热解温度对生物炭强化镉污染土壤治理的影响

为了探究污泥生物炭对Cd污染土壤的钝化修复效果，采用人工模拟Cd污染土壤进行盆栽实验，并探究了生物炭对Cd污染土壤pH、有机碳、Cd含量及价态、玉米株高、富集系数及生物转化系数的影响。结果表明:热解温度为800℃时制备的生物炭的修复效果优于300℃时制备的生物炭，且生物炭的最佳剂量为9.0 g/kg。施用800℃下制备的生物炭时，土壤中Cd含量也增加至7.9 mg/kg，较热解温度300℃增加约1.0 mg/kg。污泥生物炭显著降低了土壤中酸可提取态及还原态Cd的含量，升高了氧化态及残渣态Cd含量。当热解温度为800℃时，酸可提取态和还原态Cd含量分别降低至0.68，0.45 mg/kg，氧化态及残渣态Cd含量分别升高至0.76，1.72 mg/kg，从而降低了土壤中可生物利用Cd的含量。此外，生物炭能够降低Cd的生物富集系数及转化系数。

EFFECT OF PYROLYSIS TEMPERATURE ON BIOCHAR ENHANCED TREATMENT OF CADMIUM CONTAMINATED SOIL

In order to explore the effect of sludge biochar on passivation and remediation of Cd-contaminated soil, pot experiments were conducted to simulate the Cd-contaminated soil, and the effect of biochar on pH, organic carbon, Cd content and its valence state, plant height, enrichment coefficient and biotransformation coefficient of Cd-contaminated soil were investigated. The experimental results showed that the biochar prepared at 800℃ had better repair effect than that prepared at 300℃, and the optimum dosage of biochar was 9.0 g/kg. The content of Cd in soil also increased to 7.9 mg/kg at 800℃, which was about 1.0 mg/kg higher than that under 300℃ pyrolysis. Sludge biochar significantly reduced the content of acid extractable and reduced Cd in soil, but increased the content of oxidized and residual Cd. When the pyrolysis temperature was 800℃, the Cd content of acid extractable and reduced state was reduced to 0.68 mg/kg and 0.45 mg/kg, respectively, and the Cd content of oxidation state and residue state was increased to 0.76 mg/kg and 1.72 mg/kg, respectively, thus reduced the content of bioavailable Cd in soil. In addition, biochar could reduce the bioconcentration and transformation coefficients of Cd.