Enhanced Membrane Pre‐Treatment Processes using Macromolecular Adsorption and Coagulation in Desalination Plants: A Review

Abstract

Recent advances in membrane technology have prompted the rapid growth of the Reverse Osmosis (RO) desalination in comparison to other water desalination technologies. One of the major problems of RO is fouling which leads to major reduction in the efficiency of this process. RO membranes are usually fouled with colloids, humic substances, micro-organisms, and heavy metals. This is why it is critical to treat the feed water prior to RO filtration. Conventional pre-treatment methods include processes such as coagulation, adsorption, sedimentation, flotation, sand filtration, disinfection, and the addition of anti-scalants. Recently, membrane pre-treatment processes including micro-filtration (MF), ultrafiltration (UF) and nanofiltration have been introduced prior to RO, with or as a replacement for conventional pre-treatment. These processes are useful in providing feed water superior in quality to conventional pre-treatment, but they are limited in the range of pollutant removal and operating conditions. Full description of water composition and the interactions and aggregations between the contaminants found in feed water for RO desalination is shown in this review. The review includes introduction to membranes, including 403 Downloaded by [University of Cambridge] at 12:12 03 December 2014 retention and fouling mechanisms, conventional and membrane pre-treatment, and membrane backwashing. It also highlights the role of coagulation and adsorption in the pre-treatment process and the impact of integration of coagulation and/or adsorption with membrane pre-treatment.

The art of surface modification of synthetic polymeric membranes

“…The chapters in this book are mainly related to novel membrane materials, membrane fabrication methods, and membrane modification techniques. Hilal et al16 wrote a review on the enhanced membrane pretreatment process using macromolecular adsorption and coagulation in desalination plants. Nunes and Peinemann17 wrote an article on surface modification of membranes via chemical oxidation, plasma treatment, classical organic reactions, and polymer grafting.…”

Microfluidic Desalination: A New Era Towards Sustainable Water Resources

“…The process of removing salt is known as the desalination process. In modern life, several new techniques have been introduced to remove the salt from seawater, such as the membrane and thermal methods 4–9. The membrane‐based process relies mainly on applying pressure on one side of semi‐permeable porous materials to move water molecules through the material while leaving the impurities behind.…”

“…The microfluidics approach has been in rapid development in various applications due to its large surface area to volume ratio, which is important for more accurate and specific operations 6–8, 14–17. Water desalination using microfluidics is an emerging technology that has been introduced in the past few years.…”