废轮胎回转窑中试热解炭的重金属离子吸附特性

对废轮胎回转窑中试热解炭的重金属离子Pb2＋、Cr3＋和Cr6＋吸附特性进行了研究，分析了溶液pH值、接触时间、吸附剂用量以及溶液初始浓度对重金属去除率的影响。结果表明，溶液pH值对热解炭的重金属去除率有显著影响，阳离子Pb2＋、Cr3＋的去除率随pH的增加而增大，在弱酸和中性环境中去除率接近100％；Cr6＋在强酸性溶液中被还原成为Cr3＋，经二次吸附，总Cr去除率可达99％以上；Pb2＋和Cr3＋的去除率随热解炭用量和吸附时间的增大而增加，热解炭用量和吸附时间有一个最佳值。Pb2＋和Cr3＋的吸附为单分子层吸附，可用Langnuir和两段Freundlich等温吸附式描述，Freundlich拟合指数表明，热解炭具有较好的吸附性能。经酸洗后的热解炭对Pb2＋的去除率变低。

Characteristic of heavy metal ions adsorption by carbon blacks from pyrolysis of used tires in pilot-scale rotary kiln

The Characteristic of heavy metal ions(Pb~(2 ),Cr~(3 )and Cr~(6 ))adsorption by carbon blacks from pyrolysis of used tires in pilot-scale rotary kiln was studied.The effect of initial solution pH,adsorption time and dosage of PCB(pyrolytic carbon black) on the heavy metal removal was examined.It is found that the initial solution pH has a great effect on the heavy metal removal efficiency.The removal of cations such as Pb~(2 ),Cr~(3 ) increases with the increase of solution pH and reaches about 100% in weak acidic and neutral solutions.Cr~(6 ) can be reduced to Cr~(3 ) in strong acidic solutions.After the second adsorption,the removal of total Cr reaches above 99%.The removal of Pb~(2 )and Cr~(3 ) increases with the increase of adsorption time and PCB dosage which have an optimum value.The adsorption of Pb~(2 )and Cr~(3 ) is monolayer adsorption which can be described by Langnuir and two-stage Freundlich equations,and the fitting exponential of Freundlich indicates that PCB has a favorable adsorption effect for Pb~(2 )and Cr~(3 ).After acid wash,the adsorption effect of PCB for Pb~(2 ) will be reduced.