Aqueous solution of p-nitrophenol(PNP)was treated continuously by microwave assisted wet oxidation while flowing through a granular activated carbon(GAC)fixed bed.PNP was pre-adsorbed onto GAC prior to being put into the reactor so as to prevent PNP adsorption on GAC during microwave irradiation.PNP solutions with different initial concentration(218.6 mg/L and 1200 mg/L)were treated under conditions of microwave power 500 W,liquid flow 6.4 mL/min and air flow 40 mL/min or 60 mL/min.The results indicated that the removal of PNP was higher than 90%and more than 65%PNP was mineralized.Phenol,nitrobenzene,hydroquinone and benzoquinone occurred as course products during the operation process,which were degraded further.The biodegradability of the outflow was improved greatly by microwave assisted wet oxidation.
Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride （NaBH4） with reduction of Ni^2＋ and Fe^2＋ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM （transmission electron microscope）, XRD （X-ray diffractometer）, and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol （p-CP） as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L （Ni 5 wt%）. The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.
