Papers by Keyword: HCN

Abstract: Chlorine-based or per-oxygen-based decontaminants could be used for destruction of cyanide ion in the emergency management of leakage. During destruction, poisonous gases like ClCN and HCN were often produced. It may lead to serious damage for personal safety and quality of environment. In this study, the amount of gaseous products of ClCN and HCN during destruction of KCN by hypochlorite solutions and peroxyl acid were first measured. And quantitative risks assessments correspond to different damage criterions were established. Results showed that toxic HCN gas would form once KCN aqueous exposed to atmosphere. And different decontaminants would result in different hazardous gasses. Chlorine-based decontaminants reacted with KCN would cause toxic gas of ClCN, and it lead to relatively larger depth of damage. It would cause medial lethal depth of damage under certain conditions, such as higher concentration of decontaminant, lower flow speed, higher temperature and large volume of KCN being destructed. For per-oxygen-based decontaminants, toxic HCN gas produced would cause relatively smaller depth of damage.

Abstract: High activity catalyst for HCN removal were prepared by immobilizing Cu2+on γ-Al2O3. The catalyst showed great activity from 150°C to 250°C. The removal efficiency of HCN were above 98%. Based on the experimental phenomena, it can be assumed that the rate controlling step of the catalytic reaction process was the generation of HNCO by HCN and O2. A prediction model consist of HCN conversion, HCN flow rate, catalyst dosage was derived by combining the Langmuir adsorption isotherm. The experimental data fitted with the prediction model very well and the model may be a worthy reference for the catalytic oxidation process of HCN.

Abstract: For utilization of CO contained in tail gases of coal chemical industry, adsorption purification of HCN in closed carbide furnace tail gas was investigated on an activated carbon was modified with KOH (AC1) and the other activated carbon was modified with NaOH and sulfonated cobalt phthalocyanine (AC2). The experiment results show that two kinds of modified activated carbons are proved to be effective adsorbents for HCN removal, but the HCN adsorption capacity for AC2 is 1.47 times that for AC1. For AC2 adsorbent, the purification efficiency increased with the increase of oxygen content and adsorption temperature. The results show that, 1.5% for optimum oxygen content and 90°C for optimum adsorption temperature. The specific surface and the pore structure properties of AC2 adsorbent before and after HCN adsorption were tested by N2 adsorption experiments. The N2 adsorption tests show that, the predominant adsorption of HCN occurs in the micropores in radius 7.4～16.6 Å. Deactivated AC2 adsorbent could be restored to the original activated state, even after several regenerations.

Abstract: Cyanogenic Chromobacterium violaceum, Pseudomonas fluorescens, and P. plecoglossicida were able to mobilize silver, gold and platinum when grown in the presence of various metal-containing solids such as powdered platinum, platinum-containing automobile catalytic converters, powdered silver, or gold-containing electronic scrap. Five percent of silver was mobilized from powdered jewelry scrap as dicyanoargentate after one day, although 96% was mobilized when non-biological cyanide leaching was applied. Dicyanoargentate proved to inhibit growth at concentrations >20 mg/L. Gold was microbially solubilized from electronic scrap (shredded printed circuit boards). Maximum dicyanoaurate concentration corresponded to a 68.5% dissolution of the total gold added. Additionally, cyanide-complexed copper was detected during treatment of electronic scrap due to its high copper content of approximately 100 g/kg scrap. Small amounts of platinum were mobilized from pure platinum powder after 10 days. The process proved to be very slow. In summary, all findings demonstrate the potential of microbial mobilization of metals as cyanide complex from solid materials and represent a novel type of microbial metal mobilization which might find industrial application.