Magnetic nobel metal-based nanocatalysts in reduction of the priority pollutant 4-nitrophenol

The nanocatalyst technology in organic synthesis has become a subject of intense investigation. In particular, magnetic nanoparticles (MNPs) as non-toxic, readily accessible, and retrievable nanoparticles offer many advantages in clean and sustainable chemistry. The use of MNPs as catalysts in chemical synthesis has been extensively studied in recent years. The recovery of expensive catalysts after their use is one of their most noticeable features in the sustainable process development. Additionally, the activity and selectivity of magnetic nanocatalysts can be manipulated by their surface modification[1] . Noble metal nanoparticles have attracted considerable attention because of their distinctive physicochemical properties and their potential applications as a new class of efficient catalysts [2]. 4-Nitrophenol (4-NP) as an important industrial crude material has been extensively used in industrial processes such as those concerned with wood protection, explosives, herbicides, dyes, etc [1–3]. This compound is one of the most common waste pollutants because of its high solubility and stability in water. The reduction of 4-NP has become an important topic in recent years because the product, 4-aminophenol (4-AP) is an extremely useful intermediate for the preparation of analgesic and antipyretic drugs including acetaminophen and paracetamol. Various methods including chemical oxidation, biodegradation, photocatalytic degradation and solvent extraction have been employed to remove 4-NP from wastewater. Among these approaches, catalytic reduction is useful due to its being of cost, green and economically efficient [3]. To effective conversion of the 4-NP, many nanosized metal catalysts such as Au, Ag, Ru, Ir and Pd have been investigated, and represented superior catalytic activity and stability . Since the excessive cost and scarcity of nobel metals are big obstacles for their industrial applications , therefore, the utilization efficiency and recovery yield of Pt nanocatalysts are very important challenges in the design of nobel metal-based catalysts . Here we review some magnetic nobel metal-based nanocatalysts as the recoverable and reusable nanocatalysts for the highly efficient reduction of 4-NP Also we survey some of effective factors such as temperature, catalysts amounts reducing agents and pH on the reaction times and yields in our investigated magnetic nobel metal-based nanocatalysts[4].