Mikhail Borisover

Publications of Mikhail Borisover

• Enhancement effect of water associated with natural organic matter (NOM) on organic compound-NOM interactions: a case study with carbamazepine.

  Authors: Mikhail Borisover, Maggie Sela, Benny Chefetz

  Chemosphere. 03/2011; 82(10):1454-60.

  Natural organic matter (NOM) in soils and sediments is recognized to strongly affect environmental distributions of organic compounds. Water associated with NOM may have a significant impact onNatural organic matter (NOM) in soils and sediments is recognized to strongly affect environmental distributions of organic compounds. Water associated with NOM may have a significant impact on NOM-organic compound interactions. The objectives of this research were (1) to determine the effect of hydration of a model NOM sorbent on interactions with a probe organic compound, carbamazepine (CBZ), and (2) based on the comparison with the literature data, to evaluate the effect of organic compound structure on the cooperative participation of water molecules in organic sorbate-NOM interactions. CBZ is one of the most widely reported water pollutants from the pharmaceutical and personal care products family. Therefore, CBZ sorption on Pahokee peat was compared from water and from n-hexadecane, using solubility-normalized solute concentrations. CBZ-NOM interactions were enhanced by one to two orders of magnitudes when NOM became fully hydrated. This enhancement is associated with the distinct ability of CBZ to undergo strong, specific interactions with NOM which was revealed by comparing the transfer of CBZ and another model sorbate, phenanthrene, from solution in n-hexadecane to the hydrated NOM sorbent. The enhancing effect of NOM hydration on CBZ-NOM interactions was also observed when CBZ sorption was examined on partially hydrated NOM. In comparison with a smaller-size organic sorbate such as phenol, CBZ needs more NOM-associated water in order to demonstrate the strengthening of interactions with NOM. Therefore, for penetration of the larger sorbate molecules into the NOM interior, a greater number of water molecules are needed to compensate for the local NOM disintegration thus suggesting the greater extent of the cooperativity in an involvement of water molecules in the CBZ-NOM interactions.

• Spatial and seasonal patterns of fluorescent organic matter in Lake Kinneret (Sea of Galilee) and its catchment basin.

  Authors: Mikhail Borisover, Yael Laor, Arkady Parparov, Nadezhda Bukhanovsky, Marcos Lado

  Water research. 08/2009; 43(12):3104-16.

  Lake Kinneret (Sea of Galilee) is one of the major water resources in Israel. The origin and characteristics of natural organic matter (NOM) in the lake and its tributary rivers were studied usingLake Kinneret (Sea of Galilee) is one of the major water resources in Israel. The origin and characteristics of natural organic matter (NOM) in the lake and its tributary rivers were studied using fluorescence excitation emission matrices (EEM) and parallel factor analysis. Two humic-like and one proteinous components were sufficient to describe EEM variability among 167 water samples collected between 2/2005 and 9/2006. The two humic-like components showed different relations in lake and riverine samples. Their vertical distribution in the lake was affected by seasonal stratification and distance from water surface, presumably reflecting the release of humic-like matter from sediments, its production via NOM transformation in the bottom layers, and its photodegradation in the upper layers. Vertical distribution of the proteinous component, indicating biological activity at upper water layers, did not correlate with that of the humic-like components. Dissolved organic carbon concentrations did not show any vertical stratification, emphasizing the power of EEM to explore NOM dynamics.

• Organic sorbate-organoclay interactions in aqueous and hydrophobic environments: sorbate-water competition.

  Authors: Mikhail Borisover, Zev Gerstl, Faina Burshtein, Shmuel Yariv, Uri Mingelgrin

  Environmental science & technology. 10/2008; 42(19):7201-6.

  Sorption of nitrobenzene, phenol, and m-nitrophenol from water and n-hexadecane was measured on Na-montmorillonite and organoclays in which 41 and 90% of the exchange capacity of the Na-clay wasSorption of nitrobenzene, phenol, and m-nitrophenol from water and n-hexadecane was measured on Na-montmorillonite and organoclays in which 41 and 90% of the exchange capacity of the Na-clay was occupied by hexadecyltrimethylammonium. The strength of sorbate-sorbent interactions in n-hexadecane for all three sorbents was in the following order: nitrobenzene < phenol < m-nitrophenol. The magnitude of the distribution coefficients suggests that the contribution to solute uptake of partitioning between n-hexadecane and the organic pseudophase of the dried organoclays is minor, whereas the major contribution is from adsorptive sorbate-sorbent interactions. Sorption isotherms obtained in different solvents were compared using a sorbate activity scale. In the organoclays, the stronger the tendency of a sorbate to interact with sorption sites, the less pronounced is the reduction in the activity-based sorption due to competition with water. The order of this reduction for the different sorbates is nitrobenzene > phenol > m-nitrophenol. The weakening of sorbate-sorbent interactions resulting from water-sorbate competition might be mitigated by interaction between the organic sorbate and sorbed water molecules. Since the more strongly interacting organic compounds are less susceptible to suppression of sorption in the presence of water, hydrating organoclays may result in an increased differentiation between "weakly" and "strongly" interacting ("nonpolar" and "polar") compounds in the organoclay phase.

• Fluorescence-based evidence for adsorptive binding of pyrene to effluent dissolved organic matter.

  Authors: Mikhail Borisover, Yael Laor, Nadezhda Bukhanovsky, Ibrahim Saadi

  Chemosphere. 01/2007; 65(11):1925-34.

  Using fluorescence intensity measurements, pyrene interactions with different types of effluent dissolved organic matter (EDOM) originated from treated municipal wastewater are examined. MultipleUsing fluorescence intensity measurements, pyrene interactions with different types of effluent dissolved organic matter (EDOM) originated from treated municipal wastewater are examined. Multiple observations show that fluorescence intensity of pyrene-EDOM solutions is non-linearly related to pyrene concentration, with distinct concave-up dependence. Testing the effect of pyrene concentration on fluorescence intensity of pyrene-EDOM solutions provides a tool to examine whether binding of an organic compound to EDOM follows linear or non-linear isotherm. Possible coupling between static and dynamic quenching effects was addressed while analyzing fluorescence data. Limited number of EDOM binding sites results in a non-linear binding isotherm such that the concept of pyrene "partitioning" between aqueous phase and "bulky" EDOM organic phase is hardly relevant. Maximal EDOM capacity for pyrene binding is estimated approximately as 0.1% ww(-1). Examination of the differences between the total fluorescence intensity of pyrene-EDOM solution and the fluorescence intensities of separated constituents (pyrene and EDOM) was used to illustrate the accumulation of pyrene-EDOM complexes and saturation of some EDOM binding sites. Strong interactions between pyrene and EDOM binding sites may result in pyrene distribution coefficients differing at least by a factor 3.5-7 at varying pyrene concentrations.

• Monitoring of effluent DOM biodegradation using fluorescence, UV and DOC measurements.

  Authors: Ibrahim Saadi, Mikhail Borisover, Robert Armon, Yael Laor

  Chemosphere. 05/2006; 63(3):530-9.

  The potential of effluent DOM to undergo microbial degradation was assessed in batch experiments. Effluent samples from Haifa wastewater treatment plant and Qishon reservoir (Greater Haifa wastewaterThe potential of effluent DOM to undergo microbial degradation was assessed in batch experiments. Effluent samples from Haifa wastewater treatment plant and Qishon reservoir (Greater Haifa wastewater reclamation complex, Israel) were incubated either with effluent or soil microorganisms for a period of 2-4 months and were characterized by dissolved organic carbon contents (DOC), UV(254) absorbance and by fluorescence excitation-emission matrices. Three main fluorescence peaks were identified that can be attributed to humic/fulvic components and "protein-like" structures. During biodegradation, specific fluorescences (F/DOC) of the three peaks were increased at various extents, suggesting selective degradation of non-fluorescing constituents. In some cases increase in the effluent fluorescence (F) was observed thus proposing (i) the formation of new fluorescing material associated with DOM biodegradation and/or (ii) degradation of certain organic components capable of quenching DOM fluorescence. Based on the ratio between fluorescence intensity and UV(254), different biodegradation dynamics for fluorescent DOM constituents as compared with other UV-absorbing molecules was delineated. Overall, about 50% of the total DOM was found to be readily degradable such that residual resistant DOC levels were between 8 and 10 mg l(-1). Enhanced levels of residual DOM in effluent-irrigated soils may contribute to the DOM pool capable of carrying pollutants to groundwater.

• Copper-binding efficacy of water-soluble chitosans: characterization by aqueous binding isotherms.

  Authors: Noah Ben-Shalom, Nataliya Kudabaeva, Mikhail Borisover

  Chemosphere. 07/2005; 59(9):1309-15.

  The major objective of the study is to measure directly the isotherms of copper binding onto soluble chitosan preparations, using ion-selective electrode technique. Copper uptake is found to decreaseThe major objective of the study is to measure directly the isotherms of copper binding onto soluble chitosan preparations, using ion-selective electrode technique. Copper uptake is found to decrease strongly when chitosan acetylation degree or chitosan concentration increased. When relating the bound copper concentrations to content of non-acetylated amine groups in a chitosan, differences between copper uptake on different chitosan preparations become reduced but not disappear. Other effects, in addition to the contents of non-acetylated amine groups, can involve differences in the copper binding by different chitosans. Due to isotherm non-linearity, the distribution coefficient K(d) of copper between a water-soluble chitosan and an aqueous solution may vary by two orders of magnitude as the free copper concentration C(free) varied. Linear relation between logK(d) normalized by free amine group content of chitosans and logC(free) may help in preliminary estimating of the copper binding by water-soluble chitosans at a certain pH.

• Hydration of natural organic matter: effect on sorption of organic compounds by humin and humic acid fractions vs original peat material.

  Authors: Mikhail Borisover, Ellen R Graber

  Environmental science & technology. 09/2004; 38(15):4120-9.

  Natural organic matter (NOM) hydration is found to change activity-based sorption of test organic compounds by as much as 2-3 orders of magnitude, depending on the compound and the specific NOMNatural organic matter (NOM) hydration is found to change activity-based sorption of test organic compounds by as much as 2-3 orders of magnitude, depending on the compound and the specific NOM sorbent. This is demonstrated for sorption on humin, humic acid, and the NOM source material. Hydration assistance in organic compound sorption correlates with the ability of the sorbate to interact strongly with hydrated sorbents, demonstrating the important role of noncovalent polar links in organizing the sorbent structure. Differences in hydration effect between the sorbents are caused mainly by differences in compound-sorbent interactions in the dry state. For a given compound, hydration of the sorbent tends to equalize the sorption capability of the three sorbents. No correlation was found between the strength of sorbate-sorbent interactions or the type of sorbate functional groups and the extent of sorption nonlinearity. Sorption nonlinearity compared over the same sorbed concentration range is greater on the original NOM than on either of the two extracted fractions. In elucidating sorption mechanisms on hydrated NOM, it is important to explicitly consider the participation of water molecules in organic compound interactions in the NOM phase.

• Classifying NOM-organic sorbate interactions using compound transfer from an inert solvent to the hydrated sorbent.

  Authors: Mikhail Borisover, Ellen R Graber

  Environmental science & technology. 01/2004; 37(24):5657-64.

  Interactions of a wide set of organic compounds with model natural organic matter (NOM, Pahokee peat) were examined using a new approach that converts aqueous sorption to compound transfer fromInteractions of a wide set of organic compounds with model natural organic matter (NOM, Pahokee peat) were examined using a new approach that converts aqueous sorption to compound transfer from n-hexadecane to the hydrated NOM. This conversion accounts for solute-water interactions and applies the same inert reference medium for all compounds of interest, making it possible to classify sorbates according to the strength of sorbate-NOM interactions. Differences in strength of organic compound interactions in the sorbed phase as great as 4-5 orders of magnitude are demonstrated. The strongest interactions were observed for compounds with well-established H-bonding potentials. Considering hydrocarbons and Cl-substituted hydrocarbons, aliphatic compounds gain more upon distribution from the n-hexadecane medium to NOM than do aromatic compounds. Sorption nonlinearity was tested by comparing the change in n-hexadecane-hydrated NOM distribution coefficient (K(d,i)) versus sorbed concentration for the different compounds. Only those compounds that interact most strongly with NOM demonstrated significant sorption nonlinearity, expressed by a strong reduction in K(d,i) as a function of sorbed concentration. The relationship between compound ability to interact with NOM and reduction in K(d,i) as a function of sorbed concentration can be used to characterize compound distribution among different sorption domains.

• Sulfentrazone adsorbed on micelle-montmorillonite complexes for slow release in soil.

  Authors: Tamara Polubesova, Shlomo Nir, Onn Rabinovitz, Mikhail Borisover, Baruch Rubin

  Journal of agricultural and food chemistry. 06/2003; 51(11):3410-4.

  Interactions of the herbicide sulfentrazone with the cationic surfactants octadecyltrimethylammonium (ODTMA), hexadecyltrimethylammonium (HDTMA), and benzyldimethylhexadecylammonium (BDMHDA) haveInteractions of the herbicide sulfentrazone with the cationic surfactants octadecyltrimethylammonium (ODTMA), hexadecyltrimethylammonium (HDTMA), and benzyldimethylhexadecylammonium (BDMHDA) have been studied for the design of slow-release formulations based on sulfentrazone adsorbed on a micelle-montmorillonite complex. Adsorbed amounts of sulfentrazone on ODTMA- and BDMHDA-montmorillonite complexes were 99.2-99.8% of that added, and desorption of herbicide in water during 24 h was low. After 10 washings in funnels with soil, only 2.6% of herbicide was released from ODTMA-montmorillonite formulations versus 100% release from the commercial formulation. The strong binding of sulfentrazone to micelles was confirmed by pH and spectroscopic measurements and was explained by the formation of ionic pairs between cationic surfactant and anionic herbicide. The ODTMA-clay and commercial formulations of sulfentrazone yield almost complete and 40% growth inhibition of green foxtail, respectively, at 700 g of active ingredient/ha. Hence, the slow release from micelle-clay formulations of sulfentrazone promotes its biological activity and reduces environmental contamination.

• Relationship between strength of organic sorbate interactions in NOM and hydration effect on sorption.

  Authors: Mikhail Borisover, Ellen R Graber

  Environmental science & technology. 12/2002; 36(21):4570-7.

  According to a recent conceptual model for hydration-assisted sorption of organic compounds in natural organic matter (NOM), certain polar moieties of dry NOM are unavailable for compound sorptionAccording to a recent conceptual model for hydration-assisted sorption of organic compounds in natural organic matter (NOM), certain polar moieties of dry NOM are unavailable for compound sorption due to strong intra- and intermolecular NOM interactions. Water molecules solvate these moieties creating new sorption sites at solvated contacts. It is expected that the greater a compound's ability to undergo specific interactions with NOM, the greater will be the hydration-assisted sorption effect, because penetration of compounds into solvated contacts must involve competition with water at the solvated contact. To test this model, we compare the hydration effect on sorption kinetics and equilibrium for 4 compounds with differing abilities to undergo specific interactions with NOM. Sorption measured on Pahokee peat in aqueous systems was fast compared with n-hexadecane (dry) systems. No concentration effect on attainment of sorption equilibrium was observed. m-Nitrophenol exhibited the greatest hydration-assisted sorption effect, benzyl alcohol showed an intermediate effect and acetophenone and nitrobenzene showed no hydration-assisted sorption, on an activity scale. The extent of hydration-assisted sorption effect correlates with compound ability to undergo specific interactions. These results support the conceptual model and demonstrate the importance of polar NOM noncovalent links in organizing the NOM phase and in controlling the hydration effect on sorption of organic compounds.

• Thermal treatment of organoclays: Effect on the aqueous sorption of nitrobenzene on n-hexadecyltrimethyl ammonium montmorillonite

  Authors: Mikhail Borisover, Nadezhda Bukhanovsky, Isaak Lapides, Shmuel Yariv

  Applied Surface Science.

  The aim of this work was to examine the effect of thermal treatment on organoclay sorptive properties. Aqueous sorption of nitrobenzene used as a probe compound was studied on Na-montmorillonite andThe aim of this work was to examine the effect of thermal treatment on organoclay sorptive properties. Aqueous sorption of nitrobenzene used as a probe compound was studied on Na-montmorillonite and two types of HDTMA-montmorillonite (where HDTMA is n-hexadecyltrimethyl ammonium exchanged by 41 and 90% of the clay cation exchange capacity) heated in air at 150, 250, 360 and 420 °C. Mild heating of sorbents (at 150 °C) results in a distinct increase of their sorptive efficacy. Treatment of organoclays at higher temperatures (250 and 360 °C) results in the significant sorbent changes as revealed by a C loss, decrease of a basal spacing and disappearance of symmetric and asymmetric stretching vibrations of CH2 but has a little impact on the sorptive efficacy (as compared with organoclays treated at 150 °C). Hence, even a significant carbon loss in thermally treated organoclays should not be necessarily linked to the loss of their sorptive potential. Further increase of the treatment temperature results in a decrease of a sorptive efficacy of all sorbents. Mild heating of organoclays in air could be useful for improving their sorptive potential. This improvement is assumed to result from the weakening of water–sorbate competition for sorption sites on a mildly heated sorbent.

• Suitability of dye–clay complexes for removal of non-ionic organic compounds from aqueous solutions

  Authors: Mikhail Borisover, Ellen R. Graber, Fernando Bercovich, Zev Gerstl

  Chemosphere.

  Aqueous sorption of phenol, atrazine and naphthalene was measured on complexes formed from Na-montmorillonite (Fischer bentonite) and the organic cationic dyes crystal violet and rhodamine-B.Aqueous sorption of phenol, atrazine and naphthalene was measured on complexes formed from Na-montmorillonite (Fischer bentonite) and the organic cationic dyes crystal violet and rhodamine-B. Sorption isotherms were found to be non-linear. This agrees well with the rigid nature of the dye–clay organic coverage, which provides a finite surface for adsorption. High values of organic carbon-normalized distribution coefficients reached 20,000–25,000 for atrazine on rhodamine-B-montmorillonite, 7000 for atrazine on crystal violet-montmorillonite, and 1500 for phenol on crystal violet-montmorillonite. As such, dye–clays may significantly extend the variety of organoclay sorbents that effectively reduce aqueous concentrations of non-ionic organic compounds.

• Imazaquin adsorbed on pillared clay and crystal violet-montmorillonite complexes for reduced leaching in soil.

  Authors: Tamara Polubesova, Shlomo Nir, Zev Gerstl, Mikhail Borisover, Baruch Rubin

  Journal of environmental quality. 31(5):1657-64.

  Ground water pollution due to herbicide leaching has become a serious environmental problem. Imazaquin [2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)quinoline-3-carboxylic acid] is an herbicideGround water pollution due to herbicide leaching has become a serious environmental problem. Imazaquin [2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)quinoline-3-carboxylic acid] is an herbicide used to control broadleaf weeds in legume crops. Imazaquin is negatively charged at the basic pH of calcareous soils and exhibits high leaching potential in soils. Our aim was to design formulation of imazaquin to reduce herbicide leaching. Imazaquin sorption on pillared clay (PC) and crystal violet (CV)-montmorillonite complexes was studied. The CV-montmorillonite complexes become positively charged with adsorption of CV above the cation exchange capacity (CEC) of montmorillonite, and thus can sorb imazaquin. The Langmuir equation provides a good fit to isotherms of imazaquin sorption on PC and CV-montmorillonite complexes, but for charged complexes an equation that combines electrostatics with specific binding was preferred. Maximal imazaquin sorption was 17.3 mmol kg-1 for PC and 22.2 mmol kg-1 for CV-montmorillonite complexes. The extents of imazaquin desorption into water were 21% for PC and 5% for CV-clay complexes. The presence of anions decreased imazaquin sorption on both sorbents in the sequence phosphate > acetate > sulfate. Reduction of imazaquin sorption by the anions and the extent of its desorption in electrolyte solutions were higher for PC than for CV-clay complexes. Leaching of imazaquin from CV-montmorillonite formulations through soil (Rhodoxeralf) columns was two times less than from PC formulations and four times less than that of technical imazaquin. The CV-montmorillonite complexes at a loading above the CEC appear to be suitable for preparation of organo-clay-imazaquin formulations that may reduce herbicide leaching significantly.

• Fluorescence-based evidence for adsorptive binding of pyrene to effluent dissolved organic matter

  Authors: Mikhail Borisover, Yael Laor, Nadezhda Bukhanovsky, Ibrahim Saadi

  Chemosphere.

  Using fluorescence intensity measurements, pyrene interactions with different types of effluent dissolved organic matter (EDOM) originated from treated municipal wastewater are examined. MultipleUsing fluorescence intensity measurements, pyrene interactions with different types of effluent dissolved organic matter (EDOM) originated from treated municipal wastewater are examined. Multiple observations show that fluorescence intensity of pyrene–EDOM solutions is non-linearly related to pyrene concentration, with distinct concave-up dependence. Testing the effect of pyrene concentration on fluorescence intensity of pyrene–EDOM solutions provides a tool to examine whether binding of an organic compound to EDOM follows linear or non-linear isotherm. Possible coupling between static and dynamic quenching effects was addressed while analyzing fluorescence data. Limited number of EDOM binding sites results in a non-linear binding isotherm such that the concept of pyrene “partitioning” between aqueous phase and “bulky” EDOM organic phase is hardly relevant. Maximal EDOM capacity for pyrene binding is estimated approximately as 0.1% w w−1. Examination of the differences between the total fluorescence intensity of pyrene–EDOM solution and the fluorescence intensities of separated constituents (pyrene and EDOM) was used to illustrate the accumulation of pyrene–EDOM complexes and saturation of some EDOM binding sites. Strong interactions between pyrene and EDOM binding sites may result in pyrene distribution coefficients differing at least by a factor 3.5–7 at varying pyrene concentrations.