Method for strengthening anaerobic reduction of nitrobenzene by electrochemically regulating sulfur circulation

A technology of sulfur cycle and electrochemistry, which is applied in the fields of electrochemical regulation of sulfur cycle, sulfate mixed wastewater, and nitrobenzene, can solve the problems of reducing the effect of anaerobic treatment of NACs and the failure of anaerobic biological treatment, and achieve enhanced reduction conversion efficiency, solve the effect of low treatment efficiency and enhanced reduction conversion rate

Active Publication Date: 2021-06-22
NANJING UNIV OF SCI & TECH
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Problems solved by technology

At the same time, sulfate can compete with NB for electron donors, reduce the anaerobic treatment effect of NACs, and even completely fail the anaerobic biological treatment in severe cases.

Method used

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  • Method for strengthening anaerobic reduction of nitrobenzene by electrochemically regulating sulfur circulation
  • Method for strengthening anaerobic reduction of nitrobenzene by electrochemically regulating sulfur circulation
  • Method for strengthening anaerobic reduction of nitrobenzene by electrochemically regulating sulfur circulation

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Embodiment 1

[0047] This embodiment adopts the upflow bioelectrochemical reactor (UBER), figure 1 It is a schematic diagram of the structure of the upflow bioelectrochemical reactor of the present invention. Specifically, the UBER of this embodiment adopts a modular design and is assembled from 5 polytetrafluoroethylene plates with a width of 3.0 cm. The appearance of the reactor is prismatic , the specific size is 16×12×12cm, the internal reaction zone is a cylindrical structure (ID 8.0cm×H 12.0cm), and the total internal volume is about 600mL. The lower part is the cathode area, and the upper part is the anode area. The height of each area occupied by the cathode and anode is about 6cm, and the middle is the sampling area with a height of 4cm.

[0048] Two pieces of graphite felt with a diameter of 6cm and a thickness of 1cm are used as the cathode and anode to increase the contact area of ​​the cathode and anode. Before use, the graphite felt is cleaned and soaked with 32% hydrochloric ...

Embodiment 2

[0061] The operating steps of this embodiment are basically the same as those in Embodiment 1, the difference being:

[0062] This embodiment is by selecting glucose, sodium acetate, sodium propionate as electron donor (carbon source), compares the removal efficiency of these three kinds of electron donors at different hydraulic retention times p-nitrobenzene and the removal efficiency of sulfate and in Effects on the Anaerobic Reduction Process to Determine Electron Donor Selection Criteria.

[0063] Using 500mg / L sodium propionate as the electron donor to continuously feed UBER, the HRT (hydraulic retention time) was reduced from 22h to 10h (influent load from 5.69mol m -3 d -1 increased to 12.49mol m -3 d -1 ), the removal rate of NB decreased from 99.32% to 76.14%, and the removal rate of sulfate decreased from 90.67% to 60.89%. The removal rate of NB corresponding to sodium acetate decreased from 98.82% to 68.14%, and the removal rate of sulfate decreased from 87.76% ...

Embodiment 3

[0066] The processing steps of this embodiment are basically the same as in Embodiment 1, the difference is that:

[0067] Keep the COD concentration stable at 500mg / L, and then gradually increase the sulfate concentration on this basis, and the C / S ratio decreases in turn, respectively 11.21:1, 5.6:1, 3.7:1, 2.5:1, 1.67:1 . Compare different COD / SO 4 2- Compare NB, SO 4 2- The effect of removal rate. The up-flow bioelectrochemical experimental group and the anaerobic reduction control group were set up. Except for the difference of applied voltage, the other parameters were the same. For the test results of the UBER experimental group and the anaerobic biological reduction control group, see Figure 4 (A) and Figure 4 (B).

[0068] Compared with the anaerobic reduction system, by Figure 4 (A) It can be seen that in the bioelectrochemical system, the removal rate of nitrobenzene will fluctuate slightly with the decrease of the carbon-sulfur ratio, showing a trend of ...

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Abstract

The invention belongs to the technical field of industrial wastewater treatment, and discloses a method for strengthening anaerobic reduction of nitrobenzene by electrochemically regulating sulfur circulation. According to the invention, an electric field regulation and control technology is introduced into a traditional anaerobic reduction system, a diaphragm-free up-flow bioelectrochemical reactor is constructed, real-time conversion of sulfate reduction product sulfides is realized through regulation and control of cathode potential, electrons are synchronously released, reduction of nitrobenzene and sulfate in a cathode region is further promoted, the toxicity inhibition of H2S is effectively reduced, the consumption of an external carbon source is reduced, and the system stability is improved. Compared with an existing treatment process, the reduction conversion rate of NB is remarkably increased in a bioelectrochemical system with sulfur metabolism conversion, and the method has a wide application prospect in wastewater treatment.

Description

technical field [0001] The invention belongs to the technical field of industrial wastewater treatment, and in particular relates to a method for electrochemically regulating and controlling the sulfur cycle, which is used to strengthen the treatment of mixed wastewater containing nitrobenzene and sulfate produced in the production process of fine chemical fields such as medicine and dye explosives. Background technique [0002] As a typical nitroaromatic compound (NACs), nitrobenzene (NB) is widely used in the production of various products and intermediates (such as pharmaceuticals, dyes, plastics, explosives, and pesticides), thereby generating a large amount of refractory wastewater . Nitrobenzene is difficult to degrade in the natural environment. The fundamental reason is that the nitro group on the benzene ring has a strong electron-withdrawing property, which reduces the electron cloud density on the connected benzene ring, inhibits the activity of benzene ring lyase...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F3/00C02F3/28C02F101/38
CPCC02F3/005C02F3/28C02F3/286C02F2101/38C02F2209/10C02F2305/06Y02E60/50
Inventor 沈锦优李陈李燕江心白陈丹刘晓东
Owner NANJING UNIV OF SCI & TECH
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