摘要：
In this work, bentonite was encapsulated into PVA/SA matrix to fabricate bentonite/PVA/SA aerogel (BPS) using lanthanum (La) as the cross-linking agent. La (III) cross-linking reaction with polymers realized synchronous gelation and lanthanum introduction into the composite, which endowed BPS with efficient phosphate removal performance and convenient separation property. Batch experiments indicated that BPS aerogel could maintain efficient and stable phosphate removal (> 95%) within a wide solution pH range (4-10), and well-performed phosphate capturing of BPS at NaCl and seasalt salinity of 0-4% implied its promising application potential in saline environment. Besides, the good fitness of pseudo-second-order kinetic model suggested chemisorption of phosphate on BPS surface, and film diffusion was the primary rate-limiting step. Isotherm study with the preferred fitness of Sips model suggested monolayer adsorption characteristic of BPS at high phosphate con-centration, whereas multi-layer coverage of phosphate occurred at low concentration. Maximum experimental adsorption capacity of BPS was detected as ~28.9 mg P/g, which was competitive among similar adsorbents. In addition, long-term phosphate leakage detection at varied systematic pH suggested the stable binding of phosphate on BPS. The combined characterization analysis illustrated that multiple function including electrostatic attraction, ligand exchange and Lewis acid-base interaction drove the loading of phosphate on BPS surface. Overall results demonstrated certain potential of BPS aerogel as candidate sorbent for phosphate adsorption from complicated aqueous environment.
作者机构：
School of Civil and Hydraulic Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China;School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha, 410114, China
通讯机构：
School of Civil and Hydraulic Engineering, Huazhong University of Science and Technology, Wuhan, China
作者机构：
[Tang, Dong; Xiao, Zhezhen; Jiang, Zhongming] School of Hydraulic Engineering, Changsha University of Science and Technology, Changsha;410114, China;[Yin, Tianzuo] Changsha Water Industry Group Water Supply Co., Ltd., Changsha;410015, China;[Li, Yi] Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha
通讯机构：
[Zhongming Jiang] S;School of Hydraulic Engineering, Changsha University of Science and Technology, Changsha, People’s Republic of China
作者机构：
[Xin Chen] Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System,China Agricultural University,Beijing 100083,China;[Xin Chen] Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha University of Science and Technology,Changsha 410114,China
通讯机构：
[Xin Chen] B;Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System, China Agricultural University, Beijing, China<&wdkj&>Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha University of Science and Technology, Changsha, China
摘要：
The oscillatory flow provides the major dynamic force for the mass and energy transport in estuary and coastal areas.An analytical approximate velocity formula is proposed to evaluate the oscillation in the boundary layer over the mobile sediment bed of the sheet flow induced by the asymmetric wave and current.The velocity formula consists of an oscillatory force part and a constant force part corresponding to the Navier-Stokes equation of the asymmetric oscillatory sheet flow over the mobile sediment bed.The mobile sediment bed is defined by an erosion depth formula with consideration of the phase lag,the acceleration and the flow asymmetry.The wave part includes the phase lead parameters from all components of the free stream velocity.The development of the wave part is affected by the current part through the erosion depth and the boundary layer thickness.The erosion depth,the roughness height and the boundary layer thickness of the mobile sediment bed are introduced into the current part without a transition area for the wave-current eddy viscosity.The current part is induced by the wave eddy viscosity within the boundary layer and influenced by the wave-current apparent roughness outside the boundary layer.The velocity profile and duration are evaluated by an approximate velocity formula through experiments for both asymmetric wave and wave-current cases.The oscillation feature in the boundary layer is illustrated by the approximate velocity formula through the asymmetric wave cases over the mobile sediment bed.
期刊：
Journal of Environmental Management,2021年296:113271 ISSN：0301-4797
通讯作者：
Hong Chen
作者机构：
[Du, Chunyan; Yang, Min; Wang, Hong; Chen, Hong; Yang, Enzhe; Yu, Guanlong] Changsha Univ Sci & Technol, Key Lab Water Sediment Sci & Water Disaster Preve, Sch Hydraul Engn, Changsha 410004, Peoples R China.;[Wang, Hong; Chen, Hong] Tohoku Univ, Grad Sch Engn, Dept Civil & Environm Engn, Sendai, Miyagi 9808579, Japan.;[Deng, Zhengyu; He, Weining] China Machinery Int Engn Design & Res Inst Co Ltd, Changsha 410007, Peoples R China.;[Wang, Dongbo] Hunan Univ, Coll Environm Sci & Engn, Changsha 410082, Peoples R China.;[Zhou, Yaoyu] Hunan Agr Univ, Coll Resources & Environm, Changsha 410128, Peoples R China.
通讯机构：
[Hong Chen] K;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha, 410004, China<&wdkj&>Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, 980-8579, Japan
关键词：
Anammox;Autotrophic nitrogen removal;Dissolved oxygen;Micro-granules;Partition control
摘要：
Autotrophic nitrogen removal (ANR) processes have not been widely applied in wastewater treatment due to their long start-up time and unstable performance. In this study, a novel dissolved oxygen-differentiated airlift internal circulation reactor was developed to enhance ANR from wastewater. During 200 days of continuous operation, the reactor start-up was achieved within 30 days; a high total nitrogen removal efficiency of 80% was achieved and stably maintained under an aeration rate of 0.90L/min and hydraulic retention time of 6h. Additionally, the color of sludge went from a light yellow to dark red, and the amount and size of the micro-granules increased obviously. Medium-sized (1.0-2.5mm) micro-granules accounted for 72.4% on day 190. The specific anammox activity increased from 0.53 to 1.43g-N/g-VSS/d, while the SNOA decreased from 0.93 to 0.08g-N/g-VSS/d. Furthermore, the microbial analysis showed that the Nitrosomonas (4.2%) and Candidatus Brocadia (22.6%) were enriched and formed the micro-granules after the reactor's long-term operation. The results indicate that novel configuration realizes the partitioning of dissolved oxygen (DO), optimizes nitritation and anammox reactions, and accelerates biochemical reactions, thereby enhancing ANR performance. This study provides a practical alternative to enhance ANR performance and a scientific basis for the development and application of novel nitrogen removal reactors.
作者机构：
[Yao, Yu; Chen, Long; Luo, Haiwen; Wu, Zhiyuan; Wang, Hao] Changsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Hunan, Peoples R China.;[Chin, Ren Jie] Univ Tunku Abdul Rahman, Lee Kong Chian Fac Engn & Sci, Dept Civil Engn, Kajang 43000, Malaysia.;[Yao, Yu; Chen, Long; Wu, Zhiyuan] Key Lab Water Sediment Sci & Water Disaster Preve, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Ren Jie Chin] D;Department of Civil Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 43000, Kajang, Malaysia
关键词：
Artificial neural network;Multi-layer perceptron neural network;Tidal energy;Turbine wake
摘要：
Deployment of tidal array farms is the next stage of tidal energy development which concentrates on the capture of the enormous energy. Characterization into the wake of tidal turbine aids in determining the tidal farm layout and energy yields. This paper develops a framework that employs the Computational Fluid Dynamics (CFD) simulation and machine learning to analyze turbine wake with high accuracy and good efficiency. Multilayer perceptron neural network (MLP-NN) was introduced to establish the interrelation between the incoming flow conditions and the wake profiles. The Reynolds-averaged Navier-Stokes equations (RANS) are associated with a k -epsilon turbulence model to offer a number of datasets of wake profile for training, testing, and validation of the MLP-NN models. It was found that the MLP & ndash;NN & ndash;based model has achieved a considerably high level of accuracy by comparing it with empirical and numerical models. The reliability of the MLP-NN based model coupled with the wake combination RSS model to predict the resultant wake profile and power output of multiple turbines are also assessed. The techniques significantly enhance the efficiency and accuracy of wake predictions. <comment>Superscript/Subscript Available</comment
作者机构：
[邓自源; 欧阳钰榕; 万发] School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha, 410114, China;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha, 410114, China;Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha University of Science & Technology, Changsha, 410114, China;[蒋中明] School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha, 410114, China, Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha, 410114, China;[唐栋] School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha, 410114, China, Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha University of Science & Technology, Changsha, 410114, China
