Boron removing

Boron Removal. Boron [7440-42-8] is occasionaHy present in water suppHes at an unacceptable level. It cannot be removed with the standard anion-exchange resins unless the water is deionized. Selective removal is possible by using an anion exchanger functionalized with /V-methy1g1ucamine [6284-40-8]. This resin is in limited commercial supply. The borate form of conventional strong base anion exchangers is used in some nuclear reactors to adjust the concentration of boron in water used as a moderator. The resin releases boron as the water temperature rises. 

Core damage can result most likely from heat imbalance. Figure 6.3-3 is an example from the Indian Point PRA that uses heat imbalance to approach completeness. This diagram shows that cote damage may result from either a loss of cooling or excess power (or both). The direct causes of insufficient heat removal may be loss of flow, makeup water, steam flow, or heat extraction by the turbine. Indirect causes are reactor trip or steam line break inside or outside of containment. Cau.ses of excess power production are rod withdrawal, boron removal, and cold water injection. 

See also Borates Boric acid Sodium borates boron oxides, 4 246-249 boron oxides table,4 242t environmental concerns, 4 284—285 health and safety factors, 4 285-288 occurrence, 4 245—246 Boron perchlorates, 18 278 Boron phosphate, 4 242t, 283 Boron removal, from water, 14 418 Boron-stabilized carbanions, 13 660-661 Boron subhalides, 4 141 Boron suboxide, 4 242t Boron tribromide, 4 138 manufacture, 4 145—146 physical properties of, 4 139-140t, 325 reactions, 4 141 specifications, 4 147t uses of, 4 149 Boron trichloride, 4 138 manufacture, 4 145—146 physical properties of, 4 139-140t reactions, 4 141... 

Nuttall, W.F., H. Ukrainetz, J.W.B. Stewart, and D.T. Spurr. 1987. The effect of nitrogen, sulphur and boron on yield and quahty of rapeseed (Brassica napus L. and B. campestris L.). Canad. Jour. Soil Sci. 67 545-559. Ohlendorf, H.M., D.J. Hoffman, M.K. Sadd, and T.W. Aldrich. 1986. Embryonic mortality and abnormalities of aquatic birds apparent impacts of selenium from irrigation drainwater. Sci. Total Environ. 52 49-63. Okay, O., H. Guclu, E. Soner, and T. Balkas. 1985. Boron pollution in the Simav River, Turkey and various methods of boron removal. Water Res. 19 857-862. 

Smith, B.M., P. Todd, and C.N. Bowman, Boron removal by polymer-assisted ultrafiltration. Separation Science and Technology, 1995. 30(20) p. 3849-3859. 

Jiang, J.-Q., Xu, Y., Quill, K. et al. (2007) Laboratory study of boron removal by Mg/Al double-layered hydroxides. Industrial and Engineering Chemistry Research, 46(13), 4577-83. 

Figure 20.6 An integrated reverse-osmosis-membrane contactor system for boron removal (From Ref. [31].)...

Boron rejection membranes exhibit up to 90+% rejection of boron, while standard membranes reject about 50-70%.(20, 29) These membranes are typically used for seawater applications where boron removal is a concern. Boron is difficult to remove with membranes because boron, which exists as boric acid, is not ionized a typical seawater pH, 7.0 - 8.0, whereas the pKa of boric acid is 9.14 - 9.25.20... 

So, to kick off, ketone 262 is reacted to form lruns boron enolate 266 that combines with acetaldehyde to give the intermediate 267. The 1,2-anti stereocontrol comes from the enolate geometry and the chiral centre of the original ketone imposes the 1,3-anti control in the way we have seen already in this chapter. The intermediate 267 is reduced without working the reaction up and the boron removed to give 268. 

The aims of reclamation are to make Ca2+ the major exchangeable ion and to reduce the salt concentration in the soil solution. The main requirement to reclaim salt-affected soils is that sufficient water must pass through the plant root zone to lower the salt concentration to acceptable values. Passing 1 m of leaching water per meter of soil depth under ponded conditions normally removes approximately 80% of the soluble salt from soils (Fig. 11.6). If leaching is under unsaturated conditions, such as with the use of intermittent pending or sprinkler irrigation, this quantity of water may be reduced to as little as 350 to 200 mm of water. Boron removal can require up to three times more water than removal of Na and Cl salts, because B is retained to some extent by soils. 

Rieck [Rl] has used the computer codes LEOPARD IBl] and SIMULATE [FI] to predict the power distribution in the fuel and poison arrangement shown in Fig. 3.19 for the first fuel cycle for this reactor, and the amount of thermal energy produced by each assembly up to the time when the reactor ceases to be critical with all soluble boron removed from the cooling water. Figure 3.20 is a horizontal cross section of one-quarter of the core of this reactor. Each square represents one fuel assembly. The core arrangement has 90° rotational symmetry, about the central assembly 1AA at the upper left of the figure. 

Development of Membranes for Boron Removal, Chlorine Tolerance, and Antibiofouling.38... 

Koseogju H, Kahay N, Yiiksel M, Sarp S, Arar O, and Kitis M, Boron removal fiom seawater using high rejection SWRO memhranes— Impact of pH, feed concentration, pressure and cross-flow velocity. Journal of Membrane Science 2008, 227, 253-263. 

Gtiler E, Kahay N, Yuksel M, Yigit NO, Kiti M, and Bryjak M, Integrated solution for boron removal from seawater using RO process and sorption-membrane filtration hybrid method. Journal of Membrane Science 2011, 375, 249—257. 

Gtiler E, Kahay N, Yuksel M, Yavuz E, and Yiiksel U, A comparative study for boron removal from seawater by two types of polyamide thin film composite SWRO membranes. Desalination 2011, 273, 81-84. 

D. Hou, J. Wang, X. Sun, L. Zhaokun, C. Zhao, and X. Ren, Boron removal from aqueous solution by direct contact membrane distillation, J. Hazard. Mater. 177 (2010) 613-619. 

N. Ozturk, D. Kavak, and T.E. Kose, Boron removal from aqueous solution by reverse osmosis, Desalination 223 (2008) 1-9. 

M. Turek, B. Bandura, and P. Dydo, Electrodialytic boron removal from SWRO permeate. Desalination 223 (2008) 17-22. 

P. Dydo, M. Turek, J. Ciba, J. Trojanowska, and J. Kluczka, Boron removal from landfill leachate by means of nanofiltration and reverse osmosis. Desalination 185 (2005) 131-137. 

RO membrane array Partial second pass for boron removal 2-pass 2-stage, partial 2-pass 4-stage, partial 2-pass... 

More complex multi-pass SWRO systems include the system used in Ashkelon, Israel, which uses four RO passes in series to treat seawater from an open water intake in the Mediterranean Sea (40,700 mg/1 TDS). The permeate must be produced with less than 0.4 mg/1 boron and 20 mg/1 chloride. Thus, a series of passes with changes in pH was necessary to obtain the required permeate water quaHty. The first pass has a recovery of 45% and is operated at neutral pH. Permeate from the feed end is collected as product, while permeate from the concentrate end is collected and flows to the second pass, which operates at 85% recovery and pH > 8.5 to achieve greater boron removal. The concentrate firom the second pass continues to the third stage, also operated at 85%, but at low pH. The objective of the third pass is to achieve higher recovery without salt precipitation. However, the boron removal in the third pass is minimal at low pH, and a fourth pass (high pH, 90% recovery) treats the third pass permeate for boron removal. Overall, the recovery is approximately 44%, and the plant uses 25,600 SWRO membranes and 15,100 BWRO membranes [3,51]. 

Integrated process for boron removal in sea water desalination. SWRO = sea water RO BWRO = brackish water RO BSR = boron selective ion-exchange resin Cg = boron concentration. (Adapted from Busch et al., 2003.)... 

Busch M, Mickols ME, Jons S, Redondo J and de Witte J (2003), Boron removal in seawater desalination IDA World Congress, Bahrain, BAH03-039. 

A closed system of primary coolant purification and boron removal that excludes leakages of the radioactive medium of the primary circuit from entering the atmosphere during plant operation ... 

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