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Summary: Process intensification (PI) is devoted to obtaining safer, smaller, cost‐effective, environmentally friendly, energy‐efficient and sustainable technologies, playing a major role in chemical process industries. Conventional technologies applied in the adsorptive separations may suffer from low selectivities, conversions and energy efficiencies; higher costs, kinetic and thermodynamic limitations related to the specific separation systems. Suitable PI techniques based on material, equipment and process development methodologies can play a major role in the proper organization of the adsorption separations. This article provides an overview of the concept of PI, starting from the history and its evolution over the years. Recent advances on the adsorptive separation applications through chemical PI are discussed with illustrative examples. Type of adsorption technology, intensification technique in terms of various intensification parameters are illustrated for a variety of adsorption separation systems. Product purity, productivity, gas uptake, recovery, separation efficiency, adsorbent property, bed volume, production yield, selectivity, energy efficiency, process cost and environmental sustainability are among the intensification parameters involved depending on the type of the separation system. The significant process enhancements achieved through PI in the examples are given. Conclusions, perspectives and future approaches are proposed with the aim for further contribution to the development of adsorption separations. Novelty statement: Since the concept of process intensification (PI) has been introduced in the early 80s, a quite diverse range of definitions have been offered for PI during the years, which do not involve an exact standard definition that has been accepted commonly. Since then, PI has been a rapidly growing field in chemical process industries and generated many innovative processes, resulting in higher production yields, higher recovery, high‐purity products, energy‐efficient, cost competitive and environmental‐friendly sustainable clean technologies. The paper aims to compile the concepts and definitions of PI proposed by different researchers starting from the first limited definitions until the more extensive recent ones. Then the recent advances on the various adsorptive separation applications through chemical PI are presented with illustrative examples. The type of adsorption technology, the specific adsorbate/adsorbent system and the applied intensification technique in terms of various intensification parameters involved in each study are given. The benefits of PI, the role of applying PI in all these recent works on adsorptive separations are emphasized. Conclusions and perspectives with future approaches are presented with the aim to contribute to future development. [ABSTRACT FROM AUTHOR]

Summary: Biofuel has emerged as an alternative source of energy to reduce the emissions of greenhouse gases in the atmosphere and combat global warming. Biofuels are classified into first, second, third and fourth generations. Each of the biofuel generations aims to meet the global energy demand while minimizing environmental impacts. Sustainability is defined as meeting the needs of the current generations without jeopardizing the needs of future generations. The aim of sustainability is to ensure continuous growth of the economy while protecting the environment and societal needs. Thus, this paper aims to evaluate the sustainability of these four generations of biofuels. The objectives are to compare the production of biofuel, the net greenhouse gases emissions, and energy efficiency. This study is important in providing information for the policymakers and researchers in the decision‐making for the future development of green energy. Each of the biofuel generations shows different benefits and drawbacks. From this study, we conclude that the first generation biofuel has the highest biofuel production and energy efficiency, but is less effective in meeting the goal of reducing the greenhouse gases emission. The third generation biofuel shows the lowest net greenhouse gases emissions, allowing the reduction of greenhouse gases in the atmosphere. However, the energy required for the processing of the third generation biofuel is higher and, this makes it less environmentally friendly as fossil fuels are used to generate electricity. The third and fourth generation feedstocks are the potential sustainable source for the future production of biofuel. However, more studies need to be done to find an alternative low cost for biofuel production while increasing energy efficiency. [ABSTRACT FROM AUTHOR]