  As water shortages intensify globally under the stresses of increasing
demand, aquifer depletion, and climate change, the market for efficient
desalination technologies has grown rapidly to fill the void. One such
developing technology, membrane distillation (MD), has experienced keen
academic interest and an increase in start-up businesses in the past decade. MD
has expanded into a niche of small scale thermal desalination using solar and
waste heat resources, due to its fouling resistance, scalability, and
acceptable efficiency. Recent studies indicate that MD could attain the
efficiencies of state-of-the-art mature thermal desalination technologies,
although additional engineering and scientific challenges must first be
overcome.
  The aim of this research is to better understand and provide solutions for
two major challenge areas for MD: efficiency and membrane fouling. Studies on
improving MD efficiency included examining the effects of tilt angle on MD
performance using numerical simulations paired with experiments, devising a
novel MD system design for with superhydrophobic surfaces to improved
efficiencies, and an entropy-generation comparison of MD to other desalination
technologies. For fouling studies in MD, a review of MD fouling was undertaken
to synthesize conclusions from the literature and to explore gaps in the
literature. This review lead to studies of the effect of filtration and bulk
nucleation on MD fouling, a study on heterogeneous nucleation of inorganic
salts with a fouling regime map to avoid nucleation, and fouling prevention via
induced air-layers.
