城市污泥与花生壳制活性炭的重金属形态分析及生态风险评价

采用BCR提取法对以污泥和花生壳为原料制备的活性炭进行重金属形态分析,利用原子吸收法测定污泥热解前后Cd、Cr、Cu、Zn、Ni、Pb的不同形态含量。结果表明,污泥中Zn的含量最高,Zn和Cu的含量超过了污泥农用标准。热解可使污泥中的可溶解态和可还原态重金属转化为性质稳定的残渣态重金属,在此基础上,利用重金属潜在生态风险指数法（IR）对污泥活性炭的重金属潜在生态风险进行评价,结果得出花生壳添加量为20%,热解温度为600℃条件下,制备出来的活性炭风险最小。同时证实Cd的潜在生态风险系数较大,在利用时应引起足够的重视。

Morphological Analysis and Ecological Risk Assessment on Heavy Metals in the Activated Carbon Prepared from Sewage Sludge and Peanut Hull

The speciation analysis of heavy metals had been carried out by BCR extraction method in activated carbon which was made of sewage sludge and peanut hull.The contents of Cd,Cr,Cu,Zn,Ni and Pb with their four speciation states in sewage sludge and the products of sludge pyrolysis had been measured by AAS（Atomic Absorption Spectrometry）for the study the speciation changing of heavy metal after pyrolysis.The results showed that the total content of Zn was the higher than the other heavy metal in the sewage sludge,and the total contents of Zn and Cu were exceeded that the values in the farming standards.Moreover,the acid-soluble and the reduction state of heavy metals in the sewage sludge could be transformed into the residual states in the activated carbon after the process of pyrogenation.With the comprehensive studying of various stable state ratios of heavy metals in the carbons obtained at different conditions,the pyrolysis temperature for the activated carbon was obtained at 600 ℃.Furthermore,a potential ecological risk assessment on heavy metals in sludge activated carbon was analysed and it revealed that the lowest risk index product of sewage sludge activated carbon could be obtained at the conditions of peanut hull was added by 20% and the pyrolysis temperature was 600 ℃.However,It also showed that the potential ecological risk index of Cd in activated carbon was higher than the others,which should be paid more attention before it was used.