Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China.
Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
Environ Pollut. 2020 Jun;261:114133. doi: 10.1016/j.envpol.2020.114133. Epub 2020 Feb 5.
Biochar has a wide range of feedstocks, and different feedstocks often resulted in different properties, such as element distribution and heavy metal immobilization performance. In this work, batch experiments were conducted to assess the effectiveness of biochar pyrolyzed from kitchen waste (KWB), corn straw (CSB), and peanut hulls (PHB) on immobilization of Cd and Pb in contaminated soil by planting swamp cabbage (Ipomoea aquatica Forsk.) with a combination of toxicological and physiological tests. The results showed that biochar could all enhance the soil pH, and reduce extractable Pb and Cd in soil by 22.61%-71.01% (KWB), 18.54%-64.35% (CSB), and 3.28%-60.25% (PHB), respectively. The biochar led to a drop in Cd and Pb accumulation in roots, stems, and leaves by 45.43%-97.68%, 59.13%-96.64%, and 63.90%-99.28% at the dosage of 60.00 mg/kg, respectively. The root length and fresh weight of swamp cabbage were promoted, while superoxide dismutase (SOD) and peroxidase (POD) decreased after biochar treatment. The distribution of heavy metal fractions before and after biochar treatment indicated that biochar could transform Cd and Pb into a state of lower bioavailability, thus inhibiting Cd and Pb uptake by swamp cabbage. Biochar with different feedstocks could be ranked by the following order according to immobilization performance: KWB > CSB > PHB.
生物炭的原料来源广泛，不同的原料往往导致其性质不同，如元素分布和重金属固定性能。本研究采用盆栽试验，结合毒理学和生理学测试，评估了由厨余垃圾（KWB）、玉米秸秆（CSB）和花生壳（PHB）制备的生物炭对污染土壤中 Cd 和 Pb 的固定效果。结果表明，生物炭均能提高土壤 pH 值，降低土壤可提取态 Pb 和 Cd 的含量，降幅分别为 22.61%-71.01%（KWB）、18.54%-64.35%（CSB）和 3.28%-60.25%（PHB）。在 60.00 mg/kg 投加量下，生物炭导致植物根部、茎部和叶片中 Cd 和 Pb 的积累量分别降低了 45.43%-97.68%、59.13%-96.64%和 63.90%-99.28%。生物炭处理后，菹草的根长和鲜重增加，而超氧化物歧化酶（SOD）和过氧化物酶（POD）活性降低。生物炭处理前后重金属形态分布表明，生物炭可以将 Cd 和 Pb 转化为生物利用性较低的状态，从而抑制菹草对 Cd 和 Pb 的吸收。不同原料制备的生物炭对重金属的固定效果可以按以下顺序排列：KWB＞CSB＞PHB。
