[Inhibition of sulfite oxidation catalyzed by heavy metals in dual alkali flue gas desulfurization slurry].

Heavy metals accumulated in slurry of dual alkali flue gas desulfurization (FGD) present a significant catalysis to SO3(2-) oxidation, resulting in a waste of effective components for desulfurization. Na2S was adopted to precipitate heavy metal ions in FGD slurry, and the oxidation rate of SO3(2-) was obtained under different concentrations of heavy metal ions, to reveal the inhibition effect of Na2S on SO3(2-) oxidation catalyzed by heavy metal ions. Mn2+ showed a remarkable catalysis to SO3(-2) oxidation, as the initial oxidation rate of SO3(2-) was tripled to 0.

[Phosphorus pollution of the sediment from Hangzhou urban river and hydraulic simulation of phosphorus release].

The phosphorus pollution of the sediment from Dongxin River, an urban river in Hangzhou, was surveyed. Phosphorus release under various flow velocity (0.002-0.

[Mechanism and kinetic of methyldopa removal by Fenton's reagent].

Methyldopa was selected to be degraded by Fenton's reagent in the experiment. The experimental results showed that it was feasible to the removal of Methyldopa and COD by Fenton's reagent. The mechanism of Methyldopa removal by Fenton's reagent was significantly different according to the Fe2+ :H2O2 ratio.

Oxidation inhibition of sulfite in dual alkali flue gas desulfurization system.

A laboratory-scale well-mixed thermostatic reactor with continuously blasting air was used to investigate the oxidation inhibition of sulfite in dual alkali flue gas desulfurization (FGD) system. The effects of operating parameters such as pH value and catalyst concentration on the oxidation were studied. Sodium thiosulfate was used in the system, and was found that it significantly inhabited the sulfite oxidation.

Application of chitosan as flocculant for coprecipitation of Mn(II) and suspended solids from dual-alkali FGD regenerating process.

Heavy metals and suspended solid (SS) needed to be removed from the recirculation of dual-alkali flue gas desulfurization (FGD) system. The feasibility of coprecipitation of heavy metal and SS by water-soluble chitosan was studied in a lab scale experiment. The association between chitosan and metal ions was verified through DSC and FT-IR.

Enhanced degradation of carbon tetrachloride by surfactant-modified zero-valent iron.

Sorption of carbon tetrachloride (CT) by zero-valent iron (ZVI) is the rate-limiting step in the degradation of CT, so the sorption capacity of ZVI is of great importance. This experiment was aimed at enhancing the sorption of CT by ZVI and the degradation rate of CT by modification of surfactants. This study showed that ZVI modified by cationic surfactants has favorable synergistic effect on the degradation of CT.

Stability of expanded granular sludge bed process for terylene artificial silk printing and dyeing wastewater treatment.

Terylene artificial silk printing and dyeing wastewater (TPD wastewater), containing averaged 710 mg/L terephthalic acid(TA) as the main carbon source and the character pollutant, was subjected to expanded granular sludge bed (EGSB) process. The stability of the EGSB process was firstly conducted by laboratory experiment. TA ionization was the predominated factor influencing the acid-base balance of the system.

Kinetics of aerobically activated sludge on terylene artificial silk printing and dyeing wastewater treatment.

Aerobically activated sludge processing was carried out to treat terylene artificial silk printing and dyeing wastewater (TPD wastewater) in a lab-scale experiment, focusing on the kinetics of the COD removal. The kinetics parameters determined from experiment were applied to evaluate the biological treatability of wastewater. Experiments showed that COD removal could be divided into two stages, in which the ratio BOD/COD (B/C) was the key factor for stage division.

Biodegradability of terephthalic acid in terylene artificial silk printing and dyeing wastewater.

As the characteristic pollutant, terephthalic acid (TA) was in charge of 40%-78% of the total COD of terylene artificial silk printing and dyeing wastewater (TPW-water). The studies on biodegradability of TA were conducted in a serial of activated sludge reactors with TPW-water. TA appeared to be readily biodegradable with removal efficiency over 96.