Air gap membrane distillation: A review

Abstract

Membrane distillation provides a feasible and optimal solution to potable water issues. The literature contains a number of studies and research studies that aim to understand the behavior of membrane distillation systems and to provide the best possible solutions under different conditions. The purpose of this article is to discuss the air gap membrane distillation (AGMD) specifically and its development to date. The areas for future research in the field of AGMD are suggested. Membranes used in AGMD were discussed, including nanocomposite membranes and graphene membranes. In addition, the long-term performance issues regarding membrane fouling and scaling and the ways to prevent and to reduce them were discussed. Performance parameters that have not been explored sufficiently, such as energy efficiency and performance ratio, are discussed. Evolution of new membrane distillation processes from AGMD, such as the material gap and permeate gap, and conductive gap membrane distillation, is discussed. A generalized theoretical model for heat and mass transfer is presented for air gap membrane distillation systems. Coupling AGMD to form a hybrid combination with renewable energy sources is considered as a good answer to energy specific issues. Hybrid renewable energy systems with AGMD are discussed in detail. Novel designs for coupling AGMD systems with different forms of renewable energies are suggested, which presents an excellent area to be considered for developing advanced hybrid AGMD systems. It is suggested that future research should include economic studies, long-run system performance, operational problems and maintainance requirements, and related issues for better understanding and better acceptance of AGMD systems for industrialization.

Recent Progress in the Membrane Distillation and Impact of Track-Etched Membranes

“…This is probably due to the growing gradient of temperature inside vapor space [ 45 , 53 ]. It has been stated that when the thickness of the air gap is less than 5 mm, it significantly affects the membrane distillation process [ 54 , 55 ]. Pangarkar et al [ 53 ] tested the effect of air gap thickness on the permeate flux using hydrophobic PTFE membrane in AGMD.…”

Theoretical analysis and parametric investigation of an innovative helical air gap membrane desalination system

“…Usually, AGMD has been used with conventional plate and frame (Khalifa and Lawal 2016;Charfi et al 2010;Khayet and Matsuura 2011b) and hollow fiber (Cabassud and Wirth 2003;Cheng et al 2009;Guijt et al 2005a, b) designs, but nowadays number of different configurations are appearing in the literature that explore new design possibilities to study AGMD systems (Shahu and Thombre 2019a). Aryapratama et al (2016) designed a hollow fiber module with multiple cooling channel network made up of stainless steel.…”

Dynamic Simulation of an Air-Gap Membrane Distillation (Agmd) Process Using Photovoltaic Panels System and Flat Plate Collectors

“…Hanemaaijer et al [16] introduced an idea of internal heat recovery that is called memstill membrane distillation. Sequentially, Duong et al [17,18] conducted a study that allowed only AGMD to restore the latent heat without any external heat exchanger. Minier-Matar et al [19] found through their study that AGMD provides a higher resistance to mass transfer and runs at low water flow.…”