ResearchSpace

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Welcome to ResearchSpace, the institutional repository of the CSIR. ResearchSpace is an open access electronic archive collecting, preserving and distributing scholarly digital materials created by the CSIR.

Recent Submissions

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Thermocatalytic decomposition of methane to low-carbon hydrogen using LaNi1-xCuxO3 perovskite catalysts

(2024) Duma, Zama G; Swartbooi, Ashton M; Musyoka, NM

The thermocatalytic decomposition (TCD) of methane is an attractive alternative to produce low-carbon hydrogen and solid carbonaceous materials. In this study, substituted LaNi1-xCuxO3 perovskite catalysts prepared via self-combustion method were investigated for methane TCD. The effect of Ni partial substitution with Cu, varying gas hourly space velocity, temperature and stability on methane conversions were evaluated. PXRD, H2-TPR, SEM-EDS, TGA, and XPS were used to characterize the catalysts. An increase in Cu loading to 50%, increase in temperature and decrease in GHSV resulted in an improvement in methane conversions to 92%. At a GHSV of 2400 ml/gcat.h, no significant deactivation was observed as the stability of the LaNi0.5Cu0.5O3 catalyst increased from 6 to 20 hours’ TOS with methane conversions maintained at 92% where carbon nanofibers were observed on the surface of the spent catalysts. The study demonstrates the potential to prepare LaNi1-xCuxO3 catalysts and identify optimal testing conditions for the novel production of low-carbon hydrogen with minimal catalyst deactivation.

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Reactively processed poly(butylene adipate terephthalate) composite–based multilayered films with improved properties for sustainable packaging applications: structural characterization and biodegradation mechanism

(2024)

In this study, it is attempted to enhance the properties and biodegradability of poly(butylene adipate terephthalate) (PBAT) using nanocomposite technology to meet the demand for sustainable packaging applications. Two nanoclays containing PBAT composites are reactively processed and integrated into the multilayered films. Reactive processing facilitates the dispersion and distribution of nanoclay particles in the PBAT matrix. The multilayered films comprising reactively processed PBAT composites exhibited a 24.5%–31.5% reduction in the oxygen transmission rate and improved dimensional stability and tensile properties. Moreover, the degradability of the multilayered film comprising reactively processed PBAT composites reached 82% in 180 days. In contrast, a neat PBAT film of similar thickness attained only 53% degradation in the same period. The biodegradation mechanism is proposed based on the topology of the disintegrated films studied using scanning electron microscopy, chemical bond vibrations determined by Fourier-transform infrared spectroscopy, and structural evolution by small and wide-angle X-ray scattering (SWAXS). The SWAXS analysis is used to understand the changes in the degree of crystallinity, long-range periodic order, and crystalline and amorphous layer thickness of the multilayered films before and after degradation. Such multilayered films can find applications where packaging or biomedical devices cannot be recycled.

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Algae infused enhancement of PBAT stiffness: Investigating the influence of algae content on mechanical and thermal properties

(2024) Letwaba, J; Motloung, Mpho P; Muniyasamy, Sudhakar; Mavhungu, L; Mbaya, R; Okpuwhara, R

This study investigates the impact of algae loading on the properties of PBAT/algae bio-composites produced through a melt extrusion process. The integration of algae as a filler demonstrated a reinforcing effect on the PBAT matrix,leading to an increase in modulus with higher algae loading. Concurrently, the tensile strength and maximum tensile strain of PBAT decreased with an increase in algae content. The thermal stability of PBAT was affected by adding algae, resulting in bio-composites exhibiting an intermediate behavior compared with their neat precursors. The optimal formulation is achieved with 20 wt.% of algae incorporated into the PBAT matrix. The produced PBAT/algae bio-composites, demonstrated versatile applications across a wide range of products.

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Localized surface plasmon resonance optical biosensor for simple detection of deoxyribonucleic acid mismatches

(2024) Lugongolo, Masixole Y; Ombinda-Lemboumba, Saturnin; Hlekelele, Lerato; Nyokana, Nontsikelelo; Mthunzi-Kufa, Patience

Optical biosensors are optical technologies that evaluate changes in the refractive index as they monitor non-covalent molecular interactions in real time. These make use of unsophisticated, label-free analytical approaches, which do not require dyes to produce a visible signal. In this study, the efficiency of localized surface plasmon resonance (LSPR) biosensor in detecting a single nucleotide mismatch in deoxyribonucleic acid is examined. The detection is based on the hybridization of a target DNA at 100 ng μL−1 with a complementary biotinylated probe as well as a partially complementary biotinylated with one nucleotide mismatch probe on a gold-coated surface. Both probes are used at a concentration of 0.1 μm. The LSPR exhibited sensitivity by differentiating sample M+ from sample C+ through varying transmission intensities of 0.28 and 0.26 μA, respectively. Based on these findings, this approach demonstrates a great potential due to its ability to distinguish samples that differ with a single base pair, and its efficiency will be explored in the development of a point-of-care device as a simpler and cost-effective approach for detection of various biologically and medically significant mutations such as antimicrobial resistance mutations. More work is underway to determine the robustness of the LSPR biosensor using the biotin–neutravidin approach.

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AmLight - Maximizing Technological Advancements in Research and Education; Network Connectivity for Open Science between South Africa, the US, and South America

(2024) Morgan, H; Inarra, J; Bezerra, J; Lopez, LF; Chergarova, V; Cox III, DAC; Alvarez, GE; Hazin, A; Pillay, Kasandra; Makan, Ajay K; Greaves, D; Shariff, A; Sullivan, P

Connecting South and North America with Africa via a South Atlantic high performance Research & Education Network (REN) has become a strategic priority. Africa offers unique biological, astronomical, environmental, geological, anthropological, and cultural resources, making it a valuable partner in global research and education. Enhanced technological and social connections between the United States, Brazil, and Africa are advancing research in multiple disciplines. The high-performance networking infrastructure of AmLight-ExP, in collaboration with the South African National Research and Education Network, provides unprecedented resources for open science research and education communities. This paper presents the architecture, capabilities, and impact of the AmLight-ExP network, highlighting its role in fostering international collaboration and addressing significant scientific challenges.