{"title":"Adsorption of phosphorus onto nanoscale zero-valent iron/activated carbon: removal mechanisms, thermodynamics, and interferences","authors":"Adel Adly, Nagwan G. Mostafa, Abdelsalam Elawwad","doi":"10.2166/wrd.2022.103","DOIUrl":null,"url":null,"abstract":"<p>This study investigated removal mechanisms, thermodynamics, and interferences of phosphorus adsorption onto nanoscale zero-valent iron (nZVI)/activated carbon composite. Activated carbon was successfully used as support for nZVI particles to overcome shortcomings of using nZVI include its tendency to aggregate and separation difficulties. A comprehensive characterization was done for the composite particles, which revealed a high specific surface area of 72.66 m<sup>2</sup>/g and an average particle size of 37 nm. Several adsorption isotherms and kinetic models have been applied to understand the removal mechanisms. Adsorption isotherm is best fitted by Freundlich and Langmuir models, which indicates that the estimated maximum phosphorus adsorption capacity is 53.76 mg/g at pH 4. Adsorption kinetics showed that the chemisorption process behaved according to a pseudo-second-order model. An adsorption mechanism study conducted using the intra-particle diffusion and Boyd kinetic models indicated that the adsorption rate is limited by surface diffusion. A thermodynamic study showed that phosphorus removal efficiency increased as the solution temperature increased from 15 to 37 °C. Finally, the results of an interference study showed that the presence of Ni<sup>2+</sup>, Cu<sup>2+</sup>, Ca<sup>2+</sup>, Na<sup>+</sup> cations, nitrate ions (<span><img alt=\"\" data-src=\"https://iwa.silverchair-cdn.com/iwa/content_public/journal/jwrd/12/1/10.2166_wrd.2022.103/1/m_wreuse-d-21-00103if01.gif?Expires=1651762139&Signature=mC4pvIcqjh7ScdlVBarklSj9BT0HppbRKVmmAsIVlupWE0SSjSia~1oqF16URluPJ5jMmAQ7K1~UFkkr6DJqnrJ-m0vl-HxFPunw8Dl3WVwx1~wHwGaotWJD93h3TaFGL8ZqX-QQU7rTeDZl2AW8ZKIYhECq2FW~ckLw~N9W-BRA36KyZp588j-MwkyMq3a2F5~uV2FwyTMTJEKg9U~RGdBQsh~xhTI8cTLWbDjohyvlfBRsX4yfrQU00O~I8dS-jLdnZ91yMSCXKe5IFFuCxEnfDUdenl5BvdoK0PVfkUOX-3H3jekukO9aekXCT~uOXPCwJZJwIK7uUZhXdgn44Q__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA\" path-from-xml=\"wreuse-d-21-00103if01.gif\" src=\"https://iwa.silverchair-cdn.com/iwa/content_public/journal/jwrd/12/1/10.2166_wrd.2022.103/1/m_wreuse-d-21-00103if01.gif?Expires=1651762139&Signature=mC4pvIcqjh7ScdlVBarklSj9BT0HppbRKVmmAsIVlupWE0SSjSia~1oqF16URluPJ5jMmAQ7K1~UFkkr6DJqnrJ-m0vl-HxFPunw8Dl3WVwx1~wHwGaotWJD93h3TaFGL8ZqX-QQU7rTeDZl2AW8ZKIYhECq2FW~ckLw~N9W-BRA36KyZp588j-MwkyMq3a2F5~uV2FwyTMTJEKg9U~RGdBQsh~xhTI8cTLWbDjohyvlfBRsX4yfrQU00O~I8dS-jLdnZ91yMSCXKe5IFFuCxEnfDUdenl5BvdoK0PVfkUOX-3H3jekukO9aekXCT~uOXPCwJZJwIK7uUZhXdgn44Q__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA\"/></span>), and sodium acetate improves removal efficiency, while the presence of sulfate ions (<span><img alt=\"\" data-src=\"https://iwa.silverchair-cdn.com/iwa/content_public/journal/jwrd/12/1/10.2166_wrd.2022.103/1/m_wreuse-d-21-00103if02.gif?Expires=1651762139&Signature=Xh2YjnzypwuJnKmNkqGYhGVKqDTu8-t6K5DVm82-FeZoGi~FXSQgfUhGxrs3yMR5UayN0jBxkS07R0Wh0tClEnytxQXPFKxThs8K41-Nsqyan1pbFJuoJT0VOOgX3ETVdP26QwdPlF5y2Xz9eWNJ27sli5P0bIuSJDUiCrRbHnB9MShy7uKKA~dEzbGIz63Jf36CxYKcLu6vqmTEixknf1HOmAaF-SeziezYCAKXj7JHhX4kuU6lP75A1Wy2HofuMztMuHHegIAAmLq~IDGXjJP~fX1EP91E2pGktkdqdn9uN5VcxeVaIS3CHV3okY5CW8b~kuynpizrNPBedpYbpA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA\" path-from-xml=\"wreuse-d-21-00103if02.gif\" src=\"https://iwa.silverchair-cdn.com/iwa/content_public/journal/jwrd/12/1/10.2166_wrd.2022.103/1/m_wreuse-d-21-00103if02.gif?Expires=1651762139&Signature=Xh2YjnzypwuJnKmNkqGYhGVKqDTu8-t6K5DVm82-FeZoGi~FXSQgfUhGxrs3yMR5UayN0jBxkS07R0Wh0tClEnytxQXPFKxThs8K41-Nsqyan1pbFJuoJT0VOOgX3ETVdP26QwdPlF5y2Xz9eWNJ27sli5P0bIuSJDUiCrRbHnB9MShy7uKKA~dEzbGIz63Jf36CxYKcLu6vqmTEixknf1HOmAaF-SeziezYCAKXj7JHhX4kuU6lP75A1Wy2HofuMztMuHHegIAAmLq~IDGXjJP~fX1EP91E2pGktkdqdn9uN5VcxeVaIS3CHV3okY5CW8b~kuynpizrNPBedpYbpA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA\"/></span>) and urea reduces removal efficiency.</p>","PeriodicalId":17556,"journal":{"name":"Journal of Water Reuse and Desalination","volume":"1 1","pages":""},"PeriodicalIF":2.3000,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Water Reuse and Desalination","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.2166/wrd.2022.103","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"Environmental Science","Score":null,"Total":0}
引用次数: 0
Abstract
This study investigated removal mechanisms, thermodynamics, and interferences of phosphorus adsorption onto nanoscale zero-valent iron (nZVI)/activated carbon composite. Activated carbon was successfully used as support for nZVI particles to overcome shortcomings of using nZVI include its tendency to aggregate and separation difficulties. A comprehensive characterization was done for the composite particles, which revealed a high specific surface area of 72.66 m2/g and an average particle size of 37 nm. Several adsorption isotherms and kinetic models have been applied to understand the removal mechanisms. Adsorption isotherm is best fitted by Freundlich and Langmuir models, which indicates that the estimated maximum phosphorus adsorption capacity is 53.76 mg/g at pH 4. Adsorption kinetics showed that the chemisorption process behaved according to a pseudo-second-order model. An adsorption mechanism study conducted using the intra-particle diffusion and Boyd kinetic models indicated that the adsorption rate is limited by surface diffusion. A thermodynamic study showed that phosphorus removal efficiency increased as the solution temperature increased from 15 to 37 °C. Finally, the results of an interference study showed that the presence of Ni2+, Cu2+, Ca2+, Na+ cations, nitrate ions (), and sodium acetate improves removal efficiency, while the presence of sulfate ions () and urea reduces removal efficiency.
期刊介绍:
Journal of Water Reuse and Desalination publishes refereed review articles, theoretical and experimental research papers, new findings and issues of unplanned and planned reuse. The journal welcomes contributions from developing and developed countries.