• 关键词：多环芳烃  白腐真菌  生物吸附  Cu²⁺  吸附  脱附

• 基金项目：国家高技术研究发展计划(863)重点项目(No.2007AA061101);国家自然科学基金(No.20737002)

• 丁洁
• 浙江大学环境科学系, 杭州 310028

• 王银善
• 浙江大学环境科学系, 杭州 310028

• 沈学优
• 浙江大学环境科学系, 杭州 310028

• 陈宝梁
• 浙江大学环境科学系, 杭州 310028

• 摘要：为准确了解生物修复过程中多环芳烃(PAHs)的生物吸附行为,采用化学方法(脱蜡、皂化)分离白腐真菌样品并制得3个组分,探讨了白腐真菌组分的结构特征.同时,用批量平衡法研究了菲和芘在白腐真菌样品上的生物吸附-脱附行为及共存重金属Cu²⁺对吸附作用的影响,探讨了PAHs生物吸附的作用机制及构-效关系.结果表明,菲和芘在白腐真菌体上的等温吸附-脱附曲线均呈线性(Freundlich,N=1),为可逆吸附过程,其生物吸附机理为PAHs在白腐真菌体上的分配作用;经脱蜡和皂化后,菲在白腐真菌体上的分配系数K_p(F₁)分别为K_p(F₂)和K_p(F₃)的4.5倍和7.5倍,芘的分配系数K_p(F₁)则分别为K_p(F₂)和K_p(F₃)的3.8倍和7.2倍,表明主要分配介质为白腐真菌体上的脂类和聚酯类物质;PAHs的有机碳标化的分配系数K_oc值与白腐真菌体的极性指数(O+N)/C呈反比.共存Cu²⁺离子促进白腐真菌体对菲的生物吸附,随着Cu²⁺浓度的增加,菲的生物吸附作用逐渐增强;增强吸附机制为Cu²⁺通过配合作用吸附到白腐真菌体上中和微生物表面的负电荷,降低白腐真菌体表面的亲水性,进而提高其疏水性分配作用;同时,吸附态Cu²⁺与菲之间形成阳离子-π键等特殊作用,其作用大小随白腐真菌体的极性指数(O+N)/C增大而降低.

• Abstract：White-rot fungi biomass and its fractions were isolated by chemical methods including de-waxing and saponification. The elemental compositions,polarity index [(O+N)/Catomic ratio] and functional groups of three white-rot fungi fractions were characterized by elemental analysis and Fourier transform infrared spectrometry. To elucidate the biosorption of organic pollutants for bioremediation,the biosorption-desorption behavior of phenanthrene and pyrene to the isolated white-rot fungi fractions were investigated using a batch equilibration technique,and the effects of co-existing Cu²⁺ on the biosorption of phenanthrene were also compared. The correlation of sorption properties with the structural characterization is discussed. The sorption-desorption isotherms of phenanthrene and pyrene to the sorbents were linear (Freundlich,N>=1) and had the characteristics of a reversible process,suggesting that the biosorption mechanism to white-rot fungi fractions is dominated by partitioning into white-rot fungi biomass. The partition coefficients (K_p) of white-rot fungi decreased significantly after de-waxing and saponification,i.e.,by 4.5-and 7.5-fold for phenanthrene,and by 3.8-and 7.2-fold for pyrene,indicating that the partition medium is attributed to the extractable lipids and polymeric lipids. Polarity apparently played a regulating role in the biosorption of phananthrene and pyrene. The carbon-normalized biosorption coefficient (K_oc) was negatively correlated with the polarity index of the white-rot fungi fractions. The biosorption of phenanthrene to white-rot fungi fractions was promoted by coexisting heavy metal ions such as Cu²⁺ at the environmental level (0～32 μg·mL^-1),and the sorption enhancement (△K_p) increased with the concentration of Cu²⁺,and decreased with the polarity index of the sorbent. Binding of Cu²⁺ neutralized the negative charge of the fungi surface,making it less hydrophilic and enhancing hydrophobic partitioning of phenanthrene. Aspecific interaction mechanism,cation-π bonding between phenenathrene and complexed Cu²⁺,contributed significantly to the total biosorption enhancement. The cation-π interaction favored a relatively hydrophobic medium.

• Key words：polycyclic aromatic hydrocarbon  white-rot fungi  biosorption  copper(II)  sorption  desorption

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