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[Display omitted] • Size and type of MWCNTs have a crucial impact on the Bi-based composite properties. • Enhancement of the composite photoactivity depends on the type of carbon nanotubes. • Multifunctional role of ionic liquid: reagent, template and dispersion agent. The use of various types of multi-walled carbon nanotubes in the synthesis of bismuth oxybromide semiconductors via imidazolium ionic liquid was studied in detail. The effect of the MWCNT shape, specific surface area, and various diameters on the morphology, surface properties and photoactivity of the Bi-based composites has been investigated for the first time. So far, the literature has only shown the enhancement of photocatalytic activity of composites containing MWCNT; however, our research shows a broader view of the issue. The photocatalytic activity of the individual composites under UV–Vis irradiation was assessed by the degradation of various micropollutants, showing the diversity of properties of the obtained composites. It is also significant that in the composite system, the imidazolium ionic liquid played a crucial role in the formation of microspheres and acted as a dispersing agent, leading to an even distribution of MWCNTs on the surface of the spherical bismuth oxybromide. [ABSTRACT FROM AUTHOR]

In this publication, a new dispersive solid-phase extraction (dSPE) method combined with gas chromatography-mass spectrometry and atomic absorption spectrometry was developed for the simultaneous determination of 9 PAHs and chromium, cadmium, and lead ions in water samples. For this purpose, non-modified multi-walled carbon nanotubes (MWCNTs) and modified -MWCNTs (OH-MWCNTs and COOH-MWCNTs) were used as sorbents. Parameters affecting the extraction, such as the amount of sorbent, the pH of the sample, the composition and volume of eluents and the extraction time were optimized. Sequential elution was applied using 6 mL of dichloromethane for the elution of PAHs and 5 mL of 3 M HNO 3 for cadmium, lead, and chromium. The optimal values of other parameters were as follows: 50 mg of sorbent per 250 mL of water sample, pH in a range from 6 to 7 and 30 min of contact time between the sorbent and analytes. The results demonstrated the high extraction capability of modified MWCNTs with recoveries between 80 and 101% for cadmium, chromium, and lead ions and between 83 and 92% for PAHs. Finally, the optimized method was validated, and the matrix effects were determined. [ABSTRACT FROM AUTHOR]

[Display omitted] Effective methods of water and wastewater purification are still being investigated. Among several methods, sorption onto carbon nanotubes (CNTs) is very promising solution. CNTs possess high potential to remove a wide range of chemicals from water, including pharmaceuticals, which are frequently found in various aqueous samples. Crucial aspect of the application of CNTs as adsorbents is the possibility to use the material multiple times with the material maintaining its sorption potential and capacity. For this reason, thermal and chemical regeneration of Multi-Walled Carbon Nanotubes (MWCNTs) was investigated in our study. The conditions of thermal regeneration were set at 300 °C for 2 h. Higher temperatures caused large losses of MWCNTs. Next, the adsorbent was put in a cycle of contamination – regeneration, where it was mixed with wastewater treatment plant influent for 16 h, then dried and thermally regenerated. After thermal treatment, the sorption level (%) of three anticancer drugs — cyclophosphamide, ifosfamide and 5-fluorouracil — was determined. The obtained results proved that there was no negative influence on the sorption level of any investigated pharmaceuticals after 5 cycles of contamination – thermal regeneration. An additional regeneration method of MWCNTs with 3 M HNO 3 was proposed, but the sorption level of cyclophosphamide after such treatment decreased from around 50 % (for untreated and thermally regenerated MWCNTs) to around 30 %. It suggests that contact with acid changed MWCNTs, probably by introducing additional functional groups onto their surface. The performed elemental analysis, Raman spectroscopy and both SEM and TEM images, confirm these predictions. [ABSTRACT FROM AUTHOR]