Photocatalytic degradation of bisphenol A in aqueous solution using TiO2/clinoptilolite hybrid photocatalyst

Enhanced sorption and fluorescent detection of bisphenol A by using sodium alginate/cellulose nanofibrils/ZIF-8 composite hydrogel

To address the issue of bisphenol A (BPA) contamination in wastewater, a novel hydrogel, sodium alginate/cellulose nanofibrils/ZIF-8 composite hydrogel (SCZC), was synthesized for efficient BPA removal. The SCZC exhibited an exceptional adsorption capacity of 1696 mg/g, aligning well with both Langmuir and pseudo-second-order models. Furthermore, it exhibited remarkable regeneration properties, maintaining 89.1 % of its adsorption capacity even after undergoing five adsorption-desorption cycles. The synthesized SCZC also acted as a fluorescent sensor for detecting BPA, employing dynamic quenching and offering linear detection ranges of 10-100 mg/L and 0.2-1.0 μg/L, with a low detection limit of 0.06 μg/L. Analysis of adsorption and detection mechanisms revealed that SCZC's exceptional performance could be attributed to the three-dimensional (3D) porous structure formed by sodium alginate and cellulose nanofibrils. Economic analysis indicated that SCZC, in comparison to commercially activated carbon, was relatively inexpensive. This study introduces a novel approach for designing and preparing a sodium alginate-based hydrogel incorporating metal-organic frameworks, offering simultaneous BPA detection and removal capabilities.

Sonocatalytic degradation of Bisphenol A from aquatic matrices over Pd/CeO2 nanoparticles: Kinetics study, transformation products, and toxicity

In this work, different ratios of palladium - cerium oxide (Pd/CeO2) catalyst were synthesized and characterized, while their sonocatalytic activity was evaluated for the degradation of the xenobiotic Bisphenol A (BPA) from aqueous solutions. Sonocatalytic activity expressed as BPA decomposition exhibited a volcano-type behavior in relation to the Pd loading, and the 0.25Pd/CeO2 catalyst characterized by the maximum Pd dispersion and lower crystallite size demonstrated the higher activity. Using 500 mg/L of 0.25 % Pd/CeO2 increased the kinetic constant for BPA destruction by more than two times compared to sonolysis alone (20 kHz at 71 W/L). Meanwhile, the simultaneous use of ultrasound and a catalyst enhanced the efficiency by 50.1 % compared to the sum of the individual processes, resulting in 95 % BPA degradation in 60 min. The sonocatalytic degradation of BPA followed pseudo-first-order kinetics, and the apparent kinetic constant was increased with ultrasound power and catalyst loading, while the efficiency was decreased in bottled water and secondary effluent. From the experiments that were conducted using appropriate scavengers, it was revealed that the degradation mainly occurred on the bubble/liquid interface of the formed cavities, while the reactive species produced from the thermal or light excitation of the prepared semiconductor also participated in the reaction. Five first-stage and four late-stage transformation products were identified using UHPLC/TOF-MS, and a pathway for the sonocatalytic degradation of BPA was proposed. According to ECOSAR software prediction, most transformation by-products (TBPs) present lower ecotoxicity than the parent compound, although some remain toxic to the indicators chosen.