Desalination by direct contact membrane distillation using a superhydrophobic nanofibrous poly (methyl methacrylate) membrane

Abstract

A practical, high-productive and superhydrophobic nanofibrous membrane was firstly introduced for membrane distillation (MD) process using poly (methyl methacrylate) (PMMA) and the electroblowing process. Wrinkled PMMA nanofibers demonstrated nano/micro-structure improving hydrophobicity greatly. Direct contact membrane distillation (DCMD) performance of the cold-pressed nanofibrous PMMA membrane was assessed using 35 and 150 g/L saline feed waters for 24 h and the results were compared with commercial polytetrafluoroethylene (PTFE) and polypropylene (PP) membranes. The PMMA membrane exhibited highest permeate flux (41.04 and 35.94 kg/m2 h for 35 and 150 g/L feeds, respectively) with stable electrical conductivity (EC) (˂ 5 μS/cm) resulting from superhydrophobicity (164.2°) and high liquid entry pressure (LEP) of 227.3 kPa. Although the commercial membranes presented good DCMD performance for 35 g/L feed, partial pore wetting with final EC of 11.93 and 17.62 μS/cm was measured for the PTFE and PP membranes using 150 g/L feed, respectively. The nanofibrous PMMA membrane is a promising applicant for conducting promising desalination using the DCMD process considering high production rate, simplicity of fabrication process and cost-effectiveness.