{"title":"Novel bifunctional thio-methylene-pyridine grafted polymeric resin for mercury removal from acidic solutions","authors":"Nikhilesh Iyer , Ritesh Ruhela , Suvarna Saundarajan , Sanjukta Abhay Kumar , Dhruva Kumar Singh","doi":"10.1016/j.scenv.2025.100280","DOIUrl":null,"url":null,"abstract":"<div><div>This work brings forth a novel porous solid sorbent, thio-methylene-pyridine (TMP) ligand grafted polymeric resin (TMP resin), for selective mercury removal over a wide range of acidity in which the bi-functional group catered to sorption of both cationic and anionic species of Hg<sup>2 +</sup> in aqueous hydrochloric acid medium. TMP resin showed quantitative sorption of ‘Hg<sup>2+</sup>’ in high as well as low acidic solutions (chloride medium) with uptake capacity in the range of 70–80 mg Hg/g, indicating sorption of ‘Hg<sup>2+</sup>’ in both cationic and anionic form as (HgCl<sub>4</sub>)<sup>2-</sup>, hence utilizing the bi-functionality of TMP ligand. Spectroscopic investigation on metal-ligand interactions, as well as DFT calculations indicated towards two separate mechanisms, one being preference for soft-soft co-ordinate complexation at lower acidity and other being anion exchange of Hg-chloride complex by pyridinium group at higher acidity. Near complete back extraction of Hg<sup>2+</sup> from the Hg-loaded sorbent was achieved using 0.1 M thiourea solution at 0.1 M HCl. Resin was regenerated upto 5 cycles of repeated loading and elution wherein there was no appreciable change in the performance with respect to Hg<sup>2+</sup> sorption & desorption.</div></div>","PeriodicalId":101196,"journal":{"name":"Sustainable Chemistry for the Environment","volume":"11 ","pages":"Article 100280"},"PeriodicalIF":0.0000,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Sustainable Chemistry for the Environment","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2949839225000756","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
This work brings forth a novel porous solid sorbent, thio-methylene-pyridine (TMP) ligand grafted polymeric resin (TMP resin), for selective mercury removal over a wide range of acidity in which the bi-functional group catered to sorption of both cationic and anionic species of Hg2 + in aqueous hydrochloric acid medium. TMP resin showed quantitative sorption of ‘Hg2+’ in high as well as low acidic solutions (chloride medium) with uptake capacity in the range of 70–80 mg Hg/g, indicating sorption of ‘Hg2+’ in both cationic and anionic form as (HgCl4)2-, hence utilizing the bi-functionality of TMP ligand. Spectroscopic investigation on metal-ligand interactions, as well as DFT calculations indicated towards two separate mechanisms, one being preference for soft-soft co-ordinate complexation at lower acidity and other being anion exchange of Hg-chloride complex by pyridinium group at higher acidity. Near complete back extraction of Hg2+ from the Hg-loaded sorbent was achieved using 0.1 M thiourea solution at 0.1 M HCl. Resin was regenerated upto 5 cycles of repeated loading and elution wherein there was no appreciable change in the performance with respect to Hg2+ sorption & desorption.