Abstract

Membrane distillation enhances reverse osmosis brine desalination by producing high-purity water from high-salinity sources. This study optimizes hollow fiber modules for industrial-scale air gap membrane distillation (AGMD) using the nondominated sorting genetic algorithm II (NSGA-II), aiming to maximize permeate flux and thermal efficiency while minimizing specific electrical energy consumption. Seven decision variables, related to module geometry and operating conditions, were assessed through a phenomenological AGMD model and multicriteria decision-making approach. Optimal results yielded a permeate flux of 5.28 kg/m2 h, a specific electrical energy consumption of 238 kWh/m3, and a thermal efficiency of 97%, with a module length of 1.09 m, air gap thickness of 4.39 mm, 4003 fibers, and 3121 tubes. These findings demonstrate the effectiveness of NSGA-II in optimizing AGMD module design, supporting energy-efficient configurations and offering strong potential for integration into sustainable water treatment systems.