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This review investigates scalability, environmental performance, and socio-economic sustainability of biochar production in sub-Saharan Africa with a focus on traditional/low-tech solutions. Low-tech methods, including open pits, metal drum kilns, and earth mounds, are easily accessible and reasonably priced, but they can have high emissions, uneven biochar quality, and poor thermal efficiency. Standardizing enhanced low-technology designs, putting strong quality assurance systems in place, mobilizing underutilized biomass streams, and using digital monitoring and artificial intelligence to optimize pyrolysis operations are some of the main strategies proposed to achieve scalable and sustainable biochar production in the region. Retort kilns or sophisticated pyrolysis units with gas recirculation are considered medium-to-high technology to stabilize product qualities, lower emissions, and call for a moderate amount of capital and technical know-how. Along with evaluating feedstock possibilities such as invasive species, forestry wastes, and crop residues, the review incorporates techno-economic analysis, climate-smart forestry tools, and circular economy principles. Economically viable biochar systems in Sub-Saharan African contexts require either (i) integration with existing agro-industrial waste streams (e.g., rice mills, sugarcane processing) where collection infrastructure already exists, or (ii) decentralized production using low-cost kilns (< US500 capital cost) that eliminate transport through on-farm processing. To align waste management and forest conservation with goals for negative carbon soil enhancement, the paper recommends policymakers support standardized low-technology designs, create frameworks for ensuring the quality of biochar, increase the use of underutilized biomass streams, and use digital monitoring and artificial intelligence to optimize pyrolysis processes.
This study investigates the synthesis, characterisation, and application of titanium dioxide nanoparticles (TNP) as an adsorbent for effectively removing Methylene Blue (MB) dye from aqueous solutions. The TNP was synthesised through a biogenic route using Pseudomonas aeruginosa as a bio-reducing and stabilising agent. The synthesised nanoparticles were characterised using various analytical techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The UV–visible spectrophotometer was used to monitor nanoparticle formation at a wavelength of 393 nm. Results from the study showed that XRD confirmed the nanostructured and amorphous nature of TNP, while SEM–EDX analysis indicated a coarse and rough surface of the nanoparticles. TEM analysis revealed their uniform spherical morphology, and FTIR spectroscopy identified the presence of O–H, C-O, and N–H functional groups likely responsible for MB adsorption. The adsorption experiments examined factors such as initial dye concentration, adsorbent dosage, contact time, solution pH, and temperature via batch adsorption methods. Kinetic studies demonstrated that the pseudo-second-order model accurately described the complex dynamics of the adsorption process. The Langmuir isotherm model was found to be the best fit for the experimental data, indicating monolayer adsorption on the TNP surface. Thermodynamic studies provided insights into the energetics of the adsorption process, with positive ∆H (12.75 kJ) indicating an endothermic reaction, while positive ∆S (62.27 J/mol) suggested increased disorderliness between adsorbent and adsorbate. Negative values of ∆G (− 8.522 and − 13.967 kJ/mol) confirmed the feasibility and spontaneity of the adsorption system, demonstrating a strong affinity for MB. After five cycles of adsorption and desorption, the regeneration study revealed that TNP maintained an MB removal capacity of over 80
Unveiling a hidden threat in the heart of West Africa's industrial landscape, this study deciphers the complex fingerprint of polycyclic aromatic hydrocarbons (PAHs) in atmospheric dust from major cement-producing regions in Ogun and Ondo States, Nigeria. By analyzing 25 PAH compounds, we reveal alarmingly high concentrations of carcinogenic species, including Benzo(a)pyrene (up to 4.25 mu g/g) and Dibenzo(a,l)pyrene (up to 5.66 mu g/g), exceeding levels reported in marine sediments and comparable industrial environments, with levels posing significant health concerns for local communities. Employing Principal Component Analysis (PCA), a powerful statistical lens, we achieve a remarkable breakthrough: just two components explain 99.96% of the data's variability, a rare clarity in environmental studies. The first component (61.2%), rich in high molecular weight PAHs, fingerprints intense combustion from kilns and traffic, while the second (38.8%) signals mixed industrial releases. This study delivers the first high-resolution source apportionment of PAHs in an African cement corridor, exposing inhalation as a critical exposure route, particularly for adults, with estimated lifetime excess cancer risks via inhalation reaching up to 2.06 & times; 10-4, approaching or exceeding the United States Environmental Protection Agency (USEPA) upper benchmark of 1 & times; 10-4. Our findings are not just data, they are a compelling call to action for urgent emission controls, improved industrial hygiene and long-term health surveillance in one of the world's most rapidly developing industrial zones.
In modern times, time-lapse electrical resistivity tomography (TL-ERT) has become a powerful investigative tool that can be used in conjunction with regular point-based procedures to track seasonal soil moisture content (SMC) at engineering sites and to monitor the effects of induced biodegradation of contaminant plumes/effluents when released into the environment. These applications are crucial for mitigating the potential risk of geotechnical instabilities and protecting the environment, human health, and ecosystems from the risks associated with contaminants when released into the surface. TL-ERT data sets from two locations in Effurun Delta State, southern Nigeria, were employed in monitoring seasonal variations in SMC at an engineering site and the effect of biodegradation of contaminant plumes on the environment in an automobile workshop. In total, six (6) 2D ERT and four (4) 2D ERT profiles acquired during two time seasons in an engineering site and automobile workshop, respectively, were used to perform simultaneous inversion. The 2D ERT data acquired at the engineering site in the rainy and dry seasons characterized the hydrogeological behavior of the subsurface, with high and low water content (with a resistivity range of 200–356 Ωm) observed in both seasons. The geology of the study site is predominantly sand with low water-retaining capacity. The fine/clayey sand layers with fine particles that retain more water can initiate geotechnical instabilities, making the overlying materials susceptible to failure. The percentage differences in electrical conductivity (EC) between the monitoring periods showed little or no significant change in the EC of subsurface water. Also, the results of 2D ERT data sets acquired between September 2023 and September 2024 at the auto mechanic workshop showed increasing evidence of biodegradation of high-ER contaminants indiscriminately spilled on the surface into low-resistivity/conductive plumes with an ER range of 10-31.6 Ωm and percentage conductivity differences in the order of 50 to 100
ABSTRACT Elliptic curve cryptography ( ECC ) underpins the security of most blockchain systems, yet its practical implementations face numerous vulnerabilities. In this systematic literature review ( SLR ), we catalogue and analyze attacks on ECC in the context of blockchain security, including side‐channel attacks, nonce/ PRNG failures, cryptanalysis, and implementation flaws, and we survey proposed countermeasures. We follow rigorous SLR methodology with defined inclusion/exclusion criteria, search strategies across databases such as IEEE Xplore, ACM , Scopus, Web of Science, and clear data synthesis, ensuring replicability. Emphasizing empirical case studies and real‐world exploits, we discuss instances where ECC weaknesses led to blockchain breaches including biased elliptic curve digital signature algorithm nonces exposing Bitcoin/Ethereum private keys, smartphone power analysis revealing wallet keys, and Trezor hardware‐wallet key extraction via single‐trace side‐channel analysis ( SCA ). We tabulate known attack vectors versus affected systems, and similarly compare countermeasure techniques such as hybrid classical/quantum schemes, threshold signatures, and zero‐knowledge proofs, along with implementation trade‐offs. We evaluate advances such as Curve25519/ EdDSA and ARM SVE2 to mitigate side‐channel leakage. Our findings highlight that practical security of blockchain cryptosystems depends on correct ECC implementation and emerging cryptographic upgrades, not merely on the mathematical hardness of the elliptic curve discrete logarithm problem.
