Coal tar 5% in Zinc ointment

One of the major obstacles to Nigeria's techno-economic development has been a lack of good road infrastructure. Despite a large deposit of natural bitumen in the form of semi-liquid and bitumen sand, the reliance on imported bitumen/asphalt for road construction and maintenance in Nigeria has reduced road coverage and quality. To use local bitumen as a binder in pavement construction, an efficient upgrading process is required using polymers, nanomaterials, and other chemical additives. However, the selection of an appropriate modifier depends on many factors including the origin, elemental and chemical composition of bitumen. This review presents vital properties of Nigerian bitumen extracted from oil wells and tar sands with the view to identifying potential additives as solutions for its upgrading. Based on predefined selection criteria, we conducted a systematic review of the literature. We gathered information on the current state of knowledge about the major issues encountered during the polymeric modification of bitumen. In addition, data on existing practices used by various road researchers to address such issues was gathered. Effort was made to review waste packaging polymers and plastics for possible utilization to ensure sustainable pavement infrastructure in Nigeria. The results of this review showed relatively little information on Nigerian bitumen upgrading. Many authors have investigated different polymer additives on asphaltic bitumen sourced from different countries and the results has pointed to the capability of polymeric modification to improve some of the properties of bitumen. A knowledge gap however, exists in the optimization of polymer dosage, and characterization of bitumen at the SARA level to aid the understanding of the effects of polymeric modification and mechanisms involved during the pavement degradation. Additionally, it has been challenging to generalize the effects of different polymers due to the variation of bitumen properties from different sources. This review identifies the potential for upgrading Nigerian bitumen using polymer additives, the potential of waste plastics, crumb rubbers, and packaging waste materials as alternative and sustainable additives also highlighted.

Abstract licence: CC BY-NC

Asphalt is widely used as a coating resin due to its excellent adhesion strength and cost-effectiveness; however, its limited corrosion protection necessitates enhancement. In this study, poly(amidoamine) (PAMAM), combined with zinc oxide (ZnO) nanoparticles, was incorporated into the asphalt matrix to improve its anticorrosive properties. Various ratios of PAMAM-ZnO nanocomposite (1, 2, 4, and 6% by weight) were added to the asphalt binder, with the materials characterized using XRD, ¹H-NMR, and SEM techniques. The 2% PAMAM-ZnO/asphalt ratio exhibited the most significant improvement, achieving a corrosion protection efficiency (η%) of 97.93%, as confirmed by Tafel analysis, and a charge transport resistance (RCT) of 75.91 Ω cm² according to electrochemical impedance spectroscopy (EIS) data. A combination of barrier formation and sacrificial protection drives the corrosion inhibition mechanism. The PAMAM-ZnO nanocomposite forms a highly uniform layer on the carbon steel surface, creating an effective physical barrier that prevents the penetration of corrosive agents, thereby minimizing defects like pinholes. This barrier effect is complemented by the sacrificial protection provided by the ZnO nanoparticles, which are more reactive than the underlying steel and preferentially interact with corrosive ions (e.g., chloride ions). This interaction leads to the formation of stable ZnO corrosion products, which enhance the barrier and reduce the likelihood of corrosion on the steel surface. Additionally, PAMAM facilitates the even distribution and strong adhesion of ZnO within the asphalt matrix, ensuring a durable protective layer. The synergic impact between the polymer barrier and sacrificial ZnO protection results in the exceptional corrosion resistance observed in the 2% PAMAM-ZnO/asphalt formulation, offering a promising approach for advanced anticorrosive coatings.

Abstract licence: CC BY

BackgroundLung cancer is a leading cause of death worldwide, with environmental factors playing critical roles in its development and progression. Respirable and food-borne contaminants are major contributors to lung cancer onset, influencing various physiological pathways that lead to lung injury and tumor formation.Aim of reviewThis review aims to examine the effects of common environmental pollutants on lung cancer development, highlighting the role of specific contaminants, such as PM2.5 (particulate matter with aerodynamic diameter less than 2.5  µm) and nitrogen oxides, and warning people to pay more attention to environmental pollutants.Key scientific concepts of reviewEnvironmental pollutants play a significant role in increasing the susceptibility to lung cancer by triggering various biological mechanisms that lead to lung injury and tumorigenesis. Excessive PM2.5 exposure contributes to the overall burden of lung cancer via Wnt/β-catenin, Reactive oxygen species-DNA methyltransferases (ROS-DNMT), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/Akt), Janus kinase/signal transducers and activators of transcription (JAK/STAT) signalling pathways. The primary mechanisms by which NO contributes to the occurrence and development of pulmonary neoplasm revolve around the production and regulation of ROS. Occupational exposure and ecosystem pollution to hazardous substances, including microplastics, pesticides, asbestos, cadmium, and nickel, are the well-established risk factors for the development of lung cancer via DNA damage, oxidative stress, and inflammation pathways. This review emphasizes the importance of effective prevention strategies for lung cancer by reducing environmental pollution levels.

Abstract licence: CC BY-NC-ND

Recycling and reusing industrial waste and by-products are topics of great importance across all industries, but they hold particular significance in the metal industry. Aluminum, the most widely used non-ferrous metal globally, generates considerable waste during production, including dross, salt slag, spent carbon cathode and bauxite residue. Extensive research has been conducted to recycle and re-extract the remaining aluminum from these wastes. Given their varied environmental impacts, recycling these materials to maximize residue utilization is crucial. The components of dross, salt slag, and bauxite residue include aluminum and various oxides. Through recycling, alumina can be extracted using processes such as pyrometallurgy and hydrometallurgy, which involve leaching, iron oxide separation, and the production of alumina salt. Initially, the paper will provide a brief introduction to the generation of aluminum residues-namely, dross, salt slag, and bauxite residue-including their environmental impacts, followed by an exploration of their potential applications in sectors such as environmental management, energy, and construction materials.

Abstract licence: CC BY

The discharge and accumulation of coal-based solid waste have caused great harm to the ecological environment recently. Coal-based solid wastes, such as coal gangue and fly ash, are rich in valuable components, such as rare earth elements (REY), silicon dioxide, alkali metal oxides, and transition metal oxides, which can be used to synthesize various functional Si-based porous materials. This article systematically summarizes the physicochemical characteristics and general processing methods of coal gangue and fly ash and reviews the progress in the application of porous materials prepared from these two solid wastes in the fields of energy and environmental protection, including the following: the adsorption treatment of heavy metal ions, ionic dyes, and organic pollutants in wastewater; the adsorption treatment of CO2, SO2, NOx, and volatile organic compounds in waste gas; the energy regeneration of existing resources, such as waste plastics, biomass, H2, and CO; and the preparation of Li-Si batteries. Combining the composition, structure, and action mechanism of various solid-waste-based porous materials, this article points out their strengths and weaknesses in the above applications. Furthermore, ideas for improvements in the applications, performance improvement methods, and energy consumption reduction processes of typical solid-waste-based porous materials are presented in this article. These works will deepen our understanding of the application of solid-waste-based porous materials in wastewater treatment, waste gas treatment, energy regeneration, and other aspects, as well as providing assistance for the integration of new technologies into solid-waste-based porous material preparation industries, and providing new ideas for reducing and reusing typical Chinese solid waste resources.

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This review provides an exploration of various catalytic pyrolysis techniques for bio-oil production, focusing on the effects of different pyrolysis methods (slow, fast, and flash pyrolysis) on bio-oil yield and composition. The review also discusses key factors influencing bio-oil production, including feedstock composition (cellulose, hemicellulose, and lignin), and the role of catalytic materials in enhancing yield and product selectivity. Three primary classes of catalysts-zeolites, carbonaceous materials, and metal oxides-are thoroughly examined, with a discussion on the differences between bulk catalysts and nanocatalysts. The paper highlights how these catalysts influence the formation of bio-oil components such as phenols, hydrocarbons, and oxygenated compounds. Furthermore, this review discusses recent advancements in catalyst design and modifications to optimize bio-oil production. This review provides the latest advancements in catalytic pyrolysis, emphasizing the correlation between catalyst properties and the resulting products. It aims to offer valuable insights into the future potential of catalytic pyrolysis for efficient biomass conversion and sustainable biofuel production.

Abstract licence: CC BY