MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
J Hazard Mater. 2013 Jan 15;244-245:217-24. doi: 10.1016/j.jhazmat.2012.11.046. Epub 2012 Nov 27.
Biochars were produced from pig manure to elucidate the influence of biochars with high ash contents on the fate of pesticides. Adsorption and catalytic hydrolysis of carbaryl and atrazine on original biochars and deashed biochars were investigated. The two pesticides were substantially adsorbed by the biochars, with organic carbon normalized sorption coefficient (K(oc)) values of 10(2.65)-10(3.66) L/kg for carbaryl and 10(1.90)-10(3.57) L/kg for atrazine at C(e) of 0.5 mg/L. Hydrophobic effect alone could not explain the sorption, and several other processes including pore-filling and π-π electron donor-acceptor interactions were involved in pesticide adsorption. Adsorption increased greatly on the deashed biochar, indicating that some organic sorption sites in the original biochars were blocked or difficult to access due to their interactions with inorganic moiety. The pesticides were found to hydrolyze faster in the presence of biochars, and in the presence of biochar pyrolyzed at 700 °C, carbaryl and atrazine were decomposed by 71.8% and 27.9% in 12 h, respectively. The elevated solution pH was the main reason for the enhanced hydrolysis; however both the mineral surface and dissolved metal ions released from the biochars were confirmed to catalyze the hydrolysis.
生物炭是由猪粪制成的，用于阐明高灰分生物炭对农药命运的影响。研究了原生物炭和去灰生物炭对carbaryl 和 atrazine 的吸附和催化水解作用。这两种农药被生物炭大量吸附，carbaryl 的有机碳归一化吸附系数（Koc）值为 10(2.65)-10(3.66) L/kg，atrazine 的 Koc 值为 10(1.90)-10(3.57) L/kg，在 C(e)为 0.5 mg/L 时。仅仅疏水作用不能解释吸附过程，还涉及其他一些过程，包括孔填充和π-π电子供体-受体相互作用，这些过程参与了农药的吸附。在去灰生物炭上的吸附大大增加，表明由于与无机部分的相互作用，原生物炭中的一些有机吸附位点被阻塞或难以接近。研究发现，在生物炭存在的情况下，农药的水解速度加快，在 700°C 热解的生物炭存在下，carbaryl 和 atrazine 在 12 小时内分别分解了 71.8%和 27.9%。升高的溶液 pH 是水解增强的主要原因；然而，生物炭表面的矿物质和从生物炭中释放出的溶解金属离子都被证实可以催化水解。
