Michel Martin-Bouyer

Reductive degradation of carbaryl in water by Zero-valent iron

Reduction of carbaryl solution by zero-valent iron powder (ZVIP) was studied in a rotator batch system (70 rpm) in order to evaluate the utility of this reaction in remediation of carbamate contaminated water. Degradation with different amount of ZVIP: 0.01, 0.02, 0.03, 0.04 g/ml at pH 6.6 and at ambient temperature was investigated. The results show that the process exhibits a degradation rate appearing to be directly proportional to the surface contact area of ZVIP (325-mesh) with the carbaryl molecules. Three analytical techniques were used to monitor carbaryl degradation: (1) A UV-Vis diode array spectrophotometer was used to record all spectra. (2) A high performance liquid chromatography was used to separate by-products and examine the evolution of breakdown products. (3) A home-built spectrophosphorimeter that uses the solid surface room temperature phosphorescence (SSRTP) was employed to observe selectively the decline of the carbaryl concentration at different amount of ZVIP on Whatman no. 1 filter paper. Results show that the reducing degradation of carbaryl with ZVIP as the source of electrons is effective with a half-life close to several minutes.

Rapid treatment of water contamined with atrazine and parathion with zero-valent iron

The utility of fine-grained iron metal in the remediation of water contamined with Atrazine and Parathion was investigated. Batch procedures under water treatment conditions (ambient temperature and pH of approximately 7) indicated that these pesticides degrade rapidly in the presence of iron powder (40-60 mesh, 40 g/l). The decline in the concentration of pesticide was monitored by HPLC. Experiments with unbuffered solutions showed a steady increase in pH values during the reactions. Therefore, experiments were run in buffered solutions. Different buffered solutions resulted in different degradation rates indicating that the buffer plays an important role in enhancing the degradation process. Tests were also performed on an industrial effluent solution containing a variety of pesticides. Although the products of degradation were not characterized, our HPLC results indicated the disappearance of all the parent pollutants.

Water quality monitoring using a smart sensing system

This paper presents an innovative smart sensor used for water quality monitoring. This smart sensing system utilizes spectroscopic techniques combined with the measurement of physico-chemical variables, to estimate global pollution parameters in water samples, particularly the Chemical Oxygen Demand (COD). This estimation is computed using a multisensor fusion approach, by means of an artificial neural network algorithm. The smart sensor has been tested successfully over a set of 71 wastewater samples of the city Pierre Benite (France) and it was shown that the estimated values of COD were in good agreement with the observed COD values, which were measured with a conventional method.

Evaluation of chromatographic and spectroscopic methods for the analysis of petroleum-derived compounds in the environment

SummaryAnalytical protocols have been adapted for the study of hydrocarbons at the trace level in the environment. Various samples, including sediments and biota, were collected from the Kuwaiti environment, treated according to the protocol and analyzed by chromatographic and spectroscopic methods. The methods used were synchronous scanning fluorescence spectroscopy (SSFS); high-performance liquid chromatography (HPLC) on C18 reversed-phase and NH2 normal-phase columns with UV and fluorescence detectors; gas chromatography on fused-silica capillary columns (GC) with flame ionization detector (FID), mass spectrometer (MS) and flame photometric detector (FPD); and high-resolution molecular spectrofluorimetry in Shpolskii matrix at 10 K (HRSS). The different methods were found to give complementary information. SSFS was useful for fast evaluation and preliminary assessment of oil pollution during extended programs; it permitted sample selection for deeper analyses but, when applied to biota, needed special care in the clean-up procedure. GC/FID, was used to analyze saturated and ethylenic compounds and was useful for obtaining information on the origin of hydrocarbons but inconvenient for analyzing the aromatic fraction. GC/FPD was difficult to use with sediment samples and yielded little information on biota samples, although it did permit confirmation of high oil contamination in some examples. HPLC on a normal-phase column with UV and fluorescence detectors was useful for the fractionation of samples and for the separation of different families of aromatic compounds according to aromatic carbon number. GC/MS was used to quantify polycyclic aromatic hydrocarbons (PAHs) of less than four cycles but was not sensitive enough for PAHs of higher molecular weight. HRSS, however, was useful for the quantification of heavy PAHs and was also faster, could be automated, and gave accurate results. However, in an oil-pollution study, it must be backed up by the other techniques. In fact, no single analytical technique was found to be sufficient, and only judicious combinations of the tested techniques yielded adequate information on the origin of hydrocarbons in the environment.

Use of diffuse reflectance spectrometry in spot test reactions for quantitative determination of cations in water

Diffuse reflectance spectroscopy can be successfully used for the quantitative determination of small amounts of pollutants like metals. The remission function was found to be linearly proportional to the concentration, when we applied the Kubelka-Munk equation. The color reactions of Cu(II), Co(II), and Ni(II) with dithiooxamide, were realised on filter paper. Reaction between Fe(III) and ammonium thiocyanate was realized on filter paper and gelatine matrix. All measurements were accomplished with a laboratory-constructed reflectometer. We have obtained a calibration curve by plotting the optical density of reflectance A(R) vs log of the mol l(-1) concentration. Limits of detection at the 10(-4) M level were estimated for all the compounds. Linear dynamic range extend over one order of magnitude and shows the potential of device for the quantitative analysis of environmental pollutants.

Room temperature phosphorescence analyses of polycyclic aromatic hydrocarbons using an imaging sensing system combined with a bifurcated optical fiber and a cooled charge coupled device detector.

This paper presents a development of a solid support RT phosphorescence procedure for the determination of polycyclic aromatic hydrocarbons, based on the use of a Xenon flash lamp as the excitation source, a fiber optic sensor as a guide of light, an imaging spectrograph and a cooled two dimensional charge coupled device as the detector. Non fluorescent Whatman N degrees 1 filter paper was used as the solid substrate and, thallium nitrate and sodium iodide were used to enhance room temperature phosphorescence of pyrene, benzo (a) anthracene, naphtalene, phenanthrene, dibenzothiophene, fluorene, coronene and fluoranthene. Analytical curves of eight phosphors give linear dynamic ranges from one and a half to two decades and limits of detection of femtomolar to picomolar/spot were reported. Quantitative analyses in mixtures were also carried out using the internal standard method. Results led to a 10% better accuracy for determinations of pyrene and benzo (a) anthracene.

Application of the high-resolution low temperature spectrofluorometry to analysis of PAHs in lake sediments, marine intertidal sediments and organisms

SummaryThis study presents an application of high-resolution low temperature spectrofluorometry (Shpolskii effect) to quantitative analysis of PAHs in lake sediments, marine intertidal sediments and marine organisms. The main characteristics of the analytical computerized set-up are developed and show the selectivity, the sensitivity and the high speed of the experimental procedure, necessary for routine analysis of hydrocarbon traces. A correlation assay between PAHs distribution in sediments of an Alpine lake and that determined in vehicle exhaust emissions weighted from the accurate representation of the total number of passenger cars in France has been studied. We also present an investigation of concentration profiles and PAHs distributions in intertidal sediments and biota bivalves in the Gulf of Kuwait.

Computerized data acquisition and processing for Shpol'skii high-resolution spectrofluorimetry

Abstract The program described provides simultaneously digital control of a high-resolution spectrofluorimeter, acquisition of analog signals and data storage, and contains graphics processing to visualize spectra. Automatic evaluation software, which evaluates peak heights and calculates concentrations is included. The program runs on an IBM PC-AT2 (or compatible) equipped with interface cards; it is composed of distinct modules which are obtained through a menu. The system has been applied to the determination of 13 polynuclear aromatic hydrocarbons (PAHs); it offers high selectivity, excellent detection limits, and rapidity of data acquisition. Results obtained for 9 PAHs in a standard urban dust (SRM-1649) were satisfactory.

Analysis of Polycyclic Aromatic Hydrocarbons in Lacustral Sediments by High Resolution Shpol' skii Spectrofluorimetry at 10K

Abstract Among the numerous sensitive analytical methods developed, the high resolution Shpolskii spectrofluorimetry at 10 K is particularly suitable for quantitative determination of traces of Polycyclic Aromatic Hydrocarbons (PAH) in complex mixture, because of its high selectivity and high sensitivity. Indeed PAH incorporated into n-alkane matrix at low temperature yield high resolution fluorescence spectra of quasi lines with multiplet structure related to several insertion sites. A method for qualitative and quantitative analysis has been developed from these Shpolskii spectra. Quantitative results have been obtained from various origins, water and air. In this paper, this method is carried out for quantitative determination of PAHs in lacustral sediments (Benzo(a)Pyrene, Benzo(k)Fluoranthene, Indeno(1,2,3-cd)Pyrene, Benzo(ghi)Perylene, Benzo(b)Fluoranthene, Benzo(j)Fluoranthene, Benzo(b)Chrysenes, Benzo(e)Pyrene, Pyrene, Perylene). An extraction and purification procedure of samples must be adapted...

Cleaning of water contaminated by heavy metals using beetroot fibers as biofilter

We report for the first time the use of beetroot fibers to eliminate heavy metals from polluted water. This biomass is used to remove lead, copper and zinc ions. The kinetics and beetroot fibers fixation capacities of lead, zinc and copper according to various physico‐chemical parameters such as pH, and the concentration of metal solutions were studied. The experiments were carried out in a laboratory column with fixed bed. For kinetic studies, samples of metal solutions were taken at regular intervals and measured by atomic absorption spectrometry. pH at 6.6 shows a maximum retention of the above cited metals by beetroot fibers (98%, 92%, 90% respectively). Quantity of cations retained by this biomass in simple and mixture solution is respectively estimated to be 23.6, 14.02 and 14.64 mg/g. Results indicate the usefulness of this biomass in the remediation of water contaminated by heavy metals by a rapid, practical and efficient method.