Use of some natural and waste materials for waste water treatment.

A fundamental study was conducted to assess removal and filtration capacity of waste and natural indigenous materials as treatment mediums e.g., shell, limestone, waste paper mixed with refuse concrete, refuse cement, also processed nitrolite, charcoal-bio and charcoal. Under room temperature condition removal of phosphoric, nitric and ammonium-ions, filtration of suspended substance (SS) together with removal of COD in waste water was investigated. Influence of particle size effect for all treatment mediums except for waste paper was pursued. Significant improvement of waste water quality with respect to SS, phosphoric ions and decrease in COD is possible by treating with these filtration mediums. With specific reference to some treatment mediums NO3-N and NH4-N showed reasonable improvement in quality, although generally removal effect was not very significant. Efficacy of treatment was dependent on the particle size of treatment mediums in general, however, nitrolite for NH4--N, charcoal-A for SS and COD, refuse cement mixed with waste paper for PO4 ion removal showed insignificant variability on the particle size effect. Results of this fundamental study demonstrate effectiveness and feasibility for applied application of these proposed waste and naturally available treatment ingredients at lower cost.

Preconcentration of trace copper with yeast for river water analysis.

A new preconcentration method with yeast is presented. The method was evaluated for the determination of trace copper in river water by graphite furnace atomic absorption spectrometry (GFAAS). A suitable cultivation bed for preconcentration of copper was 3.5 mg ml(-1) 2-ammonium hydrogen phosphate. The optimal cultivation time and temperature were 2 h and 40 degrees C. Under optimal conditions, copper in aqueous sample was concentrated about seven-fold by yeast. The detection limit was 85 pg ml(-1) (3S/N) for copper in river waters. The yeast preconcentration method was applied to the determination of copper in river waters. The recovery of spiked copper was in the range of 93-100%. By the preconcentration, it was found that ultra trace copper in river waters could be determined without interferences of matrix elements, after only the cultivation and no chemical treatment.

Determination of chromium in river waters by electrothermal atomic absorption spectrometry with preconcentration on a tantalum wire.

The preconcentration of chromium on tantalum wire followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer is described. The preconcentration is accomplished by adsorbing chromium on a tantalum wire. The optimal immersion time was 3 mm. The best pH for chromium adsorption was 3. Under optimal conditions, the detection limit was 15 pg mU1 (3 x SIN). The effects on the preconcentration of chromium by large amounts of contaminants were evaluated. Even though matrix elements existed in 10(3)-10(4)-fold excess in water, the chromium absorption signal was not affected by the matrix elements. The method with preconcentration on tantalum wire was applied to the determination of chromium in river water.

Direct determination of cadmium in calcium drug samples using electrothermal atomic absorption spectrometry with a metal tube atomizer and thiourea as a matrix modifier.

A laboratory constructed molybdenum tube atomizer was used for direct determination of trace cadmium in drug samples by the electrothermal atomic absorption spectrometric (ETAAS) method. An ultrasonic agitation method for a solution including the sample powder was used. A calibration curve was constructed with a cadmium standard solution including matrix. To eliminate interference from other matrix elements, a chemical modifier thiourea, was used. The detection limit were 17 pg ml(-1) (3 S/N), and the RSD of the direct analysis was 5-17%. The results for cadmium in the four drug samples analysed by the direct ETAAS method matched well with those obtained with nitric acid digested samples. The recovery of added cadmium was 103-106%. An accurate method is elaborated for the determination of cadmium in drug samples by direct ETAAS techniques. The merits of this method are rapid calibration, simplicity, fast analysis, and low cost.

Sequential metal vapor elution analysis for the determination of Cu and Mn in biological materials and waters.

The determination of copper and manganese in biological materials and river waters by sequential metal vapor elution analysis (SMVEA) using an atomic absorption detector (AA) is reported. An improved molybdenum column (open column, i.d. 1.22 mm) with three ring supporters was developed for SMVEA. An optimum flow rate of carrier gas (pure argon) for separation of metal vapors was 4.0 ml min(-1). Copper and manganese peaks separated from Al, Ca, Cd, Fe, K, Mg, Na, Pb, and Zn peaks at a vaporization temperature of 1950 degrees C and a column temperature of 1900 degrees C. The appearing order of these metals was Cd, Zn, Pb, Cu, Na and Mn. It was understood by considering the boiling points of these metals or chlorides. The delay of appearing time is due to an interaction between the metal vapors and inside surface of the column. Under the experimental conditions, the number of theoretical plates was 11.3 for Cd, 89.6 for Cu, 160 for Na, and 258 for Mn in the improved column. Under the optimal experimental conditions, NIST biological standards and river waters were analyzed for copper and manganese. The analytical results agreed well with the certified values and the recoveries were in the range of 94 to 109%. By SMVEA, it was found that copper and manganese in biological materials and waters were determined without interference of matrix elements, after only acid digestion for biological materials and no chemical treatment for river water samples.

Determination of rhodium in waters by Mg-W cell-electrodeposition and electrothermal atomic absorption spectrometry.

A new concentration method of rhodium using Mg-W cell-electrodeposition has been developed. The method was combined with electrothermal atomic absorption spectrometry (ETAAS) with a tungsten tube atomizer. The optimal immersing time was 120 s. The most suitable pH for rhodium electrodeposition was 1.0. Under optimal conditions, the detection limit of rhodium by the ETAAS with the preconcentration was 13 ng ml(-1) (3S/N). The severe interferences on the AAS signal of rhodium by large amounts of Ca, Cu, Fe, K, Na, Pb and Zn were eliminated by the Mg-W cell-electrodeposition method. The method was applied to the determination of rhodium in river and sea water. The recovery of rhodium spiked environmental samples was in the range of 95.6-109%. The present Mg-W cell-electrodeposition method can be utilized in in-situ sampling of trace elements in environmental samples (water). Furthermore, after sampling, it is easy to carry and store the W-sheet without contamination for a long time.