ENVIRONMENTAL POLLUTION
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2024
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IF 7.6
Xuanxuan Xian,Chen Luo,Gang Lian,Xin Yu,Liang Zhu
Pre-chlorination is usually applied to facilitate coagulation process when treating cyanobacteria-laden source waters. However, the responses of cyanobacteria after chlorination were varied in different growth phases, hence how these differences affect the coagulation is not clear. In this study, Microcystis aeruginosa ( M. aeruginosa ) in late lag and exponential phases were selected for comparing the remove effect of cyanobacterial coagulation after varied doses (0, 0.5, 1.0 and 2.0 mg/L) of pre-chlorination. Results showed that the M. aeruginosa in late lag phase held higher removal efficiencies (48–86%) than those in exponential phase (1–60%). Lower pH and buoyancy, higher Zeta potential and hydrophobicity were beneficial to its coagulation. The application of 0.5–2.0 mg/L pre-chlorination in late lag phase did not promote its coagulation, mainly due to the impediment by released hydrophilic humus. In contrast, the remove efficiency increased about 40% with the addition of 2.0 mg/L chlorine and 15 mg/L polyaluminum chloride (PACl) in exponential phase. The increased macromolecular organic matters, Zeta potential and decreased buoyancy made for this promotion. In addition, the removal of extracellular organic matters, aromatics and microcystin was not that productive after coagulation in exponential phase, but both of chlorination and coagulation could reduce microcystin in late lag phase. The findings suggest that optimizing the application methods of pre-chlorine and coagulant according to the growth phases is necessary for cyanobacterial control.
研究领域:
环境科学
·
水处理工程
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产品关联
DOI
PubMed
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Jiao Liu,Fan Yang,Yanjie Xie,Meijie Ren
This study confirmed the discrepancy of growth period and molecular weight (MW) of extracellular organic matter (EOM) on the photodegradation of carbamazepine (CBZ) and theophylline (TF). Comparing to high MW EOM (100 kDa), low MW components (<100 kDa) acted as stronger competitors to photons and free radicals, which restrained the photodegradation of CBZ and TF. 3 EOM* played an important role in the degradation of CBZ and TF. Lignin was considered as a new precursor of 3 EOM*, which was highly depended on the MW of EOM. The high MW 3 EOM* was derived from the CHON compound, while the low MW 3 EOM* was derived from the CHONS compound. The results demonstrated that the discrepancy of EOM properties in algae growth period might play a non-negligible influence in the migration and transformation of CECs in the true natural water system.
研究领域:
环境科学
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药理学
✓ 已验证
产品关联
DOI
高影响因子
Chemical Engineering Journal Advances
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2022
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IF 0
Jiangya Ma,Bangtao Jia,Sha Li,Yanli Kong,Yong Nie,Huiwen Zhang,Meng Xiao,Tian Gao
The enhanced coagulation performance for algae and extracellular organic matter (EOM) removal by using novel Al/Fe-based covalently bonded composite coagulants (CAFM) coupled with potassium permanganate oxidation was evaluated in the current study. For the CAFM coagulation and potassium permanganate oxidation combination process, two dosage sequences of oxidant and coagulant, the potassium permanganate pre-oxidation method, and the simultaneous oxidation method, was compared for algae and EOM removal. Polyaluminum chloride (PAC) and polyacrylamide (PAM) were selected as common used coagulants to compare with CAFM. The results show that 21.1% UV 254 , 99.6% OD 686, and 98.2% turbidity were removed from EOM algae laden water at CAFM dosage of 5.4 mg/L and KMnO 4 dosage of 1 mg/L. UV 254 removal rate was increased by 10% in potassium permanganate oxidation treatment compared with CAFM coagulation. In addition, pre-oxidation method exhibited better extracellular organic matter removal efficiency compared with simultaneous oxidation method. Furthermore, SEM, FTIR, XRD and XPS were employed to study the physical and chemical structure of flocs, whereas ICP-MS, EEM, GCMS– and GPC were used to analyze water quality before and after treatment for coagulation and oxidation in mechanism exploration. This study proposes a new process for algal bloom control, organic pollution reduction and ensure water quality of water plant effluent to provide research basis.
研究领域:
环境科学
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水处理工程
✓ 已验证
DOI
WATER RESEARCH
·
2023
·
IF 12.8
Zhicheng Liao,Huan He,Danni Cui,Jingye Cui,Xiaoxia Yang,Ziwei Guo,Hao Chen,Guohua Dao,Bin Huang,Hongwen Sun,Xuejun Pan
Algal extracellular organic matter (EOM), a major fraction of the dissolved organic matter found in eutrophic plateau lakes, can act as a photosensitizer to drive the abiotic oxidation of Mn(II). This process has the potential to generate reactive Mn(III) and influence the fate of organic pollutants. In this study, the photodegradation of 17α-ethinylestradiol (EE2) in the presence of Mn(II) and EOM was investigated with emphasis on the photogeneration mechanism of Mn(III). The results indicated that Mn(II) can accelerate EE2 photodegradation in EOM solution owing to the photogeneration of reactive Mn(III), and the enhancement was greater at higher Mn(II) concentrations. The generation of reactive Mn(III) was mainly attributable to the action of superoxide radical generated by photosensitization of EOM. In addition, the photodegradation of EE2 was slower at higher pH, possibly because of the deactivation of Mn(III) under alkaline conditions. Single-electron transfer was an indispensable process in the photodegradation. The differences in fluorophore content, pH, and NO 3 − concentrations are all important determinants for EE2 photodegradation in natural waters. The information obtained in this research would contribute to the understanding of reactions between Mn(II) and EOM, and provide new insights into the behaviors of reactive Mn(III) in eutrophic water irradiated by sunlight.
研究领域:
环境科学
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水污染治理
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产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
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2017
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IF 5.651
Zhi-Yi Ni,Jing-Ya Li,Zhao-Zhao Xiong,Li-Hua Cheng,Xin-Hua Xu
Microalgal wastewater treatment has been considered as one of the most promising measures to treat nitrogen and phosphorus in the municipal wastewater. While the municipal wastewater provides sufficient nitrogen and phosphorus for microalgal growth, the microalgae still faces serious biological contamination caused by bacteria in wastewater. In this study, the commercial granular activated carbon (GAC) was added into the simulated municipal wastewater to avoid the influence of bacteria on the growth of microalgae. The extracellular organic matter (EOM) in microalgal broth was then characterized to enlighten the role of GAC in reducing the bioavailability of EOM. The results showed that the GAC addition could increase the dry weight of microalgae from 0.06 mg L −1 to 0.46 mg L −1 under the condition of bacterial inoculation. The GAC could mitigate bacterial contamination mainly due to its adsorption of both bacteria and EOM that might contain algicidal extracellular substances. Moreover, compared to the control group, the GAC addition could mitigate the microalgal lysis caused by bacteria and thus greatly reduce the bioavailability of EOM from 2.80 mg L −1 to 0.61 mg L −1 , which was beneficial for the improvement of biostability and reuse of effluent after the microalgal harvesting.
研究领域:
环境科学
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微生物学
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2022
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IF 10.53
Shuhong Jiang,Huaqiang Chu,Jingjing Sun,Wei Zhang,Mingchao Yang,Yongsheng Chen,Xuefei Zhou,Yalei Zhang
The mechanism of the effects of extracellular organic matter (EOM) on membrane fouling in a vibration membrane system remains unclear, which partially impedes the membrane efficiency enhancement in the process of microalgae harvesting. This work conducted a systematic study on the fouling effects of two typical foulants in EOM, bovine serum albumin (BSA) and sodium alginate (SA) at different vibration frequencies. The results of water flux behavior revealed that vibration could effectively alleviate membrane fouling under shear action, and the water flux reached a peak when the BSA/SA was 3:1. By analyzing the bulk and permeate solution and characterizing the fouled membrane surface, it was proved that there was a strong interaction between the BSA/SA mixture and the PES membrane. Thermodynamic and hydrodynamic forces analysis results suggested that the BSA/SA of 3:1 exhibited superior membrane antifouling performance and vibration could effectively mitigate membrane fouling. Further, the relationship between the BSA/SA mixture and the PES membrane was confirmed by molecular dynamics (MD) simulation from a microscopic point of view. The results revealed the reason why the BSA/SA mixture generated membrane fouling in the membrane system. Moreover, the MD simulation strongly proved that when the BSA/SA was 3:1, the membrane fouling was the lowest and the water flux was the highest. Overall, regulating the concentration ratio of the main substances in the EOM and optimizing the feeding conditions, should be a feasible method for controlling membrane fouling to break through the technical bottleneck of microalgae harvesting technology.
研究领域:
环境科学
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生物技术
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Weiwei Huang,Weiwei Lv,Tian Li,Hang Yang,Quan Yuan,Wenzong Zhou,Junxia Liu
The membrane fouling induced by algal extracellular organic matter (EOM) remain a bottleneck in restricting ultrafiltration (UF) application during harmful algal-water treatment. In current study, the application of heat-activated peroxydisulfate (PMS) and coagulation (Aluminum chlorohydrate, PACI) on membrane fouling behavior during Chlorella -laden water treatment was investigated. The membrane fouling mechanism was analyzed using the extended Derjaguin-Landau-Verwey-Over-beek (XDLVO) theory. The results revealed that separated heat-activated PMS could enhance the filtration flux of EOM at high PMS does >0.2 mM, whereas the membrane fouling was further alleviated by combined heat-activated PMS (0.2–1.0 mM) and PACI (20 mg/L) treatment, especially at low PMS dose. Combined heat-activated PMS and PACI pretreatment could effectively increase the adhesive repulsion between membrane and foulants and reduce the cohesion free energies between organic foulants than those by separated heat-activated PMS treatment, making the initial filtration flux reduced and the cake layer looser. Moreover, the organic foulants of proteins, polysaccharides, and humic-like organics were removed. Cake formation was the major fouling mechanism when EOM was treated with/without separated heat-activated PMS treatment, whereas the membrane fouling mechanism was changed from cake layer formation to pore blocking after combined heat-activated PMS and PACI treatment. Overall, this research provided a feasible method in membrane fouling control during Chlorella -laden water treatment.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
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2018
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IF 7.051
Xiaoxiang Cheng,Daoji Wu,Heng Liang,Xuewu Zhu,Xiaobin Tang,Zhendong Gan,Jiajian Xing,Xinsheng Luo,Guibai Li
Algal extracellular organic matter (EOM) released from Microcystis aeruginosa can cause severe membrane fouling during algae-laden water treatment . To solve this problem, three typical sulfate radical-based advanced oxidation processes (SR-AOPs), i.e., ferrous iron/peroxymonosulfate (Fe(II)/PMS), UV/PMS and UV/Fe(II)/PMS, were employed as membrane pretreatment strategies. Their performance on mitigating EOM fouling of a ceramic UF membrane was systematically investigated and compared in the present study. The results indicated that SR-AOPs pretreatments could promote the reduction of DOC and UV 254 , and the removal performance showed an apparent regularity of UV/Fe(II)/PMS > Fe(II)/PMS > UV/PMS. The pretreatments were very effective for decomposing high-MW biopolymers (>20,000 Da) into low-MW humic substances (1000–20,000 Da), thus reducing the accumulation of high-MW biopolymers on membrane surface. With respect to membrane fouling control, Fe(II)/PMS significantly mitigated both reversible and irreversible membrane fouling, whereas UV/PMS only reduced reversible fouling, and exhibited little effect on irreversible fouling. By contrast, UV/Fe(II)/PMS showed the best performance for fouling reduction due to the synergistic effect of UV and Fe(II) for PMS activation . The dominating fouling mechanism was governed by both pore blockage and cake filtration, likely due to the bimodal MW distribution of EOM, and SR-AOPs pretreatments delayed the transition from pore blockage to cake filtration. In addition, SR-AOPs prior to UF membrane were also very effective to improve the removal of micropollutants (i.e., ATZ, SMT and p -CNB). These results demonstrate the potential application of SR-AOPs as pretreatment for membrane fouling control during algae-laden water treatment.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Nan Wang,Zhiwei Zhou,Chunjiao Liu,Yongwang Liu,Xing Li,Yanling Yang,Li Zhao
Algae-derived organic matter (AOM) limits the effectiveness of conventional water treatment processes, affects the normal operation of water treatment plants, and causes water quality deterioration. Efficient elimination of AOM is an urgent issue in the advanced treatment of drinking water. In this study, A heterogeneous interface for AOM removal was established based on BT/C, which can be driven by visible light. The removal efficiencies of extracellular organic matter (EOM), intracellular organic matter (IOM), and AOM by BT/C reached the optimal levels at 30 min, 60 min, and 90 min, respectively, reaching 48.5 %, 81.8 %, and 74.0 %. BT/C can oxidize and break down a large amount of high-molecular-weight organic matter in EOM into medium- and low-molecular-weight organic substances, and effectively remove the low-molecular-weight organic matter in EOM. In addition, BT/C can efficiently remove humic acids(HS) and aromatic protein organic matter in IOM, directly mineralize or decompose high-molecular-weight biopolymers into small-molecular-weight acidic and neutral organic matter; electron paramagnetic resonance spectroscopy and reactive oxygen species trapping experiments verified that hydroxyl radical (·OH) have play most important role on the degradation of various molecular weight organic matters. Superoxide radical (·O 2 – ) plays a dominant role in the oxidation process of soluble microbial metabolites and HS, and ·OH plays a significant role in the oxidation process of amino acid-like proteins. This study provides new ideas and technical support for the complete removal of algae-derived organic matter and the protection of drinking water safety.
研究领域:
环境科学
·
水处理技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2020
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IF 5.778
Pengcheng Zhao,Shihu Liu,Wei Huang,Lei He,Jiao Li,Jiong Zhou,Jian Zhou
Essential oils (EOs) are naturally occurring substances that have shown great prospect in the field of antimicrobial, antioxidant and pest control by nontoxic mechanisms. In this regard, EOs are considered the promising and eco-friendly approach for controlling harmful algae. In this study, the anti-cyanobacterial activity of EOs eugenol against Microcystis aeruginosa are evaluated from the perspective of photosynthetic efficiency, the behavior of extracellular organic matter (EOM), endogenous plant hormone synthesis, and nitric oxide signaling pathway. Results showed that the photosynthetic activity of M. aeruginosa decreased significantly after eugenol treatments. Eugenol treatment resulted in cells rupture and the release of EOM. Levels of endogenous plant hormones salicylic acid (SA) and jasmonic acid (JA) were enhanced separately by 2.32 and 2.01 times after 4 d of exposure to eugenol. And the inhibition of SA and JA biosynthesis further promotes the inhibitory effects of eugenol on algae. Additionally, the signaling molecule nitric oxide (NO) increased significantly by 3.78-fold. Furthermore, the influence of NO on microalgae exposed to eugenol was also determined, suggesting that the inhibitory effect of eugenol stress might be associated with NO generation in M. aeruginosa . These findings will be helpful for the understanding of the fate and potential of eugenol in harmful algae control.
研究领域:
环境科学
·
微生物学
·
植物生理学
·
生态毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ULTRASONICS SONOCHEMISTRY
·
2023
·
IF 8.4
JuanJuan Wang,Yuting Wang,Wenshu. Li,Xiaoge Wu
1000 kHz high-frequency ultrasound at 0.12 and 0.39 W/mL intensity was used to enhance the inactivation of suspensions of Microcystis aeruginosa cells using KMnO 4 . With 10 mg/L of KMnO 4 , ultrasound at 0.12 W/mL intensity was found to be effective in inactivating the cyanobacteria within 10 min. A Weibull model was found to describes the inactivation well. Its concave shape shows that some cells have a certain resistance to this treatment. Cytometry and microscopic analysis confirm that the treatment damages cell integrity. Despite that the extracellular organic matter in the water was not significantly increased. The concentration of extracellular cyanobacterial toxins even decreased. The filtered suspension of inactivated cyanobacteria was used to cultivate mung beans, and the suspension did not hinder their germination. This provides a new idea for using cyanobacteria-laden wastewater. These findings suggest a technique for speeding up the oxidation of Microcystis cells using KMnO 4 with ultrasound at moderate intensity, which provide new insights into the biological effects of ultrasound.
研究领域:
环境工程
·
微生物学
·
水处理
·
生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Yajun Tian,Li Feng,Renna Li,Jun Li,Ziwen Du,Liqiu Zhang,Yongze Liu
In algae rich waters, sunlight-driven transformation of antibiotics could be accelerated via sensitization by algae extracellular organic matter (EOM), and this photosensitization process will be affected by coexisting humic substances . In this study, we explored the effect and mechanism of humic substances on photodegradation of chlortetracycline (CTC) mediated by EOM. We found that humic substances exhibited a marked inhibitory effect on the EOM-mediated photodegradation of CTC. Given that humic substances exhibited little effects on the EOM-mediated formation of triplet state species, the quenching effect of humic substances on reactive species was excluded. The inhibitory effect of humic substances was mainly attributed to the back reduction of CTC oxidation intermediates by the antioxidant moieties in humic substances. The ozone oxidation treatment for humic substances was applied to destroy antioxidant moieties. After ozonation , the inhibitory effects of humic substances were greatly decreased, confirming the dominant role of antioxidant moieties in humic substances, which inhibited CTC photodegradation mediated by EOM via reducing oxidation intermediates of CTC. This back reduction was further verified to be exergonic via reactive Gibbs free energy , indicating the back reduction by humic substances of CTC oxidation intermediates could occur spontaneously. The present study will be helpful for predicting the fate and risk of CTC in algae rich water environments, and is of great significance for the study of phototransformation of other antibiotics.
研究领域:
环境化学
·
水生科学
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药学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）