Decoloration on complex dyes and heavy metals leaching of activated carbon from sewage sludge
污泥活性炭对复合染料的脱色及其重金属浸出毒性

Activated carbons from sewage sludge were used to treat complex dyes wastewater of methenyl blue and acid magenta.The effects of pH,temperatures and adsorption times on the decoloration rates were investigated.The leaching concentrations of heavy metals were analyzed.The results show that the decoloration rates of complex wastewater from methenyl blue and acid magenta are much higher than those of methenyl blue or acid magenta only.The effect of pH on the decoloration rates is difficult to be explained.Competitive adsorption of methenyl blue and acid magenta appears on the activated carbons from sewage sludge.The adsorption of complex wastewater from methenyl blue and acid magenta follows Langmuir isotherm.The leaching concentrations of Cd,Zn and Cr increase with treatment time.The leaching concentrations all meet the standard for hazardous wastes in China.However,the leaching concentrations of Cr nearly arrive the limit of the standard.