Environmental pollution by toxic metals causes serious health complications, thus requiring advanced remediation methods for waters and effluents. In particular, chitosan-based magnetic materials have been recently developed to remove metals from aqueous solutions, industrial wastewater and water from lakes and rivers. Here, we review the adsorption of lead (Pb), cadmium (Cd), mercury (Hg) and arsenic (As) using magnetic chitosan. The manuscript presents recent experimental findings on the synthesis of magnetic adsorbents, focusing on magnetization methods, the main aspects of adsorption and adsorbent regeneration. The major findings are: (1) Kinetic patterns are mostly correlated by pseudo-second-order equations. (2) Langmuir isotherm model provides satisfactory estimations of monolayer capacity, the highest reported values being 341.7 mg/g for lead, 152 mg/g for mercury, 321.9 mg/g for cadmium and 65.5 mg/g for arsenic. (3) Most magnetic chitosan-based adsorbents keep their magnetic features and adsorption efficiency in consecutive adsorption–desorption runs. Overall, most chitosan-based magnetic adsorbents provide effective uptake of toxic metals ions from aqueous media and have a high degree of reusability.

Removal of toxic metals from water using chitosan-based magnetic adsorbents. A review

The aim of this review is to provide a comprehensive overview of the direct trifluoromethylation of olefinic C–H bonds with special attention on the mechanistic aspects of the reactions. The review is divided into two major sections. The first focuses exclusively on trifluoromethylation of terminal alkenes, while the second will cover trifluoromethylation of internal alkenes. Literature has been surveyed until the end of April 2019.

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Recent advances in direct trifluoromethylation of olefinic C–H bonds

Magnetically recyclable ZnCo2O4/Co3O4 nano-photocatalyst: Green combustion preparation, characterization and its application for enhanced degradation of contaminated water under sunlight

Abstract An efficient methodology dealing with the Fe3O4@TiO2 nanocomposite-catalyzed direct condensation reaction of 4-hydroxycoumarin, aromatic aldehydes, and 6-amino-1,3-dimethyluracil in aqueous media at room temperature is reported. This new process has been successfully applied to the synthesis of 6-amino-5-[(4-hydroxy-2-oxo-2H-chromen-3-yl)(aryl)methyl]-1,3-dimethyl-2,4,6(1H,3H)-pyrimidinediones in high to excellent yields within 2–3 h.

An expedient synthesis of 6-amino-5-[(4-hydroxy-2-oxo-2H-chromen-3-yl)(aryl)methyl]-1,3-dimethyl-2,4,6(1H,3H)-pyrimidinedione derivatives using Fe3O4@TiO2 nanocomposite as an efficient, magnetically separable, and reusable catalyst

Rapid and mild synthesis of quinazolinones and chromeno[d]pyrimidinones using nanocrystalline copper(I) iodide under solvent-free conditions

Abstract We report on the preparation of a series of 2,4-diamino-6-aryl-5-pyrimidinecarbonitriles, a new efficient protocol, via the condensation reaction of aromatic aldehydes, malononitrile, and guanidine nitrate using a TiO2–SiO2 nanocomposite with a molar ratio of 1:1 as a heterogeneous catalyst. The use of a low-cost and reusable catalyst under mild and solvent-free conditions, and simplicity in operation with easier isolation of the products in high to excellent yields are the main advantages of this highly versatile and eco-friendly protocol.

A green approach for an efficient preparation of 2,4-diamino-6-aryl-5-pyrimidinecarbonitriles using a TiO2-SiO2 nanocomposite catalyst under solvent-free conditions

The advantages of this novel multicomponent reaction protocol are operational simplicity, easy work up, reusability of the catalyst and an environmentally friendly procedure.

Faezeh Shafaei

Papers

A green approach for an efficient preparation of 2,4-diamino-6-aryl-5-pyrimidinecarbonitriles using a TiO2-SiO2 nanocomposite catalyst under solvent-free conditions

TiO2 Nanoparticles as an Efficient Catalyst for the One-pot Preparation of Tetrahydrobenzo[c]acridines in Aqueous Media

Biosynthesis of Fe3O4‐magnetic nanoparticles using clover leaf aqueous extract: Green synthesis of 1,3‐benzoxazole derivatives

A Novel Synthesis and Antioxidant Evaluation of Functionalized [1,3]‐Oxazoles Using Fe3O4‐Magnetic Nanoparticles

Green Synthesis of Imidazole Derivatives via Fe3O4‐MNPs as Reusable Catalyst