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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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Author: search.filters.author.Singh, Nikita

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    Minimisation of waste via the valorisation of spent coffee grounds into high-value products
    (Italian Association of Chemical Engineering - AIDIC, 2023-11-30) Singh, Nikita; Chetty, Manimagalay; Deenadayalu, Nirmala
    Spent coffee grounds (SCG) valorisation can produce high-value products to supply cosmetics, petroleum and pharmaceutical industries among others. An overview of the various products achievable from spent coffee grounds valorisation are established, while the effect of temperature, reaction time and solid-to-liquid loading ratio on the yield of caffeine extracted from SCG was investigated. The best extraction solvent between (i) dichloromethane, (ii) 1-ethyl-3-methylimidazolium chloride (IL) and (iii) water was established. Characterisation of SCG using Technical Association of the Pulp and Paper (TAPPI) methods was carried out. Variations of parameters were established using the Box-Behnken design of experiment (DOE) which varied the investigated parameters; (i) temperature (88 – 120 ºC), (ii) reaction time (15 - 35 min) and (iii) solid-to-liquid loading ratio (5 g SCG per 10 -25 mL). The conventional extraction method used dichloromethane as the extraction solvent, whereas the green method used the ionic liquid and water in a Parr pressure reactor. High performance liquid chromatography (HPLC) quantified the yield of extracted caffeine. Recrystallised caffeine is analysed using scanning electron microscopy (SEM), transition electron microscopy (TEM) and energy dispersive spectroscopy (EDS) for its structural properties, crystalline structure and physical analysis, while differential scanning calorimetry (DSC) established the purity of extracted caffeine achieved from each extraction solvent. The expected yield of caffeine is between 4.67 and 8.0 mg/g SCG. According to this experimental methodology, at 120 ºC, 25 min reaction time and 25 mL solvent volume the extraction yield ranged from 2.83 to 3.67 mg/g SCG
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    39th Johannesburg International Conference on “Chemical, Biological and Environmental Engineering” (JCBEE-23) Nov. 16-17, 2023 Johannesburg (South Africa)
    (International Institute of Chemical, Biological & Environmental Engineering (IICBEE), 2023-11-16) Chetty, Manimagalay; Rathilal, Sudesh; Tetteh, Emmanuel; Singh, Nikita
    Abstract—Recent energy demand and environmental concerns associated with fossil fuels makes algae biomass a desirable energy source. Algal biomass has a high organic content and a variety of metabolic properties that make it a promising resource for managing wastewater and sequestering CO₂, in addition to producing profitable biobased products. However, the operation and valorization of algae biomass on a large scale are accompanied by significant costs and setbacks. Therefore, the transition towards a biobased economy requires this study to examine emerging technologies that could utilize algae biomass as an industrialized feedstock from the wastewater settings. A comprehensive analysis of various green technologies of producing high-value products (lipids and hydrocarbons) from algae biomass was reviewed. The fundamental principles that limit the cultivation , extraction, and conversion of different types of algae biomasses for commercialization are discussed. Furthermore, the challenges, future research directions and potential opportunities of valorizing algae biomass was highlighted. It was noted that, exploring algae biomass towards sustainable waste management with resources recovery is viable for industrialization.