采用OECDGuideline106批平衡方法研究了由凋落松针、玉米秸秆、牛粪制备的3种生物炭对As(V)在棕壤中的吸附和解吸特性的影响.结果表明:3种生物炭的添加量为0.5%时,对As(V)在土壤中的吸附量大小顺序为牛粪炭处理〉松针炭处理〉玉米秸秆炭处理,这与生物炭的基本性质密切相关;等温吸附曲线能用Langmuir方程进行很好的拟合(R。=0.997);与对照相比,生物炭处理对砷的吸附容量(1g墨为1.99—2.10)和吸附强度(1/N为0.413~0.449)降低,生物炭对As(V)的主要吸附机制为物理吸附;生物炭处理对As(V)解吸率大小顺序为:玉米秸秆炭处理〉松针炭处理〉牛粪炭处理,解吸率在14.5%-18.7%.添加3种来源生物炭降低了棕壤对As(V)的吸附,这可能会导致砷的有效性增强,更易被生物吸收,进而增强土壤中砷的毒性.
By using OECD Guideline 106 batch equilibrium method, this paper studied the charac- teristics of As ( V ) adsorption and desorption in brown soil as affected by the biochars produced from dairy manure, pine needle, and corn straw. When the addition amount of the biochars was 0. 5 % , the maximum adsorption amount of As ( V ) was decreased in the order of dairy manure biochar 〉 pine needle biochar 〉 corn straw biochar, which was related to the basic characteristics of the biochars. The adsorption isotherm of As ( V ) could be well fitted by Langmuir model ( R2 = 0. 997). In comparing with CK, both the adsorption capacity (lgKf= 1.99-2.10) and the adsorp- tion intensity ( l/N= O. 413-0.449) of As ( V ) were low, and the main adsorption mechanism was physical adsorption. The desorption rate of As ( V ) ( 14.5% -18.7% ) was decreased in the order of dairy manure biochar 〉 pine needle biochar 〉 corn straw biochar. The addition of the biochars decreased the adsorption of As ( V ) by brown soil, which could induce the increase of the bioavail- ability of As, and strengthen the toxicity of As in soil.