| Since the rapid increase of the number of our industries after the accession ofthe World Trade Organisation, our country’s reliance on the traditional steel industrygrows rapidly. The growth of domestic and international demands in China increasesin the rapid rate of10%. Vanadium is a kind of metal additive which can strengthenthe ductility of steel. Our country’s reserve of Vanadium is quite abundant, which isa unique domestic mine and mainly stores in stone coal. Our Country usuallyextracts V2O5from stone coal in industrial manufacture. Since the limitation oftechnological innovation, our environmental pollution of manufacturing enterprisesare serious. In order to protect our environment, prevent the produce ofcontamination and promote the development of pollution-control technology, ourcountry puts forward stricter discharge standards of Vanadium enterprise and higherrequirements of pollution abatement equipments and technologies.Due to the extraction process of Vanadium, the wastewater contains abundantheavy metals and ammonia ions, the concentration of which far exceeds the capacityof environmental capacity. If we untreatedly discharge the wastewater into the river, itwill cause serious environmental contamination.Therefore, the purification ofabundant heavy metals and ammonia ions in Vanadium extraction wastewater not onlyhas economic significance, but maintains the health of the water and ecologicalenvironment.Ion exchange resin, which is a new-fashioned wastewater treatment absorbsabundant heavy metals and ammonia ions in Vanadium extraction wastewater. Threedifferent types of resins, D706, D707and D708, are selected to the adsorption ofheavy metals and ammonia ions in wastewater on different resins’ preprocessing,resins’ quantity, pH value, oscillation time and temperature conditions. Compare theadsorption rate of three resins with dynamics and thermodynamics models. Twodifferent types of resins, D706and D708, are selected to deal with the heavy metals inwastewater, while D707and D708, two cation resins are selected to the treatment ofammonia ions. It is determined by the selection of the resins that D706resin adsorbsV[Ⅴ] and Cr[Ⅵ], while D708resin adsorbs Cu[Ⅱ] and Zn[Ⅱ].Static adsorption experiments showes that: Adsorption rate of metal ionscompared with quantity of D706and D708resins. In acidic condition, adsorption of V[Ⅴ] and Cr[Ⅵ] increase with the decrease of pH value, while adsorption rates of Cu [Ⅱ] and Zn[Ⅱ] increase with the rise of pH value; adsorption rate of NH4+increasealong with quantity of D707and D708resins. In acidic condition adsorption rate ofNH4+for D707and D708resins increase with the rise of pH value. When oscillationtime reaches90min, adsorption of three resins would all reach equilibrium, and whenpH=2adsorption capacity of D706for V [V], Cr [VI] are54.054,50.251mg/g, whilepH=7, adsorption capacity of D708for Cu[Ⅱ],Zn[Ⅱ] reach to25.316,21.142mg/g.when pH=7adsorption capacities of D707, D708reach to196.078,217.391mg/g.All the resins’ adsorption corresponds with endothermic process. At298K, theadsorption of activation energy: Ea(V)=26.05, Ea(Cr)=21.62, Ea(Cu)=23.01,Ea(Zn)=20.58kJ/mol. Liquid film diffusion is the main control of the adsorption of V[V], Cr [VI] and NH4+, while the adsorption of Cu[Ⅱ],Zn[Ⅱ] is chiefly controlled byparticle diffusion. At298K, the NH4+adsorption of activation energy:Ea(D707)=54.674kJ/mol, Ea(D708)=34.455kJ/mol. Experiment data for V[Ⅴ],Cr[Ⅵ], Cu[Ⅱ],Zn[Ⅱ] and NH3-N correspond with Langmuir adsorption isotherm andare inclined to single molecule layer of chemical adsorption. Adsorption of Cr[Ⅵ] andCu[Ⅱ] are preferential adsorption.1mol/L NaOH and2mol/L HCl are respectivelyused for desorption of D706, D707and D708resins and the desorption rate are bothup to96%. The adsorption rate remains unchanged after repeated experiments. |
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