Oxidative degradation of Methyl Orange catalyzed by lab prepared nickel hydroxide in aqueous medium

Abstract

A B S T R A C TThis study is focused on oxidative degradation of Methyl Orange, a common azo dye, catalyzed by nickel hydroxide in aqueous solution at 303, 313, 323, and 333 K. Sodium hypochlorite, sodium hydroxide, and nickel sulfate hexahydrate in distilled water were used as starting material for preparation of nickel hydroxide. Pyrex glass batch reactor was used to study the effect of various conditions such as temperature, concentration, agitation, and catalyst dose on catalytic degradation of Methyl Orange in aqueous medium. About 80% Methyl Orange was degraded in 120 min. Experimental data were subjected to kinetic analysis using CurveExpert software. Degradation reaction was taking place according to Langmuir-Hinshelwood mechanism. According to this mechanism, the reactants adsorb at the surface of catalyst in first step followed by reaction between adsorbed reactants in second step. Adsorption of Methyl Orange on surface of catalyst followed Langmuir adsorption isotherm. Apparent activation energy, true activation energy, and heat of adsorption were determined as 13.2, 32.7 and -23.5 kJ mol −1 , respectively.

Synthesis of a CoO–ZnO photocatalyst for enhanced visible-light assisted photodegradation of methylene blue

“…The decrease in the catalytic efficiency with a higher concentration of dye is due to the following reasons: (1) the dye absorbs a significant fraction of light rather than the catalyst, (2) the path length of a photon decreases with an increase in the concentration of dye, and (3) the ratio of OH radicals to molecules of the dye decreases with an increase in the concentration of the dye. 45,46 The CoO-ZnO photocatalyst reported in this study was found much active towards the photodegradation of methylene blue as compared to several ZnO based catalysts reported in the literature. Table 1 shows a comparison of various ZnO-based photocatalysts reported for the photodegradation of methylene blue.…”

Synthesis of p-n CoO-ZnO Heterojunction for Enhanced Visible-Light Assisted Photodegradation of Methylene Blue

“…Figure 3c shows that catalytic efficiency decreases with an increase in the concentration of methylene blue. The decrease in catalytic efficiency with a higher concentration of dye is due to (1) dye absorbs a significant fraction of light rather than a catalyst, (2) the path length of a photon decreases with an increase in the concentration of dye, (3) the ration of OH radicals to molecules of dye decreases with increase in the concentration of dye (Balcha et al 2016) (Saeed et al 2016).…”

Synthesis and characterization of nickel oxide and evaluation of its catalytic activities for degradation of methyl orange in aqueous medium

“…For kinetics investigation, all the kinetics models were applied to time profile data for degradation of methyl orange as described in our previous study [13][14][15][16][17] . It was found that degradation of methyl orange follows pseudo 1st order kinetics expression according to Eley-Rideal (E-R)…”