Revealing the Combined Effect of Active Sites and Intra-Particle Diffusion on Adsorption Mechanism of Methylene Blue on Activated Red-Pulp Pomelo Peel Biochar
Phosphoric acid-activated biochar has been proven to be a promising adsorbent for pollutant removal in an aqueous solution. It is urgent to understand how surface adsorption and intra-particle diffusion synergistically contribute to the adsorption kinetic process of dyes. In this work, we prepared a...
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| Format: | Article |
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MDPI AG
2023-05-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/11/4426 |
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| author | Fang Wei Shenglong Jin Chunyi Yao Tianhao Wang Shengpu Zhu Yabiao Ma Heng Qiao Linxi Shan Rencong Wang Xiaoxue Lian Xiaoqiang Tong Yan Li Qiang Zhao Weiguo Song |
| author_facet | Fang Wei Shenglong Jin Chunyi Yao Tianhao Wang Shengpu Zhu Yabiao Ma Heng Qiao Linxi Shan Rencong Wang Xiaoxue Lian Xiaoqiang Tong Yan Li Qiang Zhao Weiguo Song |
| author_sort | Fang Wei |
| collection | DOAJ |
| description | Phosphoric acid-activated biochar has been proven to be a promising adsorbent for pollutant removal in an aqueous solution. It is urgent to understand how surface adsorption and intra-particle diffusion synergistically contribute to the adsorption kinetic process of dyes. In this work, we prepared a series of PPC adsorbents (PPCs) from red-pulp pomelo peel under different pyrolysis temperatures (150–350 °C), which have a broad specific surface area range from 3.065 m<sup>2</sup>/g to 1274.577 m<sup>2</sup>/g. The active sites on the surface of PPCs have shown specific change laws of decreasing hydroxyl groups and increasing phosphate ester groups occurring as the pyrolysis temperature rises. Both reaction models (PFO and PSO models) and diffusion models (intra-particle diffusion models) have been applied to simulate the adsorption experimental data to verify the hypothesis deduced from the Elovich model. PPC-300 exhibits the highest adsorption capacity of MB (423 mg/g) under given conditions. Due to its large quantities of active sites on the external and internal surfaces (1274.577 m<sup>2</sup>/g), a fast adsorption equilibrium can be achieved within 60 min (with an initial MB concentration of 100 ppm). PPC-300 and PPC-350 also exhibit an intra-particle-diffusion-controlled adsorption kinetic process with a low initial MB concentration (100 ppm) or at the very beginning and final stage of adsorption with a high initial MB concentration (300 ppm) at 40 °C, considering that the diffusion is likely hindered by adsorbate molecules through internal pore channels at the middle stage of adsorption in these cases. |
| first_indexed | 2024-03-11T03:01:41Z |
| format | Article |
| id | doaj.art-7183372e92784087bf2329a3065faa7e |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-11T03:01:41Z |
| publishDate | 2023-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-7183372e92784087bf2329a3065faa7e2023-11-18T08:16:28ZengMDPI AGMolecules1420-30492023-05-012811442610.3390/molecules28114426Revealing the Combined Effect of Active Sites and Intra-Particle Diffusion on Adsorption Mechanism of Methylene Blue on Activated Red-Pulp Pomelo Peel BiocharFang Wei0Shenglong Jin1Chunyi Yao2Tianhao Wang3Shengpu Zhu4Yabiao Ma5Heng Qiao6Linxi Shan7Rencong Wang8Xiaoxue Lian9Xiaoqiang Tong10Yan Li11Qiang Zhao12Weiguo Song13College of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaCollege of Science, Civil Aviation University of China (CAUC), Tianjin 300300, ChinaLaboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, ChinaPhosphoric acid-activated biochar has been proven to be a promising adsorbent for pollutant removal in an aqueous solution. It is urgent to understand how surface adsorption and intra-particle diffusion synergistically contribute to the adsorption kinetic process of dyes. In this work, we prepared a series of PPC adsorbents (PPCs) from red-pulp pomelo peel under different pyrolysis temperatures (150–350 °C), which have a broad specific surface area range from 3.065 m<sup>2</sup>/g to 1274.577 m<sup>2</sup>/g. The active sites on the surface of PPCs have shown specific change laws of decreasing hydroxyl groups and increasing phosphate ester groups occurring as the pyrolysis temperature rises. Both reaction models (PFO and PSO models) and diffusion models (intra-particle diffusion models) have been applied to simulate the adsorption experimental data to verify the hypothesis deduced from the Elovich model. PPC-300 exhibits the highest adsorption capacity of MB (423 mg/g) under given conditions. Due to its large quantities of active sites on the external and internal surfaces (1274.577 m<sup>2</sup>/g), a fast adsorption equilibrium can be achieved within 60 min (with an initial MB concentration of 100 ppm). PPC-300 and PPC-350 also exhibit an intra-particle-diffusion-controlled adsorption kinetic process with a low initial MB concentration (100 ppm) or at the very beginning and final stage of adsorption with a high initial MB concentration (300 ppm) at 40 °C, considering that the diffusion is likely hindered by adsorbate molecules through internal pore channels at the middle stage of adsorption in these cases.https://www.mdpi.com/1420-3049/28/11/4426activated biocharpyrolysis mechanismsadsorption thermodynamicskinetic modelsmechanisms of adsorption dye |
| spellingShingle | Fang Wei Shenglong Jin Chunyi Yao Tianhao Wang Shengpu Zhu Yabiao Ma Heng Qiao Linxi Shan Rencong Wang Xiaoxue Lian Xiaoqiang Tong Yan Li Qiang Zhao Weiguo Song Revealing the Combined Effect of Active Sites and Intra-Particle Diffusion on Adsorption Mechanism of Methylene Blue on Activated Red-Pulp Pomelo Peel Biochar Molecules activated biochar pyrolysis mechanisms adsorption thermodynamics kinetic models mechanisms of adsorption dye |
| title | Revealing the Combined Effect of Active Sites and Intra-Particle Diffusion on Adsorption Mechanism of Methylene Blue on Activated Red-Pulp Pomelo Peel Biochar |
| title_full | Revealing the Combined Effect of Active Sites and Intra-Particle Diffusion on Adsorption Mechanism of Methylene Blue on Activated Red-Pulp Pomelo Peel Biochar |
| title_fullStr | Revealing the Combined Effect of Active Sites and Intra-Particle Diffusion on Adsorption Mechanism of Methylene Blue on Activated Red-Pulp Pomelo Peel Biochar |
| title_full_unstemmed | Revealing the Combined Effect of Active Sites and Intra-Particle Diffusion on Adsorption Mechanism of Methylene Blue on Activated Red-Pulp Pomelo Peel Biochar |
| title_short | Revealing the Combined Effect of Active Sites and Intra-Particle Diffusion on Adsorption Mechanism of Methylene Blue on Activated Red-Pulp Pomelo Peel Biochar |
| title_sort | revealing the combined effect of active sites and intra particle diffusion on adsorption mechanism of methylene blue on activated red pulp pomelo peel biochar |
| topic | activated biochar pyrolysis mechanisms adsorption thermodynamics kinetic models mechanisms of adsorption dye |
| url | https://www.mdpi.com/1420-3049/28/11/4426 |
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