Industrial developments in the oil and gas, petrochemical, pharmaceutical and food sector have contributed to the large production of oily wastewater worldwide. Oily wastewater pollution affects drinking water and groundwater resources, endangers aquatic life and human health, causes atmospheric pollution, and affects crop production. Several traditional and conventional methods were widely reported, and the advantages and limitations were discussed. However, with the technology innovation, new trends of coupling between techniques, use of new materials, optimization of the cleaning process, and multiphysical approach present new paths for improvement. Despite these trends of improvement and the encouraging laboratory results of modern and green methods, many challenges remain to be raised, particularly the commercialization and the global aspect of these solutions and the reliability to reduce the system’s maintenance and operational cost. In this review, the well-known oily wastewater cleaning methods and approaches are being highlighted, and the obstacles faced in the practical use of these technologies are discussed. A critical review on the technologies and future direction as the road to commercialization is also presented to persevere water resources for the benefit of mankind and all living things.

Corrosion wreaks havoc on our properties, our lives, and environment. So, prevention of corrosion is of the utmost importance. Inorganic inhibitors are used to prevent corrosion, but these are toxic. Therefore, environment-friendly inhibitor is necessary. Green corrosion inhibitors are a probable solution to this. Their demand both environmentally and economically, is increasing. This review article briefly deals with different types of corrosion prevention methods, various green inhibitors with their source and methods of their efficient applications. The working principle of green inhibitors in different media is also explained. Corrosion determination methods are briefly discussed. Of course, the economic significance of these inhibitors has been debated. In the end, considering the current research gaps, future research directions are put forward.