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Recent Submissions

Innovative techniques for combating a common enemy forever chemicals: A comprehensive approach to mitigating per- and polyfluoroalkyl substances (PFAS) contamination
(Environmental Research, 2024-07-03) Ajibola A. Bayode
The pervasive presence of per and polyfluoroalkyl substances (PFAS), commonly referred to as “forever chemicals,” in water systems poses a significant threat to both the environment and public health. PFAS are persistent organic pollutants that are incredibly resistant to degradation and have a tendency to accumulate in the environment, resulting in long-term contamination issues. This comprehensive review delves into the primary impacts of PFAS on both the environment and human health while also delving into advanced techniques aimed at addressing these concerns. The focus is on exploring the efficacy, practicality, and sustainability of these methods. The review outlines several key methods, such as advanced oxidation processes, novel materials adsorption, bioremediation, membrane filtration, and in-situ chemical oxidation, and evaluates their effectiveness in addressing PFAS contamination. By conducting a comparative analysis of these techniques, the study aims to provide a thorough understanding of current PFAS remediation technologies, as well as offer insights into integrated approaches for managing these persistent pollutants effectively. While acknowledging the high efficiency of adsorption and membrane filtration in reducing persistent organic pollutants due to their relatively low cost, versatility, and wide applicability, the review suggests that the integration of these methods could result in an overall enhancement of removal performance. Additionally, the study emphasizes the need for researcher attention in key areas and underscores the necessity of collaboration between researchers, industry, and regulatory authorities to address this complex challenge.
Contamination Levels, Source Apportionments, and Health Risks Evaluation of Heavy Metals from the Surface Water of the Riruwai Mining Area, North-Western Nigeria
(POLLUTION, 2023-05-23) Ajibola A. Bayode
Mining is one of the most environmentally damaging human activities, having long-term health effects on humans. In this research, the levels of contamination, source distribution, and health risks of heavy metals to residents from drinking surface water near Riruwai mining sites were investigated. The findings of the study indicated that the heavy metal levels ranged from As (0.00–0.04 mg/L), Cd (0.00–0.04 mg/L), Cr (0.02–0.06 mg/L), Mn (0.02–0.07 mg/L), and Pb (0.00–0.05 mg/L), with mean levels of 0.02, 0.013, 0.03, 0.02, and 0.04 mg/L, respectively. The concentrations of all metals, with the exception of Mn and Cr, are higher than acceptable limits. The values of the heavy metal pollution index (HPI) for all the metals, with the exception of Mn, exceed the threshold limit of 100, indicating serious pollution of the surface water. This was confirmed by the results of Nemerow’s pollution index (NPI). Multivariable analysis revealed anthropogenic and natural sources as the main sources of heavy metal contamination, with Cd, As, Cr, and Pb originating from mining activities and Mn possibly coming from parent materials. The total hazard index (HI) and non-cancer risk (HQ) values in children and adults are within acceptable limits. However, the total life cancer risks (TLCR) of As and Cd were higher than the tolerable limit of 1.00E-06. Therefore, heavy metals in surface water, particularly As, Cd, and Pb, should be properly monitored and a treatment program implemented to safeguard the health of local residents, especially children.
Humic substances derived from unconventional resources: extraction, properties, environmental impacts, and prospects
(Environmental Science and Pollution Research, 2023-04-04) Ajibola A. Bayode
Humic substances comprise up to 70% of the total organic matter in soils, between 50 and 80% of the dissolved organic matter in water, and about 25% of dissolved organic matter in groundwater. Elucidation of the complex structure and properties of humic substances requires advanced analytical tools; however, they are of fundamental importance in medicine, agriculture, technology, and the environment, at large. Although they are naturally occurring, significant efforts are now being directed into their extraction owing to their relevance in improving soil properties and other environmental applications. In the present review, the different fractions of humic substances were elucidated, underlying the mechanisms by which they function in soils. Furthermore, the extraction processes of humic substances from various feedstock were illustrated, with the alkali extraction technique being the most widely used. In addition, the functional group and elemental composition of humic substances were discussed. The similarities and/or variations in the properties of humic substances as influenced by the source and origin of feedstock were highlighted. Finally, the environmental impacts of humic substances were discussed while highlighting prospects of humic acid production. This review offers enormous potential in identifying these knowledge gaps while recommending the need for
Enhanced photocatalytic removal of tetracycline using Ag/AgBr embedded activated carbon with different chemical activators
(surface and interfaces, 2025-05-23) Ajibola A. Bayode
This study compares the enhanced photocatalytic properties and performance of the silver/silver bromide (Ag/AgBr) nanoparticles embedded in the activated carbon (AC) prepared from pinecone biomass activated using ZnCl2 (AB-ACPC-Z), and KOH (AB-ACPC-K), for removal of tetracycline (TC). The characterization results confirmed the incorporation of uniform dispersed Ag/AgBr (AB) species on the ACPCs with a particle size between 150 and 250 nm. A quasi-cubic morphology of AB NPs was achieved using the ACPC-Z catalyst promoter. The AB-ACPC-Z photocatalyst had a bandgap of 2.43 eV, with an improved optical absorption in the visible light, compared to that of AB-ACPC-K, and AB NPs. A lower degree of recombination of photogenerated charge carriers resulted from adding ACPC-Z to the AB NPs. AB-ACPC-Z and AB-ACPC-K exhibited high removal efficiencies of TC (89.08 % and 87.8 %), respectively at pH 7. Using central composite design (CCD), the optimum experimental parameters for photocatalytic activity in order of significance, were determined to be an initial TC concentration of 20 mg/L, a photocatalyst dosage of 0.45 g/L and an irradiation time of 120 min. LC/MS analysis revealed the influence of reactive oxidative species and ring-opening degradation pathway.
Seasonal distribution, source apportionment and risk assessment of polycyclic aromatic hydrocarbons in groundwaters in Owo, Southwestern Nigeria
(water practice and technology, 2023-01-22) Ajibola A. Bayode
The study focused on evaluating the seasonal distribution, source apportionment, and probabilistic risk assessment of polyaromatic hydrocarbons (PAHs) in groundwater. Groundwater samples were obtained from Owo, southwestern Nigeria and subjected to liquid–liquid extraction and quantified using gas chromatography–mass spectrometry. Total PAH concentrations varied from about 180 to 23,600 ng/L during the dry season. The wet season, on the other hand, exhibited a wider range, from about 1,550 to 150,000 ng/L. Seasonal variations were also found in PAH types and concentrations, with relatively higher concentrations recorded during the wet season. Diagnostic ratios and positive matrix factorization indicated that coal/biomass combustion and traffic-related vehicular emissions were the prevalent sources of PAHs in groundwater. Health risk assessment indicated potential carcinogenic risks (incremental lifetime cancer risk (ILCR).1E 04), while ecological assessment suggested medium (RQNC,800 and RQMPC 1) and high ecological risks (RQNC 800 and RQMPC 1). The study reflected the need for effective mitigation strategies.