Removal of cyanide from aquatic solution by using of iron and copper powder: equilibrium and kinetic study

Industrial wastewater included the cyanide is one of the important sources of environmental pollution which founded in Industrial wastewater which are harmful for human health and environment. Therefore, the purpose of this research that was fundamental designed is investigation of Removal of cyanide from aquatic solution by using of iron and copper powder in experimental scale. At first, pilot was designed. Then, acquired pH optimum equal to 2,7 for copper and iron by variation pH= [2,4,6,8,12] and constant other parameters. The effect of initial cyanide concentration [40,60,80 mg/1], initial iron and copper dosage [0.08-1 g/100CC] and contact time [15-12 min] studied at the constant of optimum pH. The result showed removal efficiency Increased from 46.6% to 90.56% and 31% to 93.78% for copper and iron by increasing of contact time from 15 to 120 minute in constant conditions, respectively. Also result showed Removal efficiency decreased and increased by increasing initial cyanide concentration and initial iron and copper dosage. The results showed equilibrium data were explained acceptably by Langmuir isotherms and kinetic parameters were obtained by application of Langmuir and Hinshelwood equation. The results showed that removal of cyanide can be quick and effective done by iron and copper in experimental scale

Effects of stimulator substances on aerobic methyl tert-butyl ether biodegradation by microbial consortium

In this study dissolved humic substances and yeast extract were tested in different concentrations for enhancing methyl tert-butyl ether mineralization by isolated microorganisms from a variety of sources. All experiments were conducted at a constant temperature of 25?C. Vials of 50 mL and 125 mL volume sealed with Teflon-lined Mini-Nert caps was used for microcosm experiments. In all experiments 1% sodium azide were used as control. Samples of bacterial cultures that metabolize methyl tert-butyl ether have been analysed by direct GC analysis using flame ionization detector. Cultures able to metabolize have been found in activated sludge and soils. These microorganisms were gram-positive bacterium. An aerobic microbial consortium was enriched in laboratory for four months. Methyl tert-butyl ether has been shown to biodegrade under aerobic and co-metabolic conditions. A microbial consortium isolated from activated sludges was identified as Cocobacillus. The concentration of the initial attached biomass was about 0.11 g/L of dry weight. The maximum mineralization rate and beneficial effects of stimulator substances on aerobic biodegradation of methyl tert-butyl ether occurred with the culture by combined concentrations of 500 mg/L of yeast extract and 20 mg/L of peat humic growth support of microbial consortium within 216 h and in presence of high oxygen levels and well mixing conditions. It was shown that adding, peat humic and yeast extract together had better stimulatory effect on methyl tert-butyl ether biodegradation. Results clearly showed a stimulatory effect on methyl tert-butyl ether consumption higher than 20%. Consortium was capable of degrading concentrations of 1000 mg/L, were not degraded

[ study on biodegradability enhancement of landfill leachate by fenton oxidation]

Leachate is one of the landfill products and also a wastewater bearing the most advers effects on the environment. Biological methods are usually employed for treatment of young leachate [1-2 years] wich is of high concentration of organic compounds with low molecular weight. However these methods are not approprate for mature leachate [5-10years] due to having high rate of compounds with molecular weight and the presence of materials resistant to biodegradation and toxic compounds. Advanced oxidation process such as Fenton reagent used in treatment or biodegrability improvement of strong wastewater. In the present study the degrability improvement of mature leachate through oxidation fenton process in bench scale and in batch reactor has been investigated. The samples have been taken from Ahwaz landfill and factors such as initial COD and BOD, pH, BOD5/COD were studies as degradability, the amount of Hydrogen Peroxide, Fe[II], optimal reaction time and optimal pH. The highest amount of COD removal was observed in PH=3-3.5 and 90 minutes of reaction time. H2O2=29700mg/land Fe2+=16500 mg/l in [Fe2+]/[H2O2]=1/14.8 molarity ratio were obtained as optimal amounts BOD5/COD was equal to 0.38. This study indicates that Fenton oxidation enhances the biodegradability of leachate

Comparative efficacy of misoprostol and oxytocin as labor preinduction agents: a prospective randomized trial

The purpose of this study was to compare the efficacy and safety of misoprostol and oxytocin for induction of labor. In this prospective and randomized controlled trial one hundred twenty women with an unfavorable cervix who underwent labor induction were assigned to receive either intravenous high dose oxytocin [6 mlu/min] or intravaginal misoprostol 50 |ug every 6 hours for two doses. Twelve hours later if labor was not established oxytocin induction was initiated per standardized protocol [3 mlu/min]. Mean Bishop Score change [ +/- SD] over the initial 12 hours interval was significantly greater in the misoprostol group [11.98 +/- 1.55] compared with the oxytocin group [8.83 +/- 2.61]. There were no statistically significant differences in the median duration of labor [449 +/- 261.1 min, 514.5 +/- 288.5 min, respectively; P = 0.22], the mode of delivery or the adverse maternal /neonatal out come among the two groups. Use of misoprostol as a labor preinduction / labor induction agent results in greater Bishop score changes compared with high dose oxytocin and both of them are comparable

Characteristics of fenton's oxidation of 2, 4, 6 trichlorophenol

2, 4, 6 trichlorophenol [TCP] is one of the most toxic chlorophenols which is very difficult to biodegradation. Advanced Oxidation Processes [AOPs] is one of the most effective processes for degradation of persistent compounds. Since the mineralization of recalcitrant compound by AOPs often requires long reaction time and strong doses of oxidant, the combination of this process with biological one, is considered as an efficient and economic method. In this work degradation of 2, 4, 6 trichlorophenol in aqueous solution with Fenton reagent [H2O2 +Ferrous ion] was studied. The experiment was done in batch mode, and the initial concentration of TCP was 0.60mM. In pH=3, H202=1.8mM, Fe=0.6mM, more than 99% of TCP was degraded in 10 minutes after the reaction was started. Chloride ion generation as TCP degradation by product was investigated, and it was found that the scavenging effect of chloride is negligible. PH and UV215 absorbance analysis, after reaction completion, indicated that generated intermediates had the less chlorinated nature, acidic properties and nonphenolic structure. Chloride ion increases from 0 mg/L to 40 mg/L, pH decreased from 3 to 2.7 and UV215 absorbance decreased from 3.2 to 0.6, therefore it can be resulted that their biodegradability modified and their recalcitrance reduced. COD analysis indicated that TCP did not mineralize and in H2O2/TCP = 3 and oxidation time of 1 h, COD reduction was only 37%.