Cyanoguanidine-Modified Chitosan as an Efficacious Adsorbent for Removing Cupric Ions from Aquatic Solutions: Kinetics, Isotherms, and Mechanisms

One of the most critical environmental needs is to remove metal ions from industrial wastewater. In this investigation, chitosan modified by cyanoguanidine (CCs) was employed for the first time to adsorb cupric ions. The optimal conditions for eliminating cupric ions were adsorbent dose = 0.015 g, c...

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Main Authors: Ard elshifa M. E. Mohammed, Nouf F. Al-Harby, Muneera Alrasheedi, Shaimaa M. Ibrahim, Nadia A. Mohamed
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Inorganics
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Online Access:https://www.mdpi.com/2304-6740/13/4/116
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author Ard elshifa M. E. Mohammed
Nouf F. Al-Harby
Muneera Alrasheedi
Shaimaa M. Ibrahim
Nadia A. Mohamed
author_facet Ard elshifa M. E. Mohammed
Nouf F. Al-Harby
Muneera Alrasheedi
Shaimaa M. Ibrahim
Nadia A. Mohamed
author_sort Ard elshifa M. E. Mohammed
collection DOAJ
description One of the most critical environmental needs is to remove metal ions from industrial wastewater. In this investigation, chitosan modified by cyanoguanidine (CCs) was employed for the first time to adsorb cupric ions. The optimal conditions for eliminating cupric ions were adsorbent dose = 0.015 g, cupric ion concentration = 0.2 g L<sup>−1</sup>, pH = 6, and temperature = 25 °C. The adsorption kinetics fit the pseudo-second-order model, showing a value of correlation coefficient (R<sup>2</sup>) of 1.00, which is the highest. The experimental q<sub>e</sub> value was determined to be 99.05 mg g<sup>−1</sup>, which is comparable to 100 mg g<sup>−1</sup> (the theoretical one). The adsorbent’s removal efficacy was 96.05%, and the adsorption isotherms, which conform to the Freundlich model, show that adsorption is multi-layered and homogeneous. The chemosorption and physisorption processes are major factors in the elimination of copper ions. Therefore, a good approach to generate an appropriate efficient adsorbent, which is a good alternative approach in cupric ion elimination, is to incorporate cyanoguanidine, which possesses additional binding sites for cupric ions between chitosan chains. Further, the mechanism of Cu<sup>2+</sup> adsorption onto CCs was proposed on the basis of FTIR analysis and computational studies.
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spelling doaj-art-00a0b207184d4ae798fe3931d6b2c33c2025-08-20T02:28:36ZengMDPI AGInorganics2304-67402025-04-0113411610.3390/inorganics13040116Cyanoguanidine-Modified Chitosan as an Efficacious Adsorbent for Removing Cupric Ions from Aquatic Solutions: Kinetics, Isotherms, and MechanismsArd elshifa M. E. Mohammed0Nouf F. Al-Harby1Muneera Alrasheedi2Shaimaa M. Ibrahim3Nadia A. Mohamed4Department of Chemistry, College of Science, Qassim University, Buraidah 51452, Saudi ArabiaDepartment of Chemistry, College of Science, Qassim University, Buraidah 51452, Saudi ArabiaDepartment of Chemistry, College of Science, Qassim University, Buraidah 51452, Saudi ArabiaDepartment of Chemistry, Faculty of Education, Ain Shams University, Roxy, Cairo 11711, EgyptDepartment of Chemistry, College of Science, Qassim University, Buraidah 51452, Saudi ArabiaOne of the most critical environmental needs is to remove metal ions from industrial wastewater. In this investigation, chitosan modified by cyanoguanidine (CCs) was employed for the first time to adsorb cupric ions. The optimal conditions for eliminating cupric ions were adsorbent dose = 0.015 g, cupric ion concentration = 0.2 g L<sup>−1</sup>, pH = 6, and temperature = 25 °C. The adsorption kinetics fit the pseudo-second-order model, showing a value of correlation coefficient (R<sup>2</sup>) of 1.00, which is the highest. The experimental q<sub>e</sub> value was determined to be 99.05 mg g<sup>−1</sup>, which is comparable to 100 mg g<sup>−1</sup> (the theoretical one). The adsorbent’s removal efficacy was 96.05%, and the adsorption isotherms, which conform to the Freundlich model, show that adsorption is multi-layered and homogeneous. The chemosorption and physisorption processes are major factors in the elimination of copper ions. Therefore, a good approach to generate an appropriate efficient adsorbent, which is a good alternative approach in cupric ion elimination, is to incorporate cyanoguanidine, which possesses additional binding sites for cupric ions between chitosan chains. Further, the mechanism of Cu<sup>2+</sup> adsorption onto CCs was proposed on the basis of FTIR analysis and computational studies.https://www.mdpi.com/2304-6740/13/4/116chitosancyanoguanidinecupric ionsadsorption studieskineticsisotherms
spellingShingle Ard elshifa M. E. Mohammed
Nouf F. Al-Harby
Muneera Alrasheedi
Shaimaa M. Ibrahim
Nadia A. Mohamed
Cyanoguanidine-Modified Chitosan as an Efficacious Adsorbent for Removing Cupric Ions from Aquatic Solutions: Kinetics, Isotherms, and Mechanisms
Inorganics
chitosan
cyanoguanidine
cupric ions
adsorption studies
kinetics
isotherms
title Cyanoguanidine-Modified Chitosan as an Efficacious Adsorbent for Removing Cupric Ions from Aquatic Solutions: Kinetics, Isotherms, and Mechanisms
title_full Cyanoguanidine-Modified Chitosan as an Efficacious Adsorbent for Removing Cupric Ions from Aquatic Solutions: Kinetics, Isotherms, and Mechanisms
title_fullStr Cyanoguanidine-Modified Chitosan as an Efficacious Adsorbent for Removing Cupric Ions from Aquatic Solutions: Kinetics, Isotherms, and Mechanisms
title_full_unstemmed Cyanoguanidine-Modified Chitosan as an Efficacious Adsorbent for Removing Cupric Ions from Aquatic Solutions: Kinetics, Isotherms, and Mechanisms
title_short Cyanoguanidine-Modified Chitosan as an Efficacious Adsorbent for Removing Cupric Ions from Aquatic Solutions: Kinetics, Isotherms, and Mechanisms
title_sort cyanoguanidine modified chitosan as an efficacious adsorbent for removing cupric ions from aquatic solutions kinetics isotherms and mechanisms
topic chitosan
cyanoguanidine
cupric ions
adsorption studies
kinetics
isotherms
url https://www.mdpi.com/2304-6740/13/4/116
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AT nouffalharby cyanoguanidinemodifiedchitosanasanefficaciousadsorbentforremovingcupricionsfromaquaticsolutionskineticsisothermsandmechanisms
AT muneeraalrasheedi cyanoguanidinemodifiedchitosanasanefficaciousadsorbentforremovingcupricionsfromaquaticsolutionskineticsisothermsandmechanisms
AT shaimaamibrahim cyanoguanidinemodifiedchitosanasanefficaciousadsorbentforremovingcupricionsfromaquaticsolutionskineticsisothermsandmechanisms
AT nadiaamohamed cyanoguanidinemodifiedchitosanasanefficaciousadsorbentforremovingcupricionsfromaquaticsolutionskineticsisothermsandmechanisms