Luming Ma

Enhanced mineralization of aqueous Reactive Black 5 by catalytic ozonation in the presence of modified GAC

AbstractA modification of granular activated carbon (GAC) by Fe–Mn–O was proposed to improve the catalytic activity of GAC for the enhanced mineralization of aqueous RB5. The efficiency, kinetics, and possible mechanism of ozonation of aqueous RB5 catalyzed by GAC and mGAC have been investigated. mGAC exerted enhanced catalytic activity in the mineralization of aqueous RB5 and a slight promotion in decoloration. An additional 18% TOC removal efficiency was observed in the degradation of RB5 by O3/mGAC compared with O3/GAC under identical experimental conditions within 1xa0h. The pH exerted an evident impact on the degradation of RB5, with maximal mineralization achieved at pH 7. mGAC showed stable catalytic activity in the ozonation of aqueous RB5. Reaction kinetics showed that the TOC removal rate constant of RB5 degradation by O3/mGAC was 5.4 times higher than that by O3 alone. The reaction mechanism involved the enhanced mineralization of aqueous RB5 at the catalyst–solution interface via hydroxyl radica...

Enhancing simultaneous removal of nitrogen and phosphorus from municipal wastewater by Fe–Cu shavings

AbstractTo alleviate the environmental stress and meet the increasingly strict regulation requirements for total nitrogen (TN) and total phosphorus (TP) discharge, hybrid system of Fe–Cu shavings with activated sludge was studied in a lab-scale to treat actual municipal wastewater. The results showed that Fe–Cu shavings could enhance TN and TP removal from municipal wastewater without external carbon source addition. Compared with the simple biological system, TP and TN removal efficiency raised about 30 and 10%, respectively, in the hybrid system at temperature of 3–26.5°C, while the improvement of COD removal was not obvious. Moreover, total ferrum concentration of the effluent was lower than 0.6u2009mg/L, no additional metal pollution appeared. Therefore, a new N&P removal technology is proposed, which provides an easy implementation and effective upgrading to the existing wastewater treatment plants.

Reductive Dechlorination of Chlorinated Hydrocarbons in Water by Cu/Fe Bimetallic Reductant

The influence of Cu on the dechlorination rate of various chlorinated hydrocarbons including CF, CT, 1,1,2,2-TeCA, 1,1,2,2-TeCA and HCA by Fe0 and Cu/Fe was investigated in batch experiments. All organohalides can be dechlorinated rapidly by Fe or Cu/Fe in aqueous system and the contaminants were degraded via sequential reductive dechlorination to form less chlorinated homologues. The removal of CF, CT, 1,1,1-TCA, 1,1,2,2-TeCA and HCA followed pseudo-first-order kinetics both in Fe0 system and Cu/Fe system. Cu/Fe reductant could enhance the dechlorination rate of all chlorinated hydrocarbons.The degradation rate constant of a general dechlorination was increased by a factor of 3 in Cu/Fe system than that in Fe0 system. The intermediate products of dechlorination and the major pathway were summarized in this study. Hydrogenolysis and reductive elimination was the dominant reaction for various chlorinated hydrocarbons dechlorination by Cu/Fe with respect to the products.