| In recent years, with the rapid development of economy, water environment hasalso been severely disrupted. Especially the wanton discharge of industrial refractoryorganic wastewater is a major source of pollution. The BTEX is one of the maincomponents of the industrial wastewater. Therefore, researching the efficient andeconomical methods to remove nitrobenzene is the key to dealing with industrialwastewater. The MTBE is a gasoline additive which is widely used today and also is akind of important chemical raw material. It has immeasurably effected onenvironment even at trace levels. For this, this paper took the active carbon absorptionmethod to manage nitrobenzene wastewater and the MTBE slightly pollutedwastewater comprehensively and in-depth. Based on the laboratory experiment data,the study designed active carbon adsorption tower, then proceeded with engineeringmagnification. Through site running, we have got good removal efficiency.Typical organic compounds—nitrobenzene was selected as model compounds inthis paper. The three different types of activated carbon (nut shell carbon, coal carbonand coconut shell carbon) adsorption penetration curves were put into researchthrough small fixed bed reactor, then determined the optimal activated carbon todispose nitrobenzene wastewater. The influences of velocity and temperature on theadsorption penetration curve were investigated. And the research analyzed theadsorption kinetics. The conclusions showed that: nut shell carbon needs the longesttime to arrive breakthrough point, so nut shell carbon for the optimal activated carbonand the optimum conditions of adsorption penetration curve have been obtained,Velocity for10mL/min and wastewater temperature for10℃. The reaction ofnitrobenzene solution with activated carbon adsorption could be described bypseudo-second-order kinetics in the ranges of20～100mg/L. For one thing, theadsorption process is more accord with Langmuir adsorption isotherm model. Foranother, the initial concentration range is20～500mg/L nitrobenzene in syntheticwastewater. What’s more, the maximum adsorption capacity of activated carbon incr- eased with the increasing temperature. Moreover, the largest adsorption capacity are70.92mg/g,81.30mg/g and84.03mg/g in10℃,20℃and30℃.The experiment adopted active carbon absorption method to deal with the MTBEmicro-pollution wastewater. Through the experiment of influence factors, adsorptiondynamics and adsorption equilibrium, adsorption process was studied systematically.The conclusions showed that: the bigger iodine value the active carbon has, the betterthe adsorption effect, that is to say, nut shell carbon has the best adsorption effect.Initial pH had little effect on the removal rates, the reaction times, temperature andadsorbent dosage are the important parameters of the adsorption process. The MTBEmicro-polluted wastewater which concentration is range of5～20mg/L, three typesof activated carbon (nut shell carbon, coal carbon, coconut shell charcoal) adsorptionare suitable for pseudo-second-order kinetics. Three kinds of activated carbonadsorption process is more suitable for the Langmuir adsorption isotherm model, thelargest adsorption capacity of activated carbon(nut shell carbon, coal carbon andcoconut shell carbon) are17.094mg/g,15.625mg/g and16.807mg/g in the MTBEinitial concentration ranges of5～25mg/L.Through the field experiment of groundwater pollution continuous operation, wecan draw a conclusion that the water flow of active carbon adsorption device is0.2m3/h. By continuous operation of80h, the dissolved oxygen and the pH of theeffluent are higher than it of inflow, and temperature is lower than inflow, then theremoval rate of COD is nearly100%. The removal rates of the four main organicpollutants in effluent are more than90%and effluent stability, meet the emissionstandards. |
