ORIGINALPAPER Colloid-enhanced ultrafiltration in removal of traces amounts of borates from water M. Bryjak • I. Duraj • G. Poz ´niak Received: 18 July 2009 / Accepted: 22 October 2009 / Published online: 22 April 2010 Ó Springer Science+Business Media B.V. 2010 Abstract The use of colloid-enhanced ultrafiltration for boron removal from water is investigated. Biode- gradable surfactant, 1,4-sorbitol oleate, was applied to obtain micelles and high molecular weight chitosan to reinforce their stability. Two kind of membranes were compared: neat porous polysulfone membrane and charged porous sulfonated polysylfone membrane; both with similar average pore diameter of 5 nm. The studies revealed that two key factors affect the boron rejection: presence of surfactant in the colloidal mixture and a repulsion effect of sulfone groups on the membrane surface. Both have a positive effect on boron removal. Keywords Boron separation Á Hybrid process Á Micellar enhanced ultrafiltration Introduction To satisfy the environmental standards towards water quality, a search has been launched for treatment technologies with low energy, labor, and capital costs. Among membrane processes, nanofiltration (NF) and reverse osmosis (RO) are being widely used to remove inorganic ions and small organic molecules. In both these processes, however, the use of dense membranes generates the need for high operating pressures. There are some membrane processes that are less demanding than RO and NF. Ultrafiltration (UF) is accomplished by mechanical sieving that allows obtaining of high fluxes at low pressures, and thus at low cost. Unfor- tunately, UF processes are able to remove partially ionic and small molecular contaminants as the mem- brane pores are too large to sieve all species. The place is actively filled by hybrid processes that combine sorption of small species on large bodies and filtration of them on membrane sieves. The following sorbents are used for the hybrid processes: water-soluble polymers, micellar sub-structures, powdered activated carbon, polymer resins, or inorganic materials. Since the beginning of the 1980s, micellar- enhanced ultrafiltration (MEUF) has become very attractive for separation of diluted aqueous solutions (Fang et al. 2008; Bielska and Szymanowski 2006; Krivorot et al. 2006; Akita et al. 1997; Juang et al. 2003; Witek et al. 2006; Iqbal et al. 2007; Reiller et al. 1996). However, the industrial application of this approach is still far away from positive finalization. The main disadvantage of MEUF is low stability of micelle and surfactant bleeding through the mem- brane. To avoid surfactant escape, the micelle are sometimes reinforced by complexion with water soluble polymers. The complexes form an interesting group of colloidal species for their use in hybrid processes as they show reduced thermodynamic M. Bryjak (&) Á I. Duraj Á G. Poz ´niak Division of Polymer and Carbonaceous Materials, Wroclaw University of Technology, 50-370 Wroclaw, Poland e-mail: marek.bryjak@pwr.wroc.pl 123 Environ Geochem Health (2010) 32:275–277 DOI 10.1007/s10653-010-9299-5