Process optimization is a popular strategy to improve efficiency, reduce the energy consumption and total cost of the seawater reverse osmosis (SWRO). Forward osmosis (FO) process with a nanofiltration (NF)-like membrane has emerged as a cost-effective technology for seawater desalination pretreatment, due to its high water permeability and low energy consumption compared to RO-like FO membrane. The present work comprehensively evaluated the potential of using an NF-like FO membrane for SWRO pretreatment and analyzed the feasibility of the NF-like membrane-based FO-NF-RO process for seawater desalination. The performance of the FO-NF-RO integrated process was investigated with MgSO₄, Na₂SO₄, and Mg(CH₃COO)₂ as draw solute, respectively. Besides, the energy consumption and total cost of the hybrid process were also estimated on the laboratory and large scale. The NF-like membrane-based FO process could effectively remove organic molecules and divalent ions effectively. The hybrid process product water could reach the drinking water standard in China (TDS ≤ 1000 mg/L). When water recovery was 42.0%, the hybrid process could produce freshwater with specific energy consumption of 2.99 kWh/m³ and specific water cost of 0.92 $/m³, which were comparable with the conventional SWRO process. Overall, our study revealed the feasibility of the FO-NF-RO process for seawater desalination.

工艺优化是提高海水反渗透 (SWRO) 效率、降低能耗和总成本的流行策略。由于与 RO 类 FO 膜相比具有高透水性和低能耗，具有类似纳滤 (NF) 膜的正向渗透 (FO) 工艺已成为海水淡化预处理的一种具有成本效益的技术。目前的工作全面评估了使用类 NF FO 膜进行 SWRO 预处理的潜力，并分析了基于 NF 类膜的 FO-NF-RO 工艺用于海水淡化的可行性。使用 MgSO ₄、Na ₂ SO ₄和 Mg(CH ₃ COO) ₂研究了 FO-NF-RO 集成工艺的性能分别作为吸引溶质。此外，还对实验室和大规模混合过程的能耗和总成本进行了估算。类似NF的膜基FO工艺可以有效去除有机分子和二价离子。混合工艺产水可达到我国饮用水标准（TDS≤1000mg/L）。当水回收率为 42.0% 时，混合工艺可生产淡水，比能耗为 2.99 kWh/m ³，比水成本为 0.92 $/m ³，与传统 SWRO 工艺相当。总体而言，我们的研究揭示了 FO-NF-RO 工艺用于海水淡化的可行性。