Raut Sandesh S, Kamble Sanjay P, Kulkarni Prashant S
Energy and Environment Laboratory, Department of Applied Chemistry, Defence Institute of Advanced Technology (DU), Ministry of Defence, Pune, 411 025, India.
Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Pune, 411 008, India.
Chemosphere. 2016 Sep;159:359-366. doi: 10.1016/j.chemosphere.2016.06.031. Epub 2016 Jun 16.
The zero-valent copper (Cu(0)) nanoparticles were prepared by chemical reduction method. The morphology of nanoparticles was investigated by using X ray diffraction, scanning electron microscopy-energy dispersive X ray, UV-visible spectrophotometer and Brunauer-Emmett-Teller surface area analyser. The Cu(0) nanoparticles along with reducing agents, NaBH4/5% acidified alcohol were used for the dechlorination of chloroaromatics at room temperature. Chlorobenzene (Cl-B), chlorotoluene (Cl-T), chloropyridine (Cl-Py) and chlorobiphenyl (Cl-BPh) were selected as the contaminants. The effect of various operating parameters such as pH, concentration of the catalyst and reducing agent (NaBH4), and recycling of the catalyst on dechlorination were studied. Nearly complete dechlorination of all the chloroaromatics were achieved in the presence of Cu(0) nanoparticles (2.5 g L(-1)) and NaBH4 (1.0 g L(-1)) within 12 h. On the contrary, approximately 70% of dechlorination was observed in the presence of 5% acidified alcohol at similar experimental conditions. The dechlorination mechanism highlighted the importance of Cu(0) nanoparticles as a surface mediator. The kinetics of the dechlorination of chloroaromatics was investigated and compared with chloroaliphatics. The dechlorination rate differed from 0.23 h(-1) (Cl-B) to 0.15 h(-1) (Cl-BPh) in the presence of Cu(0) nanoparticles and NaBH4. The effectiveness of Cu(0) nanoparticles with NaBH4 (1 g L(-1)) and 5% acidified alcohol as electron donors were studied by oxidation-reduction potential and observed to be -1016 mV and -670 mV, respectively. Final products of the dechlorination were benzene, toluene, pyridine and biphenyl, as identified by gas chromatograph mass spectrometer and nuclear magnetic resonance spectroscopy.
通过化学还原法制备了零价铜（Cu(0)）纳米颗粒。利用X射线衍射、扫描电子显微镜-能量色散X射线、紫外可见分光光度计和布鲁诺尔-埃米特-泰勒表面积分析仪对纳米颗粒的形貌进行了研究。在室温下，将Cu(0)纳米颗粒与还原剂NaBH4/5%酸化乙醇一起用于氯代芳烃的脱氯反应。选择氯苯（Cl-B）、氯甲苯（Cl-T）、氯吡啶（Cl-Py）和氯联苯（Cl-BPh）作为污染物。研究了pH值、催化剂和还原剂（NaBH4）浓度以及催化剂循环利用等各种操作参数对脱氯反应的影响。在Cu(0)纳米颗粒（2.5 g L(-1)）和NaBH4（1.0 g L(-1)）存在的情况下，12小时内所有氯代芳烃几乎完全脱氯。相反，在类似实验条件下，5%酸化乙醇存在时观察到约70%的脱氯率。脱氯机理突出了Cu(0)纳米颗粒作为表面介质的重要性。研究了氯代芳烃脱氯反应的动力学，并与氯代脂肪烃进行了比较。在Cu(0)纳米颗粒和NaBH4存在的情况下，脱氯速率从0.23 h(-1)（Cl-B）到0.15 h(-1)（Cl-BPh）不等。通过氧化还原电位研究了Cu(0)纳米颗粒与NaBH4（1 g L(-1)）和5%酸化乙醇作为电子供体的有效性，观察到分别为-1016 mV和-670 mV。通过气相色谱-质谱联用仪和核磁共振光谱鉴定，脱氯的最终产物为苯、甲苯、吡啶和联苯。
