Borate Ions Research Articles

Vibrational Studies of Zinc Antimony Borophosphate Glasses Doped Rare Earth

Zinc antimony borophosphate glasses has been determined for [10P2O5 –40B2O3 –xSb2O3 –(50–x)ZnO] and composition of [10P2O5 – 40B2O3 –40Sb2O3 –10ZnO] has been doped with 1 mol% of rare earth (Eu, Nd, Sm, Er). The functions of compositional changes on their structural features were examined using X–Ray Diffraction (XRD) to detect the amorphousity phase present. While Fourier Transform Infrared (IR) Spectroscopy were used to identify the presences of vibrational modes and band assignments of phosphate, borate, antimony, zinc and Rare earth ion in the system. XRD results expose that crystalline phase changes with different amount of zinc and antimony substitution. Hydroxyl group absorption also vary due to this composition changes and clearly shown in IR spectroscopy in the ranges 1400–4000 cm–1. Result of IR spectroscopy indicated that bands around 1440 cm–1 and 760 cm–1 was ascribed to the vas(B–O–B) and vs(P–O–P) vibration respectively. The changes of this vibration indicated that P–O–B linkage was formed near 660 cm–1. The modification of zinc antimony borophosphate glasses with rare earth was studied and showed present of rare earth ion in the glass system does not change the structural features.

Effect of structure on the sorption properties of chlorine-containing form of double aluminum lithium hydroxide

The effect exerted by composition and specific structural properties of commercial batches of granular sorbent based on chlorine-containing form of double aluminum lithium hydroxide on its sorption properties in lithium extraction from magnesium chloride brines was determined. Deficiency in lithium chloride in the sorbent structure and structural defects are responsible for the selectivity of granular sorbent. It was shown that sorbent is selective for lithium even in the presence of high concentrations of magnesium chloride in brine and the borate ions exhibit adverse effect on the technological process.

Assessment of Three Methods for the Identification of Enzymatically Hydrolyzed Guar Gum

Enzymatically hydrolyzed guar gum (EHGG), which is used as a thickener or a soluble dietary fiber, is produced by partial hydrolysis of the guar gum (GG) backbone using mannan endo-β-1,4-mannosidase. In this study, we compared and evaluated 3 methods to distinguish EHGG from other polysaccharides used as food additives or monosaccharides. The first method is based on cross-linking reaction of saccharide hydroxyl groups mediated by borate ions. EHGG showed gelation and was distinguished from some soluble polysaccharides, which did not form gels, and also from polysaccharides with low solubility in water. The second method is based on co-gelation with xanthan gum. It was applicable to GG, but not to EHGG. The third method is based on the alcohol precipitation of hydrophilic polymers. EHGG, some soluble polysaccharides and monosaccharides were dissolved in water at the concentration of 10%, while GG and some polysaccharides were not. The 10% solutions thus obtained were mixed with 2-propanol at the ratio of 1 : 1 (v/v). A white precipitate was formed in the EHGG solutions and the tested soluble polysaccharide solutions, while it was not produced in the monosaccharide solutions. This result demonstrated that soluble polysaccharides including EHGG can be distinguished from polysaccharides with low solubility or monosaccharides by the third method.

Cytotoxicity assessment of modified bioactive glasses with MLO-A5 osteogenic cells in vitro

The primary objective of this study was to evaluate in vitro responses of MLO-A5 osteogenic cells to two modifications of the bioactive glass 13-93. The modified glasses, which were designed for use as cell support scaffolds and contained added boron to form the glasses 13-93 B1 and 13-93 B3, were made to accelerate formation of a bioactive hydroxyapatite surface layer and possibly enhance tissue growth. Quantitative MTT cytotoxicity tests revealed no inhibition of growth of MLO-A5 cells incubated with 13-93 glass extracts up to 10mg/ml, moderate inhibition of growth with 13-93 B1 glass extracts, and noticeable inhibition of growth with 13-93 B3 glass extracts. A morphology-based biocompatibility test was also performed and yielded qualitative assessments of the relative biocompatibilities of glass extracts that agree with those obtained by the quantitative MTT test. However, as a proof of concept experiment, when MLO-A5 cells were seeded onto 13-93 B3 scaffolds in a dynamic in vitro environment, cell proliferation occurred as evidenced by qualitative and quantitative MTT labeling of scaffolds. Together these results demonstrate the in vitro toxicity of released borate ion in static experiments; however borate ion release can be mitigated in a dynamic environment similar to the human body where microvasculature is present. Here we argue that despite toxicity in static environments, boron-containing 13-93 compositions may warrant further study for use in tissue engineering applications.

Calibration of the boron isotope proxy in the planktonic foraminifera Globigerinoides ruber for use in palaeo-CO2 reconstruction

The boron isotope-pH proxy, applied to mixed-layer planktic foraminifera, has great potential for estimating past CO2 levels, which in turn is crucial to advance our understanding of how this greenhouse gas influences Earth's climate. Previous culture experiments have shown that, although the boron isotopic compositions of various planktic foraminifera are pH dependent, they do not agree with the aqueous geochemical basis of the proxy. Here we outline the results of culture experiments on Globigerinoides ruber (white) across a range of pH (∼7.5–8.2) and analysed via multicollector inductively-coupled plasma mass spectrometry (MC-ICPMS), and compare these data to core-top and sediment-trap samples to derive a robust new species-specific boron isotope-pH calibration. Consistent with earlier culture studies, we show a reduced pH dependency of the boron isotopic composition of symbiont-bearing planktonic foraminifera compared to borate ion in seawater. We also present evidence for a size fraction effect in the δ11B of G. ruber. Finally, we reconstruct atmospheric CO2 concentrations over the last deglacial using our new calibration at two equatorial sites, ODP Site 999A and Site GeoB1523-1. These data provide further grounding for the application of the boron isotope-pH proxy in reconstructions of past atmospheric CO2 levels.

Impurities Effect on Carbonate Reactive Crystallization for the Wastewater

Reactive crystallization designed to separate nickel or copper ion from effluents has been advanced for applying to actual industrial wastewater containing impurities. In the primary reaction of this method, metal sulfate solution reacts with sodium carbonate solution in a semibatch crystallizer. In the present study, during the process of nickel or copper ions incorporation, inhibitory effect on seed growth of impurities, like cobalt, manganese, zinc, and borate and phosphate ions, was investigated. Through the 8-hour reactive crystallization, obtained particles’ characters and metals removal efficient were examined. Considering analyses data on metal component ratio in produced crystals, metal ions initial uptake rate was found to be different by the kind of seeds and impurities. And the centrifugation was performed against obtained crystals aimed for examining target metal purity improvement. The results indicated that copper components can incorporate and remove other metal ions easily. In addition, when the anions are used as impurities, depending on the kind of anions, the effect of damaging the surface of seeds or producing many fine particles has been confirmed.

Probing the interactions between all components of the catalytic pool for homogeneous olefin polymerisation by diffusion NMR spectroscopy

Diffusion NMR spectroscopy was applied to investigate all individual components and combinations thereof for the Cp2ZrMe2/MAO (DMAO)/TBP (MAO = methylaluminoxane, DMAO = AlMe3 depleted MAO, TBP = 2,6-di-tert-butylphenol) ternary system, selected as a prototypical catalytic pool for homogeneous olefin polymerisation. Both MAO and DMAO were found to self-aggregate in C6D6 with the latter having a higher propensity. TBP reacts with DMAO affording MeAl(2,6-di-tert-butylphenoxide)2 and causing a structural modification of DMAO, whose aggregates become much larger. The actual dimensions and self-aggregation tendency of (D)MAO, which depend on Al concentration and the possible presence of TBP, turned out to carry over to [Cp2Zr(μ-Me)2AlMe2]MeMAO (1) OSIP (outer sphere ion pair) and [Cp2Zr(+)Me···MeMAO(-)] (2) ISIP (inner sphere ion pair) that form upon activation of Cp2ZrMe2. Once the intrinsic self-aggregation tendency of MAO has been subtracted, OSIP 1 and ISIP 2 behave exactly as analogous ion pairs with borate ions: ISIP 2 does not self-aggregate, whereas OSIP 1 exhibits the same self-aggregation trends of zirconocene OSIPs with borate counterions.

【Original Contribution】 Rate-limiting Step in Sugar Transport across an Anion-exchange Membrane Fixed with Borate Ions

【Original Contribution】 Rate-limiting Step in Sugar Transport across an Anion-exchange Membrane Fixed with Borate Ions

Sonication-based improvement of the physicochemical properties of Guar Gum as a potential substrate for modified drug delivery systems.

Guar Gum is a natural polysaccharide that, due to its physicochemical properties, is extensively investigated for biomedical applications as a matrix for modified drug delivery, but it is also used in the food industry as well as in cosmetics. A commercial sample of Guar Gum was sonicated for different periods of time, and the reduction in the average molecular weight was monitored by means of viscometric measurements. At the same time, the rheological behaviour was also followed, in terms of viscoelasticity range, flow curves, and mechanical spectra. Sonicated samples were used for the preparation of gels in the presence of borate ions. The effect of borax on the new samples was investigated by recording mechanical spectra, flow curves, and visible absorption spectra of complexes with Congo Red. The anisotropic elongation, observed in previous studies with tablets of Guar Gum and borax, was remarkably reduced when the sonicated samples were used for the preparation of the gels.

Effect of borax addition on the structural modification of bentonite in biodegradable alginate‐based biocomposites

AbstractFunctionalized next generation biodegradable polymeric systems (bioplastics) that have better compatibility, enhanced relaxation, and thermal properties were designed using bentonite‐added alginate biocomposite films in the presence of borax. A series of bentonite‐added biocomposite films crosslinked with CaCl2 were characterized by using methods like XRD, FTIR, TGA, DTA/DSC, DMA, and AFM. A plausible structural mechanism with Ca2+ crosslinking gel formation known as egg‐box and borate ion complexes was proposed to elucidate the interactions between borax and bentonite/alginate biocomposites. Enhanced compatibility and hybrid properties of raw fillers were confirmed by mineral processing steps involving hydrocyclone purification for bentonite and recrystallization steps for borax. The structure of bentonite and also bentonite hybrid biocomposites were clearly improved upon small additions of borax into the matrix. The presence of borax was found to provide a more intercalated or exfoliated morphology for a given hybrid biocomposite structure. Borate ions dissociated in aqueous solution provided a better effect on the intercalation of bentonite by imparting new hydrogen bonding sites, diol‐complexes, and didiol‐crosslinking gels. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Boron removal efficiency from Red Sea water using different SWRO/BWRO membranes

Seawater reverse osmosis (SWRO) desalination process provides high quality of fresh water. However, due to some operational constraints mainly scaling control some trace contaminant removal, such as acceptable boron concentration, cannot be achieved in a single pass SWRO system. The objective of this study was to investigate the efficiency of five difference reverse osmosis (RO) membranes (seawater SW and brackish water BW) provided by different manufacturers for boron removal. RO experiments using pretreated real Red Sea water were conducted in parallel to compare membrane performance under the same operating conditions. As expected, results showed that boron rejection increased as the feed pH increased. This was caused by dissociation of boric acid to negatively charged borate ions and more negatively charged membrane surface at elevated pH which enhanced boron rejection. Single pass RO system, with and without elevating the pH, may not be sufficient for two reasons. First, boron concentration in permeate does not fulfill local regulations (<0.5ppm). Second, severe scaling occurs due to operation in alkaline condition, since Ca2+ and Mg2+ concentrations are still high to cause salts precipitation. Techno-economical study was performed to select the best configuration and membrane giving the highest performance in terms of boron and TDS rejections and energy consumption.

Removal of boron from wastewater by the hydroxyapatite formation reaction using acceleration effect of ammonia

The mechanism was discussed for the removal of boron by the hydroxyapatite (HAp) formation reaction using Ca(OH)2 and (NH4)2HPO4 in room temperature. Time required to remove boron was 20min by adding Ca(OH)2 and (NH4)2HPO4 for the remaining boron to below 1mg/L. The removal rate of boron was controlled by the HAp precipitate formation and the presence of ammonia. From the XRD patterns and SEM images, HAp could be confirmed in the precipitate product. The reaction between borate ions and calcium hydroxide was accelerated by dehydration with ammonia; the borate-calcium hydroxide compound coprecipitated with resulting HAp. Although the removal of boron decreased in the presence of sulfate, phosphate, and aluminum, these effects could be prevented by adding excess Ca(OH)2. Interference of fluoride ions was eliminated by adding Al3+. Sodium alpha-olefin sulfonate was the most effective coagulant for HAp precipitation. The proposed boron removal method has several advantages about treating time and ability of boron removal. The method was successfully applied to the real hot spring wastewater.

Phase Equilibria of the Salt-Water System of Lithium and Borate Ions

It is well known that the exploitation of brine resources of salt lakes is based on the relevant phase equilibrium and phase diagrams. In this paper, the progresses on the stable and metastable equilibria, thermodynamic properties and predictive solubilities of the brine system containing lithium and borate ions at present were summarized. The problems existed and the new trends in the future were also carried out.

Preparation of sorbents containing ettringite phase from concrete sludge and their performance in removing borate and fluoride ions from waste water

Concrete sludge is an industrial waste slurry containing hydrated cement, aggregates and water. Solid sorbents containing ettringite, Ca6Al2(SO4)3(OH)12·26H2O, were prepared from concrete sludge by adding various amounts of aluminum sulfate to enhance ettringite formation. Anion exchange performance of the sorbents was examined using model waste waters containing boron or fluoride ions. The removal behavior depended on the calcium/aluminum ratio and the heat treatment temperature after drying. For the same Ca/Al ratio, improved removal performance was observed for sorbents treated at higher temperatures. The highest removal capacity was found when the sorbent was prepared with a molar ratio of Ca/Al of 3.2 and heat treatment at 175°C. The final concentrations of boron and fluoride were 6.3mg-B/L, and less than 4mg-F/L for initial concentrations of 100mg-B/L and 300mg-F/L. Treatment of the sorbents at higher temperature dehydrated the ettringite phase to form metaettringite phase. The sorbents prepared in the present study can be used in a boron and fluoride removal process that meets the effluent standard in Japan.

Chiral separation using capillary electromigration techniques based on ligand exchange principle

Over the last couple of decades, researchers have developed diverse chiral separation methods emerged from a few chiral separation principles. This review article is primarily focused on the application of chiral ligand-exchange (CLE) principle in capillary electromigration techniques, such as capillary electrophoresis (CE) and capillary electrochromatography (CEC). First, the most commonly used CLE-CZE separation mode by using different kinds of central ions, such as Cu(II), Zn(II), borate ion, and other metal ions, has been introduced. Meanwhile, several kinds of surfactants have been applied as the micelle-forming agents in the CLE micellar electrokinetic chromatography mode. The highlight of recent research of CLE-CEC is the exploitation of novel columns for chiral separation. Then, two kinds of capillary columns, packed capillary and monolithic capillary column, have been briefly described. Finally, the effective application of these chiral separation methods has been presented, including the application in life science and food analysis area.

Boron removal by means of chemical precipitation with calcium hydroxide and calcium borate formation

Boron removal was investigated by chemical precipitation from aqueous solutions containing boron using calcium hydroxide. pH, initial boron concentration, amount of Ca(OH)2, stirring speed and solution temperature were selected as operational parameters in a batch system. The highest boron removal efficiency was reached at pH 1.0. Increasing initial boron concentration and amount of calcium hydroxide raised to boron removal efficiency. Boron removal efficiency was highest at a stirring speed of 150 rpm. The most important parameter affecting boron removal efficiency was solution temperature. Increasing solution temperature increased importantly boron removal. XRD analysis showed that CaB3O3(OH)5·4H2O, which is a borate mineral called inyoite, occurred between Ca(OH)2 and borate ions. As a result of the obtained experimental data, when the optimum operational conditions were selected, over 96% of boron removal efficiency was reached by this method.

Structurally modified poly(vinyl alcohol) ionic composites as efficient humidity indicators

AbstractSynthesis of structurally modified poly(vinyl alcohol) (PVA) ionic composites is presented. Low‐molecular‐weight PVA (Mn = 18,000 g mol−1) is prepared and blended together with either copper or borate ions under ambient conditions to yield PVA–Cu and PVA–B ionic composites, respectively. The borate ions coalesce together with different polymeric chains of PVA, forming a 3D network structure, which is identified by the weakening of OH absorption in the infrared spectrum. On the other hand, copper ions yield a weakly crosslinked polyelectrolyte by forming a coordinated complex with the hydroxyl groups of PVA, which leads to an increase in the λmax value in the ultraviolet–visible spectrum. The surface morphology of these PVA‐based ionic composites is studied via atomic force microscopy. Furthermore, the quantitative estimation of copper in PVA–Cu composites is performed by atomic absorption spectroscopy. Among these PVA ionic composites, the PVA–Cu exhibits excellent moisture absorption capability and dramatic changes in the color of thin composite film, when exposed to 75% humidity atmosphere. The absolute recovery, recyclability, and stability of the PVA–Cu ionic composites not only enable them to be good humidity indicators but the results show that these composites can be employed as efficient humidity‐sensitive material on suitable transducers for environmental and industrial applications. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

Evaluation of rheological properties and swelling behaviour of sonicated scleroglucan samples.

Scleroglucan is a natural polysaccharide that has been proposed for various applications. However there is no investigation on its property variations when the molecular weight of this polymer is reduced. Scleroglucan was sonicated at two different polymer concentrations for different periods of time and the effect of sonication was investigated with respect to molecular weight variations and rheological properties. Molar mass, estimated by viscometric measurements, was drastically reduced already after a sonication for a few min. Sonicated samples were used for the preparation of gels in the presence of borate ions. The effect of borax on the new samples was investigated by recording the mechanical spectra and the flow curves. A comparison with the system prepared with the dialysed polymer was also carried out. The anisotropic elongation, observed with tablets of scleroglucan and borax, was remarkably reduced when the sonicated samples were used for the preparation of the gels.

Theoretical analysis and intensity calculation for the f → d absorption spectrum of Ce3+ in YAl3(BO3)4 crystal

Emission, absorption, and excitation spectra of 4f → 5d transitions of Ce3+ ions in yttrium aluminum borate (YAB) crystal are reviewed and successfully reproduced by theoretical investigations. The Ce3+ energy level diagram has been compiled after a careful analysis of the optical spectra. Theoretical calculations based on free ion and crystal field Hamiltonians are used to interpret the observed transitions. The 4f and 5d crystal field parameter permits determination of the engine states of Ce3+ ion in YAB and then calculating the absorption line intensities as well as the effective section and the decay times.

Boron removal and zeta potential of RO membranes: impact of pH and salinity

Abstract Boron removal is a challenging task for any seawater desalination plant employing a singlepass reverse osmosis (RO) system. With a pKa value of 9.25, more than 99% boron removal is normally achieved at pH >10.5. As pKa value is theoretically lower at higher salinity, an increase of borate ion and a corresponding increase in boron removal could be expected as salinity increases. However, boron removals by CPA2 and SWC4+ membranes were found to decrease or, sometimes, unchanged at higher salinity where membrane zeta potentials shifted from negative values to positive values were observed at higher salinity at both pH 7 and 9. The decrease in boron removal by CPA2 membrane with increasing salinity at pH 9 could be attributed to the reduced charge repulsion mechanism. Similarly, boron removal by SWC4+ membrane decreased with increasing salinity. However, the removal efficiency reached its lowest value at 2000 mg/l of NaCl at pH 9. The subsequent increase in boron removal efficiency at salinity higher...