Immobilization of chitosan nanolayers on the surface of nano-titanium oxide as a novel nanocomposite for efficient removal of La(III) from water

Facile synthesis of eco-friendly alginate-chitosan bio-adsorbent for critical raw materials adsorption: A comprehensive study

Sustainable management of critical raw materials is of paramount importance to ensure a steady supply and reduce environmental impact. The application of newly synthesized and environmentally friendly ALG@CS material as a bio-adsorbent for the effective rare earth elements removal from aqueous solution has been presented. The synthesized material underwent FTIR, XPS, EDX, and SEM analysis to determine its suitability for metal uptake. To evaluate the adsorption capacity of ALG@CS for rare earth elements several factors were taken into consideration. These factors included alginate:chitosan ratios, bead size, pH level, composite mass, interaction time, metal ion concentration, and temperature, being all varied during the batch mode evaluation process. Under the optimal conditions, the maximum adsorption capacities were found to be 145.90 mg La(III)/g, 168.44 mg Ce(III)/g, 132.51 mg Pr(III)/g, 128.40 mg Nd(III)/g, 154.36 mg Sm(III)/g, and 165.10 mg Ho(III)/g. The equilibrium data fits well with non-linear three-parameter Sips and Redlich-Peterson isotherm models. The PSO model finds the highest process suitability. The synthesized ALG@CS bio-adsorbent showed excellent regenerative capacity in ten cycles, making it a suitable adsorbent for rare earth elements uptake. The unique bio-adsorbents combination allows for efficient critical raw materials adsorption providing a promising solution for their recovery and recycling.

Biological, biomolecular, and bio-inspired strategies for detection, extraction, and separations of lanthanides and actinides

Lanthanides and actinides are elements of ever-increasing technological importance in the modern world. However, the similar chemical and physical properties within these groups make purification of individual elements a challenge. Current industrial standards for the extraction, separation, and purification of these metals from natural sources, recycled materials, and industrial waste are inefficient, relying upon harsh conditions, repetitive steps, and ligands with only modest selectivity. Biological, biomolecular, and bio-inspired strategies towards improving these separations and making them more environmentally sustainable have been researched for many years; however, these methods often have insufficient selectivity for practical application. Recent developments in the understanding of how lanthanides are selectively acquired and used by certain bacteria offer the opportunity for a newer, more efficient take on these designs, as well as the possibility for fundamentally new designs and strategies. Herein, we review current cell-based and biomolecular (primarily small-molecule and protein-based) methods for detection, extraction, and separations of f-block elements. We discuss how the increasing knowledge regarding the selective recognition, uptake, trafficking, and storage of these elements in biological systems has informed and will continue to promote development of novel approaches to achieve these ends.

Recent Developments in Carriers and Non-Aqueous Solvents for Enzyme Immobilization

Immobilization techniques are generally based on reusing enzymes in industrial applications to reduce costs and improve enzyme properties. These techniques have been developing for decades, and many methods for immobilizing enzymes have been designed. To find a better immobilization method, it is necessary to review the recently developed methods and have a clear overview of the advantages and limitations of each method. This review introduces the recently reported immobilization methods and discusses the improvements in enzyme properties by different methods. Among the techniques to improve enzyme properties, metal–organic frameworks, which have diverse structures, abundant organic ligands and metal nodes, offer a promising platform.

Fast microwave-assisted sorption of heavy metals on the surface of nanosilica-functionalized-glycine and reduced glutathione

Two eco-friendly nanosorbents have been designed and synthesized via surface crosslinking of nanosilica (N-Si) with glycine (Gly) and reduced glutathione (GSH) to produce (N-Si-Gly) and (N-Si-Glu) using crosslinking reagent and sonochemical reactions, respectively. An investigation was performed to search selectivity of nanosorbents via microwave-assisted removal of Ni(II)/Cu(II)/Cd(II)/Pb(II) to affirm green and fast technique. The microwave-assisted removal values of Ni(II), Cu(II), Cd(II) and Pb(II) were observed at 850, 2100, 3500 and 2150 μmol g^-1, respectively utilizing 10 mg of (N-Si-Glu) and 25.0 s heating, while those corresponded to 750, 1800, 2500 and 1850 μmol g^-1, respectively by using (N-Si-Gly). The microwave-assisted removal processes were more fitted to Freundlich compared to Langmuir isotherm except in case of Pb(II). The high percent removal of Cd(II) and Pb(II) ions exceed 95% from the second run in real wastewater samples indicating the efficiency of N-Si-Glu in the uptake of these metals utilizing microwave-assisted sorption technique.

Water-Soluble and Insoluble Polymers, Nanoparticles, Nanocomposites and Hybrids With Ability to Remove Hazardous Inorganic Pollutants in Water

The polymeric materials have presented a great development in adsorption processes for the treatment of polluted waters. The aim of the current review is to present the recent developments in this field of study by examining research of systems like functional water-soluble polymers and water-soluble polymer-metal complexes coupled to ultrafiltration membranes for decontamination processes in liquid-liquid phase. Noticing that a water-soluble polymer can be turned into insoluble compounds by setting a crosslinking point, connecting the polymer chains leading to polymer resins suitable for solid-liquid extraction processes. Moreover, these crosslinked polymers can be used to develop more complex systems such as (nano)composite and hybrid adsorbents, combining the polymers with inorganic moieties such as metal oxides. This combination results in novel materials that overcome some drawbacks of each separated components and enhance the sorption performance. In addition, new trends in hybrid methods combining of water-soluble polymers, membranes, and electrocatalysis/photocatalysis to remove inorganic pollutants have been discussed in this review.