Abstract:

3D porous biochar (LSBC600, LSBC700, LSBC800, LSBC900) was prepared from loofah sponge with different pyrolysis conditions (600, 700, 800, 900 ℃) under nitrogen protection. The physical and chemical properties of the loofah sponge biochar (LSBC) were characterized. The adsorption characteristics of PHE by LSBC with different pyrolysis temperatures were studied through batch kinetic and isotherm adsorption experiments, and the possible adsorption mechanisms were discussed. In addition, the removal capacity of LSBC for PHE was evaluated to provide a scientific basis for the protection of aquatic ecosystems and the safety of drinking water. The results showed that pyrolysis temperature would affect the surface functional group composition of biochar, and then affect its aromaticity. LSBC presented a 3D porous structure with multi tube bundles stacked, and its surface became rough with the increase of pyrolysis temperature. The specific surface area of LSBC900 reached 467 m²∙g⁻¹. The result of adsorption kinetics showed that the adsorption of PHE by LSBC was a complex multi-stage process, with the liquid film diffusion process dominating the adsorption rate, followed by the intraparticle diffusion process. With the increase of pyrolysis temperature (600‒900 ℃), the equilibrium adsorption quantity of LSBC increased, the adsorption rate accelerated. The results of adsorption isotherm indicated that an increase in pyrolysis temperature increased the adsorption capacity of LSBC for PHE. The equilibrium adsorption quantity of LSBC900 was 16.3 mg∙g⁻¹, its initial adsorption rate was 9.60 mg∙L⁻¹∙min⁻¹, and its maximum adsorption capacity reached 26.0 mg∙g⁻¹. The adsorption of PHE on LSBC is a spontaneous process (ΔG<0). Hydrophobic interaction and π-π electron-donor-acceptor interaction were the main mechanisms of adsorption of PHE by LSBC. These findings demonstrate that LSBC is effective and feasible for the removal of organic micropollutants in water bodies.

Key words: temperature, 3D porous biochar, phenanthrene, adsorption behavior, adsorption mechanism, aqueous solution

摘要：

以生活中常见的丝瓜络为原材料，在氮气保护和不同温度（600、700、800、900 ℃）的条件下热解制备了三维多孔丝瓜络生物炭（LSBC600、LSBC700、LSBC800、LSBC900）。表征了丝瓜络生物炭的理化性质，通过动力学吸附实验和等温线吸附实验研究了不同热解温度条件下制备的丝瓜络生物炭对菲的吸附动力学特征和吸附等温线特征，探讨了可能的吸附机理，评估三维多孔生物炭对菲的去除能力，为水生态系统保护和饮用水安全提供科学依据。结果表明，热解温度会影响生物炭的表面官能团组成，进而影响其芳香性。丝瓜络生物炭呈现多管束堆叠的三维多孔结构，随着热解温度的升高，挥发性物质减少，丝瓜络生物炭的表面变得粗糙，比表面积增大，芳香结构增加；LSBC900的比表面积达到了467 m²∙g⁻¹。吸附动力学结果说明，丝瓜络生物炭对菲的吸附是复杂和多阶段的，主导吸附速率的是液膜扩散过程，其次是颗粒内扩散过程。在600-900 ℃范围内，随着热解温度的升高，丝瓜络生物炭对菲的平衡吸附量升高，吸附速率加快。吸附等温线结果说明，热解温度升高可以提高丝瓜络生物炭对菲的吸附容量。根据Langmuir等温线模型，在吸附动力学实验（ρ₀=5.00 mg∙L⁻¹）中，LSBC900的平衡吸附量为16.3 mg∙g⁻¹，初始吸附速率为9.60 mg∙L⁻¹∙min⁻¹，最大吸附量达到了26.0 mg∙g⁻¹，超过了大部分已报道的材料。菲在丝瓜络生物炭上的吸附是一个自发的过程（ΔG<0），疏水相互作用和π-π电子供体受体相互作用可能是菲在丝瓜络生物炭上吸附的主要机制。这些发现证明三维多孔丝瓜络生物炭是有效和可行的，可用于水体中有机微污染物的去除。

关键词: 温度, 三维多孔生物炭, 菲, 吸附, 吸附机理, 水体