Decolorization, COD and turbidity removal of the raw vinasse effluent by a one-step electro-oxidation process on a Pb/PbO2 anode.

In this research, and for the first time, the application of anode Pb/PbO2 (prepared from combined thermal oxidation and electrochemical oxidation method) and steel cathode in a flow sample electrochemical treatment process of vinasse and in the wastewater of alcohol factories, has been investigated. The combination of electrodes of Pb/PbO2 as an anode, steel, and/or graphite as a cathode was used in the proposed electrochemical treatment setup. The efficiency of the proposed electrochemical treatment was determined by the removal percentage of chemical oxygen demand (COD), turbidity and color of vinasse samples. The response surface method (RSM) by Minitab 18 was used to determine the effect of the studied factors as well as to detect the relationship between variables. The results showed that under optimum conditions (Pb/PbO2 electrode as the anode and steel electrode as the cathode, a voltage of 30 V, pH 6.5, and reaction time of 45 min), the percentage reduction values of COD, turbidity and color were 97.7, 77.3 and 92.7%, respectively.

Optimization of dispersive liquid-liquid microextraction for the selective determination of trace amounts of palladium by flame atomic absorption spectroscopy.

A new simple and reliable method for rapid and selective extraction and determination of the trace levels of Pd(2+) ion was developed by dispersive liquid-liquid microextraction preconcentration and flame atomic absorption spectrometry detection. In the proposed approach, thioridazine HCl (TRH) was used as a Pd(2+) ion selective complexing agent. The effective parameters on the extraction recovery were studied and optimized utilizing two decent optimization methods; factorial design and central composite design (CCD). Through factorial design the best efficiency of extraction acquired using ethanol and chloroform as dispersive and extraction solvents respectively. CCD optimization resulted in 1.50 mL of dispersive solvent; 0.15 mL of extraction solvent; 0.45 mg of TRH and 250 mg of potassium chloride salt per 5 mL of sample solution. Under the optimum conditions the calibration graph was linear over the range 100-2000 microgL(-1). The average relative standard deviation was 0.7% for five repeated determinations. The limit of detection was 90 microg L(-1). The average enrichment factor and recovery reached 45.7% and 74.2% respectively. The method was successfully applied to the determination of trace amounts of palladium in the real water samples.