Enhanced sonocatalytic degradation of diethylstilbestrol using multi-walled carbon nanotubes under ultrasonic...

The continuous release of endocrine-disrupting compounds (EDCs) into Aquatic habitats have emerged as a considerable environmental issue due to their persistence, propensity for bioaccumulation, and detrimental biological consequences, even at low concentrations. Among these contaminants, diethylstilbestrol (DES), a synthetic estrogen, has attracted considerable attention because of its strong endocrine-disrupting activity and resistance to conventional wastewater treatment technologies. This study exploited multi-walled carbon nanotubes (MWCNTs) as sonocatalysts to further enhance the ultrasonic degradation of DES in educational and aquatic environments. The physiochemical properties of MWCNTs were determined using BET surface area measurements, Raman spectroscopy, and determination of the point-of-zero-charge (pHPZC). BET analyses proved the porous structure of the catalyst with pore size distribution ranging mainly from 35-45 nm. From Raman spectroscopy, well defined D, G, and 2D bands at 1338, 1584 and 2692 cm^-1 respectively were observed with ID/IG ratio 0.82 suggesting creation of active defect sites for catalyst activity. Studies were carried out with respect to varying operating parameters like liquid height, stirring speed, pH, temperature, initial DES concentration. It was found that the proposed system (ultrasonic-MWCNTs hybrid system) showed significantly higher efficiency than alone adsorption or only sonication. Optimal parameters for degradation were found to be 5 mm liquid height and 300 rpm stirring speed. From radical scavenging experiment, the reactive radical for the degradation of DES was found to be hydroxyl radicals (OH). It was also found that MWCNTs was very stable up to 5 cycles of application. The research confirmed that MWCNTs-assisted sonocatalysis is an effective and green process for removal of endocrine-disrupting pollutant from water systems.