Al-Sabahi Jamal, Bora Tanujjal, Al-Abri Mohammed, Dutta Joydeep
Department of Petroleum and Chemical Engineering, College of Engineering, Sultan Qaboos University, Al-Khoudh, Oman.
Chair in Nanotechnology for Water Desalination, Water Research Center, Sultan Qaboos University, Al-Khoudh, Oman.
PLoS One. 2017 Dec 20;12(12):e0189276. doi: 10.1371/journal.pone.0189276. eCollection 2017.
Benzene, toluene, ethylbenzene and xylenes (BTEX) are some of the common environmental pollutants originating mainly from oil and gas industries, which are toxic to human as well as other living organisms in the ecosystem. Here we investigate photocatalytic degradation of BTEX under visible light irradiation using supported zinc oxide (ZnO) nanorods grown on glass substrates using a microwave assisted hydrothermal method. ZnO nanorods were characterized by electron microscopy, X-ray diffraction (XRD), specific surface area, UV/visible absorption and photoluminescence spectroscopy. Visible light photocatalytic degradation products of BTEX are studied for individual components using gas chromatograph/mass spectrometer (GC/MS). ZnO nanorods with significant amount of electronic defect states, due to the fast crystallization of the nanorods under microwave irradiation, exhibited efficient degradation of BTEX under visible light, degrading more than 80% of the individual BTEX components in 180 minutes. Effect of initial concentration of BTEX as individual components is also probed and the photocatalytic activity of the ZnO nanorods in different conditions is explored. Formation of intermediate byproducts such as phenol, benzyl alcohol, benzaldehyde and benzoic acid were confirmed by our HPLC analysis which could be due to the photocatalytic degradation of BTEX. Carbon dioxide was evaluated and showed an increasing pattern over time indicating the mineralization process confirming the conversion of toxic organic compounds into benign products.
苯、甲苯、乙苯和二甲苯(BTEX)是一些常见的环境污染物,主要源自石油和天然气行业,它们对人类以及生态系统中的其他生物有毒。在此,我们研究了使用微波辅助水热法在玻璃基板上生长的负载型氧化锌(ZnO)纳米棒在可见光照射下对BTEX的光催化降解。通过电子显微镜、X射线衍射(XRD)、比表面积、紫外/可见吸收光谱和光致发光光谱对ZnO纳米棒进行了表征。使用气相色谱/质谱仪(GC/MS)对BTEX的各个组分的可见光光催化降解产物进行了研究。由于纳米棒在微波辐射下快速结晶,具有大量电子缺陷态的ZnO纳米棒在可见光下表现出对BTEX的高效降解,在180分钟内降解了超过80%的各个BTEX组分。还探究了BTEX各组分初始浓度的影响,并考察了ZnO纳米棒在不同条件下的光催化活性。我们的高效液相色谱分析证实了苯酚、苯甲醇、苯甲醛和苯甲酸等中间副产物的形成,这可能是由于BTEX的光催化降解所致。对二氧化碳进行了评估,结果表明其随时间呈增加趋势,这表明矿化过程正在进行,证实了有毒有机化合物已转化为良性产物。