Effect of salinity and pH on biogenic methane production of low-rank coal

Abstract：Under the condition of incubation,the biogenic methane production simulation with six salinity（0,5 000,10 000,15 000,20 000,25 000 mg/L） and five pH（6,7,8,9,10） on low-rank coal,sampled from Yima Mine in Henan Province,was carried out.The results show that：CH4 can be produced by low-rank coal under different conditions,as well as CO2 and tiny other gas;the production of CH4 decrease gradually with the increase of salinity,and it decrease rapidly when the salinity is 25 000 mg/L,at the same time,the increase of salinity lead to the decrease of CH4 concentration;concerning different pH,the maximum amount of CH4 is produced when pH=8,with deviating from pH=8,CH4 production decrease significantly,and CH4 concentration has the similar law,moreover,the time of gas generation can be delayed under unsuitable pH conditions;pH has even more obvious effect on CH4 production in contrast to salinity.These results indicate that salinity and pH are two important influence factors for CH4 production,meanwhile,the study is important content for researching biogenic methane formation mechanism.