All bis(terpyridine)metal complexes exhibit a distorted octahedral geometry due to the steric strain imposed by the terpyridine ligand. In these complexes, the central metal-nitrogen bonds are consistently shorter than the terminal metal-nitrogen bonds, indicating that every bis(terpyridine)metal complex is inherently compressed along the direction of the central metal-nitrogen bonds. However, due to the Jahn-Teller effect, additional geometric distortion and symmetry breaking occur in Jahn-Teller active bis(terpyridine)metal complexes to stabilize the system. Examples include high-spin d4 bis(terpyridine)manganese(III) and d4 bis(terpyridine) chromium(II), high-spin d6 bis(terpyridine)iron(II), low-spin d7 bis(terpyridine)cobalt(II) and bis(terpyridine) nickel(III), and d9 bis(terpyridine)copper(II). Elongation Jahn-Teller distortion in bis(terpyridine)metal complexes occurs along the opposite terminal metal-nitrogen bonds of one of the terpyridine ligands, with the highest symmetry achieved in such elongation Jahn-Teller distorted bis(terpyridine)metal compounds being C2v. Compression Jahn-Teller distortion occurs along the central metal-nitrogen bonds, with the highest symmetry in these compressed bis(terpyridine)metal compounds being D2d, although C2v symmetry is also observed, with the z-axis defined along the central metalnitrogen bonds. Distinguishing between the two possible Jahn-Teller distorted geometries for bis(terpyridine)metal complexes under C2v (or lower) symmetry is not straightforward. This contribution discusses, with examples, experimental and theoretical results reported on Jahn-Teller distortion observed in bis(terpyridine)metal complexes, providing guidelines on how to identify the kind of Jahn-Teller distortion observed.

Microplastics (MPs) are being released into the environment in large quantities, especially in less developed parts of the world. This group of pollutants is mostly leached into the environment through heavy plastic dumpsites, pharmaceutical and personal care product containers, hospital wastes, plastic package accessories, and litter from food packaging. Consequently, these compounds are found in different compartments of the ecosystem, such as soils, sediments, biota, and, surprisingly, drinking water. The present study systematically appraised recent studies on MP pollution in the Asian and African environments. It also summarized the trends in the methods for the environmental monitoring of MPs and the removal strategies that have been employed. From the data gathered, the two key instrumentations involved are the microscopes for visualization and the Fourier transform-infra-red (FT-IR) spectrometer to classify or characterize the MPs. Based on the surveyed works of literature, China and South Africa have relatively more information on MP contamination of diverse matrices within their countries. Meanwhile, studies on the status of MP contamination should be conducted across all countries. Hence, this study becomes an eye-opener regarding the commencement of research works on the MP contamination of the environment, especially in other Asian and African countries with little or no information. Furthermore, the literature on ecotoxicity studies of MPs was investigated to ascertain the toxic nature of these compounds. This aspect of research is vital because it serves as a prerequisite for the remediation of these compounds. Microplastics have been declared lethal to biotic components, so all hands must be on deck to continuously remove them from the environment.

The world demand for energy has shifted from fossil fuel to the use of bioenergy due to the skyrocketing price of fossil fuels, environmental concerns, and depleting reserves. Consequently, countries around the world have put in efforts to advance the production of biofuels from cheap and readily available feedstocks. In this chapter, we have presented a comprehensive and in-depth discussion of the current status of bioenergy in continents around the globe such as Africa, the European Union, Asia, and America. The focus was on the politics and policies embarked on by these continents to advance bioenergy production. Some of the findings revealed that South Africa, as one of the countries in Africa, has made a huge progress in bioenergy production since the 1970s because of its strong commitment to research and development in biomass conversion technologies, while the other African countries found it difficult to strike a balance between biofuel production and food availability. Also, in EU countries, different policies, including feed-in tariffs, energy efficiency, tax incentives, subsidies, regulatory framework, sustainable standards, and energy tax, have been implemented to improve bioenergy production. China's experience in practice proves that the growth of bioenergy generation can be accompanied by a balance of environmental, economic, and social development. We conclude this chapter by putting down the future perspectives as well as challenges regarding the impacts of policies and politics toward bioenergy technology advancement in major countries around the world.

Poly- and perfluoroalkyl substances (PFAS) are among the pollutants of environmental concern besides pharmaceuticals and personal care products, microplastics, and other persistent organic pollutants. Of all the different PFASs reportedly present in the environment, the most researched are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). In this study, these pollutants were detected using a precise, selective, and sensitive liquid chromatographic-electrospray ionization single quadrupole mass spectrometric (LC-ESI-Q-MS) method within a linear range of 0.002-0.02 mu g/mL. The method developed was thereafter validated according to the ICH validation parameters. This method was used to monitor PFOA and PFOS in selected surface sediments collected within the environs of two prominent rivers in the KwaZulu-Natal province of South Africa: Umgeni and Palmiet Rivers. While the PFOA levels varied from not detected to 1.490 ng/g dw, and PFOS levels ranged from 0.206 ng/g dw to 0.426 ng/g dw, the total PFOA and PFOS concentration ( n-ary sumation PFOA and n-ary sumation PFOS) in the surface sediment samples collected were 7.50 ng/g dw and 2.79 ng/g dw, respectively. The percent positive occurrence of PFOA and PFOS in all the tested sediment samples was 81.8 % and 100 %, respectively. This study becomes an eye opener to the commencement of research works with respect to developing remediation strategies for the removal of PFAS in the environment, especially the African environment.

The scarcity and shortage of clean and potable water for human consumption and/or use are of global concern. The contamination of water induced by pharmaceuticals and pharmaceutical products further worsens this problem, as intake of such contaminated water could lead to drug resistance. The reclamation of wastewater containing pharmaceuticals by adsorption is found to be an effective, simple, and cost-effective process. In this review article, we selected and evaluated ∼140 published articles on adsorption-based studies between 2010 and 2023 that have investigated the use of cheap and adsorptive carbon-based materials for remediation of pharmaceutical-laden wastewater. The application of carbon-based materials for the reclamation of varying types of organic micropollutants in wastewater is rapidly gaining attention in recent years. This is due to their sustainability, reusability, adsorption capacities, and cost-effectiveness. The uptake of pharmaceuticals as an organic micropollutant in terms of adsorption isotherm, operating parameters (temperature, initial concentration, solution pH, time), re-usability studies, kinetics, etc. for different kinds of carbon-based materials are addressed in this review article.

Perfluoroalkyl substances (PFAS) and their distribution in aquatic environments have been studied extensively, but more information is needed to link these occurrences to their physicochemical characteristics. Understanding how these parameters influence PFAS can help predict their fate, mobility, and occurrences in water. This study reviewed the influence of physicochemical parameters on the occurrences of PFAS in aquatic environment using the relevant keywords to retrieve articles from databases spanning mostly between 2017 and 2024. The result suggests that high pH, turbidity, and dissolved oxygen, give high concentration of PFAS, while high electrical conductivity, temperature and salinity give low PFAS concentration in the water. Therefore, monitoring and safeguarding the aquatic bodies for human and environmental safety is imperative. Future studies should include the effects of the physicochemical properties on PFAS occurrences in the natural environment and focus on an organism's distinctive characteristics to comprehend the bioaccumulation and biomagnification of PFAS in them and environmental matrices.

Environmental effects of active pharmaceutical compounds (APCs) in the environment are not well characterized, hence the need for comprehensive evaluation. This study employed three bioassays using three organisms, namely, Allium cepa, Daphnia magna, and Salmonella typhimurium, in the ecotoxicity study of lone and a mixture of selected APCs, namely, lamivudine (L), an antiretroviral, and ciprofloxacin (C) and sulfamethoxazole (S), antibiotics, at a concentration range between 10 and 100 ppb, in order to evaluate the potential of the lone and ternary mixture to exert synergistic toxicity. Study results from exposure to lone APCs showed that the L, C, and S trio individually had fatal impacts on daphnids, with mortality rates of 100, 75, and 95%, respectively, after 48 h. Sulfamethoxazole showed a mutagenic tendency, with a mutation ratio (background/sample ratio) of 2.0. Lamivudine showed a lethal impact on the root length of A. cepa (p > 0.05, p = 3.60E-3). Further microscopic examination of the A. cepa root tip revealed chromosomal aberrations on exposure to each compound. The LCS-mix ecotoxicology bioassays indicated a synergistic effect on the daphnids, probably due to potentiation. Although the LCS mix had a cytotoxic effect (evidenced by the absence of bacteria colonies) on exposed TA 98 P450 Salmonella typhimurium strain, this effect was not observed in other bacterial strains. Microscopic examination of A. cepa exposed to the LCS-mix revealed an aberration in the mitotic stage of the cell. The impact of combination of the pharmaceuticals in aqueous ecosystems was greater than when exposed to the tested individual pharmaceutical compounds. Study result showed that these compounds have tendencies to pose a higher risk to exposed living entities when in combined/potentiated forms, and this could lead to distortion of the regular functioning of the ecosystem, particularly bacterial and other microbial populations that are listed among primary producers of the aquatic food web.

Carbon dioxide (CO2) is the most important greenhouse gas (GHG), accounting for 76% of all GHG emissions. The atmospheric CO2 concentration has increased from 280 ppm in the pre-industrial era to about 418 ppm, and is projected to reach 570 ppm by the end of the 21st century. In addition to reducing CO2 emissions from anthropogenic activities, strategies to adequately address climate change must include CO2 capture. To promote circular economy, captured CO2 should be converted to value-added materials such as fuels and other chemical feedstock. Due to their tunable chemistry (which allows them to be selective) and high surface area (which allows them to be efficient), engineered nanomaterials are promising for CO2 capturing and/or transformation. This work critically reviewed the application of nanomaterials for the transformation of CO2 into various fuels, like formic acid, carbon monoxide, methanol, and ethanol. We discussed the literature on the use of metal-based nanomaterials, inorganic/organic nanocomposites, as well as other routes suitable for CO2 conversion such as the electrochemical, non-thermal plasma, and hydrogenation routes. The characteristics, steps, mechanisms, and challenges associated with the different transformation technologies were also discussed. Finally, we presented a section on the outlook of the field, which includes recommendations for how to continue to advance the use of nanotechnology for conversion of CO2 to fuels.

Abstract Cyanobacteria, an algae bloom that is responsible for the creation of deadly toxins. These toxins have the potential to adversely impact human and animal health. Microcystins (MC’s), are harmful toxins that are produced by cyanobacteria species. These deadly toxins are the most investigated toxins worldwide. However, in South Africa their occurrence statistics are deficient due to inaccessibility of reliable, sensitive, and precise analytical methods to investigate them in water surfaces. Thus, a development of analytical methods for the detection and accurate quantification of algal toxins is crucial to consider the health risk of exposure to toxins in wastewater and surface waters. This study recommends an analytical method for the detection and quantification of algal toxins using solid phase extraction (SPE) and high-performance liquid chromatography (HPLC) coupled with photodiode detector (PDA). The developed method was validated based on linearity which ranged from 3–2500 µg L− 1, recoveries at 99.6–113.9%, the limit of detection (LOD) ranging from 0.2–480 µg L− 1, and limit of quantification (LOQ) at 0.7–160 µg L− 1 and the regression coefficients obtained were above 0.9880 in all analytes. The developed method was applied to Darvill Wastewater Treatment Plant, Umgeni water, Durban surface waters, University of KwaZulu-Natal (UKZN) sport centre tap water and UKZN Westville two ponds), South Africa. MC-RR was the most detected analyte at concentration ranging from 0.069–30.521 ng L− 1 compared to other targeted MCs. The developed method is simple and cheap, which can consent developing countries to monitor these deadly MC toxins in water surfaces.

3D printing is a process used in a variety of industries. This has the potential to replace traditional method of fabrication in the coming years. However, 3D printed parts with a single type of raw material frequently lack robustness, resulting in failed prints. Therefore, enhancing the properties of the materials is critical for applications in a variety of fields. The synergistic combination of nanoparticles (NPs) and 3D printing technologies particularly extrusion based 3D printing may enable the creation of architecture and devices with unprecedented levels of functional integration. This review reports recent developments in the use of nanocomposites (NCs) with 3D printing technology. The outlooks and several important issues in this area are also discussed with the anticipation that this will provide additional insights to the research community.

The extensive usage of malachite green (MG) dyes in the fish and dye industries cause serious water pollution, leading to catastrophic effects on living organisms and the environment. In addressing the challenges of health risks related to the use of MG, different removal strategies have been studied and developed. This review presents the recent advances and mechanistic pathways involved in ozonation, electrochemical advanced oxidation (electrooxidation), and biological removal techniques for MG. The successful applications of these techniques in decontaminating water from MG are discussed. Furthermore, combined removal techniques for enhancing MG removal and for the reduction of operation costs are presented as it was shown in some cases to be more effective than individual remediation methods.

Malachite green (MG) dye is a common industrial dye and organic contaminant that can be found in (waste)water. Textile and food industries make use of MG as dyeing and food coloring agents, respectively. However, MG is both genotoxic and mutagenic. Hence, the elimination of MG from MG-laden-wastewater is germane. This review summarizes up-to-date researches that have been reported in literature as regards the decontamination of toxic MG wastewater. Various removal methods (adsorption, membrane, Fenton system, and heterogenous and homogeneous photodegradation) were discussed. Of the two basic technologies that are comprehensively explored and reviewed, chemical treatment methods are not as viable as physical removal methods, such as the adsorption technology, due to the lack of secondary pollutant production, simple design, low operation costs, and resource availability. This review also presents various practical knowledge gaps needed for large-scale applications of adsorptive removal methods for MG. It concludes by recommending further research on the techniques of cheap and simple decontamination of MG to get clean water.

Per and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals characterized by their ubiquitous nature in all environmental compartments which makes them of increasing concern due to their persistence, bioaccumulation, and toxicity (PBT). Several instrumental methodologies and separation techniques have been identified in the literature for the detection and quantification of PFAS in environmental samples. In this review, we have identified and compared common separation techniques adopted for the extraction of PFAS in food items, and analytical methodologies for identification and quantification of PFAS in food items of plant and animal origin, highlighting recent advances in tandem techniques for the high selectivity and separation of PFAS related compounds as well as knowledge gaps and research needs on current analytical methodologies.

Four-dimensional printing (4DP) has gained tremendous interest in the field of materials and manufacturing due to its shape changing properties. Unlike three-dimensional printing (3DP) fabricated with a stationary objects, 4DP allows a 3D printed objects to transform itself to another configuration in response to external energy inputs such as thermal, magnetic, solvent, light or other environmental factors. Utilizing the aforementioned capabil-ities of 4DP, scientists from various disciplines have investigated a wide range of 4DP with proofs-of-concept. Despite numerous initiatives, 4DP still requires additional developments to meet the industrial applications. This review exercise is therefore aimed to highlight the historical evolution, computational insights and emerging application of 4DP. The review begins by presenting historical evolution and basic fundamental ele-ments of 4DP. The review also presents computational overview on 4DP. Furthermore, different emerging ap-plications of 4DP are highlighted to enlighten the readers. The current challenges of 4DP and future perspectives are critically discussed. Finally, the findings of this review tends to structure research efforts in the next one decade toward the creation of sophisticated 4DP products that will meet the needs of consumers and industry.

Garcinia species (G. indica, G. cambogia, G. kola and G. mangostana) represent some of the most sought-after herbs globally due to their impressive medicinal qualities, hence the ever-growing interest of researchers into these plants. In this study, an extensive bibliometric analysis of the available research outputs on the widely-known Garcinia species was conducted to appraise the progress made and also highlight the future focus of research on the plants. The published articles (original and conference articles) on the selected species from 1991 to 2021 were retrieved from Scopus® database, scrutinized and further analyzed using the VOS viewer software. Over 2000 research outputs were published posting an annual publication rate of 75 articles, which have altogether garnered almost 37000 citations within the period under review. Of the 85 country affiliations on the publications, 5, which include India, Thailand, Nigeria, Indonesia, and the United States have cumulatively contributed two-thirds of the total outputs. The institutions; the University of Ibadan (97), Prince Songkla University (52) and Mahidol University (50) have the most publications revealing their research focus on herbs. However, in terms of individual influence, Prof E.O. Farombi, of the University of Ibadan, led the pack with an impressive 42 publications (1585 citations) on Garcinia kola followed by Prof Y.W. Chin of the Seoul National University, South Korea with 23 publications (452 citations) on Garcinia mangostana. The versatility in the health applications of these species especially as sources for new therapeutics, nutraceuticals or functional food ingredients, has been the main driver of the research within the past three decades. Recent research undertakings have demonstrated the potential industrial uses of herbs in the clothing and petroleum industries and these may dominate the research emphases in the immediate future.

Pharmaceutical compounds (PCs) have globally emerged as a significant group of environmental contaminants due to the constant detection of their residues in the environment. The main scope of this review is to fill the void of information on the knowledge on the African occurrence of selected PCs in environmental matrices in comparison with those outside Africa and their respective toxic actions on both aquatic and non-aquatic biota through ecotoxicity bioassays. To achieve this objective, the study focused on commonly used and detected pharmaceutical drugs (residues). Based on the conducted literature survey, Africa has the highest levels of ciprofloxacin, sulfamethoxazole, lamivudine, acetaminophen, and diclofenac while Europe has the lowest of all these PC residues in her physical environments. For ecotoxicity bioassays, the few data available are mostly on individual groups of pharmaceuticals whereas there is sparsely available data on their combined forms.

One of the popular cationic dyes that is environmentally persistent, toxic, carcinogenic and mutagenic is methylene blue (MB) dye. It is commonly applied as synthetic dye for dyeing fabrics in clothing and textile industries and also for dyeing papers and leathers. Sequel to the magnitude of industrial usage, a large volume of methylene blue dye containing wastewater is discharged into groundwater and surface water. At doses more than 5 mk/kg, the monoamine oxidate inhibitory characteristics of MB dye can induce fatal serotonin toxicity in human, apart from being a threat to fauna in aquatic ecosystem. Thus, it is highly imperative to eliminate MB dye from wastewaters. A number of different removal strategies have been reported in literature for treating methylene blue dye wastewater. In this state-of-the-art review, about 240 review and/or research published articles on methods for methylene blue dye wastewater decontamination or decontamination strategies were chosen for evaluation. This synthesis also discussed the various toxicities linked to MB dye. The assessment of elimination methods revealed that chemical removal methods (photochemical and non-photochemical) could generate secondary pollutants while biological methods are characterized with sensitivity of enzyme to pH. These drawbacks limit their industrial full-scale applications while adsorption technology was found to offer merits over others. The review comprehensively discussed each of these techniques while gaps and/or areas for future research are highlighted.

Large volume of urine is continuously released into the environment by both humans and animals, and impacts negatively on the environment and ultimately on humans and animals’ health. In this review, the negative impacts associated with the release of urine to the environment is highlighted. Instead of releasing urine into the environment, it has been used for several important applications. Various ways through which these waste discharge have been positively utilized such as in the synthesis of chemicals, evolution of hydrogen, power generation, source of raw materials, fertilizer application, diagnosis and treatment of diseases are comprehensively examined. Particularly, the use of urine in the synthesis of nanomaterials is emphasized. Since stabilization of urine is necessary for its application, several methods of treating and stabilizing urine are discussed. In addition, various analytical techniques used in the detection of substances present in the urine are presented. The aim of the present review is to explore different ways by which urine has been utilized so as to trigger more research findings on the other novel means of utilizing urine.

Good practices at harvest and postharvest could be useful in obtaining nutritious mango with high minerals and vitamins. The present study evaluated effect of harvest handling and postharvest conditions on the level of minerals and vitamins using standard methods. Ripe, half-ripe and unripe mangoes were harvested on parent plant and on ground around parent plant. The half-ripe and unripe mangoes were further divided to include heat ripened mangoes. The mango samples were separately stored naturally at 25±3oC and heat ripened at 37±5oC for 0 to 10 day after harvest (dah). The results show Ijebu-Mamu mangoes could cater for reference dietary intake of Vit C. Mango harvested on parent plant has highest level of minerals and vitamins than those picked on ground. Ripe mango has highest level of minerals, half ripe mango presented highest level of vits. B1 and B2 and unripe mango has highest level of Fe and Vit. C. Heat caused increased level of minerals and reduced level of vitamins. The minerals show increased level from 0 to 4 or 6 dah while vitamins reduced from 0 till 10 dah. High level of minerals and vitamins was obtained with optimum integrated harvest and postharvest condition of half-ripe mango naturally ripened at 6 dah. The present results highlight effects of the assessed harvest handling and postharvest conditions and their co-optimization that might be necessary for high minerals and vitamins in mango.

Antiretroviral drugs for the treatment of human immunodeficiency virus (HIV) and other viral infections are among the emerging contaminants considered for ecological risk assessment. These compounds have been reported to be widely distributed in water bodies and other aquatic environments, while data concerning the risk they may pose to unintended non-target species in a different ecosystem (environment) is scanty. In South Africa and other developing countries, lamivudine is one of the common antiretrovirals applied. Despite this, little is known about its environmental impacts as an emerging contaminant. The present study employed a battery of ecotoxicity bioassays to assess the environmental threat lamivudine poses to aquatic fauna and flora. Daphnia magna (filter feeders), the Ames bacterial mutagenicity test, Lactuca sativa (lettuce) germination test, and the Allium cepa root tip assay were conducted, testing lamivudine at two concentrations (10 and 100 µg/L), with environmental relevance. The Daphnia magna toxicity test revealed a statistically significant response (p << 0.05) with a mortality rate of 85% on exposure to 100 µg/L lamivudine in freshwater, which increased to 100% at 48-h exposure. At lower concentrations of 10 µg/L lamivudine, 90% and 55% survival rates were observed at 24 h and 48 h, respectively. No potential mutagenic effects were observed from the Ames test at both concentrations of lamivudine. Allium cepa bioassays revealed a noticeable adverse impact on the root lengths on exposure to 100 µg/L lamivudine. This impact was further investigated through microscopic examination, revealing some chromosomal aberration in the exposed Allium cepa root tips. The Lactuca sativa bioassay showed a slight adverse impact on both the germination rate of the seeds and their respective hypocotyl lengths compared to the control. Overall, this indicates that lamivudine poses an ecological health risk at different trophic levels, to both flora and fauna, at concentrations previously found in the environment.