Membrane distillation (MD) is an emerging technology capable of efficiently processing saline feeds. The hydrophobic polymers currently used in MD are fluorinated petroleum-based polymers, which raise significant environmental concerns. Recent advancements have focused on developing eco-friendly hydrophobic materials to support the Sustainable Development Goals (SDGs). The current work is one of the first comprehensive studies on a biodegradable, fluorine-free polylactic acid/cellulose acetate blend specifically optimized for air-gap membrane distillation (AGMD), with validated transport modeling. Extensive characterization was carried out on the fabricated membranes including SEM, XRD, FTIR, AFM, TGA, and tensile tests. The performance and energy efficiency of the fabricated membranes were assessed experimentally and numerically at low-temperature AGMD (40 degrees C-55 degrees C). The thermally induced phase separation method proved effective in producing uniform membranes, with the added benefit of reducing waste. The mathematical models were validated, and the dusty gas model showed good agreement with the experimental results, exhibiting an absolute relative error of 2% - 3.5% at 55 degrees C. The PLA/CA blend membrane containing 10 wt/wt.% cellulose acetate showed the highest water contact angle, increased surface roughness, the most significant salt rejection, and a consistent flux of 4.2 L m-2 h-1. Moreover, the membrane achieved good energy efficiency with GOR and STEC values reaching 0.913 and 709.1 kWh & sdot;m-3, respectively. The simple fabrication, mild operating conditions, and the use of sustainable materials offer excellent potential for further exploration in large-scale applications for freshwater production in arid regions.