In order to improve characteristics of biochar, especially enhance immobilization of heavy metals in biochar, swine manure was pyrolyzed at low pyrolysis temperature (300 °C, 400 °C and 500 °C) with different amounts of sodium hydroxide (NaOH) added (0.5% and 2%, W/W). Results showed that NaOH addition during pyrolysis increased the pH, EC, ash content, yield rate, aromaticity and hydrophily, but did not increase surface area and porosity of resultant biochars. The addition of NaOH promoted the transformation of the mobile fraction of Cu, Zn and Cd into the oxidizable fraction. With respect to Cr and Pb, the oxidizable and residual fractions were increased slightly by the presence of NaOH. Meanwhile, adding NaOH could reduce the leachability and ecological risks of heavy metals in biochars. Our study suggested that NaOH-assisted pyrolysis of swine manure was an effective disposal approach for the immobilization of heavy metals.

为了改善生物炭的特性，特别是增强生物炭中重金属的固定性，在低热解温度（300°C，400°C和500°C）下，通过添加不同量的氢氧化钠（NaOH）将猪粪热解。 ％和2％，W / W）。结果表明，在热解过程中添加NaOH可以提高pH值，EC，灰分，产率，芳香性和疏水性，但不会增加所得生物炭的表面积和孔隙率。NaOH的添加促进了Cu，Zn和Cd的可移动部分向可氧化部分的转化。对于Cr和Pb，由于存在NaOH，可氧化部分和残留部分略有增加。同时，添加NaOH可以降低生物炭中重金属的浸出性和生态风险。