Evaluation the pretreatment sugarcane bagasse supported TiO₂ on removal ciprofloxacin antibiotic under simulated solar iradiation

Kỷ yếu Hội nghị: Nghiên cứu cơ bản trong “Khoa học Trái đất và Môi trường” DOI: 10.15625/vap.2019.000238 700 EVALUATION THE PRETREATMENT SUGARCANE BAGASSE SUPPORTED TIO2 ON REMOVAL CIPROFLOXACIN ANTIBIOTIC UNDER SIMULATED SOLAR IRADIATION Pham Thi Thuy 1 , Nguyen Linh Chi 1 , Nguyen Thuy Linh 2 , Nguyen Thi Hanh 1 , Nguyen Manh Khai 1 1 Faculty of Environmental Science, VNU Hanoi University of Science, Emails: phamthithuy@hus.edu.vn, linhnguyen.chi97@gmail.com, nguyenmanhkhai@hus.edu.vn hanhnguyenmt@gmail.com 2 Faculty of Engineering, KU Leuven, thuylinh.nguyen@kuleuven.be ABSTRACT Antibiotic residues in water environment not only pose threats to ecosystems and human well- being but also they are responsible for antibiotic-resistant bacteria. In this paper, sugarcane bagasse- supported TiO2 (SCB/TiO2) has been synthesized by sol-gel method and calcination, which could be used to eliminate ciprofloxacin antibiotic from the liquid phase. The characterization of the material was analyzed by various techniques, including Scanning electron microscope (SEM), Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Photoluminescence spectroscopy (PL). It is proven that photocatalytic capability to degrade CIP of alkaline pretreated sugarcane bagasse are higher than distilled water-pretreated sugarcane bagasse and acid coupled alkaline-pretreated sugarcane bagasse. The highest efficiency removal CIP from synthetic water was obtained 67.91% at pH 5, 180 minutes reaction time, mass material 1g/L and the initial CIP concentration at 15 ppm. Degradation CIP by SCB/TiO2 which carried out under simulated solar irradiation could have advantages such as cost-saving, utilizing waste-by-product and reinforcing the sequential cycles of the material after treatment. Keywords: Ciprofloxacin, sugarcane bagasse, TiO2, photocatalytic. 1. INTRODUCTION Ciprofloxacin (CIP) is one of the most ubiquitously antibiotic used to the medical, agricultural, animal husbandry and aquaculture [1]. Along with other antibiotics and pharmaceuticals, it has been found in many samples of water contamination, groundwater and even drinking water such as hospital outflows [2]. Specifically, it is reported up to 99g/L in the effluent at the prominent hospital in Santa Maria [3]. Swiss environmental scientist groups studied the presence of CIP in sewage sludge in wastewater treatment facilities up to 2.4 mg/kg of dry matter weight [4]. CIP residues in aqueous solution are responsible for dangerous signs the aquatic organisms such as Microcystis aeruginosa and Synechococcus leopoliensis. It is reported 17 and 203 μg/L that were the EC50 toxicity values respectively [5]. Composites of cellulose with TiO2 had applied in removal organic pollutants and antibiotics. Hanyu Zhang and his co-workers in 2017 had synthesized TiO2 supported on reed straw biochar composites for removal sulfamethoxazole antibiotics on water environment under UV light successfully [6]. Gertrude Kignelman and Wim Thielemans (2017) had presented novel ideas related to using cellulose nanocrystals/TiO2 hybrids for VOCs degradation [7]. In this work, the composite sugarcane bagasse (SCB) supported TiO2 (SCB/TiO2) was synthesized to remove CIP under simulated solar irradiation. 2. METHOD 2.1. Modified sugarcane bagasse Pretreatment of sugarcane bagasse SCB was washed thoroughly with tap water to ensure the removal of dust then dried at 70 o C for 24 hours. The material then was milled to get desired particle size of 0,5mm for further treatments. Hồ Chí Minh, tháng 11 năm 2019 701 Alkali treatment Pretreated SCB was purified with 0.1mol/L sodium hydroxide solution for 2 hours to extract non-cellulosic binding materials like hemicelluloses/lignin complexes. Then, it was washed with distilled water many times. After drying at 80 o C for 24 hours, it was preserved in desiccators for further use. Acid coupled alkali treatment Two-step pretreated SCB was applied, including acid treatment (3wt% HNO3) to remove hemicelluloses and alkali step aimed predominantly at removing lignin. 2.2. Synthesis TiO2 Tetra-isopropyl-orthotitanate 98% and ethanol (v/v=1:4) were added to distilled water and ethanol 98% (v/v=1:1) at pH = 2. The white precipitate is obtained that upon stirring at room temperature for 2 hours evolves to a milky homogeneous solution. After aging for 1 day, the obtained gel solution was dried at 80 o C. Subsequently, it was calcined at 450 o C for 2 hours to create TiO2 power. 2.3. Synthesis sugarcane bagasse supported TiO2 Firstly, three types of modified SCB put into 250 mL Erlenmeyer flask with ethanol 99%, shaken for 24 hours. For SCB/TiO2, the sol TiO2 was dissolved in SCB/C2H5OH for sol-gel process before hydrolysis TiOT in acid solution. After aging for 24 hours, the aged solution was recovered by heating the solution until it was dried at 80 0 C in an oven. Next, the dried material was calcined under 450 0 C in a furnace for 2 hours. 2.4. Photocatalysis experiment 0.1g SCB/TiO2 put into 100mL CIP 15ppm in dark 45min, then turned on the compact light 35W for 2 hours. Solution after treatment was filtered and CIP concentration was determined by a UV-Vis spectrophotometer at 276nm. 3. RESULTS AND DISCUSSION 3.1. Characterization SEM Based on Figure 3.8.a, it can be observed the TiO2 particles appeared as spherical shape. Most of the spherical particles were agglomerated together irregularly. From the figures, it can be seen that unmodified sugarcane bagasse had a smooth and less porous structure. In comparison with alkali pretreated SCB/TiO2, the destruction process with sodium hydroxide successfully reduced the particle size into nanosize particles. On the other hand, modified sugarcane bagasse with acid and alkaline had more high well-developed pores and contained many small pieces in surface of the adsorbent which shows a potential possibility for organic substance to be adsorbed. a. Untreated SCB/TiO2 b. Alkali pretreated SCB/TiO2 c. Acid coupled alkali pretreated SCB/TiO2 Figure 1. SEM images of SCB/TiO2. Kỷ yếu Hội nghị: Nghiên cứu cơ bản trong “Khoa học Trái đất và Môi trường” 702 FTIR and XRD The TiO2 supported modified SCB were characterized functional group by FTIR method. It is clear that the stretching vibration adsorption of Ti-O-Ti around 675 cm - 1, 512 cm -1 and -OH stretching vibrations of water molecules ~ 3462 cm -1 , 3343 cm -1 represented successfully. The bands at 1610 cm -1 , 1649 cm -1 and 1698 cm -1 of both spectrums were characteristic of the bending mode of adsorbed water on titanium surface. From Figure 3, the diffraction peaks for the TiO2 powder located at 2θ = 25.2 o , 37.8 o , 48.1 o and 54.2 o could be indexed by the (101), (004), (200), and (105) diffraction peaks of the TiO2 anatase phase. According to JCPDS card no 00-056- 1718, peaks at 2θ = 14.5o, 16.6o and 22.7o are corresponding to (110), (101) and (002) planes were presented for crystalline cellulose. Figure 2. FT-IR results of SCB/TiO2. Figure 3. XRD results of SCB/TiO2. PL spectra The measured PL-emission spectra of SCB/TiO2 have presented in figure 4. The intensity of the PL-spectra reduced in the following order for the photocatalysts: TiO2 (322240 a.u), un- pretreated SCB/TiO2 (295064 a.u), acid coupled alkali pretreated SCB/TiO2 (63714 a.u) and alkali pretreated SCB/TiO2 (14376a.u). These results indicate that the lower PL intensity suggests the lower the recombination rate of photogenerated electron-hole pairs, resulting in enhancing the photocatalytic of semiconductors. Thus, alkali pretreated SCB/TiO2 has the highest photocatalytic activity in four semiconductors. Figure 4. Photoluminescence spectra SCB/TiO2. 3.2. Photocatalysis evaluation The photocatalytic capability of SCB/TiO2 showed in figure 5. After 180 min the removal ratio of just only obtained 41.53%, 67.91% and 62.92% for non-pretreatment, alkali pretreatment Hồ Chí Minh, tháng 11 năm 2019 703 and acid coupled alkali pretreatment respectively. In comparison with untreated SCB/TiO2 having a higher removal ratio at 120min, the percentage of acid coupled alkali nearly unchanged after 180 minutes reaction. Figure 5. Efficiency of CIP degradation using SCB/ TiO2. 4. CONCLUSION In this study, the characteristic of SCB/TiO2 was investigated. All the sample was characterized by PL, FT-IR, SEM and XRD analyses. PL results showed that SCB/TiO2 could enhance the adsorption and photocatalytic capability of TiO2. On the other hand, sugarcane bagasse was pretreated by alkali had a photocatalysis active higher than one’s nature and the other was pretreated by acid coupled alkali before supported TiO2 in photocatalysis experiments. The alkali pretreated SCB/TiO2 has 67.91% photocatalytic efficiency in removing CIP antibiotic at pH 5 180 minutes reaction time, mass material 1g/L and the initial CIP concentration at 15 ppm. REFERENCES [1]. Shi, W.M., Ding, Y.C., &WU, L.H., (2015). The Adsorption Properties of Ciprofloxacin by KMnO4 Modified DurioZibethinusMurr Shells, Advanced Materials Research, 1104, 111 - 117. [2]. Moon, R. J., Schueneman, G. T., &Simonsen, J. (2016). Overview of Cellulose Nanomaterials, Their Capabilities and Applications. JOM, 68(9), 2383-2394. [3]. Vasconcelos, T. G., Kümmerer, K., Henriques, D. M., & Martins, A. F., (2009). Ciprofloxacin in hospital effluent: Degradation by ozone and photoprocesses, Journal of Hazardous Materials, 169(1-3), 1154-1158 [4]. Alder, A. C., Giger, W., Golet, E. M., Kohler, H.P.E., McArdell, C. S., and Molnar, E., (2003). Occurrence and Fate of Antibiotics as Trace Contaminants in Wastewaters, Sewage Sludges, and Surface Waters. Chimia, 57(9), 485-491. [5]. Zhang R., Zhang G., Zheng Q., Tang J., Chen Y., Xu W., Zou Y. and Chen X., (2012). Occurrence and risks of antibiotics in the Laizhou Bay, China: Impacts of river discharge, Ecotoxicol. Environ. Saf., Vol. 80, pp. 208-215. [6]. Yang X., Cao C. Erickson L., Klabunde K., Et. Al. (2009). Photo-catalytic degration of rhodamin B on C-, S-, N-, and Fe- doped TiO2 undersisible - light irradiation, Applied Catalysis B :Envairomental, 91, 657-662. [7]. Gertrude Kignelman and Wim Thielemans (2017). Cellulose nanocrystals/titanium dioxide hybrids for volatile organic compounds degradation, Conference in KU Leuven.