Proton-Enhanced Dielectric Properties of Polyoxometalates in Water under Radio-Frequency Electromagnetic Waves

Electromagnetic pollution alert: Microwave radiation and absorption in human organs and tissues

Electromagnetic radiation from communication and electronic devices, networks, systems and base stations has drawn concern due to excessive global usage with increasing power and operating frequency level. Numerous previous researches only focus on how the radiation from certain frequency ranges of particular devices could harm specific human organs and tissues, resulting in distinct symptoms. In this research, electromagnetic propagation and properties in 14 human organs and tissues were analyzed and investigated based on the organs and tissues' electromagnetic and mechanical parameters, and chemical composition. Counting the organs and tissues as electromagnetic materials, their permittivity and conductivity, computed by a 4-Cole-Cole mode, directly respective to the operating frequency, are interrelated to wave behavior and hence influence the organs' response. Tests were conducted in 1 GHz to 105 GHz system settings, covering most microwave frequency uses: 2.4 GHz of 4G-LTE, Wi-Fi, Bluetooth, ZigBee and the 5G ranges: 28 GHz of 5G-mmW and 95 GHz of 5G-IoT. Trial human organs and tissues were placed in the wave propagation direction of 2.4 GHz and 28 GHz dipole antennas, and a waveguide port operating from 95 to 105 GHz. The quantitative data on the effects of 5G penetration and dissipation within human tissues are presented. The absorbance in all organs and tissues is significantly higher as frequency increases. As the wave enters the organ-tissue model, the wavelength is shortened due to the high organ-tissue permittivity. Skin-Bone-Brain layer simulation results demonstrate that both electric and magnetic fields vanish before passing the brain layer at all three focal frequencies of 2.4 GHz, 28 GHz and 100 GHz.

Rapid thermal-acid hydrolysis of spiramycin by silicotungstic acid under microwave irradiation

Spiramycin is a widely used macrolide antibiotic and exists at high concentration in production wastewater. A thermal-acid hydrolytic pretreatment using silicotungstic acid (STA) under microwave (MW) irradiation was suggested to mitigate spiramycin from production wastewater. Positive correlations were observed between STA dosage, MW power, interaction time and the hydrolytic removal efficiencies, and an integrative equation was generalized quantitively. Rapid and complete removal 100 mg/L of spiramycin was achieved after 8 min of reaction with 1.0 g/L of STA under 200 W of MW irradiation, comparing to 30.1% by MW irradiation or 15.9% by STA alone. The synergetic effects of STA and MW irradiation were originated from the dissociated-proton catalysis by STA and the dipolar rotation heating effect of MW. STA performed much better than the mineral acid H₂SO₄ under MW, due to the much stronger Brönsted acidity and higher Hammett acidity. After 8 min, 98.0% of antibacterial potency was also reduced. The m/z 558.8614 fragment (P1) and m/z 448.1323 fragment (P2) were identified as the primary products, which were formed by breaking glucosidic bonds and losing mycarose and forosamine for P1 and further mycaminose moiety for P2. Finally, production wastewater with 433 mg/L of spiramycin was effectively treated using this thermal-acid hydrolytic method. Spiramycin and its antibacterial potency both dropped to 0 after 6 min. The potency drop was supposed from the losing of mycarose and/or forosamine. To decrease both the concentration of spiramycin and its antibacterial potency, combinedly using STA and MW was suggested in this work to break down the structural bonds of the functional groups rather than to destroy the whole antibiotic molecules. It is promising for pretreating spiramycin-contained production wastewater to mitigate both the antibiotic and its antibacterial potency.

Radio frequency alternating electromagnetic field enhanced tetraruthenium polyoxometalate electrocatalytic water oxidation

RF-enhanced electrocatalytic water oxidation by protonated tetraruthenium polyoxometalate.