Study Of The Treatment For TNT Red Water By Process Combined Zero-Valent Iron Reduction With Macroporous Resin Adsorption

2,4,6-trinitrotoluene (TNT) red water is a kind of industrial wastewater with high content of organic matter, acute toxicity and feeble degradability,and contains a great deal of inorganic salts, the conventional methods are difficult to deal with. The current applied techniques for the treatment of TNT red water mostly adopt oxidation technology with high energy-consumption, such as incineration, which needs harsh conditions and secondary pollution has been produced. In this context, this paper had a research on treatment for TNT red water by process combined zero-valent iron reduction with macroporous resin adsorption.In this paper, the conditions for the detection of TNT red water by high performance liquid chromatography coupled with mass spectrometry were studied firstly. And the effects of different factors on the reduction of TNT red water by zero-valent iron were investigated, the reduction effect was evaluated. Then, the experiment chose macroporous resin HYA-106 as adsorbent, investigated the adsorption mechanism of phenyl amines attached on HYA-106 and their mass transfer processes by the influence factors of resin adsorption-regeneration properties, adsorption isotherms, adsorption thermodynamics and kinetics, etc. The aim was to provide a theoretical basis for the comprehensive treatment and resource utilization of TNT red water.Condition optimization experiments showed that the best conditions for the method was: the reduction pH was 2.0, reduction period was 6 h, concentration range from 18971.3 to 39888.2 mg/L, absorption pH was 3.0, absorption temperature was ambient temperature, absorption fluid rate was 1.0 BV/h, regeneration-liquid was 0.5% NaOH+absolute ethanol (v/v=4:1), regeneration liquid flow rate was 2.0 BV/h. Under this conditions, the processed TNT red water had a reduce efficiency for dinitrotoluene sulfonic acid of more than 94.0%, unit removal efficiency of CODCr of more than 272.5 mg/g, average resin regeneration rate of more than 98.0%. The reduction kinetics experiment showed that the reaction of dinitrotoluene sulfonic acid in TNT red water reduction by zero-valent iron reduction of was highly correlated with pseudo-first order kinetics, the reaction rate is proportional to the concentration. The adsorption stability test showed that the resin adsorption quantity was stable. And the mechanical strength of the resin was excellent, almost without broken case.The adsorption isotherm indicated that the adsorption amount was negatively correlated with temperature, which could be described using Freundlich adsorption model, with the correlation coefficients reaching 0.972 to 0.988. In addition, thermodynamic studies revealed that the adsorption process of phenyl amines was a physical spontaneous adsorption process, for the ?G0 and AH0 was negative. The temperature decreasing was conductive to adsorption. The main adsorption force was van der Waals force, hydrophobic interaction, dipole force and hydrogen bonding as the change of enthalpy decreased. Moreover, the adsorption process of TNT red water with resin HYA-106 consisted of two steps:outer surface diffusion of resin (0?25 min) and spreading stage (25?400 min). The adsorption onto resins obeyed pseudo-second order kinetic model and the adsorption rate was negatively correlated with concentration. As the qt was linearly correlation with t0.5, inner diffusion was the rate-limiting step.