Boron in seawater and methods for its separation — A review Nalan Kabay a, ⁎, Enver Güler a,1 , Marek Bryjak b a Ege University, Faculty of Engineering, Chemical Engineering Department, 35100 Izmir, Turkey b Wroclaw University of Technology, Faculty of Chemistry, Department Polymer & Carbon Materials, 50-370 Wroclaw, Poland abstract article info Article history: Received 20 January 2010 Received in revised form 16 May 2010 Accepted 18 May 2010 Available online 12 June 2010 Keywords: Boron removal Seawater Reverse osmosis Adsorption-membrane filtration hybrid process The seawater reverse osmosis (SWRO) membrane desalination process is a relevant and reliable technology for desalination of seawater. However, some serious limitations had recently been discovered during field practice, among them the boron problem seems to have a critical meaning. According to the WHO regulations, the boron concentration should be reduced to less than 0.5 mg/L for drinking water. It was also reported that, this limit is rarely reached for conventional reverse osmosis desalination plants equipped with commercially available membranes. This paper reviews the extensive published literature on separation methods of boron removal from seawater. © 2010 Elsevier B.V. All rights reserved. Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 1.1. Chemistry of boron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 1.2. Boron removal from seawater by reverse osmosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 1.3. Removal of boron by ion exchange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 1.4. Adsorption-membrane filtration (AMF) hybrid process for boron removal from SWRO permeate . . . . . . . . . . . . . . . . . . . 215 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 1. Introduction Generally, boron has been found to have a dual effect on the living systems on Earth. In the case of plants, the effect of boron has the unambiguous meaning. It was shown that there is a small range difference between boron deficiency and boron toxicity levels [1]. Boron plays a critical role in the metabolism of carbohydrate, sugar translocation, hormone action, normal growth and functioning of the apical meristem, nucleic acid synthesis, and biological membrane structure and function [2]. Symptoms of boron deficiency are visible in root and leaf growth, bark splitting, retardation of enzyme reactions, and can cause even a death of plants [3–5]. The initial stages of boron toxicity include yellowing of leaf tips progressing into the leaf blade. Death of chlorotic tissue occurs followed by leaf loss. This ultimately results in a loss of photosynthetic capacity and a loss in plant productivity [5,6]. There are some plants that are more sensitive to boron than others [1]. Sensitive plants can tolerate irrigation waters with only 0.3 mg/L boron, while very tolerant plants may be able to survive for 4 mg/L of boron concentration [7]. For animals, the effect of boron has not been determined so explicitly as was done for plants. It was shown that boron is the essential element in the human diet, however its specific biochemical function has not been identified yet. Newnham [8] mentioned that boron was important in the metabolism and utilization of calcium for human bone structuring. Other benefits of boron include improvement of brain function, psychomotor response, and the response to estrogen ingestion in postmenopausal women [8]. Nielsen [9] illustrated that boron plays a crucial role in keeping bones and joints healthy and it was effective in treating various forms of arthritis. Desalination 261 (2010) 212–217 ⁎ Corresponding author. Tel.: +90 232 3887600; fax: +90 232 3741401. E-mail address: nalan.kabay@ege.edu.tr (N. Kabay). 1 Present address: University of Twente, Faculty of Science and Technology, Membrane Science & Technology Group, 7500 AE Enschede, The Netherlands. 0011-9164/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.desal.2010.05.033 Contents lists available at ScienceDirect Desalination journal homepage: www.elsevier.com/locate/desal