Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs / Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, MARA / Tianjin Key Laboratory of Agro-Environment and Agro-Product Safety, Tianjin 300191, PR China.
Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs / Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, MARA / Tianjin Key Laboratory of Agro-Environment and Agro-Product Safety, Tianjin 300191, PR China.
Chemosphere. 2021 Oct;280:130639. doi: 10.1016/j.chemosphere.2021.130639. Epub 2021 Apr 23.
Phthalates (PAEs) often exist simultaneously in contaminated soil and wastewater systems, and their adsorption to biochar might impact their behavior in the environment. So far, the competitive adsorption of PAEs to biochar has not been reported. In this study, the competitive adsorption of Dibutyl phthalate (DBP) and Di(2-ethylhexyl) phthalate (DEHP) on corncob biochar (fresh and oxidized) was investigated, and experiments of kinetics, isotherms, and thermodynamics were conducted. Langmuir and Freundlich models, pseudo-first-order and second-order kinetic models were used to simulate the experimental data. In the mono PAEs component systems, the biochar showed significantly greater adsorption capacity for DEHP (11.8-16.16 mg g) than for DBP (9.86-13.2 mg g). The oxidized biochar has higher adsorption capacities than the fresh one. Moreover, a fast adsorption rate for DBP was observed, which can be attributed to the smaller size and shorter carbon chains in the DBP molecule, resulting in faster diffusion into the biochar pores. In the binary PAEs component systems, competition between DEHP and DBP in their adsorption to the biochars was observed, and DEHP (11.7-15.0 mg g) was preferred over DBP (3.4-7.9 mg g). The stronger adsorption of DEHP can be explained by stronger hydrophobic interaction with biochar. Compared to DBP, DEHP has a high octanol-water partition coefficient (logK) and low water solubility. The positive entropy (ΔS) and enthalpy(ΔH) values for the adsorption of both DEHP and DBP further indicated that hydrophobic interaction played an important role, even though H-bonds and π-π interactions could also be involved.
邻苯二甲酸酯（PAEs）通常同时存在于受污染的土壤和废水中，它们对生物炭的吸附可能会影响其在环境中的行为。到目前为止，还没有报道过 PAEs 对生物炭的竞争吸附。在这项研究中，研究了邻苯二甲酸二丁酯（DBP）和邻苯二甲酸二（2-乙基己基）酯（DEHP）在玉米芯生物炭（新鲜和氧化）上的竞争吸附，并进行了动力学、等温线和热力学实验。朗缪尔和弗雷德里希模型、拟一级和二级动力学模型被用来模拟实验数据。在单一 PAEs 组分体系中，生物炭对 DEHP（11.8-16.16 mg g）的吸附容量明显大于 DBP（9.86-13.2 mg g）。氧化生物炭的吸附容量高于新鲜生物炭。此外，观察到 DBP 的吸附速率很快，这可以归因于 DBP 分子的尺寸较小且碳链较短，导致其更快地扩散到生物炭孔中。在二元 PAEs 组分体系中，观察到 DEHP 和 DBP 在吸附到生物炭上的竞争，DEHP（11.7-15.0 mg g）优先于 DBP（3.4-7.9 mg g）。DEHP 具有较强的吸附能力，可以用其与生物炭之间较强的疏水相互作用来解释。与 DBP 相比，DEHP 的辛醇-水分配系数（logK）较高，水溶解度较低。吸附 DEHP 和 DBP 的正熵（ΔS）和焓（ΔH）值进一步表明，疏水相互作用起着重要作用，尽管氢键和π-π相互作用也可能参与其中。
