4 results on '"McKay, Gordon"'
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2. Adsorbent-Embedded Polymeric Membranes for Efficient Dye-Water Treatment.
- Author
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Saleem, Junaid, Moghal, Zubair Khalid Baig, Pradhan, Snigdhendubala, Hafeez, Ahsan, Shoaib, Mohammad, Alahmad, Johaina, and McKay, Gordon
- Subjects
POLYMERIC sorbents ,LANGMUIR isotherms ,CONTACT angle ,SORBENTS ,ADSORPTION capacity ,METHYLENE blue ,DRUG solubility ,POLYMERIC membranes ,GENTIAN violet - Abstract
Traditional bulk adsorbents, employed for the removal of dyes and metal ions, often face the drawback of requiring an additional filtration system to separate the filtrate from the adsorbent. In this study, we address this limitation by embedding the adsorbent into the polymer matrix through a process involving dissolution–dispersion, spin-casting, and heat-stretching. Selective dissolution and dispersion facilitate the integration of the adsorbent into the polymer matrix. Meanwhile, spin-casting ensures the formation of a uniform and thin film structure, whereas heat-induced stretching produces a porous matrix with a reduced water contact angle. The adsorbent selectively captures dye molecules, while the porous structure contributes to water permeability. We utilized inexpensive and readily available materials, such as waste polyethylene and calcium carbonate, to fabricate membranes for the removal of methylene blue dye. The effects of various parameters, such as polymer-adsorbent ratio, initial dye concentration, and annealing temperature, were investigated. Equilibrium data were fitted to Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms. The equilibrium data were best represented by the Langmuir isotherm, with maximum adsorption capacity of 35 mg/g and 43 mg/g at 25 °C and 45 °C, respectively. The membranes can be regenerated and recycled with a 97% dye removal efficiency. The study aims to present a template for adsorbent-embedded polymeric membranes for dye removal, in which adsorbent can be tailored to enhance adsorption capacity and efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Transforming polypropylene waste into transparent anti-corrosion weather-resistant and anti-bacterial superhydrophobic films.
- Author
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Saleem, Junaid, Moghal, Zubair Khalid Baig, and McKay, Gordon
- Subjects
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POLYPROPYLENE , *CONTACT angle , *WASTE recycling , *PRODUCT life cycle assessment , *CARBON steel , *PLASTIC scrap - Abstract
The global pollution crisis arising from the accumulation of plastic in landfills and the environment necessitates addressing plastic waste issues. Notably, polypropylene (PP) waste accounts for 20% of total plastic waste and holds promise for hydrophobic applications in the realm of recycling. Herein, the transparent and non-transparent superhydrophobic films made from waste PP are reported. A hierarchical structure with protrusions is induced through spin-casting and thermally induced phase separation. The films had a water contact angle of 159° and could vary in thickness, strength, roughness, and hydrophobicity depending on end-user requirements. The Bode plot indicated enhanced corrosion resistance in the superhydrophobic films. Antibacterial trials with Escherichia coli and Staphylococcus aureus microbial solutions showed that the superhydrophobic film had a significantly lower rate of colony-forming units compared to both the transparent surface and the control blank sample. Moreover, a life cycle assessment revealed that the film production resulted in a 62% lower embodied energy and 34% lower carbon footprint compared to virgin PP pellets sourced from petroleum. These films exhibit distinctiveness with their dual functionality as coatings and freestanding films. Unlike conventional coatings that require chemical application onto the substrate, these films can be mechanically applied using adhesive tapes on a variety of surfaces. Overall, the effective recycling of waste PP into versatile superhydrophobic films not only reduces environmental impact but also paves the way for a more sustainable and eco-friendly future. [Display omitted] • Waste PP is transformed into superhydrophobic films—transparent and non-transparent. • Films are suitable for weather resistance and self-cleaning applications. • Films demonstrate improved corrosion resistance compared to bare carbon steel. • Reduced microbial growth in films makes them suitable for antibacterial use. • Films show lower embodied energy and fewer carbon emissions than virgin PP pellets. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Towards green membranes: Repurposing waste polypropylene with a single plant-based solvent via tandem spin-casting and annealing.
- Author
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Saleem, Junaid, Moghal, Zubair Khalid Baig, Luque, Rafael, and McKay, Gordon
- Subjects
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POLYPROPYLENE , *CIRCULAR economy , *CONTACT angle , *WASTE recycling , *POLYMERIC membranes , *PERVAPORATION , *POLYMERS - Abstract
[Display omitted] • Polypropylene waste upcycled into superhydrophobic membranes. • A bio-based derived solvent (Cymene) was employed. • Surface roughness and hydrophobicity of the top layer enhanced selectivity. • The presence of micropores ensured efficient liquid passage and high permeability. • Membranes featuring 14,000 Lm-2hr-1 organic solvent flux (96 % water rejection). A key aspect of advancing sustainable membrane technology is to source eco-friendly polymers, such as recycled plastic waste, use renewable plant-based solvents, and limit the number of solvents used in dissolution-precipitation processes. In this study, we upcycle polypropylene PP waste into bi-layered microporous superhydrophobic membranes using a single plant-based solvent, Cymene, through tandem spin-casting and annealing. The surface roughness and hydrophobicity of the top layer enhance selectivity, while the presence of micropores ensures efficient liquid passage and high permeability. The microporous bottom layer serves as a substrate for the top layer, providing structural support. Various annealing conditions were employed to optimize hydrophobicity, roughness, porosity and strength of as-prepared membranes, yielding high permeance and outstanding separation efficiency. The fabricated membranes were subjected to oil–water emulsion separations, demonstrating a contact angle exceeding 155° and a surface roughness of 123 nm, resulting in an organic solvent flux of 14,000 Lm-2h−1 with a 96 % water rejection. Tensile strength and strain % were found to be 13–28 MPa and 20–27 %, respectively. This research provided access to environmentally friendly membranes, adding value to plastic waste with potential benefits to both the polymer and membrane industries as they transition towards a circular economy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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