Synthesis and characterization of nickel nanoparticles and their application as catalyst in hexacyanoferrate III oxidation of some mono azo dyes

Abstract

newline Nanotechnology has been extended to waste treatments in recent years. NPs have newlineemerged promptly in the treatments of several toxic chemicals in the environment such as azo newlinedyes, amino phenols, etc. Some researchers are using NPs in the treatment of wastewater by newlineadsorption, catalytic degradation and photocatalytic degradation etc.The development of field of newlinenanocatalysis has occoured during the last decades. The studies are made both in homogeneous newlineand heterogeneous catalysis. NPs have small size so their surface-to-volume ratio is large. newlineAzo dyes are the largest and most versatile class of dyes used in textile industry and newlineaccount for over 70% of the world dyestuff production. They have one or more azo groups (- newlineN=N-) as chromophore which are bonded to aromatic rings mostly substituted by sulfonate newlinegroups. They exhibit low biodegradability and they are assumed to be more problematic newlinecompared to other forms as their precursors and degradation products are highly carcinogenic. newlineOxidation by iron(III) in the form of various complexes has received much attention newlinepresumably due to its easy availability, less complexity involved in the oxidation and its ability newlineto act in acidic and alkaline medium both. Hexacyanoferrate(III) anion is the most important newlineiron(III) cyanide complex. Being a mild oxidant it attacks the compound at a particular stage. newlineMoreover, hexacyanoferrate (III) is single equivalent and stable oxidant, it adds less error to the newlineexperimental results, and data can be analyzed meticulously to establish the reaction path. newlineHowever, the oxidation by hexacyanoferrate (III) proceeds very slowly in absence of any newlinecatalyst. The oxidation rate can be improved by the use of some ions of metals (Os, Ru and Ag) newlineas catalyst. Pt, Os and Ir are reported to act as an efficient catalyst in the oxidation of some newlineorganic compounds by HCF (III) in aqueous medium. Iridium, an interesting member of newlineplatinum group metals, is commonly used as catalyst in the oxidation of many organic and newlineinorganic compounds. newlineTherefore, they act as good catalyst as compared to bulk materials, they are attractive to newlineuse as catalysts. In general, some reports show that Au, Pd, Pt, and Ru NPs used in the oxidation newlineprocess show good catalytic activity. Zero valent nanomaterials of silver, iron, zinc and some newlinemetal oxides like TiO2, ZnO, Fe3O4, or Fe2O4 have been used in water and wastewater treatment newlinedue to their antimicrobial and high reductive ability. High cost and low abundance of these noble newlinemetals do not allow their usage on large scale. This motivated us to synthesize nickel NPs and newlineuse them as catalyst in degradation of azo dyes. Nickel is a perfect catalyst. It is the preferred newlinenano catalyst for abundant reactions due to its life, immense activity and relatively economical newlineprice