Water: the most effective solvent for liquid-phase hydrodechlorination of chlorophenols over Raney Ni catalyst

Abstract

a b s t r a c tThe influences of solvent system on the hydrodechlorination (HDC) of transformer oil-contained PCBs with H 2 over Pd/C catalyst were studied. The addition of water in solvent system significantly accelerated the HDC reaction, which suggested its critical role for enabling Pd/C catalyst to keep high activity and stability. The mechanism of this phenomenon was studied through catalyst characterization (TEM, XRD and XPS), and the change of surface composition of Pd/C catalyst in different solvent in the HDC reaction was raveled. Above results indicated that water in isopropanol-water prevented NaCl accumulating on the surface of catalyst, which avoided the decline in activity and stability of the catalyst. On the basis of these studies, isopropanol-water (60/40, v/v) solvent system was developed to dispose high concentration transformer oil-contained PCBs, where the chloride atom removal ratio of transformer oil-contained PCBs at 2% (w/w) and 5% (w/w) concentration could reach 95.2% and 88.0% for 10 h under mild conditions respectively, and the Pd/C could be recovered and reused at least 10 times without any loss of catalytic activity.

Raney Ni as Recyclable and Selective Catalyst for the Reduction of α‐Pinene to cis‐Pinane with NaBH4 at Room Temperature

“…The fresh Raney Ni catalyst had platelike structure and large particle size. Notably, the surfaces of Raney nickel catalyst operated for 5 times and 10 times were similar to that of the fresh catalyst, which may explain the stable activity and selectivity of the catalyst in the subsequent cycles …”

Inovasi Produk Citrus Infused Honey Tea Dengan Penambahan Rosela (Hibiscus Sabdariffa Linn.) (Kajian Konsentrasi Rosela Dan Lama Infusing)

“…Hal ini dikarenakan adanya penambahan air pada seduhan sebanyak 3 kali lipat dari pekatan. Air merupakan pelarut universal karena dapat melarutkan berbagai komponen dengan ikatan yang kuat antara molekul air dan komponen lain tersebut (Pohorille, 2005;Ma et al, 2015).…”

Catalytic Hydrodechlorination of Chlorophenols in a Continuous Flow Pd/CNT-Ni Foam Micro Reactor Using Formic Acid as a Hydrogen Source

“…Chlorophenols (CPs), existing widely in polluted groundwater and the wastewater effluents of industry [1,2], have been listed as priority pollutants in many countries because of their high toxicity, adverse environmental impacts and poor biodegradability [3][4][5]. For the safe disposal of these highly toxic chlorinated organic pollutants, many detoxification techniques such as biodegradation [6], photochemical degradation [5], advanced oxidation [7,8] and catalytic hydrodechlorination [9,10] have been proposed. Among the available water treatment techniques mentioned above, hydrodechlorination (HDC) presents the advantages of greater flexibility, low energy consumption and relatively safe by-products, showing promising prospects in the treatment of wastewater containing chlorinated organic pollutants [11][12][13].…”