Globally, environmental challenges have been recognised as a matter of concern. Among these challenges are the reduced availability and quality of drinking water, and greenhouse gases that give rise to change in climate by entrapping heat, which result in respirational illness from smog and air pollution. Globally, the rate of demand for the use of freshwater has outgrown the rate of population increase; as the rapid growth in town and cities place a huge pressure on neighbouring water resources. Besides, the rapid growth in anthropogenic activities, such as the generation of energy and its conveyance, release carbon dioxide and other greenhouse gases, warming the planet. Polymer nanocomposite has played a significant role in finding solutions to current environmental problems. It has found interest due to its high potential for the reduction of gas emission, and elimination of pollutants, heavy metals, dyes, and oil in wastewater. The revolution of integrating developed novel nanomaterials such as nanoparticles, carbon nanotubes, nanofibers and activated carbon, in polymers, have instigated revitalizing and favourable inventive nanotechnologies for the treatment of wastewater and gas separation. This review discusses the effective employment of polymer nanocomposites for environmental utilizations. Polymer nanocomposite membranes for wastewater treatment and gas separation were reviewed together with their mechanisms. The use of polymer nanocomposites as an adsorbent for toxic metals ions removal and an adsorbent for dye removal were also discussed, together with the mechanism of the adsorption process. Patents in the utilization of innovative polymeric nanocomposite membranes for environmental utilizations were discussed.

The development in marine industry and its effort in building bridges has placed a huge demand on reliability and duration of service of reinforcing steel in concrete. Literature has documented several studies on corrosion of reinforcing steel in concrete induced via carbonation and chloride in marine milieus. Extension of concrete structures service life has been one of the foremost strong worries of the concrete industry, especially for marine industry. Hence, the necessity to employ a cost effect system for shielding the reinforced steel in concrete from corrosion. Studies have shown that one prospective solution in combating corrosion deterioration in reinforced steel in concrete structures is the introduction of corrosion-inhibiting admixtures into concrete. This review discussed at length corrosion in reinforced concrete and corrosion inhibitors in relation to concrete together with the classification of inhibitors based on the method of applications. This review further reports corrosion-inhibiting admixtures in concrete. As a result, the aspects of corrosion inhibitors this manuscript reviewed are corrosion inhibitors employed as admixtures in concrete for new construction in the marine industry. Furthermore, corrosion inhibitors are employed for repairs and maintenances admixed with concrete for patches on marine structures, squirted onto the surface of the concrete or put on the concrete surface via saturation treatment. As a result of the excellent properties of functional nanostructured materials, the advancement in the implementation of functional materials in inhibiting admixtures in concrete is fast growing in marine industry. Hence, the Integration of functional materials in inhibiting admixture and their compatibility were reviewed. The significance of inhibitors employed as admixtures in concrete for practical applications of corrosion are the suppression or mitigation of corrosion process of metals used in marine industry and the patches of already constructed structures. The current problems related to corrosion-inhibiting admixtures in concrete and the future research and development directions were discussed.

This research work was carried out to investigate the corrosion inhibitive performance of the extract obtained from waste peels of orange (citrus sinensis) on A36 mild steel in HCl medium. A36 mild steel metal coupons were immersed in dilute hydrochloric acid solution (1M) containing different concentrations of the waste orange peels extract inhibitor (0 -4 g/L) at different temperatures of 32 0 C & 45 0 C (during gravimetric tests), as well as 27 0 C & 50 0 C (during potentiodynamic tests). The gravimetric analysis performed revealed the highest inhibition efficiency of the extract to be 94.33% at concentration of 4 g/L and temperature of 32 0 C. Also, results from this analysis revealed a spontaneous (irreversible) and physisorption mode of adsorption of the inhibitor molecules as well as the fitness of the Langmuir adsorption isotherm for the adsorption process. The phytochemical analysis carried out revealed the presence of tannins, saponins, flavonoids, terpenoids and steriods in the inhibitor. The results of the potentiodynamic polarization analysis showed that the inhibitor retarded the anodic dissolution of mild steel more than the cathodic reaction which causes hydrogen evolution via the discharge of hydrogen ions.

A lasting solution is required to curb the corrosion attack because of the very destructive effect it has on engineering materials. Corrosion is a material degrading phenomenon that reduces the significant properties of metallic materials, making them less useful. This paper has been able to highlight the very suitable methods or techniques that help to mitigate the effect of corrosion on metals and other helpful engineering materials. Some of these methods are electrodeposition and protective coatings like organic coatings, inorganic coatings, and metallic coatings.

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Corrosion refers to the deterioration of metallic materials resulting from the reactions between the components and their environe. However, corrosion occurs every day in the human world, both in industrial operations and domestically. This happens in different ways, making it well categorized into various types. This paper has concisely reported the basic phenomenon of corrosion, its environmental effect, and the various types like a crevice, pitting, erosion, and others. The Electrochemical behavior of corrosion was also reported as reactions that include oxidation and reduction reactions; oxidation reactions increase the valence number of materials by removing particles from the material, making them positively charged. In other ways, technological advancement has provided several attempts to understand this catastrophe, providing consistent mitigating measures and control toward attaining less cost. This overview studies the electrochemical corrosion phenomena and the prospect of materials selection in curtailing the ranging challenges.

Corrosion of mild steel via chemical reaction in a corrosive environment is a problematic occurrence that is very common in oil and gas industries. Corrosion constitutes a huge part of the total costs in the production of oil and gas. Corrosion inhibitors have found interest in the scientific domain because they are mainly understood by their chemical complexes and formulations. Their utilization in small amount on metal surface used in oil and gas industries can help shield the metal from corrosion devoid of any significant alteration in the concentration of the corrosive media in the environment. An effort was made to study the possibility of using calf thymus gland DNA (CTGDNA) inhibitor in chlorine induced mild steel for possible usage in piping in oil and gas industry. The SEM micrograph shows that the adsorption of the CTGDNA biomacromolecules coat on the mild steel surfaces functions as a protection against HCl corrosive solution. Electrochemical study and weight loss analysis showed that the inhibitor efficiency (70.48 and 72%, respectively) of the tested DNA (CTGDNA) in HCl acidic corrosion environment for the mild steel was high at 1.5 M of HCl. The inhibitor efficiency decreased with increasing HCl concentrations. The open circuit potential (OPC) revealed that the mild steels got corroded until the end of the immersion. The intensities of XRD peak substantiate the existence of corrosion products of FeCl2.