{"title":"Using Iron-Based Adsorbents for the Removal of Inorganic Ecotoxicants from Aquatic Systems","authors":"S. A. Kobets, L. M. Demutskaya, G. M. Pshinko","doi":"10.3103/S1063455X24060055","DOIUrl":null,"url":null,"abstract":"<p>The study investigates the adsorption of heavy metals (HMs), specifically Cd(II) and Co(II), from aqueous solutions using synthesized iron oxides with layered structures and surface groups of a basic nature: goethite α-FeO(OH), lepidocrocite γ-FeO(OH), and ferrihydrite Fe(OH)<sub>3</sub>. The results indicate that these crystalline materials are effective in adsorbing heavy metals within pH ranges typical of natural aquatic environments (7.5). We determined the conditions for extracting heavy metals, examining the effect of pH in aqueous solutions, ionic strength, adsorbent dosage, and major components of natural waters. The results show that the majority of HM ions are extracted within the first 30 min of contact between the aqueous solution and the solid phase of the adsorbents, with adsorption equilibrium being reached for iron-containing adsorbents in approximately 4 h. To account for the relative distribution of HM species in aqueous environments with varying pH values, we calculated the distribution of these species for the concentrations studied in model water solutions, enabling an evaluation of the extraction mechanism. The adsorption of Co(II) and Cd(II) is primarily driven by the interaction of their cationic forms with ferrinol surface groups of the studied iron-containing minerals through chemisorption from aqueous solutions within the investigated pH range. The adsorption limits for goethite and ferrihydrite are nearly identical, while those for lepidocrocite are significantly lower, which can be attributed to their structure and the availability of active adsorption sites. The shape of the adsorption isotherm curves is also quite similar across the entire concentration range. Based on the data obtained regarding the adsorption efficiency of Cd(II) and Co(II), which are among the most challenging cations to remove using adsorption methods, the synthesized goethite and ferrihydrite can be recommended as cost-effective and efficient materials for the purification of natural waters contaminated with heavy metals.</p>","PeriodicalId":680,"journal":{"name":"Journal of Water Chemistry and Technology","volume":null,"pages":null},"PeriodicalIF":0.5000,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Water Chemistry and Technology","FirstCategoryId":"92","ListUrlMain":"https://link.springer.com/article/10.3103/S1063455X24060055","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, ANALYTICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The study investigates the adsorption of heavy metals (HMs), specifically Cd(II) and Co(II), from aqueous solutions using synthesized iron oxides with layered structures and surface groups of a basic nature: goethite α-FeO(OH), lepidocrocite γ-FeO(OH), and ferrihydrite Fe(OH)3. The results indicate that these crystalline materials are effective in adsorbing heavy metals within pH ranges typical of natural aquatic environments (7.5). We determined the conditions for extracting heavy metals, examining the effect of pH in aqueous solutions, ionic strength, adsorbent dosage, and major components of natural waters. The results show that the majority of HM ions are extracted within the first 30 min of contact between the aqueous solution and the solid phase of the adsorbents, with adsorption equilibrium being reached for iron-containing adsorbents in approximately 4 h. To account for the relative distribution of HM species in aqueous environments with varying pH values, we calculated the distribution of these species for the concentrations studied in model water solutions, enabling an evaluation of the extraction mechanism. The adsorption of Co(II) and Cd(II) is primarily driven by the interaction of their cationic forms with ferrinol surface groups of the studied iron-containing minerals through chemisorption from aqueous solutions within the investigated pH range. The adsorption limits for goethite and ferrihydrite are nearly identical, while those for lepidocrocite are significantly lower, which can be attributed to their structure and the availability of active adsorption sites. The shape of the adsorption isotherm curves is also quite similar across the entire concentration range. Based on the data obtained regarding the adsorption efficiency of Cd(II) and Co(II), which are among the most challenging cations to remove using adsorption methods, the synthesized goethite and ferrihydrite can be recommended as cost-effective and efficient materials for the purification of natural waters contaminated with heavy metals.
期刊介绍:
Journal of Water Chemistry and Technology focuses on water and wastewater treatment, water pollution monitoring, water purification, and similar topics. The journal publishes original scientific theoretical and experimental articles in the following sections: new developments in the science of water; theoretical principles of water treatment and technology; physical chemistry of water treatment processes; analytical water chemistry; analysis of natural and waste waters; water treatment technology and demineralization of water; biological methods of water treatment; and also solicited critical reviews summarizing the latest findings. The journal welcomes manuscripts from all countries in the English or Ukrainian language. All manuscripts are peer-reviewed.