Removal of Cadmium Ions from Aqueous Solutions Using Ion Exchange Resins Containing Chelating Functional Group

Project no. 32476 · Status: Kapanmış · 2024

Summary

<p>Today,&nbsp;environmental&nbsp;pollution&nbsp;has&nbsp;become&nbsp;a&nbsp;significant&nbsp;global&nbsp;problem&nbsp;due&nbsp;to&nbsp;increasing&nbsp;industrial&nbsp;activities&nbsp;and&nbsp;anthropogenic&nbsp;impacts.&nbsp;Heavy&nbsp;metals,&nbsp;in&nbsp;particular,&nbsp;constitute&nbsp;a&nbsp;major&nbsp;environmental&nbsp;risk&nbsp;because&nbsp;of&nbsp;their&nbsp;toxicity,&nbsp;bioaccumulation&nbsp;potential,&nbsp;and&nbsp;non-biodegradable&nbsp;nature.&nbsp;Cadmium&nbsp;(Cd²⁺)&nbsp;is&nbsp;of&nbsp;special&nbsp;concern&nbsp;due&nbsp;to&nbsp;its&nbsp;high&nbsp;toxicity&nbsp;even&nbsp;at&nbsp;low&nbsp;concentrations,&nbsp;as&nbsp;well&nbsp;as&nbsp;its&nbsp;carcinogenic&nbsp;properties.</p><p></p><p>In&nbsp;this&nbsp;study,&nbsp;two&nbsp;chelating&nbsp;resins&nbsp;containing&nbsp;different&nbsp;functional&nbsp;groups&nbsp;were&nbsp;used&nbsp;for&nbsp;the&nbsp;removal&nbsp;of&nbsp;cadmium&nbsp;ions&nbsp;from&nbsp;aqueous&nbsp;solutions:&nbsp;iminodiacetate-functionalized&nbsp;Puromet&nbsp;MTS9300&nbsp;and&nbsp;aminophosphonate-functionalized&nbsp;Puromet&nbsp;MTS9500.&nbsp;Prior&nbsp;to&nbsp;the&nbsp;experiments,&nbsp;the&nbsp;resins&nbsp;were&nbsp;converted&nbsp;into&nbsp;their&nbsp;Na⁺&nbsp;form.&nbsp;The&nbsp;performance&nbsp;of&nbsp;the&nbsp;resins&nbsp;was&nbsp;comparatively&nbsp;evaluated&nbsp;by&nbsp;investigating&nbsp;parameters&nbsp;such&nbsp;as&nbsp;optimum&nbsp;resin&nbsp;dosage,&nbsp;pH&nbsp;effect,&nbsp;equilibrium,&nbsp;kinetics,&nbsp;thermodynamics,&nbsp;and&nbsp;the&nbsp;influence&nbsp;of&nbsp;competing&nbsp;ions.</p><p></p><p>Experimental&nbsp;results&nbsp;showed&nbsp;that&nbsp;MTS9500&nbsp;achieved&nbsp;99%&nbsp;removal&nbsp;efficiency&nbsp;at&nbsp;a&nbsp;dosage&nbsp;of&nbsp;0.025&nbsp;g/25&nbsp;mL,&nbsp;whereas&nbsp;MTS9300&nbsp;required&nbsp;0.2&nbsp;g/25&nbsp;mL&nbsp;to&nbsp;reach&nbsp;a&nbsp;similar&nbsp;removal&nbsp;efficiency.&nbsp;Maximum&nbsp;cadmium&nbsp;removal&nbsp;was&nbsp;obtained&nbsp;at&nbsp;pH&nbsp;2&nbsp;for&nbsp;MTS9300&nbsp;and&nbsp;pH&nbsp;3&nbsp;for&nbsp;MTS9500.&nbsp;Adsorption&nbsp;data&nbsp;for&nbsp;both&nbsp;resins&nbsp;were&nbsp;best&nbsp;described&nbsp;by&nbsp;the&nbsp;Langmuir&nbsp;isotherm&nbsp;model&nbsp;with&nbsp;high&nbsp;correlation&nbsp;coefficients,&nbsp;indicating&nbsp;monolayer&nbsp;adsorption&nbsp;behavior.&nbsp;At&nbsp;30&nbsp;°C,&nbsp;the&nbsp;maximum&nbsp;adsorption&nbsp;capacities&nbsp;were&nbsp;determined&nbsp;as&nbsp;201.08&nbsp;mg/g&nbsp;for&nbsp;MTS9300&nbsp;and&nbsp;190.60&nbsp;mg/g&nbsp;for&nbsp;MTS9500.&nbsp;Kinetic&nbsp;analysis&nbsp;revealed&nbsp;that&nbsp;the&nbsp;adsorption&nbsp;process&nbsp;followed&nbsp;the&nbsp;pseudo-second-order&nbsp;model.&nbsp;Selectivity&nbsp;studies&nbsp;demonstrated&nbsp;that&nbsp;both&nbsp;resins&nbsp;effectively&nbsp;removed&nbsp;Cd²⁺&nbsp;ions&nbsp;in&nbsp;the&nbsp;presence&nbsp;of&nbsp;K⁺,&nbsp;Mg²⁺,&nbsp;and&nbsp;Ca²⁺&nbsp;ions.</p><p></p><p>The&nbsp;findings&nbsp;indicate&nbsp;that&nbsp;both&nbsp;resins&nbsp;offer&nbsp;an&nbsp;effective&nbsp;and&nbsp;selective&nbsp;alternative&nbsp;for&nbsp;heavy&nbsp;metal&nbsp;removal.</p><p></p><p><strong>Keywords:</strong>&nbsp;Chelating&nbsp;resins,&nbsp;Puromet&nbsp;MTS9300,&nbsp;Puromet&nbsp;MTS9500,&nbsp;Cd²⁺,&nbsp;ion&nbsp;exchange,&nbsp;aminophosphonic&nbsp;acid,&nbsp;iminodiacetic&nbsp;acid</p>

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