Eric E Houghton, Litha Yapi, Nils Haneklaus, Hendrik G Brink, Shepherd M Tichapondwa
{"title":"Coal Fly Ash-Based Adsorbents for Tetracycline Removal: Comparative Insights into Modification and Zeolite Conversion.","authors":"Eric E Houghton, Litha Yapi, Nils Haneklaus, Hendrik G Brink, Shepherd M Tichapondwa","doi":"10.3390/jox15020036","DOIUrl":null,"url":null,"abstract":"<p><p>Emerging xenobiotics, such as tetracycline (TC), pose significant risks to both the environment and human health. Adsorption is a recognized method for removing these contaminants, and in this study, fly ash (FA), a by-product of coal combustion, was modified to develop adsorbents. Acid-modified FA (AM-FA) and base-modified FA (BM-FA) were prepared, and zeolite Na-P1 (ZNa-P1) was synthesized via hydrothermal treatment. Adsorption tests revealed that BM-FA and ZNa-P1 removed 76% and 90% of TC, respectively, compared to 35% with unmodified FA. AM-FA had the lowest performance, removing just 11% of TC. ZNa-P1's superior performance was linked to its high zeolite purity, with a cation exchange capacity (CEC) of 6.37 meq/g and a surface area of 35.7 m<sup>2</sup>/g. Though BM-FA had a larger surface area of 110.8 m<sup>2</sup>/g, it exhibited a lower CEC of 3.42 meq/g. Adsorption efficiency was more closely related to CEC than surface area. Optimal TC removal with ZNa-P1 was achieved at a 7.5 g/L dosage and pH 5. The process followed pseudo second order kinetics and the Langmuir isotherm, with a maximum capacity of 46.34 mg/g at 30 °C. The adsorption thermodynamics indicated that the adsorption was endothermic and spontaneous. The adsorption mechanism of tetracycline on ZNa-P1 involved electrostatic attraction, hydrogen, and ion exchange. This study aligns with SDGs 6 (Clean Water and Sanitation) and 12 (Responsible Consumption and Production).</p>","PeriodicalId":42356,"journal":{"name":"Journal of Xenobiotics","volume":"15 2","pages":""},"PeriodicalIF":6.8000,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11932300/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Xenobiotics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3390/jox15020036","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"TOXICOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Emerging xenobiotics, such as tetracycline (TC), pose significant risks to both the environment and human health. Adsorption is a recognized method for removing these contaminants, and in this study, fly ash (FA), a by-product of coal combustion, was modified to develop adsorbents. Acid-modified FA (AM-FA) and base-modified FA (BM-FA) were prepared, and zeolite Na-P1 (ZNa-P1) was synthesized via hydrothermal treatment. Adsorption tests revealed that BM-FA and ZNa-P1 removed 76% and 90% of TC, respectively, compared to 35% with unmodified FA. AM-FA had the lowest performance, removing just 11% of TC. ZNa-P1's superior performance was linked to its high zeolite purity, with a cation exchange capacity (CEC) of 6.37 meq/g and a surface area of 35.7 m2/g. Though BM-FA had a larger surface area of 110.8 m2/g, it exhibited a lower CEC of 3.42 meq/g. Adsorption efficiency was more closely related to CEC than surface area. Optimal TC removal with ZNa-P1 was achieved at a 7.5 g/L dosage and pH 5. The process followed pseudo second order kinetics and the Langmuir isotherm, with a maximum capacity of 46.34 mg/g at 30 °C. The adsorption thermodynamics indicated that the adsorption was endothermic and spontaneous. The adsorption mechanism of tetracycline on ZNa-P1 involved electrostatic attraction, hydrogen, and ion exchange. This study aligns with SDGs 6 (Clean Water and Sanitation) and 12 (Responsible Consumption and Production).
期刊介绍:
The Journal of Xenobiotics publishes original studies concerning the beneficial (pharmacology) and detrimental effects (toxicology) of xenobiotics in all organisms. A xenobiotic (“stranger to life”) is defined as a chemical that is not usually found at significant concentrations or expected to reside for long periods in organisms. In addition to man-made chemicals, natural products could also be of interest if they have potent biological properties, special medicinal properties or that a given organism is at risk of exposure in the environment. Topics dealing with abiotic- and biotic-based transformations in various media (xenobiochemistry) and environmental toxicology are also of interest. Areas of interests include the identification of key physical and chemical properties of molecules that predict biological effects and persistence in the environment; the molecular mode of action of xenobiotics; biochemical and physiological interactions leading to change in organism health; pathophysiological interactions of natural and synthetic chemicals; development of biochemical indicators including new “-omics” approaches to identify biomarkers of exposure or effects for xenobiotics.