Adsorption and Photo-Fenton Degradation of Methylene Blue Using Nanomagnetite/Potassium Carrageenan Bio-Composite Beads

Abstract

The present study deals with the preparation of nanomagnetite (NM), potassium carrageenan (KC), and nanomagnetite/potassium carrageenan bio-composite beads (NC). Characterization of the prepared solid materials using different physicochemical techniques such as X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscope (TEM), energy-disperse X-ray spectroscopy (EDX), diffuse reflectance spectrophotometer (DRS), swelling ratio (SR%), N2 adsorption, pH of point of zero charges (pHPZC), and Fourier transform infrared spectroscopy (FTIR). Comparing between adsorption and photo-Fenton degradation process for methylene blue (MB) on the surface of the prepared solid materials. Nanomagnetite/potassium carrageenan bio-composite (NC) exhibited high specific surface area (406 m2/g), mesoporosity (pore radius, 3.64 nm), point of zero charge around pH6.0, and the occurrence of abundant oxygen-containing functional groups. Comparison between adsorption and photo-Fenton oxidation process for methylene blue (MB) was carried out under different application conditions. NC exhibited the maximum adsorption capacity with 374.50 mg/g at 40 °C after 24 h of shaking time while 96.9% of MB was completely degraded after 20 min of photo-Fenton process. Langmuir's adsorption model for MB onto the investigated solid materials is the best-fitted adsorption model based on the higher correlation coefficient values (0.9771–0.9999). Kinetic and thermodynamic measurements prove that adsorption follows PSO, endothermic, and spontaneous process, while photo-Fenton degradation of MB achieves PFO, nonspontaneous, and endothermic process. Photo-Fenton degradation is a fast and simple technique at a lower concentration of dye (< 40 mg/L) while at higher dye concentration, the adsorption process is preferred in the removal of that dye.

Multi-Stimuli-Responsive Tadpole-like Polymer/Lipid Janus Microrobots for Advanced Smart Material Applications

“…Considering all these, the purpose of exploring the properties of new JMs, which were heterogeneous Fenton catalysts, was not only to determine their catalytic performance by protecting Fe 3 O 4 NP stability but also to throw light on the various application areas of multifunctional JMs. For this purpose, the decomposition rate of H 2 O 2 was analyzed at two different temperature values, 40 and 50 °C at pH 2.5, considering the importance of the effect of temperature on heterogeneous Fenton reactions and the fact that the catalytic efficiency drops drastically when the pH is higher than 3 . Since selected Precirol ATO 5, which has a melting point of 54–59 °C, undergoes a solid–liquid phase transition above 54 °C, the Fenton reaction was studied below this value.…”

“… 59 , 60 Therefore, at these pH values, the MB degradation efficiency increases due to the formation of water and oxygen by the decomposition of hydrogen peroxide and the formation of • OH by the Fe 2+ ion. 60 However, as the reaction proceeds, the Fe 3 O 4 NPs have a tendency to clump together, forming larger aggregates. Moreover, the Fe 2+ leaching into the solution limits their ability to disperse effectively, reducing their primary larger specific surface area and their stability for subsequent reuse.…”

“…For this purpose, the decomposition rate of H 2 O 2 was analyzed at two different temperature values, 40 and 50 °C at pH 2.5, considering the importance of the effect of temperature on heterogeneous Fenton reactions and the fact that the catalytic efficiency drops drastically when the pH is higher than 3. 60 Since selected Precirol ATO 5, which has a melting point of 54–59 °C, undergoes a solid–liquid phase transition above 54 °C, the Fenton reaction was studied below this value. The catalytic degradation of MB by JPMP1 and JPMP2 is demonstrated in Figure 7 a,b.…”

“…58 Many studies underlined that the Fe 3 O 4 NPs show high stability and catalytic activity under different environmental conditions, and the optimal pH for Fe 3 O 4 NPs catalysis was around 3. 59,60 Therefore, at these pH values, the MB degradation efficiency increases due to the formation of water and oxygen by the decomposition of hydrogen peroxide and the formation of • OH by the Fe 2+ ion. 60 However, as the reaction proceeds, the Fe 3 O 4 NPs have a tendency to clump together, forming larger aggregates.…”