The performance of TiO₂ /NaY-zeolite nanocomposite in photocatalytic degradation of Microcystin-LR from aqueous solutions: Optimization by response surface methodology (RSM)

Abstract

Background: Microcystin (MC) is a hepatotoxic and carcinogenic toxin that is generated by cyanotoxins which can have adverse effects on the human health. Therefore, it is very important to remove it from the environment. This study was performed to investigate the efficiency of titanium dioxide (TiO 2)/ NaY-zeolite (T/N-Z) nanocomposite for removal of MC-LR under ultraviolet light. Methods: In the present study, T/N-Z nanocomposite was synthesized using the hydrothermal method. Specification of the photocatalysts was determined by the field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) spectra. The response surface methodology (RSM) was used to survey the effects of operating variables such as pH, contact time, and catalyst dose on the removal of MC-LR. The MC-LR concentration was measured by high-performance liquid chromatography (HPLC). Results: It was revealed that the increase of contact time and catalyst dose had a positive effect on enhancing the removal efficiency of MC-LR, but pH had a negative effect. Finally, the maximum MC-LR removal efficiency was 97.63%, which occurred at pH = 5, contact time = 120 min, and catalyst dose = 1.2 g/L. Conclusion: In general, T/N-Z composite in aqueous solutions under the UV light can easily decompose MC-LR and it can also be proposed as an efficient composite for removal of MC-LR from contaminated water.

Titania-zeolite composite for tetracycline photocatalytic degradation under visible light: A comparison between doping and ion exchange

“…Fig. 3 , b, shows the structure of TiO 2 having a smooth surface and composed of aggregates with sharp edges in a similar finding by other studies [ 10 , 28 ]. The SEM images of the ion exchanged and the unmodified TiO 2 /BEA in Fig.…”

“…The XRD diffraction patterns of TiO 2 showed peaks at 2θ = 25.2°, 36.98°, 48.4°, 54.9°, 62.7°, 68.8°, and 70.1° corresponding to the (101), (103), (200), (211), (204), (113), and (220) anatase phase planes, and 27.33°, 36°, and 41.2°, 44.1°, and 56.46° corresponding to (110), (101), (111), (210), and (220) for the rutile phase crystallographic planes based on (JCPDS 21–1272) and (JCPDS 21–1276) spectrum standards [ 25 ]. Accordingly, the sol-gel TiO 2 was observed in both anatase and rutile polymorphs consistent with those for solgel TiO 2 calcined under mild temperatures 200 °C < T < 550 °C [ 17 , 23 , [26] , [27] , [28] , [29] ]. The XRD diffraction patterns of the FeTZ catalysts and the unmodified 60TZ photocatalyst possessed very low crystallinity as compared to TiO 2 .…”

“…The FTIR of the Titania photocatalysts showed a change in the shape of the spectrum between 500 cm −1 and 900 cm −1 caused by the strong interaction between TiO 2 and the porous surface of the zeolite through Ti–O–Si bonds [ 17 , 42 ]. The existence of this bond was characterized by a band located around 960 cm −1 and whose intensity is highly affected by the amount of Ti in the photocatalyst [ 28 , 39 ]. In our photocatalyst, a wide peak with low intensity was detected at 965 cm −1 as shown in Fig.…”

Synthesis, characteristics, and photocatalytic activity of zinc oxide nanoparticles stabilized on the stone surface for degradation of metronidazole from aqueous solution

“…Thus, generation of hydroxyl radicals on the surface of catalyst for degradation of metronidazole is limited. Also, with increasing metronidazole concentration, the radiation photons, which react with catalyst surface, are prevented and screened off, therefore, the production of hydroxyl radicals is delayed and the degradation of metronidazole is decreased (8,(41)(42)(43)(44)(45)(46). Sobana et al investigated photocatalytic degradation of acid red 18 by ZnO nanoparticles and found that by increasing the concentration of acid red 18, the removal efficiency decreased, which is consistent with the results of this study (47).…”

Photocatalytic removal of Malachite green dye from aqueous solutions by nano-composites containing titanium dioxide: A systematic review

“…But today, researchers are increasingly using efficient methods, which are economically sustainable technologies for treating colored effluents (18)(19)(20). Today, the photocatalyst process is used as a simple and efficient method to remove organic pollutants and dyes from industrial effluents and has been shown to play a significant role in environmental control by decomposing organic pollutants (21)(22)(23). The photocatalytic technique is superior to traditional purification techniques.…”