Gupta Himanshu, Gupta Bina
Department of Chemistry Indian Institute of Technology Roorkee, Roorkee 247667, U.K., India.
Department of Chemistry Indian Institute of Technology Roorkee, Roorkee 247667, U.K., India.
Chemosphere. 2015 Nov;138:924-31. doi: 10.1016/j.chemosphere.2014.12.028. Epub 2015 Jan 6.
Photocatalytic decay profiles of polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (B[a]P) have been investigated on various synthesized iron oxides and on soil surfaces under a set of diverse conditions. Samples were analysed using the developed HPLC procedure. Results of the present study demonstrate fastest photodisintegration of B[a]P on goethite followed by haematite, magnetite, akaganeite and maghemite, respectively. The effect of soil pH, irradiation wavelength and iron oxide and oxalic acid dose on the degradation of B[a]P was evaluated. The studies revealed enhancement in photodegradation in the presence of oxalic acid due to the occurrence of fenton like reaction. The results showed faster B[a]P degradation under short wavelength UV radiation. Rate constants in acidic, neutral and alkaline soils under optimum dissipation conditions were 1.11×10(-2), 7.69×10(-3) and 9.97×10(-3) h(-1), respectively. The study indicates that iron oxides along with oxalic acid are effective photocatalyst for the remediation of benzo[a]pyrene contaminated soil surfaces. The degradation products of B[a]P in the soils of different pH in presence of goethite were identified and degradation pathways proposed. Peaks due to toxic metabolites such as diones, diols and epoxides disappear after 120 h in all the three soils.
在一系列不同条件下，研究了多环芳烃（PAH）苯并[a]芘（B[a]P）在各种合成氧化铁和土壤表面上的光催化衰变曲线。使用开发的高效液相色谱法对样品进行分析。本研究结果表明，B[a]P在针铁矿上的光分解速度最快，其次分别是赤铁矿、磁铁矿、纤铁矿和磁赤铁矿。评估了土壤pH值、辐照波长、氧化铁和草酸剂量对B[a]P降解的影响。研究表明，由于类似芬顿反应的发生，草酸的存在增强了光降解作用。结果表明，在短波长紫外辐射下B[a]P降解更快。在最佳消散条件下，酸性、中性和碱性土壤中的速率常数分别为1.11×10(-2)、7.69×10(-3)和9.97×10(-3) h(-1)。该研究表明，氧化铁与草酸一起是修复苯并[a]芘污染土壤表面的有效光催化剂。确定了在针铁矿存在下不同pH值土壤中B[a]P的降解产物，并提出了降解途径。在所有三种土壤中，120小时后，由于二酮、二醇和环氧化物等有毒代谢物产生的峰消失。
