Adsorptive performance of penta-bismuth hepta-oxide nitrate, Bi5O7NO3, for removal of methyl orange dye

Abstract

The adsorption of methyl orange dye from aqueous solution onto penta-bismuth hepta-oxide nitrate, Bi(5)O(7)NO(3), synthesized by precipitation method, was studied in a batch adsorption system. The effects of operation parameters such as adsorbent dose, initial dye concentration, pH and temperature were investigated. The adsorption equilibrium and mechanism of adsorption was evaluated by Langmuir and Freundlich isotherm and different kinetic models, respectively. The results indicate that adsorption is highly dependent on all operation parameters. At optimum conditions, the adsorption capacity was found to be 18.9 mg/g. The adsorption data fits well with the Langmuir isotherm model indicating monolayer coverage of adsorbate molecules on the surface of Bi(5)O(7)NO(3). The kinetic studies show that the adsorption process is a second-order kinetic reaction. Although intra-particle diffusion limits the rate of adsorption, the multi-linearity plot of intra-particle model shows the importance of both film and intra-particle diffusion as the rate-limiting steps of the dye removal. Thermodynamic parameters show that the adsorption process is endothermic, spontaneous and favourable at high temperature.

Electronic band structure of Bi5O7NO3 and its methyl orange removal mechanism

“…High positive energy values of dye adsorption confirm the presence of a strong endothermic chemisorption process, which is associated with the formation of bonds. This finding is in line with the previous experimental results [1]. The MO_zwitterion/Bi5O7NO3 system is bound more strongly than other adsorbed systems.…”

“…In this regard, several adsorbent systems have been reported for dye wastewater treatment in recent years [11,12]. The ability of Bi5O7NO3 to work as an adsorbent has been described in the prior literature [1]. In this study, the Langmuir model showed that adsorption occurs through a monolayer chemisorption coverage and fits well the pseudo-second order kinetic model in which the intraparticle diffusion is the ratedetermining step.…”

“…In recent years, bismuth oxide and its Bi5O7NO3 oxynitride derivative have been chosen as potential candidates for a visible light-driven photocatalyst and as an adsorbent for the removal of colored organic compounds [1,2]. Therefore, the structural features of Bi5O7NO3 were the center of the previous experimental investigations.…”

A hierarchical Ca/TiO2/NH2-MIL-125 nanocomposite photocatalyst for solar visible light induced photodegradation of organic dye pollutants in water

“…Typically, dye is separated from industrial wastewater by coagulation, clotting, biological treatment, 6 chemical oxidation, electrochemical treatment, 7 ion exchange, 8 and surface adsorption. 9,10 Despite showing various merits, such methods are solely able to transform the dye molecules from one phase to another, 11 and do not entirely "eliminate" or "decompose" them. This deciency could be challenging because disposal of the dye-derived sludge is problematic.…”