Nitrobenzene Removal Research Articles

Cost Effectiveness of Ozonation and AOPs for Aromatic Compound Removal from Water: A Preliminary Study

The capital and operating costs for several aromatic compounds (phenanthrene, 2,4-dimethylphenol, 2,4,6-trichlorophenol, nitrobenzene) removal from polluted groundwater using ozonation and advanced oxidation have been estimated on the basis of the laboratory experiments in semibatch conditions. The pollutants initial concentration was in the range of 0.01–1.0 mM. In the calculations the polluted groundwater flow rate was taken 40 m3/h with the initial pH = 7.0. It is shown that polluted groundwater purification from the aromatic pollutants with the initial concentration in the range of 0.01–1.0 mM using ozonation and advanced oxidation is economically feasible.

Electro-Fenton 반응을 이용한 유독성 유기화합물 처리

The feasibility and efficiency of the hydrogen peroxide produced by an electrolysis cell reactor was investigated, From regulating voltages for the given reaction time, the concentration of the hydrogen peroxide was gradually increased with increasing voltages. Optimal voltage range was found to be 10～15 V. The concentration of hydrogen peroxide was much higher with oxygen gas than without oxygen gas in the cathodic chamber. But there was a little difference in the generating rate of hydrogen peroxide regardless of the presence of nitrogen gas. Under given conditions, the maximum value of ICE(Instantaneous Current Efficiency) was about 38%, and then current density was 74 <TEX>$mA/\textrm{cm}^2.$</TEX> The specific energy consumption was <TEX>$0.694[kWh/kg-H_2O_2].$</TEX> Since Esp (Specific Energy Consumption)was very little value, It did not demand high energy in this system. Using the hydrogen peroxide gained in the experiment, Fenton's reaction was conducted and the removal of nitrobenzene, 3-chlorophenol and dye wastewater was studied. This results were very similar to the Fenton's reaction by using commercial hydrogen peroxide.

Merits of Polyoxotungstates as Environmental Remediation Catalysts: A Novel Wet Oxidation Technology for Refractory Industrial Pollutants

The catalytic effect of silicadodecatungstate (SiW12 ) on the oxidation of nitrobenzene in subcritical water (T = 100–300°C; P = 0.1–8.6 MPa, pH = 2.6) was examined. In the absence of SiW12 catalyst nitrobenzene oxidation slowed down significantly after a brief period of rapid degradation and an average of 40% nitrobenzene removal. The catalytic effect of SiW12 becomes particularly pronounced after a temperature dependent induction period. Catalyzed wet air oxidation continued until the degradation of the parent compound was complete provided that experimental conditions were harsh enough (T >200°C). Product distribution analysis suggested that the oxidation paths for catalyzed and uncatalyzed wet air oxidation of nitrobenzene are similar, but the analysis was not definitive.

Hybrid reactor for priority pollutant nitrobenzene removal

The performance of a hybrid reactor, comprising of trickling filter and activated sludge process, in treating nitrobenzene wastewater was investigated. Acetate induced cells of mixed consortia was acclimatized with gradual increase of nitrobenzene concentration up to 90 mg/l in 100 days using sodium acetate as co-substrate and considering COD and nitrobenzene concentration as paramount parameters for assessing the growth of biofilm and acclimation. A removal of 60–95.80% COD and 80–90.23% nitrobenzene was observed during acclimation. During hydraulic retention time (HRT) studies, the optimum HRT was found to be 29.55 h at which a maximum of 95.83% COD and 97.93% nitrobenzene removal was observed. Other studies included optimization of C:N ratio, substrate:co-substrate ratio, effect of shock loading and estimation of volatilization losses. The optimum C:N ratio was found to be 100:20 at which maximum 97.93% removal of nitrobenzene was observed. At optimum HRT (29.55 h) and optimum C:N ratio (100:20) optimum substrate:co-substrate ratio was found to be 1:33. From the shock load studies it can be concluded that the system can withstand shock load up to two times of usual nitrobenzene concentration. A loss of 9.44% nitrobenzene was observed due to volatilization and mass balance gave an efficiency of 87.49% biological removal of nitrobenzene.

The effect of humic acids on nitrobenzene oxidation by ozonation and O 3/UV processes

Three types of commercially available humic acids from different sources were used to simulate natural organic matter in water for the investigation of nitrobenzene oxidation by ozonation and O 3/UV. Despite the structural differences among the Fluka, Aldrich and Suwanee River humic acids as reflected by the UV absorptivity, their effects on nitrobenzene removal rate was observed to be similar for the two processes. Removal rate of nitrobenzene was hindered by the addition of humic acids in ozonation as well as in O 3/UV processes. However, the hindrance by the humic acids was more pronounced in O 3/UV as compared to the ozonation process. The effect of humic acid in O 3/UV was primarily a UV light screening. Addition of humic acids above a certain concentration did not cause any further retardation on nitrobenzene removal rate by ozonation and O 3/UV. Accumulation of hydrogen peroxide as well as probable formation of peroxy radicals in the solutions might induce chain promoting reactions to produce hydroxyl radical during the nitrobenzene oxidation. For waters containing high levels of humic acid, ozonation alone might be as effective as O 3/UV process for the removal of nitrobenzene.

Influence of nonionic surfactants and hydroxypropyl-β-cyclodextrin on the biodegradation of nitrobenzene

This paper investigates the effect of two nonionic surfactants (Tween 80 and Triton X-100) and hydroxypropyl-β-cyclodextrin (HP-β-CD) on the biodegradation of nitrobenzene (NB) by Acinetobacter sp. in liquid cultures at different dosages as well as the fate of both surfactants. When the initial concentration of NB was about 400 mg/l, neither Tween 80 nor HP-β-CD had any effect on the degradation of NB. However, Triton X-100 retarded the full removal of NB and the bacterial growth entering the stationary phase. While the initial concentration of NB was increased to about 850 mg/l, they all significantly enhanced the extent and rate of biodegradation if they were added at concentrations above 2000 mg/l. HP-β-CD could not be utilized by Acinetobacter sp. as the sole carbon source whereas both surfactants could, but no surfactant depletion was observed during the biodegradation of NB. So the rapid bacterial growth observed in the presence of each additive should be attributed to the rapid metabolism of NB. Both surfactants would promote the degradation of NB more than HP-β-CD would do if their dosages were increased properly.

Process for degradation of nitrobenzene: combining electron beam irradiation with biotransformation.

Electron beam irradiations of aqueous solutions containing 15-30 mg/L of nitrobenzene at 60 kGy dose removed 78% of the contaminant. Three mononitrophenols were detected as by-products of electron beam treatment of nitrobenzene. A mixed culture enriched on a mixture of 2-, 3-, and 4-nitrophenol degraded both the residual nitrobenzene and the nitrophenol products. Percentage removal of nitrobenzene increased with increasing electron beam dose. This observation led to the conceptual design of a two-stage electron beam microbial process for degradation of nitrobenzene. Three groups of pure isolates were characterized from the mixed culture based on their abilities to grow on cor- responding nitrophenol substrates: Group A, 2NP(-)3NP(-)4NP(+); Group B, 2NP(+)3NP(+)4NP(-); and Group C, 2NP(-)3NP(+)4NP(-). Bacteria that grew on 3-NP transformed nitrobenzene into ammonia in the electron beam-treated nitrobenzene samples.

Removal of Nitrobenzene, Isophorone, 2,6‐Dinitrotoluene and 2,4‐Dinitrotoluene from Aqueous Solution by Solvent Sublation

AbstractNitrobenzene, isophorone, 2,6‐dinitrotoluene and 2,4‐dinitrotoluene were removed from aqueous solution by solvent sublation. The separation efficiencies of three solvents (4‐methyl‐2‐pentanone, 1‐octanol and paraffin oil) as the overlaying layer were compared. The rate of separation of these organic pollutants by solvent sublation depends strongly on the size of air bubbles, which is affected by the overlaying solvent, and concentrations of sodium dodecyl sulfate (NDS), inorganic and polar organic solute.

Acidogenic-aerobic treatment of a wastewater containing nitrobenzene

A laboratory investigation was carried out on treating wastewater containing an aromatic nitro-compound, nitrobenzene, by the acidogenic-aerobic and aerobic processes. The removal efficiency of nitrobenzene was between 75 and 85% when the wastewater was treated by the aerobic process alone. However, the acidogenic-aerobic process resulted in more than 95% removal of nitrobenzene. During the acidogenic process, nitrobenzene was presumed to be converted to aniline which was more readily biodegradable in the subsequent aerobic process. The existence of an easily metabolized carbon source (sucrose) helped in the bioreduction of nitrobenzene to aniline and nitrobenzene bioreduction to aniline was improved as the sucrose concentration was increased.

Removal of nitrobenzene and chloronitrobenzene from wastewater by means of polymeric sorbents

Removal of nitrobenzene and chloronitrobenzene from wastewater by means of polymeric sorbents