Method for treating nitrobenzene wastewater

Abstract

The invention discloses a method for treating nitrobenzene wastewater. The method is characterized by including the steps that the wastewater with the COD content of 5,000-30,000 mg / L is added to inorganic acid for acidification; an electrolyte is added to supernatant of the acidified wastewater, and the mixture enters an electro-catalysis advanced oxidation tank to be electrolyzed; the mixture continues to enter an electro-Fenton tank to be electrolyzed to generate Fe2+, the mixture enters a Fenton oxidation tank, hydrogen peroxide is added, and a Fenton reaction is generated; a flocculating agent is added for settling, and the supernatant enters a biochemical system to be treated. The electro-catalysis advanced oxidation technology and an electro-Fenton oxidation method are adopted and combined, the wastewater is treated and modified through an electro-catalysis oxidation method, the iron dissolution amount can be greatly reduced through the electro-Fenton oxidation method, the adding quantity of H2O2 can be reduced, energy consumption and cost are reduced, and the method is environmentally friendly and economical.

Description

technical field [0001] The invention relates to the field of industrial wastewater treatment, in particular to a method for treating nitrobenzene wastewater. Background technique [0002] Nitrobenzene compounds are one of the important raw materials in the organic chemical industry. Such compounds are widely found in the waste water of petrochemical industry, soap, spices, dyes, explosives, pharmaceuticals and other chemical industries, and these compounds are highly toxic to humans. At present, the cost of using biotechnology to treat industrial wastewater is low, and microorganisms have strong adaptability and variability, and will not cause secondary pollution. Therefore, the use of biological treatment has become an ideal method for the treatment of organic pollutants, but nitrobenzene compounds are highly toxic, and the burden on microorganisms in water is very large, so direct biodegradation treatment is difficult. Electrocatalytic oxidation and electro-Fenton (elect...

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Problems solved by technology

[0003] The electrocatalytic oxidation method has high energy consumption: in the existing technology, the current efficiency is about 40% in the best state, generally around 20%, 1000Ah / m 3 Theoretically, in the case of 100% current efficiency, only 298mg / L of COD can be removed (1Ah=3600C, M O2 = 32g / mol1mol electron transfer requires 96500C electricity, so every cubic meter of wastewater can treat COD: 1000*3600C / (96500C / mol*4)*32g / mol=298g), remove 10000mg / L of COD, according to 20 % current efficiency, need 167785Ah / m 3 Even if the tank voltage is only 3V, it needs 503 kWh of electricity, resulting in higher energy costs

[0004] Large amount of iron dissolved by electric Fenton oxidation method: 1000Ah / m 3 The electricity can theoretically produce 1.04‰ of Fe 2 +, After the subsequent Fenton reaction, about 2% sludge with a moisture content of 90% can be produced, if 3000Ah / m is supplied 3 If there is a large amount of electricity, it can produce sludge with a moisture content of about 6% and a moisture content of 90%, which greatly increases the solid waste production and leads to a skyrocketing treatment cost

[0005] The Chinese patent application number 201010181115.7 discloses a method for degrading nitrobenzene wastewater by a heterogeneous electrocatalytic oxidation-Fenton coupling method and its reactor, which has a large electrode spacing (4-8cm) and a high tank pressure (20-40V ), and the particle electrodes and solid catalysts will continue to collide and rub during aeration, and the debris will be lost with the wastewater. Therefore, new particle electrodes and solid catalysts need to be continuously added to the electrolyzer, which increases the operational difficulty and operating costs of actual operation.

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