活性炭改性处理硝基苯废水的研究

以硝基苯为水中有机污染物的代表,探索了活性炭的有效改性方法,并进一步研究了改性活性炭吸附硝基苯的过程中吸附时间、温度及pH对硝基苯吸附量的影响,结果表明硝基苯的去除率达99.811%,活性炭的吸附量为24.054 mg/g,处理后的废水达到国家三级废水排放标准。     

Bio-reaction of nitrobenzene with Microcystis aeruginosa: characteristics, kinetics and application

The bio-reaction of nitrobenzene (NB) with Microcystis aeruginosa was investigated at different initial algal densities and NB concentrations by performing static experiments. The results showed that the elimination of NB was enhanced by the bio-reaction, and the reaction rate varied as a function of the reaction time. Moreover, the reaction rate was significantly affected by the algal density and NB concentration. A kinetic analysis showed that the elimination of NB in a solution without algae appeared to be pseudo-first-order with respect to the NB concentration, whereas a first-order model was too oversimplified to describe the elimination of NB in a solution with algae. Assuming that different algal cells have the same effect on the bio-reaction under the same conditions, the bio-reaction can be described as dC_NB = −k₀C_A^mA_NBⁿdt (where k₀ is the reaction rate constant, C_A is the algae density and C_NB is the concentration of NB). When the growth of algae was not considered, the value of k₀, m and n were 8.170 × 10⁻⁴, 0.5887 and 1.692, respectively. Alternatively, when algae were in the exponential growth phase, the value of k₀, m and n were 1.6871 × 10⁻⁵, 0.7248 and 2.5407, respectively, according to a nonlinear fitting analysis. The kinetic model was also used to elucidate the effect of nutritional limitation on the bio-reaction.     

Rapid Removal of Nitrobenzene in a Three-Phase Ozone Loaded System with Gas–Liquid–Liquid

This study explores the removal rate of nitrobenzene (NB) using a new gas–liquid–liquid (G–L–L) three-phase ozone-loaded system consisting of a gaseous ozone, an aqueous solvent phase, and a fluorinated solvent phase (perfluorodecalin, or FDC). The removal rate of NB was quantified in relation to six factors including (1) initial pH, (2) initial NB dosage, (3) gaseous ozone dosage, (4) free radical scavenger, (5) FDC pre-aerated gaseous ozone, and (6) reuse of FDC. NB removal rate is positively affected by the first three of these factors. Compared with the conventional gas–liquid (water) (G–L) two-phase ozonation system, the free radical scavenger (tertiary butyl alcohol) has much less influence on the removal rate of NB in the G–L–L system. The FDC-loaded ozone acts as an ozone reservoir and serves as the main reactive phase in the G–L–L three-phase system. The reuse of FDC has little influence on the removal rate of NB. These experimental results suggest that the oxidation efficiency of ozonation in the G–L–L three-phase system is better than that in the conventional G–L two-phase system.     

Pre-concentration and determination of traces of nitrobenzene and 1,3-dinitrobenzene in water samples using anthracite adsorbent

This study introduces a novel analytical method for the determination of nitrobenzene (NB) and 1,3-dinitrobenzene (DNB) from an aqueous solution using high performance liquid chromatography (HPLC) and anthracite as adsorbent for pre-concentration. The method showed good linearity for determination of NB and DNB concentrations in the range of 0.10–200 μg L⁻¹ with regression coefficients better than 0.9995. Limits of detections (LOD) were 0.010 and 0.055 μg L⁻¹ for DNB and NB, respectively. Relative standard deviations (RSD) for 0.50 μg L⁻¹ and 150 μg L⁻¹ were in the range of 2.0–3.8% for (DNB) and 3.0–4.8% for (NB).     

Mechanism of heterogeneous catalytic ozonation of nitrobenzene in aqueous solution with modified ceramic honeycomb

The degradation efficiencies of nitrobenzene in aqueous solution were investigated by semi-continuous experiments in the processes of ozone alone, ozone/ceramic honeycomb (CH) and ozone/modified ceramic honeycomb (MCH). MCH with 1.0% Mn and 0.5% Cu had more pronounced catalytic ability than CH to accelerate the degradation of nitrobenzene, to increase the utilization efficiency of ozone, to improve the concentrations of hydrogen peroxide (H₂O₂) formation and hydroxyl radical (OH) initiation, and to enhance the removal efficiency of TOC. The modification process of CH with the metals enhanced the density of surface hydroxyl groups, which determines the initiation of OH from ozone decomposition and the generation of intermediate species on heterogeneous catalytic surface, yielding the acceleration of the degradation of nitrobenzene in aqueous solution. Possible reaction mechanism of ozone with heterogeneous catalytic surface in aqueous solution was proposed, and the formation mechanism of H₂O₂ and OH was also discussed according to the combined reactions in heterogeneous and homogeneous catalytic systems.     

Numerical investigation of ethylbenzene dehydrogenation and nitrobenzene hydrogenation in a membrane reactor: Effect of operating conditions

This paper is a numerical study about ethylbenzene (EB) dehydrogenation and nitrobenzene (NB) hydrogenation in a membrane reactor. Both sides of the membrane reactor were filled with an appropriate catalyst. Effect of different parameters in the dehydrogenation side including inlet temperature, pressure, catalyst porosity, and initial ethylbenzene concentration was investigated on temperature distribution and ethylbenzene and nitrobenzene conversion in the membrane reactor. Generally, the results showed that an increase in all parameters except the catalyst porosity can improve ethylbenzene and nitrobenzene conversion. The temperature was firstly decreased in the dehydrogenation side as the reactions were endothermic but there was an increase in temperature after a shorter distance from the entrance because of transferring heat from hydrogenation side into dehydrogenation side. Change in pressure has a considerable effect on the hydrogen transferring from dehydrogenation side into hydrogenation side. The styrene yield was not improved by increasing the initial ethylbenzene concentration from 5 to 20 mol/s but it has a positive influence on the yields of benzene and toluene. It was possible to achieve 0.97 of ethylbenzene conversion at 950 K.     

A comparison of two different flow types on performance of a thermally coupled recuperative reactor containing naphtha reforming process and hydrogenation of nitrobenzene

Refineries have been looking for proper ways of improving reformer performance by enhancing the octane number of the product via increasing the aromatics’ compounds. To reach this goal, the endothermic catalytic naphtha reforming is coupled with the exothermic hydrogenation of nitrobenzene to aniline in a multifunctional heat exchanger reactor through the process intensification concept. Considering the higher thermal efficiency as well as the smaller size of the coupled reactor, utilizing this reactor is given priority. In this novel configuration, the first and the second reactor of the conventional naphtha reforming process are exchanged with the coupled reactors contain the endothermic naphtha reforming in the shell side and the hydrogenation reaction in the tube side. Both co-current and counter-current modes of flow are examined during the operation considering various studies in literature which show the superiority of co-current flow compared with the counter-current flow. The result of current study is compared with the corresponding results for conventional tubular reactor (CTR). The results show higher aromatic production as much as 18.73% and 16.48% in the co-current and counter-current mode, respectively. Hydrogen molar flow rate increases about 5 kmol/h by using counter-current flow regime, compared with the CTR.     

Reduced graphene oxide as co-catalyst for enhanced visible light photocatalytic activity of BiOBr

BiOBr-reduced graphene oxide (RGO) composites were successfully synthesized via a simple hydrothermal method. Their morphology, structure and photocatalytic activity in the degradation of nitrobenzene were characterized by scanning electron microscopy, X-ray diffraction, nitrogen adsorption-desorption, UV–vis absorption spectroscopy, photoluminescence spectra, electrochemical impedance spectra and total organic carbon, respectively. The results showed that the introduction of RGO could enhance the visible light photocatalytic activity of BiOBr. The BiOBr-RGO composite with 0.6 wt% RGO exhibited an optimal photocatalytic activity, and the maximum degradation rate of nitrobenzene was about 2.16 times that of pure BiOBr due to the increased light absorption and the reduced electron-hole pair recombination in BiOBr with the introduction of RGO.     

Pt／尼龙催化剂在硝基苯加氢中的应用

民了Ｐｔ／尼龙催化剂,成功地将其用作硝苯加氢一中成对氨基苯酚的催化剂,同时研究了金属负载量、催化剂还原方法、共催化剂、金属铂结晶颗粒的大小及分布与Ｐｔ／尼催化剂的活性和选择性的关系。     

Heterogeneous Photocatalysis in Microreactors for Efficient Reduction of Nitrobenzene to Aniline: Mechanisms and Energy Efficiency

Aniline was synthesized from nitrobenzene through photo‐induced reduction in microreactors under UV irradiation. Nitrobenzene solution and the nanofluid prepared by a TiO₂ nanocatalyst, PEG‐400, and deionized water were mixed in a capillary microreactor. The effects of catalyst composition, residence time, and substrate concentration on the reaction performance were systematically investigated. The conversion of nitrobenzene and the yield of aniline reached high values under optimized conditions. The excellent reusability of the photocatalyst was realized for four runs. A mechanism was proposed for this photocatalytic reduction process based on reaction kinetics. Both photo‐induced electrons and ^?CO₂^? could reduce nitrobenzene to aniline. The photonic efficiency in the microreactor was still much higher than that obtained in batch reactors, which was mainly attributed to the much larger effective radiation area of the microreactor.