This study investigated the potential of zeolites (NH4BETA, NH4ZSM-5, and NaY) to remove two frequently used dyes, methylene blue (MB) and rhodamine B (RB), from an aqueous environment. The removal of dyes with zeolites was performed via two mechanisms: adsorption and photocatalysis. Removal of dyes through adsorption was achieved by studying the Freundlich adsorption isotherms, while photocatalytic removal of dyes was performed under UV irradiation. In both cases, the removal experiments were conducted for 180 min at two temperatures (283 K and 293 K), and dye concentrations were determined spectrophotometrically. Additionally, after photodegradation, mineralization was analyzed as chemical oxygen demand. A computational analysis of the structures of MB and RB was performed to gain a deeper understanding of the obtained results. The computational analysis encompassed density functional theory (DFT) calculations and analysis of two quantum-molecular descriptors addressing the local reactivity of molecules. Experimental results have indicated that the considered zeolites effectively remove both dyes through both mechanisms, especially NH4BETA and NH4ZSM-5, due to the presence of active acidic centers on the outer and inner surfaces of the zeolite. The lowest efficiency of dye removal was achieved in the presence of NaY zeolite, which has a lower SiO2/Al2O3 ratio. A more efficient reduction was completed for RB dye, which agrees with the computationally obtained information about reactivity.

Nadolol (NAD), one of the representatives of β-blockers, is used to treat cardiovascular diseases such as angina and hypertension. Due to its frequent use, it has been detected in hospital wastewater from which it is not removed efficiently enough, so it reaches natural waters. The lack of a satisfactorily efficient method for removing NAD from wastewater has created a need to find a more efficient way for its removal. This paper aims to investigate the efficiency of photocatalytic degradation of NAD by two TiO2-C nanocomposites with different carbon content (9 and 20 wt%) under UV radiation. The applied nanocomposites, synthesized by the sol-gel hydrothermal method, showed significant efficiency in removing NAD compared to direct photolysis. Also, the reaction rate constant, according to which the decomposition of NAD in the presence of TiO2-C takes place in the pseudo-first order, was calculated. The degradation of NAD was monitored by HPLC–PDA technique.

Cefoperazone belongs to the third generation of cephalosporin antibiotics. It is accumulated in water due to its overuse and causes bacterial, environmental, and health issues. In this work, the efficiency of photocatalytic degradation of cefoperazone was studied using different types of radiation (simulated solar, UV, and LED) in the presence of different nanomaterials (ZnO and TiO2). First, the photolytic degradation of cefoperazone was examined, where UV radiation showed as most effective for cefoperazone degradation, wherein 29.5% of cefoperazone was degraded after 60 min. Photocatalysis in the presence of TiO2 leads to complete removal of cefoperazone after 30 min, while the use of ZnO leads to complete photocatalytic degradation of cefoperazone after 20 min using UV radiation. Simulated solar and LED radiation showed slightly lower efficiencies. When TiO2 was applied, the removal efficiency was around 60%, while approximately 70% of cefoperazone was degraded when ZnO was used.

In this work, the interaction between carbon nanotubes (CNT) and ephedrine (EPH) molecule have been investigated using the combination of density functional theory (DFT) and density functional tight-binding (DFTB) calculations on periodic and/or isolated structures. EPH is one of the most frequent pharmaceutical pollutants, while nanotubes belong to a group of the bestknown organic nanostructures. To address the possibility of applying CNT as adsorbers of EPH, interactions between EPH and several models of CNTs have been investigated in detail. Systems considered in this study consist of 122-187 atoms, which induced the necessity to apply the DFTB level of theory for the geometrical optimizations. DFT level of theory was used to obtain more accurate total energies, which enabled us to assess the binding energies between ephedrine and nanotubes. It has been established that CNTs might adsorb EPH with significant binding energies, which are at the same time not too strong, allowing desorption under reasonable experimental conditions.