Document

Development of Polymeric Hydrogel Systems as an Alternative Approach for Wastewater Treatment in the Kingdom of Bahrain

Linked Agent
Date Issued
2023
Language
English
Extent
[1], 28, 303, [2] pages
Place of institution
Sakhir, Bahrain
Thesis Type
Thesis (Master)
Institution
"""University of Bahrain, College of Science, Department of Postgraduate Programs
English Abstract
Abstract: The aim of this study is to prepare polymeric hydrogel beads as sustainable and environmentally friendly adsorbents for the removal of organic dyes: Methylene Blue MB and Congo Red CR) and heavy metals ions (Lead (Pb), Cadmium (Cd), Cobalt (Co) and Zinc (Zn)) from aqueous solutions. Green protocol based on physical crosslinking approach was used to fabricate various adsorbent polymeric hydrogel structures and compositions using different types of polymers (natural and synthetics) along with added nanoparticles and fillers. Two porous hydrogel beads were designed; the first one was composed of Polyvinyl alcohol, Alginate and natural Bentonite clay and was employed for the removal of organic dyes. Whereas the second hydrogel beads were consisted of Alginate, Chitosan and Cellulose and was used for the removal of heavy metals ions from aqueous solutions. The structural analysis and morphology of the prepared adsorbents were investigated by using different spectroscopic instruments such as Fourier Transform Infrared spectroscopy, Scanning Electron Microscope coupled with energy dispersive X-ray analysis and X-ray diffraction analysis. The adsorption capacity as well as kinetics and isotherms analysis of the synthesized hydrogels were then investigated for the removal of pollutants in aqueous solution. The stability and reusability of the fabricated polymeric hydrogel adsorbents as low-cost environmentally friendly systems were tested. The results demonstrate the potential of (Polyvinyl alcohol, Alginate, and natural Bentonite) hydrogels to remove organic dyes and (Alginate, Chitosan and Cellulose) hydrogel for the removal of heavy metals ions from synthetic water systems. The experimental results indicate that the incorporation of fillers (bentonite and cellulose) in the nanocomposite formulation sustain the porous structure, preserve water uptake, and increase the removal of dyes and heavy metals compared to the control beads (hydrogels without fillers). Both adsorbents possessed high adsorption capacities and fitted well to pseudo-second-order kinetic model with a high correlation coefficient. Moreover, the designed beads had good stability and reusability as they exhibited excellent removal efficiencies (90 %) for Methylene Blue, (75 %) for Congo Red, (98.01 %) for Pb(II), (98.8 %) for Cd(II), (83.13 %) for Co(II) and (99.85 %) for Zn(II) after six consecutive adsorption-desorption cycles. The maximum adsorption capacity of the designed beads system as calculated by Langmuir isotherm for Methylene Blue, Congo Red, Pb(II), Cd(II), Co(II) and Zn(II) were found to be 51.34, 16.193, 24, 24, 11.76, 12.5 mg/g respectively. Both semi-IPN nanocomposite Hydrogels beads demonstrated good adsorbent properties and could be potentially used for the removal of dyes and heavy metals ions from polluted water. The adsorption process was found be combination of both monolayer adsorption on homogeneous surface and multilayer adsorption on heterogeneous surface.
Member of
Identifier
https://digitalrepository.uob.edu.bh/id/4a757d9d-dfbb-4730-a974-8a4eccc5d730