Aniline Removal Efficiency Research Articles

Aniline degradation from aqueous solution using electro/Fe2+/peroxydisulphate process

Non-degradation compounds are nowadays not being disposed into the environment, or are removed before being disposed into the environment. The aim of this study was to assess the degradation of aniline from aqueous media by electro/Fe2+/peroxydisulphate (PDS) process. The effects of different parameters like pH (3-9), electric current (EC; 10-30 mA/cm(2)), dose of PDS (10-40 mM), Fe2+ dose (5-20 mM) and initial aniline concentration (20-100 mg/L) on the degradation of aniline were investigated in the laboratory reactor in the batch condition. The results showed that the removal efficiency of aniline decreased by increasing the initial pH and pollutant concentration; however, with increasing EC and PDS doses and ferrous concentration, the removal efficiency increased. The maximum of aniline degradation, equalling 83%, was obtained at 60 min of reaction time. Also, for reaction time of 60-min runs, PDS only, EC only, PDS + Fe, PDS + EC and PDS + Fe + Fe, respectively, have 8.9%, 53%, 43%, 65% and 83% of the removal efficiency. The degradation efficiency of aniline from synthetic wastewater was significantly improved when the combined processes PDS/electro-conduction/Fe2+ was applied. Keywords Author Keywords:Aniline; Degradation; Sulphate radical; Iron; Peroxydisulphate

Electrochemical oxidation of aniline by a novel Ti/TiOxHy/Sb-SnO2 electrode

Electrochemical oxidation of aniline in aqueous solution was investigated over a novel Ti/TiOxHy/Sb-SnO2 electrode prepared by the electrodeposition method. Scanning electron microscopy, X-ray diffraction, and electrochemical measurements were used to characterize its morphology, crystal structure, and electrochemical properties. Removal of aniline by the Ti/TiOxHy/Sb-SnO2 electrode was investigated by ultraviolet-Visible spectroscopy and chemical oxygen demand (COD) analysis under different conditions, including current densities, initial concentrations of aniline, pH values, concentrations of chloride ions, and types of reactor. It was found that a higher current density, a lower initial concentration of aniline, an acidic solution, the presence of chloride ions (0.2 wt% NaCl), and a three-dimensional (3D) reactor promoted the removal efficiency of aniline. Electrochemical degradation of aniline followed pseudo-first-order kinetics. The aniline (200 mL of 100 mg L−1) and COD removal efficiencies reached 100% and 73.5%, respectively, at a current density of 20 mA cm−2, pH of 7.0, and supporting electrolyte of 0.5 wt% Na2SO4 after 2 h electrolysis in a 3D reactor. These results show that aniline can be significantly removed on the Ti/TiOxHy/Sb-SnO2 electrode, which provides an efficient way for elimination of aniline from aqueous solution.

Enhanced removal and adsorption characters of aniline by the inorganically modified mesoporous silica nano-spheres

In this study, an inorganic modification method was established to enhance the adsorptive removal of aniline by the spherical meso-silica materials. Based on the synthesis and characterization of the pure meso-silica MCM-41 and that modified with different Fe loading amount, the removal efficiencies of aniline by the synthesized meso-silica materials were compared. It indicated that the Fe-modification had an enhancement effect on the removal of aniline, but it depended on the Fe loading amount. The increase of pH significantly decreased the removal of aniline by the Fe-modified MCM-41. Especially, adsorption kinetic and isotherm investigations indicated that the adsorption process can be well described with the Pseudo-second-order kinetic model and the Langmuir isotherm model, and it was a physiochemical process. With the help from the surface charge of the Fe-modified MCM-41 and the protonation of the aniline molecules, the loaded iron oxide increased both the adsorption capacity and affinity of the Fe-modified MCM-41 towards aniline, and it was not only attribute to the enhanced pore structure of the adsorbent but also attribute to the electrostatic interaction between the loaded iron oxide and the aniline.

Development of a novel mobile industrial-scale fluidized adsorption process for emergency treatment of water polluted by aniline: CFD simulation and experiments

This study developed a novel mobile industrial-scale fluidized adsorption process and preliminarily explored its application in the emergency water treatment. A lab-based Liquid–Solid Circulating Fluidized Bed (LSCFB) was prepared and the flow pattern was studied by validated computational fluid dynamics (CFD) models. The simulation results revealed that the particular uneven flow structure, which could weaken aniline removal performance, occurred with increasing superficial liquid velocity. Accordingly, an optimized distributor design was constructed by the established CFD models; notably, the effect of open angles on the flow pattern, which was often overlooked by previous studies, was mainly discussed. Then, the aniline removal efficiency of LSCFB pre and post optimization was compared. The experimental results demonstrate that dynamic adsorption capacity on aniline reached 70mg/g under the optimum conditions (initial aniline concentration of 100mg/L, superficial liquid velocity of 3umf and sorbent dosage of 27g/L). By comparison with fixed-bed adsorption, the LSCFB possessed significantly higher adsorption rate constants and shorter hydraulic retention time, which indicates that LSCFB could meet emergency treatment requirements in a better way. Finally, the study developed the mobile industrial-scale fluidized adsorption process and estimated process parameters for aniline removal in the Sudden Water Pollution Accident of Zhuozhang River.

Simultaneous removal of aniline, nitrogen and phosphorus in aniline-containing wastewater treatment by using sequencing batch reactor

The high removal efficiencies of traditional biological aniline-degrading systems always lead to accumulation of ammonium. In this study, simultaneous removal of aniline, nitrogen and phosphorus in a single sequencing batch reactor was achieved by using anaerobic/aerobic/anoxic (A/O/A) operational process. The removal efficiencies of COD, NH4+-N, TN, TP were over 95.80%, 83.03%, 87.13%, 90.95%, respectively in most cases with 250mgL−1 of initial aniline at 6h cycle when DO was 5.5±0.5mgL−1. Aniline was able to be completely degraded when initial concentrations were less than 750mgL−1. When DO increased, the removal rate of NH4+-N and TP slightly increased along with the moderate decrease of removal efficiencies of TN. The variation of HRT had obvious influence on removal performance of pollutants. The system showed high removal efficiencies of aniline, COD and nutrients during the variation of operating conditions, which might contribute to disposal of aniline-rich industrial wastewater.

A comparative study for the removal of aniline from aqueous solutions using modified bentonite and activated carbon

AbstractThis study was aimed to explore the potential of modified bentonite as low-cost adsorbent for the adsorption of aniline from aqueous solution. Natural bentonite was modified with hexadecyltrimethylammonium bromide (HDTMA) (referred as HDTMA-Bent herein), a commonly used surfactant, to increase its adsorption potential. The influence of important experimental parameters, including initial aniline concentration, contact time, solution pH, and adsorbent dosage were studied to optimize the experimental conditions. The results showed that with the increase in adsorbent concentration or initial pH value of the solution, the aniline removal efficiency was also increased. The prepared adsorbents were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction (XRD) analysis. According to XRD analysis, the increase in the microscopic platelets of modified bentonite could be the reason of enhanced adsorption of aniline. The adsorption kinetics followed th...

Effect of common inorganic ions on aniline degradation in groundwater by activated persulfate with ferrous iron

Aniline is widespread in groundwater and of great toxicity. Advanced oxidation processes, such as the ferrous iron (Fe2+)-activated persulfate process, have been proven to be effective for organic pollutants. However, few studies have focused on the effects of coexisting ions on the degradation of aniline. In this study, the degradation efficiency of aniline and the effects of common inorganic ions (CO32−, PO43−, HCO3−, SO42−, NO3−, Na+, K+, Mg2+, and Ca2+) on aniline degradation were examined. Under the optimum operating conditions, 86.33% aniline degradation (C0 = 11 mmol/L) was observed within 60 min. The effects of cations on aniline degradation were negligible. Anions decreased the removal efficiency of aniline because of the radicals generated by the reaction between sulfate radical or hydroxyl radical and these anions. As the concentrations of PO43−, CO32−, SO42−, HCO3−, and NO3− increased from 0 mmol/L to 5 mmol/L, the removal efficiency of aniline decreased to 19.72%, 24.56%, 66.76%, 68.76%, and 82.42%, respectively. The order of inhibitory effects was PO43− > CO32− > >SO42− > HCO3− > >NO3−.

Hydroponic removal of organic contaminants from water by using ryegrass and organobentonites simultaneously

Phytoremediation and adsorption are both important approaches for the removal of organic contaminants in water. In this study, cetyltrimethylammonium saturated bentonite as an effective adsorbent and ryegrass as a model plant, were used simultaneously to remove organic contaminants in a hydroponic system. Results showed that removal efficiency of phenol (100mg/L) by organobentonite and ryegrass (OB+RY) reached 92.5% in 6days, followed by ryegrass (RY, 88.5%) and organobentonite only (OB, 15.9%). The removal efficiency of aniline (100mg/L) by organobentonite and ryegrass (OB+RY) reached 91.9% in 9days, followed by ryegrass only (RY, 83.9%), and organobentonite only (OB, 63.0%). The combined remediation by organobentonites and the hydroponic ryegrass was an efficient and environmental friendly method for organic chemicals polluted wastewater.

Rapid degradation of aniline in aqueous solution by ozone in the presence of zero-valent zinc

The effects of Zn(0) dosage from 0.1 to 1.3gL−1, pH from 2 to 12 and temperature from 288 to 318K on the degradation of aniline in aqueous solution by ozone in the presence of Zn(0) were investigated through batch experiments. The results demonstrated that Zn(0) had a significantly synergistic role in the degradation of aniline by ozone. A complete decomposition of the initial aniline (10mgL−1) was achieved by ozone together with Zn(0) within 25min, and meanwhile nearly 70% of the total organic carbon in the solution was removed. The decomposition efficiency of aniline markedly increased with an increase of Zn(0) dosage. However, temperature exerted a slight impact on the degradation of aniline and the optimum removal efficiency of aniline was realized at 298K. Aniline was efficiently degraded at all the tested pHs except for 12. Free radicals were investigated by electron paramagnetic resonance technique and free radical scavengers. H2O2 concentration generated during the reactions was analyzed using a photometric method. Based on the results obtained in this study, it is proposed that O2− instead of OH is the dominant active species responsible for the degradation of aniline. It is concluded that ozone combined with Zn(0) is an effective and promising approach to the degradation of organic pollutants.

Stimulation of oxygen to bioanode for energy recovery from recalcitrant organic matter aniline in microbial fuel cells (MFCs)

The challenge of energy generation from biodegradation of recalcitrant organics in microbial fuel cells (MFCs) is mainly attributed to their persistence to degradation under anaerobic condition in anode chamber of MFCs. In this work, we demonstrated that electricity generation from aniline, a typical recalcitrant organic matter under anaerobic condition was remarkably facilitated by employing oxygen into bioanode of MFCs. By exposing bioanode to air, electrons of 47.2 ± 6.9 C were recovered with aniline removal efficiency of 91.2 ± 2.2% in 144 h. Limited oxygen supply (the anodic headspace was initially filled with air and then closed) resulted in the decrease of electrons recovery and aniline removal efficiency by 52.5 ± 9.4% and 74.2 ± 2.1%, respectively, and further decline by respective 64.3 ± 4.5% and 82.7 ± 1.0% occurred under anaerobic condition. Community analysis showed that anode biofilm was predominated by several aerobic aniline degrading bacteria (AADB) and anode-respiration bacteria (ARB), which likely cooperated with each other and finally featured the energy recovery from aniline. Cyclic voltammetry indicated that anodic bacteria transferred electrons to anode mainly through electron shuttle. This study provided a new sight to acquaint us with the positive role of oxygen in biodegradation of recalcitrant organics on anode as well as electricity generation.

Removal of aniline, cyanides and diphenylguanidine from industrial wastewater using a full-scale moving bed biofilm reactor

Treatment of industrial wastewaters is usually difficult due to large variations in their composition, high organic matter content and presence of poorly biodegradable compounds. This paper describes operational experience with the first full-scale application of a moving bed biofilm reactor (MBBR) in the Czech Republic. The MBBR treats industrial wastewater from the Lučební závody Draslovka a.s. (Kolín) chemical plant in the Czech Republic, and particularly that from production of diphenylguanidine. The wastewater is characterised by a high content of cyanides and aniline, very high salinity, diphenylguanidine and phenylurea residues, and considerable fluctuations in concentrations as well as temperature during the year.Long-term (5-years) MBBR operation has demonstrated that, following initial stabilisation and implementation of additional pretreatment, the system is capable of treating such hardly biodegradable industrial wastewater with high removal efficiency, with mean cyanide removal efficiency ranging from 75% to 99%. Aniline removal efficiency also reached more than 85%, while diphenylguanidine, phenylurea and N,N-diphenylurea removal was almost quantitative.

The removal of aniline from wastewater by electrodialysis in the presence of hydrochloric acid

ABSTRACT A novel method has been proposed for the treatment of aniline wastewater using electrodialysis (ED) apparatus to remove the aniline ions formed in the presence of hydrochloric acid (HCl). The optimum operating parameters, including HCl concentration, initial aniline concentration, applied voltage, and flow rate were determined via a series of experiments considering energy consumption and the aniline removal efficiency. Under the selected conditions, about 99% aniline removal was obtained within 120 min, and the aniline concentration can be reduced from 500 to 4 mg/L, which suggest the city standards of pollution discharge (namely, 5 mg/L) can be met. Further, the limiting current density was determined and the total energy consumption was calculated. It was proved that the ED apparatus can be used to remove aniline from wastewater effectively at low cost.

Comparison of Aniline Degradation by Fenton and Electro‐Fenton Reactors Using Plate and Rod Electrodes

Aniline degradation was investigated using the conventional Fenton process and an electro‐Fenton (EF) process with plate and rod electrode EF reactors. The performance of the two EF reactors was evaluated by determining the effect of important parameters (Fe2+, H2O2, and aniline concentrations) on the aniline removal efficiency and the initial aniline degradation rate. The change in the biochemical oxygen demand (BOD5) and ratio BOD5/COD of a high concentration of aniline were also studied.Experimental results reveal that compared with conventional Fenton process, aniline degradation and chemical oxygen demand (COD) removal in the EF process increased 43% and 10%, respectively. In the two EF reactors, the aniline was completely degraded (100%) when the ratio of [H2O2]:[Fe2+]:[aniline] was 5.8:0.1:1. Within the range of Fenton's reagent used in the two reactors, controlling the H2O2 concentration was the key point of promoting the aniline oxidation. The plate electrode system had a higher efficiency than rod electrode system in terms of H2O2 efficiency, due to the reactor design of decreasing the electrical resistance. Treatment with a high concentration aniline increased biodegradability (BOD5 and ratio BOD5/COD) of pollutant when plate and rod electrode EF reactors were used. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1111–1117, 2013

Effect of hydrogen peroxide on aniline oxidation by electro-Fenton and fluidized-bed Fenton processes

In this study, the electro-Fenton and fluidized-bed Fenton processes under the given conditions were used to oxidize aniline. Factors such as feeding mode and concentration of the hydrogen peroxide were explored. Results showed that the feeding mode of H 2O 2 did not significantly affect the aniline oxidation in the electro-Fenton process. However, the aniline oxidation slightly decreased with the two-step addition of H 2O 2 in the fluidized-bed Fenton process. Presumably the decline of remaining Fe 2+ led to destitute hydrogen radicals from the Fe 2+-catalyzed H 2O 2. In addition, the removal efficiency of aniline was maintained at a maximum as H 2O 2 concentration was higher than 0.04 M in the electro-Fenton process. Meanwhile, the almost exhausted H 2O 2 would increase the amount of Fe 2+ in the solution for the electro-Fenton process. This is because the Fe 2+ is regenerated through the reduction of Fe 3+ on the cathode. The electro-Fenton process has a stronger oxidative ability with regard to the production of the oxalic acid than fluidized-bed Fenton process which was attributed to a higher consumption of H 2O 2. Therefore, in the aspect of H 2O 2 depletion, the mineralization efficiency of the fluidized-bed Fenton process was higher than that of the electro-Fenton process.

Adsorption of Aniline on Cross-Linked Starch Sulfate from Aqueous Solution

A new environment friendly adsorbent, cross-linked starch sulfate (CSS), was prepared and used to adsorb aniline from aqueous solution. Different adsorption parameters like initial pH, adsorption time, equilibrium aniline concentration, and temperature were thoroughly studied, and the kinetic, equilibrium, and thermodynamics of the adsorption process were further investigated. It showed that CSS can effectively remove aniline from the solution. The adsorption capacity is highly dependent on the amount of sulfate groups on adsorbents and the initial pH. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data, and the pseudo-second-order kinetic model provided a better correlation of the experimental data in comparison with the pseudo-first-order model. The maximum removal efficiency of aniline is 75.29% using 1 g L−1 of CSS3 dose. Langmuir, Freundlich, Dubinin−Radushkevich, and Sips models have been applied to study the adsorption equilibrium, and the equili...

US/O 3 combination degradation of aniline in aqueous solution

The influencing factors and mechanism of ultrasound (US)/ozone (O 3) combination degradation of aniline in water were investigated. An increment of approximately 64% of aniline reduction and 110% of TOC reduction were observed with respect to the addition of the separated O 3 and US systems, proving US/O 3 technology had significant synergetic effects. Excellent removal performance was observed in the degradation with US/O 3. With the initial concentration of aniline at 100 mg l −1, the energy density of ultrasound at 0.1 W ml −1 and the flow rate of ozone at 2 mg min −1, the removal efficiency of aniline would be at least 82% and that of TOC would be at least 20% after reaction for 5 min. Major by-products included nitrobenzene, p-benzoquinone, p-aminophenol, carboxylic acid, etc.