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Synthesis of PVP-based hydrogels for the removal of organic and inorganic pollutants
Thesis (MSc)--Stellenbosch University, 2021.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1869484240037478400 |
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| access_status_str | Open Access |
| author | Gqola, Chuma |
| author2 | Pfukwa, R. |
| author_browse | Gqola, Chuma Pfukwa, R. |
| author_facet | Pfukwa, R. Gqola, Chuma |
| author_sort | Gqola, Chuma |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/110496 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-07-01T04:11:44.648Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/110496 Synthesis of PVP-based hydrogels for the removal of organic and inorganic pollutants Gqola, Chuma Pfukwa, R. Klumperman, L. Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. UCTD Inorganic wastes Organic wastes Pollutants Hydrogels Thesis (MSc)--Stellenbosch University, 2021. ENGLISH ABSTRACT: Hydrogels of poly(N-vinylpyrrolidone) (PVP) and the copolymer of N-vinylpyrrolidone–maleic acid, i.e. poly(NVP-MA) were prepared by free radical polymerization of NVP and MA at room temperature, using N,N’-bis(3-carboxy-1-oxo-2-prop-2-enyl)ethylenediamine (BCOPENH2) as a multifunctional crosslinker, and the ammonium persulfate (APS)/N,N’,N’,N’- tetramethylethylenediamine (TEMED) redox initiation system. The effects of BCOPENH2 and maleic acid concentration on hydrogel formation were investigated. Homopolymer PVP hydrogels were weak and brittle, and fragmented easily when swollen in water. Conversely, poly(NVP-MA) hydrogels retained their shape when swollen. The effect of MA concentration and variation of pH on the swelling behaviour of PVP/MA hdyrogels was investigated. The swelling behaviour of the poly(NVP-MA) hydrogels showed a pH dependency. Furthermore, the maleic acid concentration influenced the degree of swelling. At lower MA concentrations poly(NVP-MA) hydrogels exhibited lower swelling ability, only achieving % swelling ratio (% SR) < 250 %. An increase in MA concentration resulted in an increase in swelling ability, with hydrogels achieving % SR > 1000 %. In addition to preparing chemically crosslinked hydrogels, preliminary studies on nanocomposite hydrogels composed of PVP and laponite clay was conducted. The effect of clay and NVP content on the formation of hydrogels was investigated, and these were characterized via TGA SEM, STEM and XRD analysis. In addition, the mechanical behaviour of formulated hydrogels were studied using compression tests. Owing to the high swelling ability, PVP/MA hydrogels were used in preliminary adsorption experiments of methylene blue (MB). The PVP/MA hydrogels achieved 133 mg/g adsorption capacity towards MB. The effect of adsorbent dosage, pH, initial MB concentration and temperature, on hydrogel adsorption capacity were investigated. Adsorption behaviour of PVP/MA hydrogels was concentration dependant; at low MB initial concentrations, the adsorption behaviour followed pseudo-first order kinetics, whilst pseudo-second order kinetic behaviour was followed at high initial MB concentration. AFRIKAANSE OPSOMMING: Hidrogels gebaseer op die polimeer poli(N-vinielpirrolidoon) (PVP) en die kopolimeer poli(N-vinielpirrolidoon-maleïnes anhidried) (PVP-MA), was voorberei deur vryradikale polimerisasie by kamertemperatuur, met die hulp van N,N’-bis(3-karboksi-2-propaan) etileendiamien (BCOPENH2) as ʼn multifunksionele dwarsbinder asook die ammoniumpersulfaat (APS) en tetrametieletileendiamien (TEMED) redoks inisiëringstelsel. Die vorming gedrag van die hirogels was ondersoek deur BCOPENH2 en maleïnesuur konsentrasies te wissel. Daar is bevind dat die PVP-hidrogels swak en bros was, en dat hul maklik gefragmenteer na waterswelling. Die NVP-MA-hidrogels het teenoorgesteld opgetree en het hul vorm behou soos dit geswel was. Die effek van MA-konsentrasie en variasie van pH op die swelgedrag van NVP-MA-hidrogels was ook ondersoek. Die swelselgedag van hierdie hidrogels het ʼn pH-afhanklikheid getoon. Die maleïnsuurkonsentrasie het die swelsel beïnvloed; by laer MA-konsentrasies vertoon die NVP-MA-hidrogels ʼn laer swelvermoë en bereik slegs ʼn klein persentasie van die swelverhouding (% SR) < 250 %. Soos MA-konsentrasie toneem, is daar ʼn toename in swelvermoë met hidogels wat tot en met 1000 % SR behaal het. Benewens die voorbereiding van chemiese verknoopte hidrogels, voorlopige studies was gedoen oor nanokomposiet hirogels wat bestaan uit PVP en laponiet klei. Die effek van klei en polimeer inhoud op die vorming van hidrogels was ondersoek, en dit is gekarakteriseer deur middel van verskei analitiese tegnieke. Daarbenewens is die meganiese gedrag van geformuleerde hidrogels bestudeer met behulp van kompressietoetse. Vanweë die hoë swelvermoë van die PVP-MA-hidrogels, voorlopige adsorpsie-eksperimente met metileenblou (MB) was uitgevoer. Die hidrogels het 133 mg/g (MB/hidrogel) adsorbeer. Die effek van adsorberende dosis, pH, aanvanklike MB konsentrasie en temperatuur op die hidrogel adsorpsie kapasiteit was ondersoek. Adsopsiegedrag van die hidrogels was konsenstrasie afhanklik; by lae MB-konsentrasies het die adsorpsiegedrag die pseudo-eerse-orde kinetika gevolg, terwyl die pseudo-tweede-orde kinetiese gedrag gevolg is by hoë aanvanklike MB-konsentrasies. Masters 2021-05-24T12:57:32Z 2021-05-24T12:57:32Z 2021-03 Thesis http://hdl.handle.net/10019.1/110496 en_ZA Stellenbosch University 88 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | UCTD Inorganic wastes Organic wastes Pollutants Hydrogels Gqola, Chuma Synthesis of PVP-based hydrogels for the removal of organic and inorganic pollutants |
| title | Synthesis of PVP-based hydrogels for the removal of organic and inorganic pollutants |
| title_full | Synthesis of PVP-based hydrogels for the removal of organic and inorganic pollutants |
| title_fullStr | Synthesis of PVP-based hydrogels for the removal of organic and inorganic pollutants |
| title_full_unstemmed | Synthesis of PVP-based hydrogels for the removal of organic and inorganic pollutants |
| title_short | Synthesis of PVP-based hydrogels for the removal of organic and inorganic pollutants |
| title_sort | synthesis of pvp based hydrogels for the removal of organic and inorganic pollutants |
| topic | UCTD Inorganic wastes Organic wastes Pollutants Hydrogels |
| url | http://hdl.handle.net/10019.1/110496 |
| work_keys_str_mv | AT gqolachuma synthesisofpvpbasedhydrogelsfortheremovaloforganicandinorganicpollutants |