Novel designs of microwave discharge electrodeless lamps (MDEL) in photochemical applications. Use in advanced oxidation processes

Abstract

Novel light sources based on microwave discharge electrodeless lamps (MDEL) are examined as potential light sources to drive photochemical processes, in particular advanced oxidation processes (AOPs) of which various applications are described. The MDELs possess several features that make them attractive as possible environmental remediation lamps and as light sources to activate metal oxide photocatalysts in environmental remediation processes. Accordingly, the article describes some of the many features, albeit non-exhaustively, of MDEL devices and reports some photoreactors that incorporate these MDELs. Fundamental issues of MDEL light sources in remediation processing of actual pollutants are introduced. Examples are taken from the oxidative destruction of volatile organic compounds (VOCs; e.g. acetaldehyde and toluene), from the oxidative degradation of contaminants present in wastewaters (e.g. the 2,4-D herbicide and the endocrine disruptor bisphenol-A) and from the remediation of dioxin-contaminated fly-ash, along with an actual industrial wastewater sample from the manufacturing of cement.

Microwave specific effects in organic synthesis: A proposed model from the solvent-free synthesis of monoglycerylcetyldimethylammonium chloride

“…No glycerin was detected in the upper phase by TLC techniques. The residue obtained after distillation was recrystallized 3 times from acetone-ethanol mixtures to give a white powder of high purity [12] as evidenced by 300-MHz 1 H NMR spectrometry (CDCl 3 ): d (ppm) = 0.86 (3H, t, CH 3 -(CH 2 ) 14 -), 1.25 (28H, m, -(CH 2 ) 14 -), 1.78 (2H, d, -(CH 2 ) 14 5.78 (1H, t, -CH 2 -OH). FAB-mass spectra showed m/z = 344.35.…”

“…In the oil-bath heating method, the oil heated the sample initially by thermal conduction through the reactor walls, after which the heat on the inner walls radiated throughout the solution by convection and vigorous mechanical agitation. By contrast, microwave radiation penetrated the reactor walls and heated the dielectric substances directly by the dielectric heating mechanism [14,15]. The dielectric constants (e 0 ) and the dielectric loss factors (e 00 ) for pure CP, DMHA, and 2-propanol solution were analyzed at the 2.45 GHz microwave frequency using an Agilent Technologies HP-85070B Network Analyzer; they are summarized in Table 1.…”

Photodegradation of Fluoxetine Applying Different Photolytic Reactors: Evaluation of the Process Efficiency and Mechanism

“…3 Due to the observation of the presence of these compounds in different ecosystems and especially their persistence in the environment (difficult degradation), many studies have been carried out to find new alternatives for the treatment of effluents of persistent compounds. [4][5][6][7] Many of these new processes have been applied in the degradation of FLX. [8][9][10][11] It is important to note that the efficiency of degradation of chemical compounds through different processes needs to be verified through some important parameters, such as energy consumption, reagent costs, process time, TPs and, in particular, chemical kinetics.…”

Microwave Discharge Electrodeless Lamps. Part VIII: Continuous On‐Site Solar Energy Remediation of Contaminated Water

“…Microwave discharge electrodeless lamps (MDELs) have proven useful light sources to decontaminate polluted water since both UV and microwave radiations can be applied simultaneously to induce degradative processes for destroying organics and microorganisms 2–10. For equal power consumption, MDELs are more effective than conventional low‐pressure Hg lamps 11.…”