Molybdenum Trioxide: Efficient Nanosorbent for Removal of Methylene Blue Dye from Aqueous Solutions

Abstract

Nano Molybdenum trioxide (α-MoO3) was synthesized in an easy and efficient approach. The removal of methylene blue (MB) in aqueous solutions was studied using this material. The effects of various experimental parameters, for example contact time, pH, temperature and initial MB concentration on removal capacity were explored. The removal of MB was significantly affected by pH and temperature and higher values resulted in increase of removal capacity of MB. The removal efficiency of Methylene blue was 100% at pH = 11 for initial dye concentrations lower than 150 ppm, with a maximum removal capacity of 152 mg/g of MB as gathered from Langmuir model. By comparing the kinetic models (pseudo first-order, pseudo second-order and intraparticle diffusion model) at various conditions, it has been found that the pseudo second-order kinetic model correlates with the experimental data well. The thermodynamic study indicated that the removal was endothermic, spontaneous and favorable. The thermal regeneration studies indicated that the removal efficiency (99%) was maintained after four cycles of use. Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM) confirmed the presence of the MB dye on the α-MoO3 nanoparticles after adsorption and regeneration. The α-MoO3 nanosorbent showed excellent removal efficiency before and after regeneration, suggesting that it can be used as a promising adsorbent for removing Methylene blue dye from wastewater.

Highly Efficient Methylene Blue Dye Removal by Nickel Molybdate Nanosorbent

“…As a matter of fact, the data show a decrease in dye removal from 99% to 73% with a decrease in removal capacity from 15,900 to 11,608mg/g. The maximum adsorption capacity obtained after four cycles of use (11,608 mg/g) was higher than that obtained by several nanosorbents [ 30 , 87 , 88 , 89 , 90 , 91 , 92 ]. The high level of removal efficiency showed that the adsorbent regeneration by way of calcination under atmospheric air at a temperature of 400 °C was extremely efficient and indicative of outstanding recycling capability.…”

“…Regeneration techniques suggested in the literature include chemical extraction, thermal treatment, supercritical regeneration, microwave irradiation, bio-regeneration, etc. [ 25 , 88 , 93 , 94 , 95 ]. The thermal regeneration, which has been applied for molybdenum oxide nanosorbent, was described in our previously published work [ 88 ].…”

“…[ 25 , 88 , 93 , 94 , 95 ]. The thermal regeneration, which has been applied for molybdenum oxide nanosorbent, was described in our previously published work [ 88 ]. In this investigation, the thermal treatment technique was examined for purposes of regeneration testing, as the structure of the α-NiMoO 4 removal agent was steady.…”

“…Additionally, α-NiMoO 4 reacts with the hydroxyl groups (OH − ) in the solution to generate the ion nickel molybdate (NiMoO 5 2− ) with no intermediate compounds present [ 99 ]. Hence, the adsorption is directed by the strong electrostatic interactions between the negatively charged surface of nickel molybdate (NiMoO 5 2− ) and the positive charge of methylene blue cations [ 88 ].…”

Iron Molybdate Fe2(MoO4)3 Nanoparticles: Efficient Sorbent for Methylene Blue Dye Removal from Aqueous Solutions

“…Temperature is another parameter of prime importance that has a great impact on dye removal [45]. The process of removing the MB dye was investigated from 20 to 70 • C, as can be seen in Figure 4.…”