Qualitative and quantitative determination of critical coagulation concentration for pristine graphene oxide in various ionic compounds
Graphene oxide (GO) nanoparticles have been widely used in wastewater treatment applications. However, most studies have conducted treatment experiments using synthetic wastewater that does not contain ionic compounds. The presence of ionic compounds could suppress the electrical double layer of the...
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| Format: | Article |
| Language: | English |
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Elsevier
2022-12-01
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| Series: | Results in Engineering |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590123022003528 |
| _version_ | 1797996550380584960 |
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| author | Mei Kei Chow Chong Eu Jee Swee Pin Yeap |
| author_facet | Mei Kei Chow Chong Eu Jee Swee Pin Yeap |
| author_sort | Mei Kei Chow |
| collection | DOAJ |
| description | Graphene oxide (GO) nanoparticles have been widely used in wastewater treatment applications. However, most studies have conducted treatment experiments using synthetic wastewater that does not contain ionic compounds. The presence of ionic compounds could suppress the electrical double layer of the GO nanoparticles and thus, promote particle agglomeration. This study aims to evaluate the effect of ion valency (Na+, Ca2+, Al3+, Cl−, and SO42−) and concentration (1 mM up to 200 mM) on the colloidal stability of a pristine GO. The sedimentation profile of GO in those ionic solutions was captured through a novel qualitative photoimaging method coupled with ImageJ analysis. Results showed that a GO with O/C ratio of 0.69 experiences sedimentation even when dispersed in pure distilled water. In line with the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the extent of sedimentation increases with the increasing ion concentration in the medium. In terms of cationic valences, trivalent cation (Al3+) was more effective than divalent (Ca2+) and monovalent (Na+) cations in destabilizing GO; here, the corresponding critical coagulation concentration (CCC) was found to be ∼1 mM, ∼1.5 mM, and ∼150 mM, respectively. It was found that NaCl exhibited a higher destabilization effect as compared to Na2SO4 despite the latter is having a higher ionic strength. Besides the expected electrical double layer screening effect, density of the ionic solution also showed substantial effects on the GO's sedimentation profile. The obtained results align with other reported works, thus, confirming the feasibility of the novel photoimaging coupled with ImageJ processing method in assessing colloidal stability of nanoparticles. |
| first_indexed | 2024-04-11T10:19:07Z |
| format | Article |
| id | doaj.art-1565588887054e55b31e0afa3ad74a5c |
| institution | Directory Open Access Journal |
| issn | 2590-1230 |
| language | English |
| last_indexed | 2024-04-11T10:19:07Z |
| publishDate | 2022-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Results in Engineering |
| spelling | doaj.art-1565588887054e55b31e0afa3ad74a5c2022-12-22T04:29:49ZengElsevierResults in Engineering2590-12302022-12-0116100682Qualitative and quantitative determination of critical coagulation concentration for pristine graphene oxide in various ionic compoundsMei Kei Chow0Chong Eu Jee1Swee Pin Yeap2Department of Chemical & Petroleum Engineering, Faculty of Engineering, Technology & Built Environment, UCSI University, 56000, Cheras, Kuala Lumpur, MalaysiaDepartment of Chemical & Petroleum Engineering, Faculty of Engineering, Technology & Built Environment, UCSI University, 56000, Cheras, Kuala Lumpur, MalaysiaDepartment of Chemical & Petroleum Engineering, Faculty of Engineering, Technology & Built Environment, UCSI University, 56000, Cheras, Kuala Lumpur, Malaysia; UCSI-Cheras Low Carbon Innovation Hub Research Consortium, Kuala Lumpur, Malaysia; Corresponding author. Department of Chemical & Petroleum Engineering, Faculty of Engineering, Technology & Built Environment, UCSI University, 56000, Cheras, Kuala Lumpur, Malaysia.,Graphene oxide (GO) nanoparticles have been widely used in wastewater treatment applications. However, most studies have conducted treatment experiments using synthetic wastewater that does not contain ionic compounds. The presence of ionic compounds could suppress the electrical double layer of the GO nanoparticles and thus, promote particle agglomeration. This study aims to evaluate the effect of ion valency (Na+, Ca2+, Al3+, Cl−, and SO42−) and concentration (1 mM up to 200 mM) on the colloidal stability of a pristine GO. The sedimentation profile of GO in those ionic solutions was captured through a novel qualitative photoimaging method coupled with ImageJ analysis. Results showed that a GO with O/C ratio of 0.69 experiences sedimentation even when dispersed in pure distilled water. In line with the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the extent of sedimentation increases with the increasing ion concentration in the medium. In terms of cationic valences, trivalent cation (Al3+) was more effective than divalent (Ca2+) and monovalent (Na+) cations in destabilizing GO; here, the corresponding critical coagulation concentration (CCC) was found to be ∼1 mM, ∼1.5 mM, and ∼150 mM, respectively. It was found that NaCl exhibited a higher destabilization effect as compared to Na2SO4 despite the latter is having a higher ionic strength. Besides the expected electrical double layer screening effect, density of the ionic solution also showed substantial effects on the GO's sedimentation profile. The obtained results align with other reported works, thus, confirming the feasibility of the novel photoimaging coupled with ImageJ processing method in assessing colloidal stability of nanoparticles.http://www.sciencedirect.com/science/article/pii/S2590123022003528Colloidal stabilityCritical coagulation concentrationGraphene oxideIon valencyIon concentration |
| spellingShingle | Mei Kei Chow Chong Eu Jee Swee Pin Yeap Qualitative and quantitative determination of critical coagulation concentration for pristine graphene oxide in various ionic compounds Results in Engineering Colloidal stability Critical coagulation concentration Graphene oxide Ion valency Ion concentration |
| title | Qualitative and quantitative determination of critical coagulation concentration for pristine graphene oxide in various ionic compounds |
| title_full | Qualitative and quantitative determination of critical coagulation concentration for pristine graphene oxide in various ionic compounds |
| title_fullStr | Qualitative and quantitative determination of critical coagulation concentration for pristine graphene oxide in various ionic compounds |
| title_full_unstemmed | Qualitative and quantitative determination of critical coagulation concentration for pristine graphene oxide in various ionic compounds |
| title_short | Qualitative and quantitative determination of critical coagulation concentration for pristine graphene oxide in various ionic compounds |
| title_sort | qualitative and quantitative determination of critical coagulation concentration for pristine graphene oxide in various ionic compounds |
| topic | Colloidal stability Critical coagulation concentration Graphene oxide Ion valency Ion concentration |
| url | http://www.sciencedirect.com/science/article/pii/S2590123022003528 |
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