Yinseo Song, GunYoung Kim, Min Seok Lee, Min-kyu Kim, Ji Woong Chang, Dae Ryook Yang, Kiho Park
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引用次数: 0
Abstract
Forward osmosis (FO) systems operating under low or zero cross-flow velocities present modeling challenges due to the limitations of conventional external concentration polarization (ECP) formulations, which often predict near-zero flux under stagnant conditions, contradicting experimental observations. To address this, we propose a revised ECP model incorporating an asymptotic Sherwood number that enables continuous mass transfer prediction as the Reynolds number approaches zero. The model accounts for both molecular diffusion and natural convection, allowing accurate flux prediction in spacer-free and low-flow environments. Model parameters were estimated from experimental data and validated through simulations of a hydration pack (zero flow) and a commercial FO module operating at 0–10 cm/s cross-flow velocity. Simulated results closely matched experimental trends and successfully reproduced water flux behavior across operating regimes. Sensitivity analysis revealed that baseline mass transfer parameters (Sh₀, a, b, c, d) had influence comparable to intrinsic membrane properties (A and S), particularly in no-spacer systems where diffusion and boundary layer resistance dominate. These findings confirm the critical role of mass transfer coefficients in FO performance. In the low cross-flow regime, analysis of the recovery–flux–velocity relationship demonstrated the feasibility of low-velocity operation and clarified key distinctions from RO. The model supports FO system design under minimal flow conditions, facilitating the development of compact modules suitable for portable and hybrid applications.
期刊介绍:
Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include:
•Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management;
•Urban hydrology including sewer systems, stormwater management, and green infrastructure;
•Drinking water treatment and distribution;
•Potable and non-potable water reuse;
•Sanitation, public health, and risk assessment;
•Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions;
•Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment;
•Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution;
•Environmental restoration, linked to surface water, groundwater and groundwater remediation;
•Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts;
•Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle;
•Socio-economic, policy, and regulations studies.