煤矸石淋溶液重金属释放规律与生物毒性研究

Study on release law and biological toxicity of heavy metals in coal gangue leaching solution

为了解煤矸石堆放过程中的污染物释放规律及环境危害,以贵州某酸性煤矸石堆为研究对象,采用静态淋溶与动态淋溶对不同固液比、不同粒径条件下的煤矸石中重金属的释放规律进行了研究,同时通过明亮发光杆菌T3(Photobacterium phosphoreum T3)法测定了不同粒径煤矸石动态淋溶液的发光度,以此分析其生物毒性。结果表明:①静态淋溶时,固液比越大,静态淋溶液的pH值越小,SO_(4)^(2-)及Fe、Mn元素的含量越大,而重金属的溶出量并未随固液比增加表现出明显的变化;在相同的淋溶条件下,中粒径溶出的重金属浓度相对较大;②动态淋溶时,随着淋溶时间的增加,淋溶液的pH值逐渐增加,SO_(4)^(2-)及重金属的溶出浓度逐渐减小。不同粒径的煤矸石累计释放的重金属总量不同,对不同粒径的煤矸石累计重金属释放量与时间的关系进行2次拟合,发现重金属的释放速率不受煤矸石粒径的影响,淋溶初期时的重金属释放速率最快,随后逐渐减缓直至趋于稳定;③未稀释时的淋溶液相对发光度均为0,表现为剧毒状态。稀释100倍后,不同粒径的相对发光强度在56%~65%范围内,中粒径煤矸石的淋溶液的生物毒性最大。对不同重金属浓度与发光度进行线性拟合结果表示,所研究的6种重金属均对发光菌有抑制性,其中Zn、Pb、Mn起主要抑制作用。

In order to get a comprehensive understanding of coal gangue in the pile in the process of coal gangue release law and environmental hazards,an acidic coal gangue stack in Guizhou was taken as the research object,using static leaching,dynamic leaching with different solid-liquid ratio and different particle size under the condition of coal gangue releasing regularity of heavy metals in the leaching solution was studied,at the same time,and the luminosity of dynamic leaching solution of coal gangue with different particle sizes was measured by Photobacterium phosphoreum T3 method to analyze its biological toxicity.The results show that:①During static leaching:the larger the solid-liquid ratio,the smaller the pH value of the static leaching solution,and the larger the contents of sulfate,Fe and Mn elements,while the dissolution amount of heavy metals does not change significantly with the increase of the solid-liquid ratio.For coal gangue with different particle sizes,under the same leaching conditions,the concentration of heavy metals dissolved in the medium particle size is relatively large;②During dynamic leaching,with the increase of leaching time,the pH value of the leaching solution gradually increases,and the leaching concentration of sulfate and heavy metals gradually decreases.The cumulative amount of heavy metals released by gangue with different particle sizes is different.The relationship between the cumulative heavy metal release amount and time of coal gangue with different particle sizes was fitted twice,and it was found that the release rate of heavy metals is not affected by particle sizes.The release rate of heavy metals is the fastest at the initial leaching stage,and then slows down gradually until it becomes stable;③The relative luminosity of undiluted eluviate solution is 0,showing a highly toxic state.After being diluted 100 times,the relative luminescence intensities of different particle sizes are in the range of 56%-65%.The lowest luminescence rate of coal gangue with medium particle size is 56,so its biological toxicity is the highest.The linear fitting results of different heavy metal concentrations and luminescence showed that the six heavy metals studied all had inhibitory effects on luminescence bacteria,among which Zn,Pb and Mn played the main inhibitory role.