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Cao Z, Zhu R, Li Y, Kakade A, Zhang S, Yuan Y, Wu Y, Mi J. Mitigation of ammonia and hydrogen sulfide emissions during aerobic composting of laying hen waste through NaOH-modified biochar. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 365:121634. [PMID: 38943752 DOI: 10.1016/j.jenvman.2024.121634] [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: 03/20/2024] [Revised: 06/05/2024] [Accepted: 06/27/2024] [Indexed: 07/01/2024]
Abstract
The impact of NaOH-modified biochar on the release of NH3 and H2S from laying hens' manure was examined for 44 days, using a small-scale simulated aerobic composting system. The findings revealed that the NaOH-modified biochar reduced NH3 and H2S emissions by 40.63% and 77.78%, respectively, compared to the control group. Moreover, the emissions of H2S were significantly lower than those of the unmodified biochar group (p < 0.05). The increased specific surface area and microporous structure of the biochar, as well as the higher content of alkaline and oxygenated functional groups, were found to facilitate the adsorption of NH3 and H2S. This enhanced adsorption capability was the primary reason for the significant reduction in NH3 emissions. Furthermore, during the high-temperature phase of composting, there was a notable alteration in the microbial community. The abundance of Limnochordaceae, Savagea, and IMCC26207 increased significantly which aided in the conversion of H2S to stable sulfate. These microorganisms also influenced the abundance of functional genes involved in sulfur metabolism, thereby inhibiting cysteine synthesis, along with the decomposition and conversion of sulfate to sulfite. This led to a significant decrease in H2S emissions. This study provides valuable data for the selection of deodorizers in the composting process of egg-laying hens. The results have significant implications for the application of NaOH-modified biochar for odor reduction in aerobic composting processes.
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Affiliation(s)
- Ze Cao
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou, 730000, China; State Key Laboratory of Herbage Improvement and Grassland Agro-ecocystems, International Centre of Tibetan Plateau Ecosystem Management, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Run Zhu
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Yong Li
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Apurva Kakade
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecocystems, International Centre of Tibetan Plateau Ecosystem Management, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Shiyu Zhang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Yilin Yuan
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Yinbao Wu
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Jiandui Mi
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou, 730000, China; Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, 730000, China.
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Li Y, Chai Z, Song C, Chen J, Gu A, Mu G, Ge R, Zheng M. The superiority of hydrophilic polyurethane in comammox-dominant ammonia oxidation during low-strength wastewater treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 935:173017. [PMID: 38719054 DOI: 10.1016/j.scitotenv.2024.173017] [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: 01/22/2024] [Revised: 04/09/2024] [Accepted: 05/04/2024] [Indexed: 05/26/2024]
Abstract
Carriers have been extensively employed to enhance nitrification performance during low-strength wastewater treatment by retaining slow-growing ammonia oxidizing microorganisms (AOMs). Still, there is a dearth of systematic understanding of biofilm properties and microbial community structure formed on different carriers. In this study, hydrophilic polyurethane foam (PUF) carriers were prepared and compared with five widely used commercial carriers, namely Kaldness 3, Biochip, activated carbon, volcanic rock, and zeolite. The results indicated that the biofilms formed on carriers enhanced microbial ammonia oxidation activity. Additionally, the biofilm developed on the PUF demonstrated the most superior performance among all selected carriers, not only exhibiting the highest abundant and the most active AOMs, with amoA gene abundance of 1.41 × 1013 copies/m3 and specific ammonia oxidation rate of 9.84 g NH4+-N/(m3 × h), but also possessing a compact structure, with 3.41 kg VSS/m3 and 46.83 mg extracellular polymeric substances/g VSS. The high-throughput sequencing analysis revealed that the comammox (CMX) Nitrospira dominated on biofilm due to the intrinsically low apparent half-saturation constant for substrate. A unique ecological community structure was established on PUF, characterized by low species diversity and high homogeneity in alignment with community characteristics of CMX. The biofilms on PUF contributed to the proliferation of CMX Nitrospira dominated by Nitrospira nitrosa, achieving the highest proportion among colonial three AOMs at 86.58 %. The appropriate average pore size, superior hydrophilicity, and large specific surface area of PUF carriers provided a robust foundation for the exceptional ammonia oxidation performance of the formed biofilms.
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Affiliation(s)
- Yunlong Li
- 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
| | - Zimin Chai
- 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
| | - Chao Song
- 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
| | - Jin Chen
- 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
| | - Ailu Gu
- 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
| | - Guangli Mu
- 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
| | - Ruxin Ge
- 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
| | - 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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Xue Y, Wang X, Liu Q, Feng M, Ding Z, Chu J, Zhu W, Liu N, Li Z. In situ electro-generated Ni(OH) 2 synergistic with Cu cathode to promote direct ammonia oxidation to nitrogen. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2024; 90:225-237. [PMID: 39007316 DOI: 10.2166/wst.2024.214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 06/07/2024] [Indexed: 07/16/2024]
Abstract
To solve the problem of low removal rate and poor N2 selectivity in direct electrochemical ammonia oxidation (EAO), commercial Ni foam and Cu foam were used as anode and cathode of the EAO system, respectively. The coupling effect between the cathode and anode promoted nitrogen cycling during the reaction process, which improved N2 selectivity of the reaction system and promoted it to achieve a high ammonia removal rate. This study showed that the thin Ni(OH)2 with oxygen vacancy formed on the surface of Ni foam anode played an effective role in the dimerization of intermediate products in ammonia oxidation to form N2. This electrochemical system was used to treat real goose wastewater containing 422.5 mg/L NH4+-N and 94.5 mg/L total organic carbon (TOC). After treatment, this electrochemical system achieved good performance with an ammonia removal rate of 87%, N2 selectivity of 77%, and TOC removal rate of 72%. Therefore, this simple and efficient system with Ni foam anode and Cu foam cathode is a promising method for treating ammonia nitrogen wastewater.
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Affiliation(s)
- Yuzhou Xue
- School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China; Research Center of Non-Point Source Pollution Control and Ecological Remediation Technology of Tuohe River Basin, Suzhou University, Suzhou Anhui, 234000, China E-mail:
| | - Xuanxuan Wang
- School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China; Research Center of Non-Point Source Pollution Control and Ecological Remediation Technology of Tuohe River Basin, Suzhou University, Suzhou Anhui, 234000, China
| | - Qing Liu
- School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China; Research Center of Non-Point Source Pollution Control and Ecological Remediation Technology of Tuohe River Basin, Suzhou University, Suzhou Anhui, 234000, China
| | - Mengru Feng
- School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China; Research Center of Non-Point Source Pollution Control and Ecological Remediation Technology of Tuohe River Basin, Suzhou University, Suzhou Anhui, 234000, China
| | - Zimo Ding
- School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China; Research Center of Non-Point Source Pollution Control and Ecological Remediation Technology of Tuohe River Basin, Suzhou University, Suzhou Anhui, 234000, China
| | - Jiayue Chu
- School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China; Research Center of Non-Point Source Pollution Control and Ecological Remediation Technology of Tuohe River Basin, Suzhou University, Suzhou Anhui, 234000, China
| | - Wenyan Zhu
- School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China; Research Center of Non-Point Source Pollution Control and Ecological Remediation Technology of Tuohe River Basin, Suzhou University, Suzhou Anhui, 234000, China
| | - Na Liu
- School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China; Research Center of Non-Point Source Pollution Control and Ecological Remediation Technology of Tuohe River Basin, Suzhou University, Suzhou Anhui, 234000, China
| | - Zhichun Li
- School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China; Research Center of Non-Point Source Pollution Control and Ecological Remediation Technology of Tuohe River Basin, Suzhou University, Suzhou Anhui, 234000, China
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Xie Z, Liu R, Lu F, Jing D, Zhao Y, Liang J, Huang W, Liu Y. Study on harmless treatment of electrolytic manganese residue by low temperature thermochemical method. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:42342-42356. [PMID: 38872036 DOI: 10.1007/s11356-024-33932-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 06/03/2024] [Indexed: 06/15/2024]
Abstract
The Electrolytic Manganese Residue (EMR) is a by-product of the electrolytic manganese metal (EMM) industry, containing high concentrations of potential pollutants such as NH4+-N and soluble Mn2+. These components pose a serious threat to the ecological environment. To explore accurate, efficient, and harmless treatment methods for EMR, this study proposes a low-temperature thermochemical approach. The orthogonal experiment design investigates the effects of reaction temperature, reaction time, quicklime (CaO), sodium carbonate (Na2CO3), sodium phosphate (Na3PO4) (Reviewer #3), and water consumption on manganese solidified and ammonia removal from EMR. The results indicate that optimal conditions are a reaction temperature of 60 ℃ (Reviewer #3) and a reaction time of 10 min. CaO precipitates Mn2+ as manganese hydroxide (Mn(OH)2) (Reviewer #3), achieving effective manganese solidified and ammonia removal. The addition of Na2CO3 causes Mn2+ to form manganesecarbonate (MnCO3) (Reviewer #3)precipitate, while Na3PO4 makes Mn2+ form Manganese phosphate trihydrate (Mn3(PO4)2·3H2O) (Reviewer #3). Increased water consumption enhances the interaction adequacy between ions. Under optimal conditions (CaO 10%, Na2CO3 1%, Na3PO4 0.5%, and 80% water consumption), the removal rate of ammonium ions reaches 98.5%, and the solidification rate of soluble Mn2+ is 99.9%. The order of influence on ammonium ion removal is CaO > water consumption > Na3PO4 > Na2CO3. Therefore, this study provides a new method for low-cost process disposal and efficient harmless treatment of EMR (Reviewer #3).
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Affiliation(s)
- Zhihan Xie
- College of Material Science and Engineering, Guilin University of Technology, Guilin, 541004, China
- Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources in Guangxi, Guilin University of Technology, Guilin, 541004, China
| | - Rongjin Liu
- College of Material Science and Engineering, Guilin University of Technology, Guilin, 541004, China.
- Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources in Guangxi, Guilin University of Technology, Guilin, 541004, China.
- Key Laboratory of New Processing Technology for Nonferrous Metal & Materials, Ministry of Education, Guilin University of Technology, Guilin, 541004, China.
- Guangxi Engineering and Technology Center for Utilization of Industrial Waste Residue in Building Materials, Guilin, 541004, China.
| | - Fuhua Lu
- College of Material Science and Engineering, Guilin University of Technology, Guilin, 541004, China
- Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources in Guangxi, Guilin University of Technology, Guilin, 541004, China
| | - Daiyan Jing
- Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources in Guangxi, Guilin University of Technology, Guilin, 541004, China
| | - Yanrong Zhao
- College of Material Science and Engineering, Guilin University of Technology, Guilin, 541004, China
- Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources in Guangxi, Guilin University of Technology, Guilin, 541004, China
- Key Laboratory of New Processing Technology for Nonferrous Metal & Materials, Ministry of Education, Guilin University of Technology, Guilin, 541004, China
- Guangxi Engineering and Technology Center for Utilization of Industrial Waste Residue in Building Materials, Guilin, 541004, China
| | - Jianbo Liang
- College of Material Science and Engineering, Guilin University of Technology, Guilin, 541004, China
- Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources in Guangxi, Guilin University of Technology, Guilin, 541004, China
| | - Wanyu Huang
- College of Material Science and Engineering, Guilin University of Technology, Guilin, 541004, China
- Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources in Guangxi, Guilin University of Technology, Guilin, 541004, China
| | - Yuhang Liu
- College of Material Science and Engineering, Guilin University of Technology, Guilin, 541004, China
- Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources in Guangxi, Guilin University of Technology, Guilin, 541004, China
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Tan HJ, Si R, Li XB, Tang ZK, Wei XL, Seriani N, Yin WJ, Gebauer R. How spin state and oxidation number of transition metal atoms determine molecular adsorption: a first-principles case study for NH 3. Phys Chem Chem Phys 2024; 26:7688-7694. [PMID: 38372067 DOI: 10.1039/d3cp05042d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Understanding how the electronic state of transition metal atoms can influence molecular adsorption on a substrate is of great importance for many applications. Choosing NH3 as a model molecule, its adsorption behavior on defected SnS2 monolayers is investigated. The number of valence electrons n is controlled by decorating the monolayer with different transition metal atoms, ranging from Sc to Zn. Density-Functional Theory based calculations show that the adsorption energy of NH3 molecules oscillates with n and shows a clear odd-even pattern. There is also a mirror symmetry of the adsorption energies for large and low electron numbers. This unique behavior is mainly governed by the oxidation state of the TM ions. We trace back the observed trends of the adsorption energy to the orbital symmetries and ligand effects which affect the interaction between the 3σ orbitals (NH3) and the 3d orbitals of the transition metals. This result unravels the role which the spin state of TM ions plays in different crystal fields for the adsorption behavior of molecules. This new understanding of the role of the electronic structure on molecular adsorption can be useful for the design of high efficiency nanodevices in areas such as sensing and photocatalysis.
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Affiliation(s)
- Hua-Jian Tan
- School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201, China
- Key Laboratory of Intelligent Sensors and Advanced Sensing Materials of Hunan Province, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Rutong Si
- The Abdus Salam International Centre for Theoretical Physics (ICTP), Strada Costiera 11, Trieste I-34151, Italy.
| | - Xi-Bo Li
- Department of Physics, Jinan University, Guangzhou 510632, P. R. China
| | - Zhen-Kun Tang
- College of Physics and Electronics Engineering, Hengyang Normal University, Hengyang 421008, China
| | - Xiao-Lin Wei
- Department of Physics and Laboratory for Quantum Engineering and Micro-Nano Energy Technology, Xiangtan University, Xiangtan 411105, Hunan, China
| | - Nicola Seriani
- The Abdus Salam International Centre for Theoretical Physics (ICTP), Strada Costiera 11, Trieste I-34151, Italy.
| | - Wen-Jin Yin
- School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201, China
- The Abdus Salam International Centre for Theoretical Physics (ICTP), Strada Costiera 11, Trieste I-34151, Italy.
- Key Laboratory of Intelligent Sensors and Advanced Sensing Materials of Hunan Province, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Ralph Gebauer
- The Abdus Salam International Centre for Theoretical Physics (ICTP), Strada Costiera 11, Trieste I-34151, Italy.
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Mishra S, Cheng L, Lian Y. Response of biofilm-based systems for antibiotics removal from wastewater: Resource efficiency and process resiliency. CHEMOSPHERE 2023; 340:139878. [PMID: 37604340 DOI: 10.1016/j.chemosphere.2023.139878] [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: 05/28/2023] [Revised: 07/23/2023] [Accepted: 08/17/2023] [Indexed: 08/23/2023]
Abstract
Biofilm-based systems have efficient stability to cope-up influent shock loading with protective and abundant microbial assemblage, which are extensively exploited for biodegradation of recalcitrant antibiotics from wastewater. The system performance is subject to biofilm types, chemical composition, growth and thickness maintenance. The present study elaborates discussion on different type of biofilms and their formation mechanism involving extracellular polymeric substances secreted by microbes when exposed to antibiotics-laden wastewater. The biofilm models applied for estimation/prediction of biofilm-based systems performance are explored to classify the application feasibility. Further, the critical review of antibiotics removal efficiency, design and operation of different biofilm-based systems (e.g. rotating biological contactor, membrane biofilm bioreactor etc.) is performed. Extending the information on effect of various process parameters (e.g. hydraulic retention time, pH, biocarrier filling ratio etc.), the microbial community dynamics responsible of antibiotics biodegradation in biofilms, the technological problems, related prospective and key future research directions are demonstrated. The biofilm-based system with biocarriers filling ratio of ∼50-70% and predominantly enriched with bacterial species of phylum Proteobacteria protected under biofilm thickness of ∼1600 μm is effectively utilized for antibiotic biodegradation (>90%) when operated at DO concentration ≥3 mg/L. The C/N ratio ≥1 is best suitable condition to eliminate antibiotic pollution from biofilm-based systems. Considering the significance of biofilm-based systems, this review study could be beneficial for the researchers targeting to develop sustainable biofilm-based technologies with feasible regulatory strategies for treatment of mixed antibiotics-laden real wastewater.
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Affiliation(s)
- Saurabh Mishra
- Yangtze Institute for Conservation and Development, Hohai University, Nanjing, 210098, Jiangsu, China; Institute of Water Science and Technology, Hohai University, Nanjing, Jiangsu, 210098, China; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, 210098, Jiangsu, China.
| | - Liu Cheng
- College of Environment, Hohai University, Nanjing, Jiangsu Province, 210098, China
| | - Yanqing Lian
- Yangtze Institute for Conservation and Development, Hohai University, Nanjing, 210098, Jiangsu, China; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, 210098, Jiangsu, China.
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Wang L, Zhou W, Zhang M, Zheng Z, Zhao S, Xing C, Jia J, Liu C. Environmental ammonia analysis based on exclusive nitrification by nitrifying biofilm screened from natural bioresource. CHEMOSPHERE 2023; 336:139221. [PMID: 37327822 DOI: 10.1016/j.chemosphere.2023.139221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023]
Abstract
Biofilm-based biological nitrification is widely used for ammonia removal, while hasn't been explored for ammonia analysis. The stumbling block is the coexist of nitrifying and heterotrophic microbes in real environment resulting in non-specific sensing. Herein, an exclusive ammonia sensing nitrifying biofilm was screened from natural bioresource, and a bioreaction-detection system for the on-line analysis of environmental ammonia based on biological nitrification was reported. The nitrifying microbes were aggregated into a nitrifying biofilm through a result-oriented bioresource enrichment strategy. The predominant nitrifying population and progressive surface reaction in the plug flow bioreactor led to the exclusive and exhaustive ammonia biodegradation for the establishment of a novel analytical method. The on-line ammonia monitoring prototype achieved complete biodegradation for determining ammonium nitrogen within 5 min and showed exceptional reliability in long-term real sample measurements without frequent calibration. This work offers a low-threshold natural screening paradigm for developing sustainable bioresource-based analytical technologies.
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Affiliation(s)
- Liang Wang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529000, China
| | - Wuping Zhou
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529000, China
| | - Mengchen Zhang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529000, China.
| | - Zehua Zheng
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529000, China
| | - Song Zhao
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529000, China
| | - Chao Xing
- UQ Dow Center, School of Chemical Engineering, The University of Queensland, St Lucia, 4072, Australia
| | - Jianbo Jia
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529000, China
| | - Changyu Liu
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529000, China.
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Efficient Removal of Ammonia Nitrogen by an Electrochemical Process for Spent Caustic Wastewater Treatment. Catalysts 2022. [DOI: 10.3390/catal12111357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Spent caustic wastewater produced in a soda plant has a high concentration of ammonia nitrogen (NH4+-N). As excessive NH4+-N discharging into water bodies would cause eutrophication as well as destruction to the ecology balance, developing an efficient technology for NH4+-N removal from the spent caustic wastewater is imperative in the current society. In this study, an electrochemical process with graphene electrodes was designed for the NH4+-N removal in the spent caustic wastewater. The removal efficiency of the NH4+-N during the electrochemical process could reach 98.7% at 4 A in a short treatment time (within 120 s) with an acceptable energy consumption (6.1 kWh/m3-order). NO3− and NO2− were not detected during the electrochemical process. An insignificant amount of NH2Cl, NHCl2, and NCl3 produced in the treatment suggested that little of the NH4+-N reacted with chlorine, that is, chlorination played a negligible role in the NH4+-N removal. By electron equilibrium and nitrogen conversion analysis, we think that NH4+-N was primarily converted to NH2(ads) on the surface of a graphene electrode by one-electron transfer during the direct oxidation of the electrochemical process. Due to the high calcium ion (Ca2+) in the spent caustic wastewater, the electrode scale significantly increased to 1.4 g after treatment of 240 s at 4 A. By X-ray diffraction (XRD) analysis, the composition of the electrode scale is portlandite Ca(OH)2. Although the electrode scale was obvious during the electrochemical treatment, it could be alleviated by alternating the electrode polarity. As a result, the life and efficiency of the graphene electrode for NH4+-N removal could remain stable for a long time. These results suggest that the electrochemical process with a graphene electrode may provide a competitive technology for NH4+-N removal in spent caustic wastewater treatment.
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