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Bridging transport and deposition of colloidal nanoparticles on cylindrical microfibers. POWDER TECHNOL 2023. [DOI: 10.1016/j.powtec.2023.118330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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Li T, Shen C, Johnson WP, Ma H, Jin C, Zhang C, Chu X, Ma K, Xing B. Important Role of Concave Surfaces in Deposition of Colloids under Favorable Conditions as Revealed by Microscale Visualization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4121-4131. [PMID: 35312300 DOI: 10.1021/acs.est.1c07305] [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] [Indexed: 06/14/2023]
Abstract
This study conducted saturated column experiments to systematically investigate deposition of 1 μm positively charged polystyrene latex micro-colloids (representing microplastic particles) on negatively charged rough sand, glass beads, and soil with pore water velocities (PWV) from 4.9 × 10-5 to 8.8 × 10-4 m/s. A critical value of PWV was found below which colloidal attachment efficiency (AE) increased with increasing PWV. The increase in AE with PWV was attributed to enhanced delivery of the colloids and subsequent attachment at concave locations of rough collector surfaces. The AE decreased with further increasing PWV beyond the threshold because the convex sites became unavailable for colloid attachment. By simulating the rough surfaces using the Weierstrass-Mandelbrot equation, the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) interaction energy calculations and torque analysis revealed that the adhesive torques could be reduced to be comparable or smaller than hydrodynamic torques even under the favorable conditions. Interestingly, scanning electron microscopic experiments showed that blocking occurred at convex sites at all ionic strengths (ISs) (e.g., even when the colloid-colloid interaction was attractive), whereas at concave sites, blocking and ripening (i.e., attached colloids favor subsequent attachment) occurred at low and high ISs, respectively. To our knowledge, our work was the first to show coexistence of blocking and ripening at high ISs due to variation of the collector surface morphology.
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Affiliation(s)
- Tiantian Li
- School of Environmental Engineering, Henan University of Technology, Zhengzhou, Henan 450001, China
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Chongyang Shen
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - William P Johnson
- Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, United States
| | - Huilian Ma
- Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, United States
| | - Chao Jin
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510006, China
| | - Chenxi Zhang
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Xianxian Chu
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Ke Ma
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States
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Fan Z, Ji PP, Zhang J, Segets D, Chen DR, Chen SC. Wavelet neural network modeling for the retention efficiency of sub-15 nm nanoparticles in ultrafiltration under small particle to pore diameter ratio. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119503] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Song S, Rong L, Dong K, Liu X, Le Clech P, Shen Y. Particle-scale modelling of fluid velocity distribution near the particles surface in sand filtration. WATER RESEARCH 2020; 177:115758. [PMID: 32278990 DOI: 10.1016/j.watres.2020.115758] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 03/25/2020] [Accepted: 03/26/2020] [Indexed: 06/11/2023]
Abstract
Sand filtration is widely used in drinking water treatment processes, yet the hydraulic fundamentals at particle-scale are not well defined, especially the fluid velocity profile near the sand particles surface. In this study, a numerical model is developed by combining the Lattice Boltzmann (LBM) and the Discrete Element Method (DEM), used to describe the fluid flow over the sand particles surface and the micro-structure details of the sand packed bed respectively. The model is validated by comparing the simulation results with the experimental measurements using two systems, showing that the model can describe the fluid velocity distribution around the particles surface. Critical flow velocity is introduced as the balance between hydrodynamic and adhesive torques acting on sand particle surface. Furthermore, a new concept - effective filter surface (EFS), is defined as the area where the velocity near sand particles surface is less than the critical flow velocity, aiming for indirectly evaluating the performance of sand filtration. It is quantitatively demonstrated that increasing the sand particle size or feed flow velocity results in the decrease of both critical flow velocity and EFS under the given tested conditions. The LBM-DEM model provides a useful tool for understanding the fundamentals of liquid flow distribution and also estimating sand filtration performance under different operation conditions.
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Affiliation(s)
- Shuang Song
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Liangwan Rong
- School of Civil Engineering & Transportation, South China University of Technology, Guangzhou, Guangdong, 510640, China
| | - Kejun Dong
- Centre for Infrastructure Engineering, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Xuefei Liu
- UNSW Centre for Transformational Environmental Technologies, Yixing, Jiangsu, 214200, China
| | - Pierre Le Clech
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Yansong Shen
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
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