| 层状双氢氧化物负载生物炭对磷的吸附机制及DFT |
| 摘要点击 100 全文点击 5 投稿时间：2024-06-30 修订日期：2024-09-06 |
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| 中文关键词 层状双氢氧化物（LDHs） 生物炭 吸附 密度泛函理论（DFT） 磷 |
| 英文关键词 layered double hydroxides（LDHs） biochar adsorption density functional theory （DFT） phosphate |
| DOI 10.13227/j.hjkx.20250730 |
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| 中文摘要 |
| 利用层状双氢氧化物（LDHs）负载马铃薯秸秆生物炭（SBC），制备了层状双氢氧化物负载马铃薯秸秆生物炭的复合材料（LDHs@SBC），研究了其对磷的吸附性能，并利用密度泛函理论（DFT）从分子层面分析了吸附机制. 结果表明，LDHs@SBC对磷的吸附动力学过程可被准二级动力学模型（R2=0.983）很好地拟合，主要吸附过程为化学吸附. 热力学分析表明，LDHs@SBC对磷的吸附过程为自发的放热反应. 通过DFT计算显示，LDHs@SBC吸附磷的吸附能为-5.34 eV，进一步验证了其吸附过程为化学吸附以及自发的放热过程. 吸附机制主要包括P-p/s、O-p和M-p/s轨道的杂化形成配位键P—O—M，产生较强的电子转移和轨道贡献. 溶液pH值影响磷酸盐的赋存形态及LDHs@SBC的电荷分布，通过形成普通氢键（OHB）和电荷辅助氢键（CAHB）使LDHs@SBC对磷的吸附量达到最大. LDHs@SBC吸附磷的主要机制包括静电吸引、沉淀作用、配体交换以及电荷辅助氢键等. LDHs@SBC对磷具有较强的吸附性能且重复利用性好，是一种在含磷废水处理领域具有应用前景的高效、可再生的吸附材料. |
| 英文摘要 |
| This study utilized layered double hydroxides （LDHs） loaded with potato straw biochar （SBC） to prepare a composite material （LDHs@SBC）. The adsorption performance of LDHs@SBC for phosphate was investigated， and the adsorption mechanism was analyzed at the molecular level using density functional theory （DFT）. The results showed that the adsorption kinetics of phosphate by LDHs@SBC could be well-fitted by a pseudo-second-order kinetic model （R2=0.983）， with the main adsorption process being chemical adsorption. Thermodynamic analysis indicated that the adsorption process of phosphate by LDHs@SBC was a spontaneous exothermic reaction. DFT calculations revealed that the adsorption energy of phosphate by LDHs@SBC was -5.34 eV， confirming that the adsorption process was chemical adsorption and a spontaneous exothermic reaction. The adsorption of phosphate by LDHs@SBC was due to the hybridization of P-p/s， O-p， and M-p/s orbitals forming a coordination bond P—O—M， along with significant electron transfer and orbital contribution. The pH of the solution affected the speciation of phosphate and the charge distribution of LDHs@SBC. The adsorption of phosphate by LDHs@SBC reached its maximum through the formation of ordinary hydrogen bonds （OHB） and charge-assisted hydrogen bonds （CAHB）. The main mechanisms for phosphate adsorption by LDHs@SBC included electrostatic attraction， precipitation， ligand exchange， and charge-assisted hydrogen bonding. LDHs@SBC exhibited strong adsorption performance for phosphate and good reusability， making it a promising， efficient， and renewable adsorbent material for the treatment of phosphorus-containing wastewater. |
