Pooja Shandilya

Ionic liquids (ILs) have proven to be a potential medium for the extraction and separation of essential oils (EOs) from the most varied sources. This review presents a summary of the primary outcomes obtained through the application of ionic liquid-based processes for the extraction and separation of different constituents of EOs (such as terpenes, ketones, phenols, oxides, esters, aldehydes, and alcohols). ILs have been examined as solvents, co-solvents, adjuvants, electrolytes, and cosurfactants, and they have been utilized in the synthesis of IL-supported materials for separation. In addition, the application of hybrid solvents, including deep eutectic solvents (DESs), further broadens the applicability of ILs to particular EO components. A key feature of ILs is their adaptable selectivity at the molecular level. Interactions such as hydrogen bonding, e.g., imidazolium-based ILs with hydroxyl groups of phenolic compounds, π–π stacking between aromatic cations and terpene backbones, and electrostatic or hydrophobic effects that control the solubilization and dissociation of esters and aldehydes enable ILs to achieve better resolution than conventional solvents. These interactions provide a higher extraction efficiency and better purity of the target compounds. Herein, IL-based solid–liquid green extraction techniques are reviewed and compared in terms of their extraction and separation capabilities. Modern trends, including computational methods, machine learning (ML) optimization, and advanced algorithms for process optimization techniques, are used to improve results, which are often used for single-parameter modifications, such as optimizing solvent ratios or extraction conditions. These examples show that ML can help improve IL-based extraction in practice, but complete end-to-end design systems are still in the future. Combining ML with multi-scale modeling and robotic testing for automated, iterative optimization is probably necessary to realize such dramatic potential. The environmental impact of ILs is also reviewed in terms of toxicity and biodegradability, along with reuse, recovery, and purification processes. The major achievements and future challenges in this discipline are addressed, with a specific focus on the primary loopholes encountered within the IL community devoted to the separation processes, and some measures are proposed to overcome the existing limitations.

The environmental impact of synthetic dyes presents a significant challenge due to their toxicity and persistence in ecosystems. Recent advancements in surfactant-modified adsorbent materials offer a promising solution for effective dye removal. Surfactants, recognized for their nontoxic and eco-friendly properties, enhance the performance of adsorbents by improving their dye-capturing capabilities. This review explores the innovative integration of surfactants into various adsorbent matrices for the removal of common dyes, such as methylene blue, malachite green, rhodamine B, congo red, and methyl orange. By focusing on the interactions between surfactant-modified adsorbents and dye molecules, we provide insights into the mechanisms that enhance the adsorption efficiency. We also address the influence of competing ions and salts typically found in wastewater, emphasizing their role in shaping adsorption dynamics. Furthermore, we discuss critical factors affecting the regeneration and reusability of these materials, highlighting their potential for industrial applications. Unlike previous reviews that primarily focused on either adsorbent-dye or surfactant–dye interactions, this Review emphasizes the synergistic integration of surfactants within adsorbent matrices. By exploring the interactions of surfactant-assisted modified adsorbents and dye molecules, this review aims to provide valuable insights into the development of advanced and cost-effective materials for enhanced dye removal.

The escalating presence of antibiotic contaminants, such as norfloxacin (NFX), in water resources poses a pressing environmental challenge, demanding the development of innovative and sustainable remediation technologies. Herein, we report the design and fabrication of a novel S-scheme heterojunction photocatalyst, comprising Ag₂WO₄, NiO, and MoO₃ nanoparticles anchored onto a nanocellulose matrix (NC–ANM), for the efficient photocatalytic degradation of NFX under visible light irradiation. Comprehensive structural, morphological, and physicochemical characterization techniques, including XRD, XPS, FTIR, FESEM, and HRTEM, corroborated the successful formation of the heterojunction and its constituent phases. Optical and electrochemical analyses, utilizing UV-vis DRS, PL, and EIS, revealed enhanced visible light absorption, efficient charge separation, and prolonged charge carrier lifetimes, key attributes underpinning the superior photocatalytic activity of the NC–ANM heterojunction. Mechanistic investigations, employing LC-MS and ESR spectroscopy, confirmed the S-scheme charge transfer pathway, leading to the generation of reactive oxygen species (˙OH and ˙O₂ ⁻) that efficiently degrade NFX. The heterojunction demonstrated remarkable photocatalytic performance, achieving 99.6% NFX degradation within 30 minutes under optimized conditions. This study not only showcases the potential of NC–ANM as a highly efficient and sustainable photocatalyst for wastewater treatment but also provides valuable insights into the design and engineering of advanced S-scheme heterojunctions for environmental remediation applications.

A dual S-scheme nanocellulose-based SnWO₄/Cu₂O/Ag₂WO₄ (NC-SCA) heterojunction photocatalyst was synthesized via ultrasonication followed by a hydrothermal method for the efficient photodegradation of amoxicillin (AMX). Under UV-vis light irradiation, the NC-SCA photocatalyst exhibited an impressive 97.40% AMX degradation within 30 min, attributed to its improved optical absorption and superior charge migration. The characterization techniques, including XRD, FTIR, PL, and UV-vis spectroscopy, confirmed the successful integration of nanocellulose with SnWO₄/Cu₂O/Ag₂WO₄. XPS and ESR analyses provided insights into the S-scheme charge migration mechanism within the heterojunction. Further, the trapping experiments identified hydroxyl (^•OH) and superoxide radicals as the primary reactive species. The photocatalyst displayed a specific surface area of 115.9 m²/g, offering a large active surface for photodegradation. Operational parameters such as the photocatalyst dosage, pH, and AMX concentration were systematically optimized. The NC-SCA photocatalyst exhibited high stability, retaining around 85% efficiency after seven cycles. This study presents an innovative strategy for designing high-performance photocatalysts addressing the limitations of conventional materials.