Vladimir V Gridin

Publications of Vladimir V Gridin

• A new sono-electrochemical method for enhanced detoxification of hydrophilic chloroorganic pollutants in water.

  Authors: Yakov Yasman, Valery Bulatov, Vladimir V Gridin, Sabina Agur, Noah Galil, Robert Armon, Israel Schechter

  Ultrasonics sonochemistry. 10/2004; 11(6):365-72.

  A new method for detoxification of hydrophilic chloroorganic pollutants in effluent water was developed, using a combination of ultrasound waves, electrochemistry and Fenton's reagent. The advantagesA new method for detoxification of hydrophilic chloroorganic pollutants in effluent water was developed, using a combination of ultrasound waves, electrochemistry and Fenton's reagent. The advantages of the method are exemplified using two target compounds: the common herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and its derivative 2,4-dichlorophenol (2,4-DCP). The high degradation power of this process is due to the large production of oxidizing hydroxyl radicals and high mass transfer due to sonication. Application of this sono-electrochemical Fenton process (SEF) treatment (at 20 kHz) with quite a small current density, accomplished almost 50% oxidation of 2,4-D solution (300 ppm, 1.2 mM) in just 60 s. Similar treatments ran for 600 s resulted in practically full degradation of the herbicide; sizable oxidation of 2,4-DCP also occurs. The main intermediate compounds produced in the SEF process were identified. Their kinetic profile was measured and a chemical reaction scheme was suggested. The efficiency of the SEF process is tentatively much higher than the reference degradation methods and the time required for full degradation is considerably shorter. The SEF process maintains high performance up to concentrations which are higher than reference methods. The optimum concentration of Fe2+ ions required for this process was found to be of about 2 mM, which is lower than that in reference techniques. These findings indicate that SEF process may be an effective method for detoxification of environmental water.

• Combined micro-droplet and thin-film-assisted pre-concentration of lead traces for on-line monitoring using anodic stripping voltammetry.

  Authors: Inessa Belostotsky, Vladimir V Gridin, Israel Schechter, Chaim N Yarnitzky

  Analytical and bioanalytical chemistry. 03/2003; 375(4):482-8.

  An improved analytical method for airborne lead traces is reported. It is based on using a Venturi scrubber sampling device for simultaneous thin-film stripping and droplet entrapment of aerosolAn improved analytical method for airborne lead traces is reported. It is based on using a Venturi scrubber sampling device for simultaneous thin-film stripping and droplet entrapment of aerosol influxes. At least threefold enhancement of the lead-trace pre-concentration is achieved. The sampled traces are analyzed by square-wave anodic stripping voltammetry. The method was tested by a series of pilot experiments. These were performed using contaminant-controlled air intakes. Reproducible calibration plots were obtained. The data were validated by traditional analysis using filter sampling. LODs are comparable with the conventional techniques. The method was successfully applied to on-line and in situ environmental monitoring of lead.

• Non-aqueous-phase-liquid breakthrough during evaporative drying of clay barriers

  Authors: Dorit Matmon, Vladimir V Gridin, Jacob Bear, Sam Frydman, Israel Schechter

  Journal of Contaminant Hydrology.

  In this study, an attempt has been made to model a real field scenario, whereby an initially almost saturated clay liner in a waste site is gradually drying, due to evaporation at its lower boundary.In this study, an attempt has been made to model a real field scenario, whereby an initially almost saturated clay liner in a waste site is gradually drying, due to evaporation at its lower boundary. A detailed conceptual model that deals with the penetration and breakthrough of non-aqueous-phase-liquid (NAPL) in clay liners is introduced. Water content of clay samples was monitored during ambient evaporation through apertures at the base of sample holders. Clay drying rate served as the primary parameter for the NAPL breakthrough study. The interconnection between drying rates, structural damage formation (cracks and suction) and NAPL penetration is especially addressed. The processes taking place in the clay samples during drying appear to be associated with the capillary effects between the different fluid phases in the vicinity of either the NAPL–clay or the clay–air boundaries. A conceptual model of NAPL penetration and breakthrough of the clay layer has been considered, based on both indirect and direct observations of structural damages produced on either clay boundaries. A mutual interaction between these two boundaries is suggested and discussed. NAPL breakthrough is suggested to take place through cracks initiated on the upper soil surface.

• Venturi-scrubber pre-concentration technique for electrochemical detection of airborne lead traces

  Authors: Inessa Belostotsky, Vladimir V. Gridin, Israel Schechter, Chaim N. Yarnitzky

  Analytica Chimica Acta.

  A method for ambient tracing of airborne lead-containing pollutants is reported. It is based on coupling a Venturi-scrubber aerosol sampling with square-wave anodic stripping voltammetry. The methodA method for ambient tracing of airborne lead-containing pollutants is reported. It is based on coupling a Venturi-scrubber aerosol sampling with square-wave anodic stripping voltammetry. The method was tested by a series of pilot experiments. These were performed using contamination-controlled air intakes. A linear concentration process was achieved by the Venturi-scrubber. These data were cross-referenced by means of standard analysis of the lead-containing aerosols entrapped on filter sampler. Successful modeling of experimental results was achieved. Several aspects, relevant to on-line monitoring of such lead-contaminated aerosols, have been addressed. The sampling efficiency increases with the average aerosol size and is reduced by persisting non-soluble airborne particulates. The reported pre-concentration processes are consistent with a well-known inertial impact mechanism. In regards of capturing liquid aerosols, this approach appears to be more effective than that with filters.

• Polymer film sensor for sampling and remote analysis of polycyclic aromatic hydrocarbons in clear and turbid aqueous environments

  Authors: Chanan Sluszny, Vladimir V. Gridin, Valery Bulatov, Israel Schechter

  Analytica Chimica Acta.

  A sensor for remote analysis of polycyclic aromatic hydrocarbons (PAHs) has been developed. It is based on direct solid phase extraction of the pollutants on a polymeric film, followed by monitoringA sensor for remote analysis of polycyclic aromatic hydrocarbons (PAHs) has been developed. It is based on direct solid phase extraction of the pollutants on a polymeric film, followed by monitoring the laser induced fluorescence, emitted from the film, via optical fibers. The proposed sensor has been applied to direct PAH analysis in clear and turbid aqueous environments. Linear calibration plots have been obtained for PAH solutions containing both humic substances and clay suspensions. Detection limits in the range of 10 ppt have been achieved. Results are obtained almost instantaneously (in drinking water) or within minutes, in more complicated matrices. This set-up has provided considerable improvement of the detection limits, when compared to the traditional fiber-optic fluorescence probe. In case of pyrene, a 100-fold and a 250-fold improvement in the detection limits have been obtained for the clay and humic substances-containing water, respectively. The spectral response of the polymeric film has been studied under various conditions and the feasibility of the method for analysis of PAH mixtures has been addressed.

• Application of pulsed laser methods to in situ probing of highway originated pollutants

  Authors: Valery Bulatov, Vladimir V. Gridin, Felix Polyak, Israel Schechter

  Analytica Chimica Acta.

  A possibility of a portable field kit for studying traffic originated pollutants based on laser induced fluorescence (LIF) or multi-photon ionization fast-conductivity (MPI-FC) has been addressed.A possibility of a portable field kit for studying traffic originated pollutants based on laser induced fluorescence (LIF) or multi-photon ionization fast-conductivity (MPI-FC) has been addressed. The resulting instrumentation has been successfully tested on soil samples that were collected and classified according to their radial distance, R, from a busy highway. The sampling was done in the near-field range with R varying from 3 to 50 m. Organic material from the samples was transferred into hexane solutions by short-time shaking with pure hexane. These solutions were investigated by simple LIF and MPI-FC instruments, which can be engineered as portable units (e.g., a PC plugged-in spectrometer has been used, in which case both the signal excitation and detection were accessed by means of optical fibers). Detected traces showed a nearly fall-off of the LIF and MPI-FC experimental data as a function of the sample distance from the road. It is estimated that at 50 m from the road the contamination concentrations (about 90% aliphatics and 10% aromatics) are as high as 0.1 μg g−1. Both proposed methods provide good sensitivity at the relevant concentration range and may be applied for fast screening of traffic contamination of soils.