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One of the most important factors affecting the application of advanced oxidation processes (AOPs) at full scale are the high operating costs, especially those associated with the cost of the reagents. Therefore, the optimization of operating parameters, such as a reduction in reagent consumption to achieve the partial or complete decontamination of waters, is crucial in AOP application. The present study is focused on the comparison of solar and UV photo-Fenton technologies (by using H 2 O 2 or S 2 O 8 2− ), for the removal of five micro-contaminants (antipyrine, caffeine, carbamazepine, ciprofloxacin and sulfamethoxazole) from simulated freshwater at very low concentrations (100 ppb each one). In addition, economic assessment of the implementation of UV/H 2 O 2 , UV/S 2 O 8 2− , solar/Fe(II)/H 2 O 2 and solar/Fe(II)/S 2 O 8 2− was also carried out. The total costs obtained were 0.42 €/m 3 for solar/Fe(II)/H 2 O 2 with 50 mg/L of initial H 2 O 2 , 0.72 €/m 3 for solar/Fe(II)/S 2 O 8 2− with 50 mg/L of initial S 2 O 8 2− , 0.43 €/m 3 for UV/H 2 O 2 with 50 mg/L of initial H 2 O 2 , 0.49 €/m 3 for UV/S 2 O 8 2− with 50 mg/L of initial S 2 O 8 2− and 0.61 €/m 3 for UV/S 2 O 8 2− with 25 mg/L of initial S 2 O 8 2− . It was concluded that consumption of reagents and electricity costs coming from lamp operation in the UV process had a significant impact on the total operating cost of both technologies. Furthermore, it must be stressed that solar and UV processes promoted by H 2 O 2 are more cost-effective than when employing S 2 O 8 2− . [ABSTRACT FROM AUTHOR]

Ultrafiltration polyethersulfone (PES) membranes were prepared by wet phase inversion. Commercial halloysite nanotubes (HNTs) in the quantities of 0.5 wt% vs. PES (15 wt%) were introduced into the casting solution containing the polymer and different solvents: N,N -dimethylformamide (DMF), N , N -dimethylacetamide (DMA), or 1-methyl-2-pyrrolidinone (NMP). The type of solvent influenced the membranes' morphology and topography, as well as permeability, separation characteristics, and antifouling and antibacterial properties. The membranes prepared using DMA exhibited the loosest cross-section structure with the thinnest skin and the roughest surface, while the densest and smoothest were the DMF-based membranes. The advanced contact angles were visibly lower in the case of the membranes prepared using DMF compared to the other solvents. The highest water permeability was observed for the DMA-based membranes, however, the most significant effect of the modification with HNTs was found for the NMP-based series. Regardless of the solvent, the introduction of HNTs resulted in an improvement of the separation properties of membranes. A noticeable enhancement of antifouling performance upon application of HNTs was found only in the case of DMF-based membranes. The study of the antibacterial properties showed that the increase in surface roughness had a positive effect on the inhibition of E. coli growth.

Silver nanoparticles (NPs) are effective antibacterial agents; however, aggregation of NPs and uncontrolled release of Ag + affect their efficiency and may pose a risk to the environment. To overcome these disadvantages, immobilization of Ag onto titanate nanotubes (TNTs) was investigated. This paper describes the physicochemical and antibacterial properties of silver incorporated titanate nanotubes (Ag/TNTs) prepared using five procedures and containing different Ag amounts (0.11-30.85 wt.%). The methods were (i) sol-gel followed by a hydrothermal process; (ii) photodeposition under ambient conditions; (iii) photodeposition under an inert atmosphere; (iv) NaBH 4 reduction; and (v) electroless deposition after activation of TNTs with Sn 2+ . Depending on the synthesis procedure, the presence of metallic Ag NPs, AgO or AgCl was observed. The electroless method led to an additional deposition of SnO 2 NPs. The antibacterial properties of Ag/TNTs were analyzed as a function of Ag content and released against Escherichia coli and Staphylococcus epidermidis . The best bactericidal properties exhibited Ag/TNTs prepared through the photodeposition process due to the higher interaction of exposed Ag NPs with bacteria. An increase of Ag loading resulted in improvement of antibacterial activity of Ag/TNTs although no direct correlation between silver content or release and inhibition of bacterial growth was found.

Ultrafiltration (UF) polyethersulfone (PES) membranes were prepared by wet phase inversion method. Commercial halloysite nanotubes (HNTs) in the amount of 0.5-4 wt % vs PES (15 wt %) were introduced into the casting solution containing the polymer and N,N -dimethylformamide as a solvent. The morphology, physicochemical properties and performance of the membranes were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), zeta potential, porosity and contact angle analyses, as well as permeability measurements. Moreover, the antifouling properties of the membranes were evaluated during UF of a model solution of bovine serum albumin (BSA). The research revealed a positive influence of modification with HNTs on hydrophilicity, water permeability and antifouling properties of the PES membranes. The most significant improvement of permeability was obtained in case of the membrane containing 2 wt % of HNTs, whereas the highest fouling resistance was observed for 0.5 wt % HNTs content. It was found that a good dispersion of HNTs can be obtained only at loadings below 2 wt %. Based on the results a relation between severity of membrane fouling and surface roughness was proved. Moreover, an increase of the roughness of the modified membranes was found to be accompanied by an increase of isoelectric point values., Competing Interests: The authors declare no conflicts of interest.