生物质炭对沉积物中有机污染物的吸附固定作用机理

不同来源生物质炭表面和理化性质差别很大，对沉积物中有机污染物的吸附固定不同.以3种不同来源生物质炭（椰壳粉末、草木灰和聊城电厂灰）为研究对象，应用被动采样技术监测治理过程中污染物浓度的变化，揭示生物质炭理化性质及其与吸附固定效果之间的关系.结果表明:①3种生物质炭粒径相差不大，但椰克粉末的BET比表面积比草木灰和聊城电厂灰高2个数量级，孔隙结构发达.②吸附固定沉积物中有机污染物的静态模拟试验结果显示，椰克粉末对3类有机物（多环芳烃、苯系物和酞酸酯）的吸附固定作用均很强，投加10个月，沉积物孔隙水中3类有机物的质量浓度降低92.7%以上，与其属于非极性吸附剂、BET比表面积大、孔隙结构发达有关；草木灰和聊城电厂灰对酞酸酯的吸附固定作用较弱，分别为62.5%和59.6%，与其表面积小、孔隙结构不发达有关.③生物质炭吸附固定沉积物中有机污染物的动力学研究结果显示，草木灰和聊城电厂灰对酞酸酯的吸附固定作用能很快达到平衡，也与其BET比表面积小、孔隙结构不发达相关.研究显示，生物质炭的理化性质（如BET比表面积、孔隙结构等）是影响有机物污染沉积物治理效果的主要因素. 

Adsorption and Immobilization of Organic Pollutants in Sediment by Biochars

The different source biochars have different surface and physicochemical properties, and their effects on the treatment of organic polluted sediment is different. In this study, 3 different source biochars (coconut shell powder activated carbon, plant ash, and biomass power plant ash) were studied to reveal the relationship between the physicochemical properties of biochars and their treatment effects on organic contaminated sediment. The three biochars had little difference in particle size, but the surface area of the activated carbon was 2 orders of magnitude higher than that of the plant ash and the power plant ash, and with well-developed pore structure. Laboratory static simulation experiment of in-situ biochar amendment for contaminated sediment showed that the activated carbon strongly adsorbed and stabilized 3 kinds of organic chemicals (polycyclic aromatic hydrocarbons, benzene series and phthalic esters) in the sediment. After 10 months of treatment, the concentrations of the 3 pollutants in sediment pore water decreased by more than 92.7%. This might be consistent with a nonpolar adsorbent, large surface area, and well-developed pore structure of activated carbon. The stabilization effects of the plant ash and the biomass power plant ash on phthalic esters were moderate and the reduction rates of pore water concentration were 62.5% and 59.6%, presumably due to their small surface area and underdeveloped pore structure. The kinetics of biochar treatment of the contaminated sediments showed that the adsorption and stabilization of the plant ash and the biomass power plant ash on PAEs could quickly reach equilibrium, also due to their small surface area and the underdevelopment of the pore structure. The results indicated that the effectiveness of the treatment was not only related to the physicochemical properties of the biochars but also related to the physicochemical properties of pollutants.