in an increase in proteins in extracellular organic matter (EOM) with continuous ultrasonic irradiation, indicating that a small amount of proteins could promote coagulation and that the accumulation of proteins would inhibit coagulation. Free radical content testing showed that the production of excessive free radicals was often accompanied by a deterioration of the coagulation. The proper mechanical effects were the main mechanism of ultrasonic enhanced coagulation. Thus, it was recommended that the appropriate ultrasonic condition was the one that resulted in a small amount of protein leakage and little generation of free radicals, which occurred at 740 kHz and 0.02 W/mL in approximately 5 min, and would significantly enhance the turbidity removal rate in algae-containing water from approximately 80–90%.
研究领域:
环境科学
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水处理
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微生物学
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产品关联
DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2025
·
IF 6.3
Jin Ma,Fang Bai,Zichao Gong,Guofei Dai,Licheng Huang,Wei Chen,Yunlu Jia,Lirong Song
A promising solution to combat harmful cyanobacterial blooms (CyanoHABs) is the use of naturally-derived cyanocidal compound. This study found that the crude extracts of the herbaceous plant Macleaya cordata can inhibit the growth of the bloom-forming cyanobacterium Microcystis aeruginosa . Growth inhibition test suggested that the inhibitory effect was significant at a concentration as low as 5 μg/L of the crude extracts. To comprehensively elucidate inhibitory mechanisms, we examined the responses in anti-oxidative systems, changes in triggering signals in cells, and hallmarks of programmed cell death (PCD) under the two levels of exposure to the crude extracts of M. cordata . A notable observation across all treatment groups was the significant increase in the superoxide dismutase activity of M. aeruginosa at 72 h. However, distinct patterns were observed in malondialdehyde (MDA), with no significant difference observed between the low concentration treatment group (5 μg/L) and the control group. In contrast, Microcystis cells subjected to high concentration (10 μg/L) exhibited a significant difference in MDA content at both 24 and 72 h. Furthermore, we observed that the levels of potential signaling molecules, e.g., intracellular reactive oxygen species, nitric oxide, and Ca 2+ were altered in the Microcystis cells after exposure to the crude extracts. This results in alterations to the levels of signaling molecules, which in turn stimulate the upregulation of orthocaspase, leading to PCD and population collapse eventually. This study examines the mechanisms of Microcystis suppression through naturally-derived substances, providing theoretical and technical foundations for the sustainable management of CyanoHABs.
研究领域:
环境生物学
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水生生态学
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植物化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Chunjiao Liu,Zhiwei Zhou,Xing Li,Rui Yu,Haiqing Chang,Jiawei Ren,Changyu Wang
Ultrafiltration (UF) is an effective technology for treating algae-containing water. The algal intracellular organic matter (IOM) released by dead algae during an excessive algae growth phase causes more serious membrane fouling than viable algal cells and algal extracellular organic matter (EOM), which seriously restricts stable operation of UF. This paper studied the removal of IOM by a Bi 2 O 3 –TiO 2/ PAC (Bi-doped TiO 2 nano-composites supported by powdered activated carbon) photocatalytic oxidation-ceramic ultrafiltration membrane, the inhibitory effect of membrane fouling at different photocatalytic oxidation times, and the fouling mechanism. The results show that both the adsorption and photocatalytic oxidation of Bi 2 O 3 –TiO 2 /PAC can significantly remove proteinoids and humic acid-like fluorescent components present in IOM, with removals of UV 254 and DOC reaching up to 81.8% and 44.0%. The generated superoxide radicals and hydroxyl radicals positively affect the degradation of organic compounds of various molecular weights, and holes mainly degrade acidic low-molecular weight organic compounds. When the photocatalytic oxidation time was extended to 60 min, the membrane flux increased by 70.7% and the reversible resistance and irreversible resistance decreased by 83.4% and 90.1%, respectively. Under these conditions, the fouling mechanism changed from complete blockage to intermediate blockage. In the late stage of photocatalytic oxidation (90–120min), part of the high and medium molecular weight organic components were oxidized to produce low-molecular weight organic compounds (LMW acidic and neutral organic compounds), and blockage of filter cake became the main fouling mechanism. After photocatalysis , the zeta potential decreases significantly and the interaction forces between pollutants and pollutants are transformed into repulsive forces. Application of an appropriate photocatalytic oxidation time can alleviate the ultrafiltration membrane fouling caused by algal-derived organics.
研究领域:
环境科学
·
水处理技术
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DOI
高影响因子
Toxics
·
2024
·Vol. 12
·期 10
·759
·
IF 3.9
Liang Wan,Rong Huang,Yan Zhou,Jiahao Guo,Yiying Jiao,Jian Gao
Antibiotics can affect the photosynthetic system ofMicrocystis, potentially altering the balance of carbon and nitrogen, which may influence the synthesis of different microcystin (MC) congeners. However, the regulatory mechanisms by which antibiotics affect the synthesis of various MC congeners inMicrocystisremain unknown. In this study, the effects of ciprofloxacin (CIP) on the growth, carbon and nitrogen balance, amino acid composition,mcyBgene expression, and production of different MC congeners were investigated in two toxin-producing strains ofMicrocystis aeruginosa. The results show that CIP exposure significantly inhibited the growth of both strains, achieving an inhibition rate of 71.75% in FACHB-315 and 41.13% in FACHB-915 at 8 μg/L CIP by the end of the cultivation. The intracellular C:N ratio in FACHB-315 increased by 51.47%, while no significant change was observed in FACHB-915. The levels of leucine, tyrosine, and arginine, as identified and quantified by UPLC-MS/MS, were significantly altered at higher CIP concentrations, leading to a reduction in leucine percentage and a notable increase in tyrosine in both strains, which contributed to a reduction in MC-LR proportion and an increase in MC-RR and MC-YR proportion. Additionally, the expression of themcyBgene was upregulated by as much as 5.57 times, indicating that antibiotic stress could enhance MC synthesis at the genetic level, contributing to the increased toxicity of cyanobacteria. These findings emphasize the significant role of CIP in the biochemical processes ofM. aeruginosa, particularly in MC synthesis and composition, providing valuable insights into the ecological risks posed by antibiotics and harmful cyanobacteria.
研究领域:
环境科学
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微生物学
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毒理学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Yujiao Long,Hongna Li,Xuan Xing,Jinren Ni
This study presented a significant enhanced removal of Microcystis aeruginosa by simple addition of Fe 2+ at circumneutral pH in the electrochemical system with boron-doped diamond (BDD) anode and carbon felt (CF) cathode. Results showed that over 99.9% of the M. aeruginosa cells were removed in 60 min when 0.2 mM Fe 2+ was added to the system. The pseudo-first order rate constant for BDD-CF-Fe 2+ system was almost 15 times higher than that (0.005 min −1 ) for BDD-CF system. The excellent performance of the BDD-CF-Fe 2+ system over the BDD-CF system was observed over a wide range of pH from 3 to 9. Based on the evolution of Fe 2+ /Fe 3+ , pH, H 2 O 2 and OH, mechanism of enhanced removal of M. aeruginosa was revealed in the BDD-CF-Fe 2+ system. H 2 O 2 was electrochemically generated through reduction of dissolved oxygen on the surface of the CF cathode, and the added Fe 2+ was rapidly adsorbed and precipitated also on the CF cathode. Comparisons of BDD-CF-Fe 2+ , BDD-CF-Fe 3+ and BDD-CF-Fe 2+ /Fe 3+ systems proved that the electrochemical reduction of Fe(III) to Fe(II) could guarantee the sustainable cycle between Fe(II) and Fe(III). Through heterogeneous electro-Fenton reactions, much higher amount of OH would be continuously generated compared with the BDD-CF system. Thereby, the lipid peroxidation on the cell membrane of M. aeruginosa was intensified through the addition of Fe 2+ . Moreover, the degradation of intracellular microcystin was remarkably accelerated, and the extracellular microcystin was controlled more safely due to Fe 2+ addition. This study provided an alternative method to enhance the electrochemical mitigation of cyanobacteria-polluted waters.
研究领域:
环境科学
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微生物学
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水处理技术
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产品关联
DOI
高影响因子
WATER ENVIRONMENT RESEARCH
·
2021
·Vol. 94
·期 1
·e1670
·
IF 1.946
Haidong Zhou,Jinyu Cui,Xin Li,Yadan Wangjin,Lidan Pang,Mengwei Li,Xiaomeng Chen
The behavior and removal of six antibiotics, that is, azithromycin, clarithromycin, sulfathiazole, sulfamethoxazole, ciprofloxacin, and tetracycline, in an artificial-controllable urban river (ACUR) were investigated. The ACUR was constructed to form five artificial eco-systems by planting three emergent hydrophytes and Microcystis aeruginosa : (1) Control; (2) MA: M. aeruginosa only; (3) MA-J-C: M. aeruginosa combined with Juncus effusus and Cyperus alternifolius ; (4) MA-C-A: M. aeruginosa combined with C. alternifolius and Acorus calamus L.; (5) MA-A-J: M. aeruginosa combined with A. calamus L. and J. effusus . The MA-C-A system achieved the best removal of azithromycin and clarithromycin after 15-day test with the final concentrations 0.92 and 0.83 μg/L. The contents of ciprofloxacin and tetracycline in sediment were highest, up to 1453 and 1745 ng/g. The antibiotic plant bioaccumulation was higher in roots rather than the shoots (stem and leaves). No target antibiotics were detected in algae cells. The combination of hybrid hydrophytes had a certain effect on the removal of antibiotics, and thus selecting appropriate hydrophytes in urban rivers could greatly improve water quality. The overall removal of six antibiotics was greatly improved by the ACUR containing the hybrid hydrophytes and the algae, indicating a synergistic effect on antibiotic removal. Practitioner points Controllable-mobile artificial eco-systems were developed with emergent hydrophytes and M. aeruginosa . The M. aeruginosa + Cyperus alternifolius + Acorus calamus L. system removed azithromycin and clarithromycin most at the end of tests. Emergent hydrophytes and M. aeruginosa have a synergistic effect on the removal of antibiotics. The combination of emergent hydrophytes did play an important role in the removal of antibiotics. The artificial eco-systems containing the hybrid hydrophytes and the algae could greatly improve the overall removal of antibiotics.
研究领域:
环境科学
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生态学
·
微生物学
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DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Hanqi Wu,Weizheng Zhang,Xuhui Huang,Peng Gu,Qi Li,Xingzhang Luo,Zheng Zheng
Perfluorooctanoic acid (PFOA), a widespread and emerging organic contaminant of aquatic environments, has high bioaccumulation potential and high toxicity. Consequently, major concerns have been raised worldwide regarding the management of this pollutant in aquatic ecosystems. To thoroughly understand PFOA's toxic effects on aquatic organisms, systematic investigations were conducted on the cellular responses of Microcystis aeruginosa to the environmental concentrations of PFOA under various concentrations as well as phosphorus (P) conditions (concentrations and forms). The results showed that P conditions remarkably affected cyanobacterial growth as well as photosynthetic pigment content, triggered oxidative stress to disrupt the function and structure of the cell membrane, and caused changes in the extracellular and intracellular contents of microcystin-LR (MC-LR). Furthermore, PFOA (100 μg/L) was absorbed by cyanobacterial cells through the stimulation of the secretion of extracellular polymeric substances (EPS) by M. aeruginosa . After entering the cyanobacterial cells, PFOA inhibited photosynthesis, reduced P absorption, induced oxidative damage, lead to a loss of cell integrity evident in scanning electron microscope images, and increased mcy A gene expression to promote MC-LR production. Moreover, the limited P concentration and forms conditions led to increased PFOA absorption by cyanobacterial cells, which further upregulated mcy A gene expression and increased the risk of MC-LR diffusion into the aquatic environment. Our present study provided a theoretical basis and new ideas for understanding and addressing safety issues related to the presence of PFOA in aquatic environments with varying nutritional statuses.
研究领域:
环境科学
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水生毒理学
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生态毒理学
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微生物学
·
分子生物学
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产品关联
DOI
PubMed
高影响因子
Algal Research-Biomass Biofuels and Bioproducts
·
2017
·
IF 3.994
Yangyang Yang,Jun Hou,Peifang Wang,Chao Wang,Lingzhan Miao,Yanhui Ao,Yi Xu,Xun Wang,Bowen Lv,Guoxiang You,Zijun Yang
Heteroaggregation between magnetic nanoparticles (MNPs) and cells is a crucial precondition for the harvesting and separation of algae from the aquatic environment . However, separation mechanisms have not been fully elaborated in previous studies, especially regarding cyanobacteria coated with extracellular polymeric substances (EPS). The present study was conducted to investigate the interaction between PEI-coated iron-oxide nanoparticles (IONPs) and M. aeruginosa as a function of cell type (FACHB-1343 and FACHB-905) and cells with/without extracellular polymeric substances (EPS). The results demonstrated that harvesting efficiency (HE) varied with the different cell types with/without EPS surrounding the cyanobacteria. The PEI-coated IONPs showed higher HE for M9 than for M1 with the same mass ratio of NPs/cyanobacteria. Furthermore, EPS significantly affected the HE because of their heterogeneous composition, which was interpreted by spectral analysis and the DLVO theory. Overall, this study provides guidance on cyanobacteria harvesting with different environmental conditions when employing magnetic separation technology.
研究领域:
环境科学
·
纳米技术
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水生生物学
·
化学工程
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产品关联
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2020
·
IF 5.715
Qi Song,Xiaojun Niu,Dongqing Zhang,Xiaofei Song,Yankun Li,Jinling Ma,Senchao Lai,Zhiquan Yang,Shaoqi Zhou
The frequent occurrence of toxin-producing cyanobacteria blooms driven by anthropogenic eutrophication has become a major threat to aquaculture ecosystems worldwide. In this study, the behavior of M. aeruginosa cells during flocs storage period of 6 days was first investigated after pre-oxidation and coagulation of Fe 2+ /PS. Fe 2+ /PS achieved a superior removal efficiency of 90.7% for OD 680 and 90.4% for chl-a. The contents of extracellular MCs in the pre-oxidation and coagulation system were significantly ( P < 0.05) lower than those in the control. A significant ( P < 0.05) difference in intracellular protein between the control and the coagulated systems was observed. Three-dimensional fluorescence excitation emission matrix (EEM) was employed to investigate the variations in extracellular organic matter (EOM) during flocs storage. The results indicated the presence of four peaks, representing protein-like substances, intermediate dissolved microbial metabolites, fulvic and humic-like compounds in the Fe 2+ /PS process. And the intensities of four peaks were all decreased in the Fe 2+ /PS system compared to those in the control. A low level of accumulated residual Fe of 0.28 mg/L was observed without posing potential environmental risk. The results showed that the M. aeruginosa cells were under stressful conditions after 3-d storage due to the decomposition of extracellular polymeric substances (EPSs) and the insufficient supply of nutrients. However, SEM results indicated that no significant alteration in cell morphology was observed. Therefore, with high removal of M. aeruginosa , low MCs concentrations, and trivial cell damage, the Fe 2+ /PS preoxidation-coagulation was proved to be an environmental-friendly method for cyanobacteria removal without yielding serious secondary pollution. This work will contribute to better understanding and managing the cyanobacteria-laden aquaculture water after pre-oxidation and coagulation.
研究领域:
环境科学
·
水产养殖
·
水处理
·
微生物学
·
毒理学
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产品关联
DOI
PubMed
高影响因子
BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY
·
2021
·Vol. 107
·期 1
·147-153
·
IF 2.151
Zhang Rui,Dong Pengyue,Sun Hongwen,Liu Chunguang
To investigate the combined effects of excess boron (B) and high salinity on the growth of freshwater algal species, Chlorella vulgaris and Microcystis aeruginosa were cultured in the medium with different B and salinities. The results show that high levels of B and salinity inhibited the growth of the two algal species. For C. vulgaris , low levels of B can alleviate the growth inhibition induced by salinity, and low levels of salinity can also relieve the growth inhibition induced by B. In contrast, high levels of salinity have little effect on B toxicity, while high levels of B aggravate salinity stress. For M. aeruginosa , salinity aggravates B toxicity, regardless of salinity levels. B supply worsens salinity stress on M. aeruginosa , regardless of supply doses. These results suggest that it may be possible to control algal bloom by regulating B or salinities.
研究领域:
生态学
·
环境科学
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 19
·27677-27687
·
IF 5.19
Long Yujiao,Li Hongna,Jin Hongmei,Ni Jinren
The chemical and biological mechanisms of electrochemical elimination of Microcystis aeruginosa ( M. aeruginosa ) using boron-doped diamond (BDD) anode were comparatively explored in three different electrolytes (chloride, sulfate, and phosphate solutions). The most efficient elimination of M. aeruginosa was observed in chloride solution, which was attributed to the greatest total long-lived oxidants from the favorable formation of active chlorine. Moreover, the high permeability of active chlorine resulted in profound intracellular damages to chlorophyll- a , microcystin-LR (MC-LR), superoxide dismutase (SOD) enzyme, and DNA in the chloride system. The change of membrane permeability and degradation of the released MC-LR induced by active chlorine were further confirmed by the increase of extracellular MC-LR in the initial 5 min and a complete decay in the subsequent 15 min, while the change in morphology of algae cells was insignificant from SEM images. In sulfate and phosphate electrolytes, membrane damages were much more pronounced based on lipid peroxidation observation, although changes in cell morphology was found more significant in phosphate system. The higher concentrations of oxidants (·OH, O 3 , H 2 O 2 , S 2 O 8 2− ) generated in sulfate than in phosphate solution explained the greater efficiency of electrochemical elimination of M. aeruginosa in the sulfate electrolyte in terms of changes of cell density, OD 680 , chlorophyll- a , MC-LR, lipids, SOD enzyme, and DNA.
研究领域:
环境科学
·
电化学
·
水生生物学
·
毒理学
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DOI
PubMed
高影响因子
ACS ES&T Water
·
2025
·
IF 4.3
Jiahui Zhang,Mingliang Wu,Miao Yu,Yue He,YuXin Xi,Chenyulin Wang,Yun Pan
Taste and odor (T&O) issues in drinking water sources are common sensory concerns, with thioethers being major contributors to septic odors. Although algal metabolism is a known source of these odors, the mechanisms driving thioether production remain insufficiently explored. This study systematically analyzed the primary thioethers present in a reservoir-based drinking water source in southeastern China. Multiple algal species were cultured under near-natural conditions, both individually and in combination, to investigate the mechanisms of thioether release. The results revealed that dimethyl sulfide (DMS), reaching concentrations up to 2.54 μg/L, was primarily produced by Cyclotella (diatom). Dimethyl trisulfide (DMTS), with a peak concentration of 0.26 μg/L─exceeding its odor threshold by 26-fold─posed the highest odor risk and was mainly produced by Microcystis aeruginosa (cyanobacteria) and Cyclotella. Cyclotella emerged as the primary thioether-producing algae, particularly when coexisting with Microcystis aeruginosa. As the biomass of Microcystis aeruginosa increased, the growth of Cyclotella was inhibited and its proliferative capacity declined, resulting in a 32–54% increase in thioether release, whereas thioether production by Microcystis aeruginosa decreased by 17–76%. This study provides novel insights into algal interactions driving thioether release, guiding odor risk management in water sources.
研究领域:
水生生态学
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环境科学
·
饮用水安全
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）