Mohammad Samimifar
Abstract
A simple spectrophotometric method is developed for the determination of traces of cyanide ion in water samples. Toxic cyanide was reacted with sulfur (S8) dissolved in acetone and converted to non-toxic thiocyanate which is more stable than cyanide also. This product was reacted to Fe (III) to form ...
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A simple spectrophotometric method is developed for the determination of traces of cyanide ion in water samples. Toxic cyanide was reacted with sulfur (S8) dissolved in acetone and converted to non-toxic thiocyanate which is more stable than cyanide also. This product was reacted to Fe (III) to form red ferric-thiocyanate complex. The complex absorption rate in the first two minutes of its formation is related to the cyanide concentration. By measuring the complex absorbance at 465 nm, the cyanide in the range of 2.0-16.0 μg/mL was determined with a detection limit of 1.7 μg/mL. Relative standard deviation (n = 6) for concentrations of 4.0 and 12.0 μg/mL of cyanide was obtained 4.2 % and 1.5 %, respectively. To avoid interferences from other cations and anions, it is possible to isolate cyanide with a system converting CN- to HCN. This method was successfully applied to determine cyanide in various water samples.
Yonus Yosofi; Ali Almasi; Seyyed Alireza Mousavi
Abstract
Oil refinery wastewater as the most polluting industrial wastewater contain various hydrocarbons and sulfur with its derivatives and can cause problems in biological systems by the production of sulfuric acid. Variations of amount of sulfur depending on bioreactor condition such as temperature, pH, microbial ...
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Oil refinery wastewater as the most polluting industrial wastewater contain various hydrocarbons and sulfur with its derivatives and can cause problems in biological systems by the production of sulfuric acid. Variations of amount of sulfur depending on bioreactor condition such as temperature, pH, microbial activity and other factors. This study focused on determining variations of sulfur in anaerobic ponds for treatment of oil refinery wastewater. Samples were taken every 6 days during eight consecutive months and the type of sampling was 24-hour composite. This means that each sample is composed of 12 samples in 24 hours. 40 samples were taken from inlet and outlet of anaerobic stabilization pond for measuring sulfate, sulfide and sulfur, so a total of 240 samples were analyzed in this study. The results of the study showed that removal efficiency of COD and BOD were obtained 43 % and 24 %, respectively. Variations of sulfide and sulfur were obtained 4 % and 44 %, which increase respectively, but for sulfate have shown 15.8 % reduction. It can be said that sulfate-reducing bacteria have had significant activity to produce sulfide and sulfur form and decrease of the amount of sulfate in bioreactor.
