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Sun G, Zhang X, Zhang F, Wang Y, Wu Y, Jiang Z, Hao S, Ye S, Zhang H, Zhang X. Use microalgae to treat coke wastewater for producing biofuel: Influence of phenol on photosynthetic properties and intracellular components of microalgae. CHEMOSPHERE 2024; 349:140805. [PMID: 38040255 DOI: 10.1016/j.chemosphere.2023.140805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/12/2023] [Accepted: 11/22/2023] [Indexed: 12/03/2023]
Abstract
Using microalgae to treat coking wastewater has important application prospects and environmental significance. Previous studies have suggested that phycoremediation of pollutants from coking wastewater is feasible and can potentially enhance biodiesel production. This work investigates the effects of phenol in coking wastewater on C. pyrenoidosa and S. obliquus growth, photosynthesis activity, and intracellular components. The results indicated that when the phenol concentration was lower than 300 mg L-1, both microalgae maintained good photosynthetic and physiological activity, with a maximum quantum yield potential ranging from 0.6 to 0.7. At the phenol concentration of 300 mg L-1, the biomass of C. pyrenoidosa was 2.4 times that of the control group. For S. obliquus, at the phenol concentration of 150 mg L-1, the biomass was approximately 0.85 g L-1, which increased by 68% than that of the control group (0.58 g L-1). The lipid content in both microalgae increased with the phenol concentrations, with the maximum content exceeding 40%. The optimal phenol concentrations for C. pyrenoidosa and S. obliquus growth were determined to be 246.18 and 152.73 mg L-1, respectively, based on a developed kinetic model. This work contributes to further elucidating the effects of phenol on microalgae growth, photosynthesis, and intracellular components, and suggests that using microalgae to treat phenol-containing coking wastewater for producing biofuel is not only environmentally friendly but also holds significant energy promise.
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Affiliation(s)
- Guangpu Sun
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Xinru Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China; Beijing Engineering Research Center of Energy Saving and Environmental Protection, Beijing, 100083, China.
| | - Fan Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yi Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yuyang Wu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Zeyi Jiang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China; Beijing Key Laboratory for Energy Saving and Emission Reduction of Metallurgical Industry, Beijing, 100083, China.
| | - Siyuan Hao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Shiya Ye
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Hu Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Xinxin Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China; Beijing Key Laboratory for Energy Saving and Emission Reduction of Metallurgical Industry, Beijing, 100083, China
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Wang J, Chang F, Zheng M. Advanced Treatment of Coking Wastewater by Polyaluminum Silicate Sulfate for Organic Compounds Removal. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6342. [PMID: 37510575 PMCID: PMC10378838 DOI: 10.3390/ijerph20146342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 07/30/2023]
Abstract
Coking wastewater is a typical high-strength organic wastewater, for which it is difficult to meet discharging standards with a single biological treatment. In this study, effective advanced treatment of coking wastewater was achieved by coagulation with freshly prepared polyaluminum silicate sulfate (PASS). The performance advantage was determined through comparison with commercial coagulants including ferric chloride, polyferric sulfate, aluminum sulfate and polyaluminum chloride. Both single-factor and Taguchi experiments were conducted to determine the optimal conditions for coagulation with CODCr and UV254 as indicators. A dosage of 7 mmol/L PASS, flocculation velocity of 75 r/min, flocculation time of 30 min, pH of 7, and temperature of 20 °C could decrease the CODCr concentration from 196.67 mg/L to 59.94 mg/L. Enhanced coagulation could further help to remove the organic compounds, including pre-oxidation with ozonation, adsorption with activated carbon, assistant coagulation with polyacrylamide and secondary coagulation. UV spectrum scanning and gas chromatography-mass spectrometry revealed that the coagulation process effectively removed the majority of organic compounds, especially the high molecular weight alkanes and heterocyclic compounds. Coagulation with PASS provides an effective alternative for the advanced treatment of coking wastewater.
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Affiliation(s)
- Jiangnan Wang
- Marine Resources Research Centre, Tianjin Research Institute for Water Transport Engineering, Ministry of Transport, Tianjin 300456, China
| | - Fang Chang
- Marine Resources Research Centre, Tianjin Research Institute for Water Transport Engineering, Ministry of Transport, Tianjin 300456, China
| | - Maosheng Zheng
- Key Laboratory of Resources and Environmental Systems Optimization, Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
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Lv Z, Zhang H, Liang J, Zhao T, Xu Y, Lei Y. Microalgae removal technology for the cold source of nuclear power plant: A review. MARINE POLLUTION BULLETIN 2022; 183:114087. [PMID: 36084612 DOI: 10.1016/j.marpolbul.2022.114087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 07/22/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
In the past three decades, nuclear energy has gained much attention as carbon-free electricity. Due to the supply of cooling water in nuclear power plant, large amount of waste heat will increase the water temperature, promote the microalgae and cyanobacteria propagation and increase the chance of red tide. Excess phytoplankton of cool source will result in abnormal operation of cooling system, even core overheating and nuclear leakage. Consequently, it is very important to remove microalgae and cyanobacteria from cold source of nuclear power plants. This review summarizes the formation mechanism and monitoring methods of red tide, compares the advantages and disadvantages of traditional microalgae removal technology including physical, chemical and biological methods. Furthermore, the improved electrochemical method and micro-nano bubble method are introduced in detail. Their combination is considered to be a low-cost, efficient and environmentally-friendly technology to prevent and control red tides for cold source of nuclear power plant.
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Affiliation(s)
- Ziwei Lv
- Key Laboratory of Special Functional Materials for Ecological Environment and Information, Hebei University of Technology, Ministry of Education, Tianjin 300130, China; Institute of Power Source and Science, Hebei University of Technology, Tianjin 300130, China; Key Laboratory for New Type of Functional Materials in Hebei Province, Hebei University of Technology, Tianjin 300130, China
| | - Hong Zhang
- Key Laboratory of Special Functional Materials for Ecological Environment and Information, Hebei University of Technology, Ministry of Education, Tianjin 300130, China; Institute of Power Source and Science, Hebei University of Technology, Tianjin 300130, China; Key Laboratory for New Type of Functional Materials in Hebei Province, Hebei University of Technology, Tianjin 300130, China.
| | - Jinsheng Liang
- Key Laboratory of Special Functional Materials for Ecological Environment and Information, Hebei University of Technology, Ministry of Education, Tianjin 300130, China; Institute of Power Source and Science, Hebei University of Technology, Tianjin 300130, China; Key Laboratory for New Type of Functional Materials in Hebei Province, Hebei University of Technology, Tianjin 300130, China.
| | - Tianyu Zhao
- Key Laboratory of Special Functional Materials for Ecological Environment and Information, Hebei University of Technology, Ministry of Education, Tianjin 300130, China; Institute of Power Source and Science, Hebei University of Technology, Tianjin 300130, China; Key Laboratory for New Type of Functional Materials in Hebei Province, Hebei University of Technology, Tianjin 300130, China
| | - Yuena Xu
- Key Laboratory of Special Functional Materials for Ecological Environment and Information, Hebei University of Technology, Ministry of Education, Tianjin 300130, China; Institute of Power Source and Science, Hebei University of Technology, Tianjin 300130, China; Key Laboratory for New Type of Functional Materials in Hebei Province, Hebei University of Technology, Tianjin 300130, China
| | - Yinyuan Lei
- Key Laboratory of Special Functional Materials for Ecological Environment and Information, Hebei University of Technology, Ministry of Education, Tianjin 300130, China; Institute of Power Source and Science, Hebei University of Technology, Tianjin 300130, China; Key Laboratory for New Type of Functional Materials in Hebei Province, Hebei University of Technology, Tianjin 300130, China
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Pathways of Nitrogen and Phosphorus Utilization and Removal from Cyanobacteria Wastewater by Combining Constructed Wetlands with Aerobic Reactors. SUSTAINABILITY 2022. [DOI: 10.3390/su14148819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Due to its low C/N ratio and high concentrations of nitrogen and phosphorus, the effluent of anaerobic cyanobacteria fermentation cannot be directly discharged without further treatment. To effectively reduce nutrient loads and utilize the nutrient resources of biogas slurry generated from the anaerobic digestion of stored algae, two different aerobic treatment units (AUs) were combined with an ecological treatment unit (EU) to create two different treatment systems. The two AUEU systems paired a constructed wetland (CW) with either a cascade biological contact reactor (CBCR) or a carrousel oxidation ditch reactor (CODR). In this paper, the water quality characteristics of biogas slurry were measured, and comprehensive experiments on the two trial-treatment systems were carried out to validate their performance in removing pollutants and utilizing resources. Furthermore, the pollutant removal efficiencies of the combined systems, along with the removal mechanisms and utilization of the nitrogen and phosphorus in the CWs, were also investigated. The results showed that the CWs, with aquatic vegetation, took up the majority of removed nitrogen and phosphorus by absorption, which effectively reduced the concentration of pollutants in the effluent and enabled the nitrogen and phosphorus to be reused in plants. Biomass assimilation by the absorption by vegetation took up 75.8%, 66.1%, 70.3%, and 86% of the removed NH4+-N, NOx−-N, TN, and TP, respectively.
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Nageshwari K, Chang SX, Balasubramanian P. Integrated electrocoagulation-flotation of microalgae to produce Mg-laden microalgal biochar for seeding struvite crystallization. Sci Rep 2022; 12:11463. [PMID: 35794246 PMCID: PMC9259614 DOI: 10.1038/s41598-022-15527-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/24/2022] [Indexed: 11/18/2022] Open
Abstract
Developing sustainable materials for recovering and recycling nutrients from wastewater is critically needed for nutrients such as phosphorus that have a diminishing supply. Struvite crystallization is emerging as a promising strategy for phosphorus recovery which can be enhanced with seeding through microalgal biochar. The main bottleneck of using microalgae is its high harvesting cost. In this study, an integrated electrocoagulation-flotation (ECF) process is used to recover and at the same time modify the algal surface with magnesium anode and inert carbon cathode. Harvesting efficiency of 98% was achieved with 40.78 mA cm−2, 0.5 cm inter-electrode distance and energy consumption of 4.03 kWh kg−1 in 15 min. The harvested microalgae were pyrolyzed to obtain a yield of 52.90% Mg-laden microalgal biochar. Simultaneously, surface impregnation of 28% magnesium was attained as confirmed by Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Phosphorus recovery and struvite yield of 93.70% and 2.66 g L−1, respectively, were obtained from dosing 1.50 g L−1 Mg-laden microalgal biochar. Comparison of physicochemical characteristics of residual supernatant after microalgal harvesting and struvite recovery showed that the combined use of both the residuals can serve as a sustainable growth medium for microalgae. The overall operating cost of the integrated process was found to be 2.48 USD kg−1 with a total energy consumption of 10.76 kWh kg−1, which was found to be lower than conventional harvesting unit processes such as centrifugation and filtration. This novel approach can help attaining a circular bioeconomy by encompassing nutrient recovery and waste management in an integrated process.
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Affiliation(s)
- Krishnamoorthy Nageshwari
- Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela, 769008, Odisha, India.,Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - Scott X Chang
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - Paramasivan Balasubramanian
- Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela, 769008, Odisha, India.
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Dai B, Peng Y, Zhang M, Yang M, Wu Y, Guo X. Insight into the effects of biological treatment on the binding properties of copper onto dissolved organic matter derived from coking wastewater. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 238:113567. [PMID: 35490577 DOI: 10.1016/j.ecoenv.2022.113567] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 04/19/2022] [Accepted: 04/24/2022] [Indexed: 06/14/2023]
Abstract
Biological treatment can remove more than 89.8% of total organic carbon (TOC) and 94.4% of fluorescent dissolved organic matter (DOM) in the coking wastewater, thereby affecting the migration, transformation and bioavailability and binding characteristics of heavy metals (HMs). The results of parallel factor analysis (PARAFAC) show that protein-like materials accounted for 97.53% in the coking wastewater DOM, a large number of humic-like substances are produced and accounted for more than 55.40% after biological treatment. A new spectral data processing method, the 1/n-th power transformation after two-dimensional correlated spectroscopy (2D-COS) in combination with synchronous fluorescence spectra (SFS), can identify small features obscured by strong peaks, and reveal more binding sites as well as preserve the sequential order information. The result indicates that the preferential bonding of Cu(II) is at 306 nm (protein-like) for coking wastewater DOM, and at 514 nm (humic-like) for effluent DOM. The C-O group of esters and alcohols can preferentially complexate with Cu(II) in the coking wastewater and effluent DOM. The log KM values of PARAFAC components with Cu(II) are in the range of 3.59-5.06 for coking wastewater DOM, and in the range of 4.80-5.64 for the effluent DOM. Log KM values for protein-like materials with Cu(II) are higher than these for fulvic- and humic-like substances. Humic-like substances can form more stable complexes with Cu(II) in the effluent DOM. Biological treatment increases the chemical stability of DOM-Cu(II) complexes, thereby further reducing the environmental risk of Cu(II).
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Affiliation(s)
- Benlin Dai
- Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials, Jiangsu Engineering Laboratory for Environment Functional Materials, Jiangsu Collaborative Innovation Center of Regional Modern Agriculture and Environmental Protection, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian 223300, China
| | - Yuyao Peng
- College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, China
| | - Meifeng Zhang
- College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, China
| | - Meng Yang
- College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, China
| | - Yi Wu
- College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, China
| | - Xujing Guo
- College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, China.
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Tan FHP, Nadir N, Sudesh K. Microalgal Biomass as Feedstock for Bacterial Production of PHA: Advances and Future Prospects. Front Bioeng Biotechnol 2022; 10:879476. [PMID: 35646848 PMCID: PMC9133917 DOI: 10.3389/fbioe.2022.879476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 04/06/2022] [Indexed: 11/13/2022] Open
Abstract
The search for biodegradable plastics has become the focus in combating the global plastic pollution crisis. Polyhydroxyalkanoates (PHAs) are renewable substitutes to petroleum-based plastics with the ability to completely mineralize in soil, compost, and marine environments. The preferred choice of PHA synthesis is from bacteria or archaea. However, microbial production of PHAs faces a major drawback due to high production costs attributed to the high price of organic substrates as compared to synthetic plastics. As such, microalgal biomass presents a low-cost solution as feedstock for PHA synthesis. Photoautotrophic microalgae are ubiquitous in our ecosystem and thrive from utilizing easily accessible light, carbon dioxide and inorganic nutrients. Biomass production from microalgae offers advantages that include high yields, effective carbon dioxide capture, efficient treatment of effluents and the usage of infertile land. Nevertheless, the success of large-scale PHA synthesis using microalgal biomass faces constraints that encompass the entire flow of the microalgal biomass production, i.e., from molecular aspects of the microalgae to cultivation conditions to harvesting and drying microalgal biomass along with the conversion of the biomass into PHA. This review discusses approaches such as optimization of growth conditions, improvement of the microalgal biomass manufacturing technologies as well as the genetic engineering of both microalgae and PHA-producing bacteria with the purpose of refining PHA production from microalgal biomass.
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Affiliation(s)
| | | | - Kumar Sudesh
- School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
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Tamang M, Paul KK. Advances in treatment of coking wastewater - a state of art review. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 85:449-473. [PMID: 35050895 DOI: 10.2166/wst.2021.497] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Coking wastewater poses a serious threat to the environment due to the presence of a wide spectrum of refractory substances such as phenolic compounds, polycyclic aromatic hydrocarbons and heterocyclic nitrogenous compounds. These toxic substances are difficult to treat using conventional treatment methods alone. In recent years much attention has been given to the effective treatment of coking wastewater. Thus, this review seeks to provide a brief overview of recent developments that have taken place in the treatment of coking wastewater. In addition, this article addresses the complexity and the problems associated with treatment followed by a discussion on biological methods with special focus on bioaugmentation. As coking wastewater is refractory in nature, some of the studies have been related to improving the biodegradability of wastewater. The final section focuses on the integrated treatment methods that have emerged as the best solution for tackling the highly unmanageable coking wastewater. Attention has also been given to emerging microwave technology which has tremendous potential for treatment of coking wastewater.
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Affiliation(s)
- Markus Tamang
- Civil Engineering Department, National Institute of Technology, Rourkela, India E-mail:
| | - Kakoli Karar Paul
- Civil Engineering Department, National Institute of Technology, Rourkela, India E-mail:
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Liu J, Liu H, Yang X, Jia X, Cai M, Bao Y. Preparation of Si-Mn/biochar composite and discussions about characterizations, advances in application and adsorption mechanisms. CHEMOSPHERE 2021; 281:130946. [PMID: 34289614 DOI: 10.1016/j.chemosphere.2021.130946] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 05/10/2021] [Accepted: 05/17/2021] [Indexed: 06/13/2023]
Abstract
A novel Si-Mn binary modified biochar composite material (SMBC) was prepared after being sintered 450 °C for 2 h. The crystal structure, surface functional groups, surface morphology and element composition, specific surface area and pore structure were characterized by XRD, FTIR, XPS, SEM + EDS and BET etc. The results showed that the surface of SMBC was rough and loose, and the specific surface area increased to 35.4284 m2/g. Si and Mn were uniformly attached to the surface of biochar in the form of SiO2, MnOx, MnSiO3. Batch adsorption experiments showed that SMBC had a higher removal efficiency (139.06 mg/g, above 98%) for Cu(II) when the dosage was 2 g/L and pH = 6. The cycle experiments showed that SMBC had good reusability, and its regeneration efficiency still reached 80.24%. The leaching amount of Mn (0.65 mg/L) was greatly reduced and avoid second-pollution resulted from ion exchange, which was attributed to the existence of Si-O-Mn bonds, and they could help Mn adhere to the surface of biochar more stable. The adsorption process was dominated by single-layer chemical adsorption and mainly occurred in the membrane diffusion stage. Cu(II) mainly formed -COOCu, -OCu, Cu(OH)2, Cu(OH)2CO3, Si-O-Cu, Mn-O-Cu by the mechanisms such as precipitation (4.74%), ion exchange (13.81%), complexation and physical adsorption (total 81.45% of the two mechanisms). Among them, complexation was dominant in the adsorption process.
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Affiliation(s)
- Juan Liu
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
| | - Honghao Liu
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
| | - Xiaoyu Yang
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
| | - Xuping Jia
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
| | - Mengfan Cai
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
| | - Yongchao Bao
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
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11
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Tang CC, Zhang X, He ZW, Tian Y, Wang XC. Role of extracellular polymeric substances on nutrients storage and transfer in algal-bacteria symbiosis sludge system treating wastewater. BIORESOURCE TECHNOLOGY 2021; 331:125010. [PMID: 33773415 DOI: 10.1016/j.biortech.2021.125010] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/10/2021] [Accepted: 03/13/2021] [Indexed: 06/12/2023]
Abstract
This study reported the role and significance of extracellular polymeric substances (EPSs) on nutrients storage and transfer in an algal-bacteria symbiosis sludge (ABSS) system for wastewater treatment, and the novel algae-based sequencing batch suspended biofilm reactor (A-SBSBR, Ra) was selected as model of ABSS system. Results showed that compared to conventional SBSBR, the EPS of Ra performed better storage for NO2--N, NO3--N, total phosphorus and PO43- -P, with increase ratios of 43.7%, 36.0%, 34.1% and 14.7% in sludge phase and 174.0%, 147.4%, 150.4% and 122.0% in biofilm phase, respectively. The analysis of mechanisms demonstrated that microalgae active transport and uptake for divalent cations could enhance their local concentrations around ABS flocs and partially neutralized negative charge of EPSs, and more anions related to nutrients were absorbed in EPSs. Moreover, O2 produced by microalgae photosynthesis enhanced bacteria activity and improved the production of EPSs in both sludge and biofilm phases.
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Affiliation(s)
- Cong-Cong Tang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Xinyi Zhang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhang-Wei He
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yu Tian
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xiaochang C Wang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China
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12
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Microalgal Biomass Generation via Electroflotation: A Cost-Effective Dewatering Technology. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10249053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Microalgae are an excellent source of bioactive compounds for the production of a wide range of vital consumer products in the biofuel, pharmaceutical, food, cosmetics, and agricultural industries, in addition to huge upstream benefits relating to carbon dioxide biosequestration and wastewater treatment. However, energy-efficient, cost-effective, and scalable microalgal technologies for commercial-scale applications are limited, and this has significantly impacted the full-scale implementation of microalgal biosystems for bioproduct development, phycoremediation, and biorefinery applications. Microalgae culture dewatering continues to be a major challenge to large-scale biomass generation, and this is primarily due to the low cell densities of microalgal cultures and the small hydrodynamic size of microalgal cells. With such biophysical characteristics, energy-intensive solid–liquid separation processes such as centrifugation and filtration are generally used for continuous generation of biomass in large-scale settings, making dewatering a major contributor to the microalgae bioprocess economics. This article analyzes the potential of electroflotation as a cost-effective dewatering process that can be integrated into microalgae bioprocesses for continuous biomass production. Electroflotation hinges on the generation of fine bubbles at the surface of an electrode system to entrain microalgal particulates to the surface. A modification of electroflotation, which combines electrocoagulation to catalyze the coalescence of microalgae cells before gaseous entrainment, is also discussed. A technoeconomic appraisal of the prospects of electroflotation compared with other dewatering technologies is presented.
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Veeramuthu L, Venkatesan M, Liang FC, Benas JS, Cho CJ, Chen CW, Zhou Y, Lee RH, Kuo CC. Conjugated Copolymers through Electrospinning Synthetic Strategies and Their Versatile Applications in Sensing Environmental Toxicants, pH, Temperature, and Humidity. Polymers (Basel) 2020; 12:E587. [PMID: 32150907 PMCID: PMC7182922 DOI: 10.3390/polym12030587] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/12/2020] [Accepted: 02/19/2020] [Indexed: 11/16/2022] Open
Abstract
Conjugated copolymers (CCPs) are a class of polymers with excellent optical luminescent and electrical conducting properties because of their extensive π conjugation. CCPs have several advantages such as facile synthesis, structural tailorability, processability, and ease of device fabrication by compatible solvents. Electrospinning (ES) is a versatile technique that produces continuous high throughput nanofibers or microfibers and its appropriate synchronization with CCPs can aid in harvesting an ideal sensory nanofiber. The ES-based nanofibrous membrane enables sensors to accomplish ultrahigh sensitivity and response time with the aid of a greater surface-to-volume ratio. This review covers the crucial aspects of designing highly responsive optical sensors that includes synthetic strategies, sensor fabrication, mechanistic aspects, sensing modes, and recent sensing trends in monitoring environmental toxicants, pH, temperature, and humidity. In particular, considerable attention is being paid on classifying the ES-based optical sensor fabrication to overcome remaining challenges such as sensitivity, selectivity, dye leaching, instability, and reversibility.
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Affiliation(s)
- Loganathan Veeramuthu
- Institute of Organic and Polymeric Materials, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan; (L.V.); (M.V.); (F.-C.L.); (J.-S.B.); (C.-W.C.)
| | - Manikandan Venkatesan
- Institute of Organic and Polymeric Materials, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan; (L.V.); (M.V.); (F.-C.L.); (J.-S.B.); (C.-W.C.)
| | - Fang-Cheng Liang
- Institute of Organic and Polymeric Materials, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan; (L.V.); (M.V.); (F.-C.L.); (J.-S.B.); (C.-W.C.)
| | - Jean-Sebastien Benas
- Institute of Organic and Polymeric Materials, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan; (L.V.); (M.V.); (F.-C.L.); (J.-S.B.); (C.-W.C.)
| | - Chia-Jung Cho
- Institute of Organic and Polymeric Materials, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan; (L.V.); (M.V.); (F.-C.L.); (J.-S.B.); (C.-W.C.)
| | - Chin-Wen Chen
- Institute of Organic and Polymeric Materials, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan; (L.V.); (M.V.); (F.-C.L.); (J.-S.B.); (C.-W.C.)
| | - Ye Zhou
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China;
| | - Rong-Ho Lee
- Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan;
| | - Chi-Ching Kuo
- Institute of Organic and Polymeric Materials, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan; (L.V.); (M.V.); (F.-C.L.); (J.-S.B.); (C.-W.C.)
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14
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Abstract
Flotation constitutes a separation process that originated from mineral processing. Nowadays, wider applications have been found and compared to flotation for water and wastewater treatment. Stress in the present review paper was mainly applied to heavy metal ions recovery by flotation and the respective mechanism followed, being either ion, precipitate, or sorptive flotation. In the latter case, the use of adsorbents is included (such as powdered activated carbon, zeolites, and goethite), as well as various biosorbents. The flotation of the following metals was reviewed: copper, zinc, nickel, lead, iron, chromium, arsenic, gold, and others. The bubble generation method could be applied for typical dispersed-air flotation column, electroflotation, or dissolved-air flotation; the latter being the most appropriate established technique in water treatment. The role of particle size (for example, studying flotation of salt-type mineral fines) was also examined.
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