Study On Mechanism And Process Of The Phosphine Released

Phosphine is the common trace gases in the nature, the current research to phosphine ismainly concentrated in the environment of atmospheric and sediments. its form in theatmospheric is free, while in the sediment is bound. The research to phosphine has veryimportant significance. It is an important supplement to phosphorus biogeochemical cycleson Earth, is a new conversion pathway of phosphorus in the eutrophication of water bodies,and provide new method for anaerobic phosphorus removal from wastewater. In anaerobicconditions，the influence of different environmental factors is researched on the generationof phosphine. Mud source was inoculated from the sludge which have a acclimation byanaerobic reactor （ASBR）. Both gas chromatograph with NPD and cryo-trappingenrichment machine was carried out to analysis production and process of phosphine, Andthe effect of all were studied on the anaerobic generation of phosphine which werePhosphine precursors and energy substances, as well as redox potential, trace elements, pHand temperature. The main results are as follows:Five kinds of precursors of phosphine are studied. The yield of phosphine is the highestfor82.19μg/m~3when the dipotassium hydrogen phosphate which have a concentration of50mg/L is used,.In contrast, the sodium hexametaphosphate is the lowest for28.63μg/m~3.The result show the generation of phosphine is promoted by the dipotassium hydrogenphosphate as a phosphorus source. It has a negative correlation between TP and PH3. In thecourse of the study of the different initial concentrations of phosphorus source, when theinitial phosphorus concentration is less than about50mg/L.With the increase in phosphorusconcentration, the production phosphine is also increasing.When the initial phosphorusconcentration continued to increase,the yield of the phosphine will decrease instead.When the glucose as carbon source, the production of phosphine is lowest compared tothe other four carbon sources. If the methanol as a carbon source, the highest yield of thephosphine to achieve133.64μg/m~3, methanol is the best carbon source. In the process ofstudying different initial COD/TP, we found that the the highest yield of phosphine at the COD/TP ratio of16:1, regardless of the fixed carbon source or fixed phosphorus source. Sothe best COD/TP ratio is16:1, the optimal concentration of carbon source and phosphorussource concentrations were800mg/L and50mg/L.There is more significant impact on the production of phosphine after adding sodiumsulfide. The content of phosphine has increased gradually with increasing dosage. When thedosage of sodium sulfide is arrived at the concentration of10mg/L, the production ofphosphine is reached the highest for151.88μg/m~3. And then, with the increase in theconcentration of sulfide dosing,the production of phosphine began to decline. The excesssodium sulfide inhibited microbial restoring phosphate restore phosphate.The production of phosphine is promoted by adding Mo element. After dosing traceelements Co, Ni and Fe, the yield of phosphine is almost the same as the blank samples.There is little effect on production of phosphine. The orthogonal method to determine theoptimal dosing concentration is taken, In the three levels and four factors which were taken,the best of the four elements (Mo, Co, Ni and Fe) concentrations were100μg/L,20μg/L,100μg/L and20μg/L.The influence of different pH is studied on production of phosphine. The phosphinehave the highest yield for138.66μg/m~3at the pH of7, while at the pH of5and9, the lowestyield of phosphine. The largest output of phosphine is arrived at the reactor temperaturecondition of35°, it is141.51μg/m~3.The yield of phosphine in the conditions of25°islower than at the temperature condition35°conditions. While the other three temperatures5°,15°and45°which the production of phosphine is very low at the conditions. Theoptimum temperature range from25°to35°.