The rejection efficiency of boron by RO membranes is poor especially when a large proportion of boron in seawater exists as uncharged boric acid which can diffuse through most of the available RO membranes.1,2 Among the several methods suggested for boron removal from water and waste water, adsorption is a very useful and economical technique. Magnetic sorbents containing boron selective chelating precursors have been used as smart, fast and simple method for the separation and pre-concentration of boron3. After adsorption, the adsorbents can be isolated from the medium by a simple magnetic separation. Here, we present novel magnetic nanocomposite for the selective removal of boron from seawater. The nanocomposites have been synthesized and fully characterized using SEM, TEM, FTIR, and PXRD. TEM showed individual and aggregated rod-like crystalline cellulose fragments, ranging from 10 to 20 nm in diameter with a corresponding length of 120�300 nm and the magnetic nanoparticles exhibit super-paramagnetic properties at room temperature with a saturation magnetization value as high as 60 emu/g. The technology provides a simple method for the adsorption and separation of boron from seawater with a facile magnetic separation mechanism. Indirect spectrophotometric method, inductively coupled plasma mass spectrometry (ICP-MS), ICP- optical emission spectrometry (OES), have been used to analyze the initial boron concentration as well the residual concentration after the treatment. Experimental results indicated that boron sorption increased with increasing sorbent dosage up to 6 mg/mL. The effect of pH on the boron removal efficiency using the nanosorbents was studied at initial boron concentrations of 4-5 ppm, concentrations commonly found in seawater. The sorption of boron was found to be highest at a pH range of 7-7.5 at a sorption efficiency of 87.6 � 1%. This new process can eliminate the need for a second pass in the RO desalination plants which commonly used for boron removal. This will impart a significant cost reduction to the process. Conceptual studies indicated the feasibility of integrating the nanocomposites with a pilot scale RO unit. The nanocomposite can be modified to have antimicrobial properties for the optimum goal of developing dual function nanosorbents for seawater pretreatment.Figure 1. Schematic representation for boron capture and separation from saltwater using the magnetic nanocomposite.  Sorption t= 30 min., pH = 7.5, T= 25 �C.   (1)  Prats, D.; Chillon-Arias, M. F.; Rodriguez-Pastor, M.: Analysis of the influence of pH and pressure on the elimination of boron in reverse osmosis. Desalination 2000 , 128, 269�273.(2)  Sagiv, A.; Semiat, R.: Analysis of parameters affecting boron permeation through reverse osmosis membranes. J. Membr. Sci. 2004 , 243, 79�87.(3) Liu, H.; Qing, B.; Ye, X.; Li, Q.; Lee, K.; Wu, Z.: Boron adsorption by composite magnetic particles. Chemical Engineering Journal 2009 , 151, 235-240.

Magnetic nano-sorbent based on cellulose nanocrystals (CNC)/Fe<sub>3</sub>O<sub>4</sub> NPs for the selective removal of boron from seawater

248th National Meeting (2014)

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Magnetic nano-sorbent based on cellulose nanocrystals (CNC)/Fe3O4 NPs for the selective removal of boron from seawater

Magnetic nano-sorbent based on cellulose nanocrystals (CNC)/Fe₃O₄ NPs for the selective removal of boron from seawater