Nowadays, water pollution has been considered a global concern on environmental sustainability, calling for high-performance materials in effective pollution treatments. Adsorption approach has great potential to eliminate persistent inorganic and organic compounds. Activated carbon (AC) materials including their composite materials have been largely investigated under various experimental conditions as low-cost, promising adsorbents to remove contaminants from water resources. In this review, the authors report the most recent development in activated carbon materials for the removal of organic and inorganic pollutants and its modeling counterpart using response surface methodology (RSM) statistical calculations. We also highlights up-to-date studies for the removal of organic pollutants and heavy metals from water using activated carbon materials as adsorbents with a focus on structure-to-properties and the effects of surface functions on adsorption processes. This review also summarizes for the first time the advantages and disadvantages of RSM method in the investigations related to adsorption of pollutants to assess the potential opportunities and challenges for the application of activated carbon materials in wastewater treatment. The critical analyses and conclusions highlighted in this present study should be of benefit to environmental scientists, chemists and engineers interested in the use of AC and optimization tools in environmental remediation.

Bismuth vanadate (BVO) has been established as an efficient photocatalyst for water remediation and energy applications. Its crystal structure stability, high light quantum and electronic transmission efficiency, and outstanding energy utilization capacity are the main reasons for its enhanced utilization as a robust photocatalytic material. Several studies have reported many synthesis methods and strategies to design highly efficient BVO photocatalysts with different shapes, morphologies, facets, oxygen vacancies. This review systematically encapsulates the effects of morphologies on the photodegradation properties. Here, we have surveyed the synthesis methods of BVO photocatalysts followed by their different synthesized morphologies. The photosensitization mechanism whereby the organic dye plays both the role of photosensitizer as well as sample to be degraded is addressed. Further, we have highlighted the general sequential photocatalytic processes and the recent advances on degradation of three model pollutants (Methylene Blue, Rhodamine B and Methyl Orange). The 3 steps photocatalytic mechanism of BVO photocatalysts have discussed. This review provides also the effects of crystal facets, heterojunction BVO materials and elemental doping on the photocatalytic efficiency. Finally, current status, challenges to improve the photoactivity and the future possible scenarios are summarized.

Metal organic frameworks (MOFs) are attracting significant attention for applications including adsorption, chemical sensing, gas separation, photocatalysis, electrocatalysis and catalysis. In particular, zeolitic imidazolate framework 8 (ZIF-8), which is composed of zinc ions and imidazolate ligands, have been applied in different areas of catalysis due to its outstanding structural and textural properties. It possesses a highly porous structure and chemical and thermal stability under varying reaction conditions. When used alone in the reaction medium, the ZIF-8 particles tend to agglomerate, which inhibits their removal efficiency and selectivity. This results in their mediocre reusability and separation from aqueous conditions. Thus, to overcome these drawbacks, several well-designed ZIF-8 structures have emerged by forming composites and heterostructures and doping. This review focuses on the recent advances on the use of ZIF-8 structures (doping, composites, heterostructures, etc.) in the removal and photodegradation of persistent organic pollutants. We focus on the adsorption and photocatalysis of three main organic pollutants (methylene blue, rhodamine B, and malachite green). Finally, the key challenges, prospects and future directions are outlined to give insights into game-changing breakthroughs in this area.

This review paper provides a comprehensive overview of the recent trends in bismuth tungstate (Bi ₂ WO ₆ ) research, covering its structural, electrical, photoluminescent, and photocatalytic properties.