Journal of Chemistry
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2022
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IF 3.241
Yan Jin,Xinyuan Wang,Ya-Ping Dong
The Yellow River is very important for human health and social development in China to require good water quality. This study selected the Ningxia section of the Yellow River as the study area to investigate the water quality variation in 2016–2020. A total of 9 water quality parameters were monitored, and 8 parameters including pH, dissolved oxygen, biological oxygen demand, chemical oxygen demand, total phosphate, fluoride, ammonia-nitrogen, and permanganate index were in the range of Class II standard requirement. Dissolved oxygen concentrations ranged from 7.5 to 9.4 mg/L. However, total nitrogen concentrations in 2018–2020 ranged from 1.87 to 2.8 mg/L to cause the pollution. Both the Nemerow index method and the contamination degree method showed that total nitrogen with high concentration exerted the water pollution. Principal component analysis also proved this. Stricter environmental management strategies for controlling total nitrogen should be taken in the future. The findings provided some useful information for water pollution of the Ningxia section of the Yellow River.
研究领域:
环境科学
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水资源管理
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产品关联
DOI
高影响因子
ACS Omega
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2024
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IF 3.7
Xinyue Jiang,Defu Liu,Guodong Jiang,Yuqun Xie
A technique for monitoring chemical oxygen demand (COD), total nitrogen (TN), ammonia (N-NH4), and phosphate (P-PO4) in surface water with a targeted signal multielectrode system (Cu, Ir, Rh, Co(OH)2, and Zr(OH)4 electrodes) is proposed for the first time. Each water quality index is specifically detected by at least two electrodes with distinct selectivity sensing mechanisms. Cyclic voltammetry and electrochemical impedance measurements are employed for multidimensional signal acquisition, complemented by normalization and Least Absolute Shrinkage and Selection Operator (LASSO) for principal feature extraction and dimension reduction. Multiple linear regression (MLR), partial least-squares (PLS), and eXtreme Gradient Boosting (XGBoost) were employed to evaluate the established prediction model. The precisions of the multielectrode system are ±10%/±5 ppm of COD, ±10%/±0.2 ppm of TN, ±5%/±0.1 ppm of N-NH4, and ±5%/±0.01 ppm of P-PO4. The analysis time of the multielectrode system is reduced from hours to minutes compared with traditional analysis, without any sample pretreatment, facilitating continuous online monitoring in the field. The developed multielectrode system offers a feasible strategy for online in situ monitoring of surface water quality.
研究领域:
环境科学
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分析化学
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产品关联
DOI
PubMed
高影响因子
Water Science and Engineering
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2024
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IF 3.7
Shan-Shan Gao,Xing Yin,Rui Huang,Jia-Yu Tian
Simultaneous nitrification and denitrification (SND) is an efficient method to remove nitrogen in municipal wastewater treatment. However, low dissolved oxygen (DO) concentrations are generally required, leading to serious membrane fouling in membrane bioreactors (MBRs). This study aimed to clarify the synergistic effect of biomass and DO on nitrogen removal and membrane fouling. To achieve this goal, four submerged MBRs equipped with ceramic membranes were operated with different biomass (mixed liquor suspended solids (MLSS)) concentrations (3 000 mg/L, 5 000 mg/L, 7 500 mg/L, and 12 000 mg/L) under various DO concentrations (2.0 mg/L, 1.0 mg/L, and 0.5 mg/L). As a result, increasing biomass in the MBRs enhanced total nitrogen (TN) removal via SND, and excellent TN removal efficiencies of 60.7% and 75.8% were obtained using the MBR with an MLSS concentration of 12 000 mg/L and DO concentrations of 2.0 mg/L and 1.0 mg/L. However, a further decrease in DO deteriorated TN removal due to the inhibition of nitrification. Moreover, high MLSS concentrations were beneficial to membrane fouling control for ceramic membranes in MBRs. The lowest transmembrane pressure development rate was observed for the MBR with an MLSS concentration of 12 000 mg/L. High biomass offset the adverse effect of DO decrease on membrane fouling to some extent, and improved the stability of the reactor. Therefore, biomass might be an important parameter for membrane fouling reduction in ceramic MBRs. Overall, optimal biomass and DO concentrations for TN removal were identified, providing useful information for the successful operation of MBRs with efficient TN removal and membrane fouling control.
研究领域:
环境工程
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污水处理
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微生物学
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Shuyin Zhang,Jing Zou,Lingxuan Chen,Chunhua Shen,Jian Lu,Jianlin Zhang,Hangyu Cui,Geng Huang,Jun Ma
Although thermal-activated peroxymonosulfate (PMS) system possesses good performance on the removal of organic pollutants, thermal/PMS system exhibited poor capacity to remove ammonia nitrogen (NH 4 + -N). This study demonstrated the huge enhancement on the removal of NH 4 + -N by thermal/PMS system with the commonly coexistent bromide ion (Br - ). The elimination of NH 4 + -N by thermal/PMS/Br - system fitted the pseudo -zero-order kinetics model well, while the corresponding k obs in the presence of 200 μM Br - was 5.76 times greater than that by thermal/PMS system. Bromine (HBrO) was confirmed as the dominant oxidant responsible for removing NH 4 + -N and TN, while the radicals of HO ⋅ , SO 4 ⋅- and Br ⋅ were also generated but made minor contribution to removing NH 4 + -N. HBrO was mostly produced by PMS reacting directly with Br - , while these radicals were produced from the cleavage of the O-O bond in PMS and the reaction between PMS and HBrO under high temperature. Thermal/PMS/Br - system exhibited superior performance on TN removal (up to 90 %) than that by thermal/PMS system (less than 5 %) and Cl - -enhanced system (about 80 %). The main removal product of NH 4 + -N was identified as the environmentally friendly gas of N 2 , although nitrate was also detected. Neutral pH condition was the optical pH for NH 4 + -N removal. Increasing reaction temperature, PMS dosage and Br - concentration were beneficial to accelerating the removal of NH 4 + -N. Cations of Cu 2+ and Fe 3+ , anions of SO 4 2- , CO 3 2 - and NO 3 - , humic acid and the actual water matrix of landfill leachate negligibly influenced the removal of NH 4 + -N, while Cl - exhibited strong enhancement on NH 4 + -N removal. In summary, this study provided an effective method to improve the oxidizing capacity of thermal/PMS system, especially for NH 4 + -N removal in wastewater containing Br - .
研究领域:
环境科学
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污水处理
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产品关联
DOI
高影响因子
CHEMOSPHERE
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2021
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IF 7.086
JiaJia Xue,Dandan Lei,Xiumei Zhao,Yaru Hu,Shijie Yao,Kuangfei Lin,Zejian Wang,Changzheng Cui
Various pollutants are released during pharmaceutical production processes, which is of great concern. Most studies have focused on the terminal treatment results of mixed pharmaceutical wastewater, and further research on wastewater from the production processes is required. This study investigated the wastewater quality indicators, residual antibiotics, and biological toxicity of the wastewater during the production process in a large pharmaceutical producing factory in Northern China. The wastewater contained numerous organic pollutants, with the chemical oxygen demand (COD) values ranging from 2.0 × 10 3 to 2.6 × 10 5 mg L −1 and the total nitrogen (TN) values ranging from 1.3 × 10 3 to 2.0 × 10 4 mg L −1 . High concentrations of cephalexin and cefradine remained in the wastewater of the production workshop, with the highest concentration of cefradine reaching 1328 mg L −1 . The wastewater from the oxidation and solvent recovery workshops was more toxic to Vibrio fischeri and Daphnia magna than that of other workshops. Moreover, the biological acute toxicity of wastewater was significantly correlated with the concentration of COD and TN ( p < 0.01). This study provides new insights into the treatment of antibiotic production wastewater, illuminating the incomplete extraction of products and the significant risk posed by pharmaceutical wastewater to the environment.
研究领域:
环境科学
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药学
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毒理学
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DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Mian Hu,Xiaotong Huang,Letao Sun,Weicheng Zheng,I-Ming Chou,Libo Wu,Jinling Wan,Zhiyan Pan,Junliang Wang
Catalytic oxidation of o -chloroaniline ( o- ClA) in hot compressed water (HCW) was investigated in a fused quartz tube reactor (FQTR) to determine the effects of catalyst, temperature, oxygen stoichiometric ratio (OSR) and reaction time on o- ClA mineralization, total nitrogen (TN) removal rate and nitrogen-containing products distribution. The results showed that o -ClA can be effectively degraded in HCW. With the increased of OSR, retention time and temperature or added of Mn 2 O 3 as catalyst, the mineralization rate of o -ClA and the removal rate of TN increased. Ammonia-N was the main nitrogen-containing intermediate product of o -ClA degradation, however, when the oxidant was excessive, ammonia-N was oxidized to form nitrate-N. Althought the catalytic effect of Mn 2 O 3 on the mineralization of o -ClA was not outstanding, it promoted the removal of ammonia-N from the benzene ring, improved the degradtion of ammonia-N, and inhibited the production of nitrate-N. GC–MS analyzed results indicated that o -chlorophenol was the main degradation intermediate product of o -ClA in HCWO process. Meanwhile, the potential degradation pathway of o -ClA was proposed. This work thus provides basic knowledge about o -ClA catalytic oxidation removal in HCW process.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Jiaqian Yang,Jining Jia,Jiade Wang,Qingqing Zhou,Ruihao Zheng
An inverse computation machine learning (ML) framework that couples genetic algorithm (GA) to feedforward neural network was developed to optimize the operating parameters for maximizing electrochemical removal of chemical oxygen demand (COD) and total nitrogen (TN) from wastewater. Conventional neural networks (NN) are generally unable to implement inverse computation from a desired abatement to feasible input conditions, and NN trained from small-scale datasets tends to be unreliable for multivariate simulation. To address this issue, we employed GA for tuning the weights and biases of the network to enhance the stability and generalization performance of NN, the optimization of multiple operating conditions was performed by the GA strategy of iterative evolution and global search. In this work, we investigated and analyzed the performance of multivariate optimization approaches such as orthogonal design, response surface methodology (RSM), traditional NN, and the developed neuro-genetic model (GANN). Significance and error analysis demonstrate that GANN exhibits superior stability and generalization ability with the highest R 2 of 0.946 (COD), 0.874 (TN), and the lowest RMSE of 0.022 (COD), 0.028 (TN). The introduction of GA is significant for improving the prediction accuracy of NN derived from small-scale datasets. The average error of the GANN trained by 25 data points is lower than that of the RSM model derived from 54 data points. According to the validation outcomes, the scheme suggested by GANN achieves the best COD (93.6%) and TN (62.8%) degradation efficiencies, which are 6.1% and 9.9% higher than the optimal values in the original dataset, respectively. The proposed multivariate global optimization strategy can be extended to other cases, and the computational framework of GANN also contributes to the progress of more reliable ML models.
研究领域:
环境科学
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机器学习
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电化学工程
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2023
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IF 13.6
Wenzhe Liu,Baiyang Chen,Yang Yang,Boqiang Li,Huimei Pan,Wang Luo
Excessive ammonia (NH 4 + ) discharge can lead to algal blooms and disrupt water sustainability, so its control is imperative. Although microbiology-triggered anammox process is promising, its application is limited due to time-consuming cultivation of specific microorganisms and need for skilled operation. To bypass these barriers, this study proposed and verified a photo-induced anammox technology that removes NH 4 + and total nitrogen (TN) from water by ultraviolet (UV)/vacuum UV (VUV)/chlorine under anoxic conditions . Under the Cl/N mass ratio of 5:1, the anoxic VUV/UV/chlorine process achieved 66.8% removal of 10 mg-N/L NH 4 + within 10 min along with 57.8% reduction in TN. Besides the evidence from TN loss, this study confirmed nitrogen gas (N 2 ) as the primary degradation product at low dissolved oxygen (DO) concentration of 2.0 mg/L. The selective conversion of NH 4 + into N 2 was mainly attributed to reactive nitrogen species (RNS, 42.5%) and reactive chlorine species (RCS, 57.5%). The TN removal efficiency was insensitive to certain variations of pH (7.0–9.0), NH 4 + concentration (1–30 mg-N/L), chloride (50–125 mg/L), and sulfate (25–100 mg/L), but sensitive to DO and bicarbonate (25–100 mg/L). Given its robustness and high efficiency, the anoxic VUV/UV/chlorine technology may serve as a potentially promising alternative for NH 4 + and TN alleviation in wastewater.
研究领域:
环境科学
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微生物学
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DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2024
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IF 8.4
Min-Min Zhang,An-Kang Li,Ming-Jian Tang,Qin-Yuan He,Yi-Hao Peng,Ren-Jie Fan,Shi-Peng Sun,Xue-Li Cao
Nitrite-containing wastewater poses an imminent threat to both human health and ecosystems. Conventional methods like nitrification and denitrification rely heavily on chemical reagents, while emerging membrane separation has limitations in permselectivity. Here, a conductive membrane with both electroresponsive and electrocatalytic capabilities was developed by integrating Keggin-type polyoxometalates (POMs) through combining layer-by-layer self-assembly and interfacial polymerization. The pore size of the membranes remained largely unaffected by an electric field, but its Donnan effect was significantly enhanced, leading to a substantial increase in nitrite removal from 23.1% to an impressive 81%. Nitrite underwent a reductive degradation at the cathode, producing nitrogen-containing gases (8.3%), while oxidation at the anode yielded hypotoxic NO 3 − (11.3%), respectively exhibiting 79.9% rejection of NO 2 − and 83.1% rejection of NO 3 − under the electric field-enhanced Donnan effect. Therefore, the high-level total nitrogen removal was composed of three key components: 64.2% from direct NO 2 − rejection, 9.4% from oxidation-generated NO 3 − rejection, and 7.4% attributed to gas generation. Significantly, our work underscored the consistently robust structural stability of the POMs-based membrane under an electric field, maintaining an outstanding total nitrogen removal exceeding 75%. Consequently, this research introduced a promising electrochemical-membrane fusion approach for efficiently removing high-activity nitrite-containing wastewater, emphasizing the potential for environmental applications.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Journal of Water Process Engineering
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2024
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IF 6.3
Ye Yang,Chao-Kun Li,Liu Han,Zhi-Peng Yang,Ning-Ning Xiao,Nan Zhang,Ying-Ying Dong,Zhi-Wen Chen,Hui Xi,Wen-Dong Wang
Water pollution poses a significant challenge to the development of rural human settlements in China, necessitating the development of wastewater treatment systems tailored to the local economic conditions and discharge characteristics. This study introduces a novel wastewater treatment process, namely solar photovoltaic power generation-constructed wetland (SPPG-CW) and conducts a comprehensive evaluation of its performance on rural domestic sewage treatment. The findings reveal that the solar photovoltaic power generation unit ensures stable off-grid operation, providing a reliable power supply to the wetland unit. Simulation results demonstrate that the LAB achieves stable energy output and absorption during SPPG unit operation, thus avoiding energy loss. Long-term monitoring experiments confirm that the SPPG-CW efficiently treats real wastewater. Upon stabilization, the system consistently achieves over 90 % removal efficiency for turbidity, chemical oxygen demand (COD), linear alkyl-benzene sulfonates (LAS), and petroleum. The influent concentrations of COD and petroleum were identified as critical water quality indicators. Post-treatment, the SPPG-CW reduces COD and petroleum concentrations to as low as 5.49 mg/L and 0.02 mg/L, respectively, meeting the irrigation water quality standards. The average removal rates for total nitrogen (TN) and total phosphorus (TP) were 88.38 % and 79.41 %, respectively. Further investigation into the purification pathways reveals that microbial activity primarily drives the degradation of LAS and TN, while TP removal is largely attributed to plant uptake. Remarkably, the SPPG-CW, incurring only 20.37 % of the total cost of existing rural wastewater treatment facilities, demonstrates promise for applications in areas endowed with abundant solar energy resources.
研究领域:
环境科学
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废水处理
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产品关联
DOI
高影响因子
CHEMOSPHERE
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2022
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IF 8.943
Bicun Jiang,Aimin Li,Chendong Shuang,Yan Tan,Yang Pan,Fuqiang Liu
In this work, p -Nitrophenol ( p -NP) was electro-chemically removed by using a prepared Co 3 O 4 /Ti cathode and a BDD anode to achieve the simultaneous reduction of total organic carbon (TOC), total nitrogen (TN) and toxicity. The prepared Co 3 O 4 /Ti cathode showed higher electro-activity than the Ti cathode towards p -NP reduction with the removal rate higher than 90.6% but without mineralization. The electro-oxidation removed 84.3% of TOC but none of TN. To develop an optimized process for mineralization and TN removal during p -NP electrolysis, the combination of electro-oxidation and electro-reduction were evaluated by using a dual-chamber cell and a single-chamber cell, respectively. As a result of the re-oxidation and re-reduction in the single-chamber cell, the typically used mode of the simultaneous redox, showed a lower removal of TOC and TN than the combination processes as well as an increased toxicity. The TN removal for both combined modes (21.0%–32.9%) was all higher than that of the mode of reduction because the produced inorganic nitrogen such as ammonia and nitrate could be partially oxidized or reduced to nitrogen gas. The results suggested that the combination process could significantly improve the mineralization and TN reduction for p -NP removal, accompanied with 60.3% decrease of acute toxicity for the reduction after oxidation mode.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2019
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IF 7.149
Yan Zhang,Jinhua Li,Jing Bai,Linsen Li,Shuai Chen,Tingsheng Zhou,Jiachen Wang,Ligang Xia,Qunjie Xu,Baoxue Zhou
The conversion of excess ammonia N into harmless N2 is a primary challenge for wastewater treatment. We present here a method to generate ClO• directionally for quick and efficient decomposition of NH4+ N to N2. ClO• was produced and enhanced by a bifacial anode, a front WO3 photoanode and a rear Sb–SnO2 anode, in which HO• generated on WO3 reacts with HClO generated on Sb–SnO2 to form ClO•. Results show that the ammonia decomposition rate of Sb–SnO2/WO3 is 4.4 times than that of WO3 and 3.3 times than that of Sb–SnO2, with achievement of the removal of NH4+ N on Sb–SnO2/WO3 and WO3 being 99.2 and 58.3% in 90 min, respectively. This enhancement is attributed to the high rate constant of ClO• with NH4+ N, which is 2.8 and 34.8 times than those of Cl• and HO•, respectively. The steady-state concentration of ClO• (2.5 × 10–13 M) is 102 times those of HO• and Cl•, and this is further confirmed by kinetic simulations. In combination with the Pd–Cu/NF cathode to form a denitrification exhaustion system, Sb–SnO2/WO3 shows excellent total nitrogen removal (98.4%), which is more effective than WO3 (47.1%) in 90 min. This study provides new insight on the directed ClO• generation and its application on ammonia wastewater treatment.
研究领域:
环境科学
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化学工程
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水处理
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产品关联
DOI
PubMed
高影响因子
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