Search

Hazardous pollutants in dredged sediment pose great threats to ecological environment and human health. A novel approach, named pulsed discharge plasma (PDP), was employed for the degradation of p-nitrophenol (PNP) in dredged sediment. Experimental results showed that 92.9% of PNP in sediment was smoothly removed in 60 min, and the degradation process fitted the first-order kinetic model. Roles of some active species in PNP degradation in sediment were studied by various gas plasmas, OH radical scavenger, hydrated electron scavenger and O2(·-) scavenger; and the results presented that O3, OH radical, eaq(-) and O2(·-) all played significant roles in PNP removal, and eaq(-) and O2(·-) mainly participated in other oxidising active species formation. FTIR analysis showed that PNP molecular structure was destroyed after PDP treatment. The main degradation intermediates were identified as hydroquinone, benzoquinone, phenol, acetic acid, NO2(-) and NO3(-). PNP degradation pathway in dredged sediment was proposed. It is expected to contribute to an alternative for sediment remediation by pulse discharge plasma., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Ozonation of p-nitrophenol adsorbed on activated carbon fiber (ACF) was conducted in a semiwet atmosphere, and its effect on the textural and chemical characteristics of ACF was examined. The decomposition kinetics of p-nitrophenol followed a pseudo–first-order reaction, and an increase in O3input enhanced the removal of p-nitrophenol. Ozone slightly etched ACF and resulted in a decrease in the pore volume of ACF, but slightly different changes in pore diameter also occurred on virgin and spent ACF. An increase in the surface oxygen-containing groups (C=O, COOH, etc.) after ozonation might have influence on the adsorption capacity of ACF. [ABSTRACT FROM PUBLISHER]

p -Nitrophenol (PNP) removal in dredged sediment during pulsed discharge plasma process was studied in terms of adjustable trim capacitance, electrode distance and gas-flow rate. PNP degradation efficiency reached up to 88.5% under the conditions of adjustable trim capacitance of 2.0 nF, electrode distance of 16 mm, and air flow rate of 0.8 L min −1 . To a certain extent, increasing the adjustable trim capacitance and decreasing the electrode distance leaded to high PNP degradation efficiency. An appropriate air flow rate was determined for gaining relatively high PNP removal efficacy. PNP mineralization was analyzed by UV–Vis spectrum, COD, and TOC evolution. [ABSTRACT FROM AUTHOR]