Synthesis of Zeolite-Supported Magnesia-magnetite Nanoparticles and Its Efficient Application in Ultrasound-Assisted Adsorption of Dairy Wastewater: Optimization and Modeling of Process by RSM and ANN

In the present study, the ternary magnesia-magnetite-zeolite composite was prepared via a facile method. The XRD patterns and EDX-elemental mapping analysis confirmed the formation of composite with components of MgO, Fe3O4, and zeolite. The FE-SEM and TEM images, along with BET-BJH results, corroborated the construction of the composite with appropriate morphology and mesoporous structure (SBET: 68.90 m2 g-1). The VSM analysis demonstrated the ferromagnetic property of the prepared composite (Ms: 8 emu g-1). The as-prepared ternary composite was used for the adsorption of dairy effluent by ultrasound-assisted approach. The optimization of the adsorption operational parameters, employing response surface methodology (RSM), led to a swift reduction in COD (83%). The modeling of the process by artificial neural network (ANN) showed that the adsorbent dosage was the most important factor with 38.30% impact on the COD extent. The adsorption of dairy wastewater by composite was consistent with Temkin isotherm model and the kinetics data were well described by both Ho’s pseudo 2nd order and Elovich models. This indicates that the process is attributed to chemical adsorption. The studies associated with thermodynamics revealed that this process was endothermic (ΔH°> 0) and spontaneous (ΔG°< 0). Accordingly, the MgO-Fe3O4-zeolite could be considered as a potential adsorbent in reducing the COD of dairy wastewater.

Weak Ferromagnetic Property and Electromagnetic Waves Absorption Characteristic of La(1-x)BaxMnO3

The weak ferromagnetic property and the electromagnetic waves absorption characteristic of La(1-x)BaxMnO3 (LBMO) compounds have been investigated. The samples of LBMO that are LaMnO3 (S0), La0.9Ba0.1MnO3 (S1); La0.8Ba0.2MnO3 (S2); and La0.7Ba0.3MnO3 (S3) were synthesized using high energy milling (HEM) method. Samples were characterized by means of XRD (X-ray diffractometer), HRPD (high-resolution powder neutron diffractometer), EDS (energy dispersive X-ray spectroscopy, VSM (vibrating sample magnetometer), and VNA (vector network analyzer). There is no magnetic ordering of ferromagnetic in S1 and S2 samples due to the Ba occupation factors of both less than 0.2. The Ba content in the S3 sample is greater than 0.2, hence the ferromagnetic property of the compound is not so visible with the VSM as well as the VNA. The absorption characteristics of electromagnetic waves using VNA indicated that there is an absorption of EM waves in the frequency range between 8-12 GHz with almost the same peak frequency for all four samples at 10.8 GHz with the absorption of around 5 dB. The existence of a weak ferromagnetic property can be detected clearly using HRPD. Neutron diffraction as a probe can observe the magnetic structure accurately even in a material having a weak ferromagnetic property.