LUO Youfa1,WU Yonggui1,2,FU Tianling1,2, WU Dongmo1 ,MENG Qingjun1,ZHOU Jiajia1
(1. College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China;
2.College of Resources and Environmental Engineering Institute of applied ecology, Guizhou University, Guiyang 550025, China)
Abstract: Effect of different organic acids on contaminant release from weathered coal gangue was studied by adding different kinds of organic acids (humic acid, citric acid, oxalic acid, and salicylic acid). Pollution contents of leaching solution and TCLP extractable heavy metal contents of the medium were tested after stabilition for 7 d. Results show that the weathered coal gangue leaching liquid has typical characteristics of acid mine drainage. Addition of a small amount of citric acid, oxalic acid and salicylic acid can significantly (p<0.05) reduce the leaching solution of pH and Eh value and increase significantly (p<0.05) the salinity of the leaching solution, ferrous and total iron content. However, humic acid treatment can reduce the content of sulfate in leaching solution. The addition of a small amount of organic acids can promote the dissolution of Fe, Mn, Cu, and Zn in different degrees from weathered coal gangue, and salicylic acid treatment can promote four kinds of metal dissolution at the highest degree. However, four kinds of organic acid can effectively restrain Pb dissolution, and the inhibiting effect of citric acid and salicylic acid treatment is the most obvious. Four kinds of exogenous organic acid treatment can significantly increase the effectiveness of Mn and reduce the effectiveness of Zn, but the effect of organic acids on Fe is not obvious. Different kinds of organic acids have different effects on the effectiveness of Cu. Humic acid and oxalic acid treatment can obviously reduce Cu validity, however, citric acid and salicylic acid have the opposite effect.
Keywords: Acid; weathered gangue; pollution release; effectiveness
EARTH AND ENVIRONMENT Vol. 43, No.6 Tot No.308, 2015, Page 680-686
