02784nas a2200241   4500008004100000022001400041245011900055210006900174260010600243300001200349490000800361520183000369653002202199653002002221653002402241653001002265653002502275653004402300100002202344700002302366700002702389856012602416       2016                        eng d  a0045-653500aEfficacy of zero-valent copper (Cu-0) nanoparticles and reducing agents for dechlorination of mono chloroaromatics0 aEfficacy of zerovalent copper Cu0 nanoparticles and reducing age  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcSEP  a359-3660 v1593 a<p>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 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. (C) 2016 Elsevier Ltd. All rights reserved.</p>10aAcidified alcohol10aChloroAromatics10aHydrodechlorination10aNaBH410aWastewater treatment10aZero-valent copper (Cu-0) nanoparticles1 aRaut, Sandesh, S.1 aKamble, Sanjay, P.1 aKulkarni, Prashant, S.  uhttps://library.ncl.res.in/content/efficacy-zero-valent-copper-cu-0-nanoparticles-and-reducing-agents-dechlorination-mono02499nas a2200265   4500008004100000022001400041245014800055210006900203260000800272300001100280490000800291520156300299653001901862653001801881653002401899653001301923653002601936653002701962100002201989700001802011700002302029700002302052700002702075856013102102       2020                        eng d  a0045-653500aScreening of zero valent mono/bimetallic catalysts and recommendation of Raney Ni (without reducing agent) for dechlorination of 4-chlorophenol0 aScreening of zero valent monobimetallic catalysts and recommenda  cJUL  a1262980 v2503 a<p>Chlorophenol (CP) is considered as environmentally hazardous material due to its acute toxicity, persistent nature and strong bioaccumulation. The dechlorination of 4-CP was investigated by using various catalysts such as bimetallic (Fe-0/Cu-0, Al-0/Fe-0), Pd/C, Raney Ni and Fe-0 at room temperature. Among the catalysts studied, Raney Ni proved to be very economical and efficient catalyst that worked without the use of an external reducing agent. The dechlorination of 4-CP by Raney Ni was therefore further explored. Complete dechlorination of 4-CP (30 mg L-1) was achieved in 6 hat an optimum Raney Ni catalyst loading of 3 g L-1. The effect of triethylamine (TEA) and tripropylamine (TPA) was also investigated and it was observed that 100% dechlorination is possible in presence of 45 mg L-1 of TEA. The kinetics of dechlorination of 4-CP was investigated and found to be first order with a rate constant of 0.017 min(-1) at 50 degrees C, and it enhances to 0.109 min(-1) with addition of TEA. In the absence of a reducing agent, acidic to neutral pH favors dechlorination of 4-CP. The final product of dechlorination was estimated to be phenol by performing HPLC, LCMS and NMR analysis. Based on the results, a probable dechlorination mechanism of 4-CP is also proposed. It can be concluded that the catalytic hydrodechlorination is an effective and economical technique for dechlorination of 4-CP and it has a potential for the dechlorination of other toxic derivatives of chlorinated aromatics. (C) 2020 Elsevier Ltd. All rights reserved.</p>
10a4-Chlorophenol10aCl- scavenger10aHydrodechlorination10aRaney Ni10aRecycling of catalyst10aWithout reducing agent1 aRaut, Sandesh, S.1 aShetty, Rohit1 aRaju, Nikhi, Maria1 aKamble, Sanjay, P.1 aKulkarni, Prashant, S.  uhttps://library.ncl.res.in/content/screening-zero-valent-monobimetallic-catalysts-and-recommendation-raney-ni-without-reducing