Lindum AS, 3036 Drammen, Norway; Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), 1433 Ås, Norway.
Lindum AS, 3036 Drammen, Norway.
Sci Total Environ. 2024 Dec 10;955:177191. doi: 10.1016/j.scitotenv.2024.177191. Epub 2024 Nov 1.
To better characterize properties governing the sorption of per- and polyfluoroalkyl substances (PFAS) to biochar, twenty-three diverse biochars were characterized and evaluated as sorbents for perfluorooctanoic acid (PFOA). Biochars were produced at various temperatures, using two different technologies, and made from sewage sludge, food waste reject, wood wastes, and one reference substrate (wood pellets). The biochars were characterized in terms of surface area, pore volume and pore size distributions, elemental composition, leachable elements, ash content, pH, zeta potential, condensed aromatic carbon (ConAC) content (determined by benzenepolycarboxylic acid (BPCA) markers), and their -OH functional group content (infrared spectroscopy). PFOA sorption isotherms were determined using Polanyi-Dubinin-Manes (PDM) and Freundlich models. The sludge-based biochars [Freundlich coefficients (log K) between 2.56 ± 0.11 and 6.72 ± 0.22 (μg/kg)/(μg/L); fitted free energy of adsorption (E) and pore volume (V) from the PDM model between 13.27 and 17.26 kJ/mol, and 0.50 and 523.51 cm/kg] outperformed wood biochars [log K between 1.02 and 4.56 ± 0.22 (μg/kg)/(μg/L); E between 9.87 and 17.44 kJ/mol; V between 0.21 and 7.16 cm/kg] as PFOA sorbents. Multivariate statistical analysis revealed that the sorption capacity was mainly controlled by pore volume within the pore diameter region that could accommodate the molecular size of PFOA (3-6 nm). Hydrophobic interactions between PFOA and aromatic carbon rich regions controlled sorption affinity, especially in the wood biochars.
为了更好地描述控制全氟和多氟烷基物质（PFAS）吸附到生物炭上的特性，本研究对 23 种不同的生物炭进行了表征，并将其作为全氟辛酸（PFOA）的吸附剂进行了评估。生物炭是在不同温度下，使用两种不同的技术，由污水污泥、食品废物、木材废物和一种参考基质（木屑）制成的。生物炭的特性包括表面积、孔体积和孔径分布、元素组成、可浸出元素、灰分含量、pH 值、动电电位、凝聚芳香碳（ConAC）含量（通过苯多羧酸（BPCA）标记物确定）和 -OH 官能团含量（红外光谱）。使用 Polanyi-Dubinin-Manes（PDM）和 Freundlich 模型确定了 PFOA 吸附等温线。基于污泥的生物炭 [Freundlich 系数（log K）在 2.56±0.11 和 6.72±0.22（μg/kg）/（μg/L）之间；PDM 模型拟合的自由能吸附（E）和孔体积（V）在 13.27 和 17.26 kJ/mol 之间，0.50 和 523.51 cm/kg] 优于木质生物炭 [log K 在 1.02 和 4.56±0.22（μg/kg）/（μg/L）之间；E 在 9.87 和 17.44 kJ/mol 之间；V 在 0.21 和 7.16 cm/kg]，是 PFOA 的良好吸附剂。多元统计分析表明，吸附容量主要受孔径范围内孔体积的控制，该孔径范围可容纳 PFOA（3-6nm）的分子尺寸。PFOA 和富含芳香碳的区域之间的疏水相互作用控制着吸附亲和力，特别是在木质生物炭中。
