Sahara Thera, Wongsawaeng Doonyapong, Ngaosuwan Kanokwan, Kiatkittipong Worapon, Hosemann Peter, Assabumrungrat Suttichai
Research Unit on Plasma Technology for High-Performance Materials Development, Department of Nuclear Engineering, Faculty of Engineering, Chulalongkorn University, 254 Phayathai Road, Pathumwan, 10330, Bangkok, Thailand.
Division of Chemical Engineering, Faculty of Engineering, Rajamangala University of Technology Krungthep, Bangkok, 10120, Thailand.
Sci Rep. 2023 Aug 14;13(1):13210. doi: 10.1038/s41598-023-40197-3.
Adsorption is regarded as an efficient method to eliminate per- and polyfluoroalkyl substances from an aqueous solution. In the present investigation, an adsorbent based on rice husks (RHs) was successfully prepared by phosphoric acid (PA) activation and dielectric barrier discharge (DBD) plasma treatment, and it was used to adsorb perfluorooctanoic acid (PFOA) from water. The electrodes employed in the experiment were planar type. This research investigated RH surface properties and adsorption capacity before and after modification using DBD plasma. The results revealed that the He-O plasma modification introduced oxygen-containing functional groups and increased the PFOA removal efficiency. Increasing the oxygen content and total gas flow rate to 30 vol.% and 1.5 L/min, respectively, with 10 min of RH plasma treatment time at 100 W plasma discharge power enhanced the PFOA removal efficiency to 92.0%, while non-treated RH showed the removal efficiency of only 46.4%. The removal efficiency of the solution increased to 96.7% upon adjusting the pH to 4. The adsorption equilibrium isotherms fitted the Langmuir model, and the adsorption kinetic followed the pseudo-second-order model. The maximum adsorption capacity was 565 mg/g when the Langmuir isotherm model was applied.
吸附被认为是从水溶液中去除全氟和多氟烷基物质的一种有效方法。在本研究中，通过磷酸（PA）活化和介质阻挡放电（DBD）等离子体处理成功制备了一种基于稻壳（RHs）的吸附剂，并将其用于从水中吸附全氟辛酸（PFOA）。实验中使用的电极是平面型的。本研究调查了DBD等离子体改性前后RH的表面性质和吸附容量。结果表明，He-O等离子体改性引入了含氧官能团并提高了PFOA的去除效率。在100 W等离子体放电功率下，将氧气含量和总气体流速分别提高到30 vol.%和1.5 L/min，对RH进行10分钟的等离子体处理，可将PFOA的去除效率提高到92.0%，而未处理的RH的去除效率仅为46.4%。将溶液的pH值调节至4时，去除效率提高到96.7%。吸附平衡等温线符合朗缪尔模型，吸附动力学遵循准二级模型。应用朗缪尔等温线模型时，最大吸附容量为565 mg/g。
