| Acrylic acid,which widely used in coatings,adhesives,superabsorbent resins,etc,is an important chemical raw material,However,in the process of production and use,AA and its products produce a large amount of wastewater with the high concentration of COD,complex composition,and contains biologically toxic substances,which is difficult to degrade.In this paper,the treatment of acrylic acid wastewater by D301-TETA ion exchange resin was investigated,The COD removal rate of effluent was about 80%.No acrylic acid content was detected,As reducing the burden of subsequent biochemical treatment wastewater,the recycling of acrylic acid resources was realized.In this paper,D301 weakly basic anion exchange resin was selected for the experiment.The D301 resin was activated by triethylenetetramine(TETA).The static adsorption experiment of acrylic simulated wastewater was carried out with activated D301-TETA resin.The exchange time was investigated.The effects of solution pH,initial concentration,reaction temperature,shaking speed and acetic acid concentration in solution on the removal efficiency of acrylic acid and the repeated regeneration performance of the resin further explored the dynamic adsorption and desorption effect of resin on the actual wastewater of acrylic acid,and investigated the flow rate of wastewater.The effects of factors such as the height-diameter ratio of the resin column,the concentration of the desorbing solution,the flow rate of the desorbing solution on the breakthrough curve and the elution curve,and the adsorption and elution effects of the wastewater,and the feasibility of the series adsorption and the adsorption performance of the resin for 20 times of reuse were investigated.At the same time,the adsorption process was analyzed from two aspects of thermodynamics and kinetics to study its adsorption mechanism.The static experiment results show that D301 weakly basic anion resin has good adsorption potential for acrylic acid.After the resin was activated by triethylenetetramine,the total exchange capacity was increased from 3.782 mmol/g to4.981 mmol/g.At 298K,the initial concentration of acrylic acid was 7000 mg/L,the pH was 2.5,and the oscillation speed was 160 r/min.The adsorption equilibrium of D301-TETA resin reached about 120 min,and the equilibrium adsorption amount was289 mg/g.High concentrations of acetic acid cause competitive adsorption and reduce the amount of acrylic acid adsorbed,but the effect is small.The five-cycle adsorption regeneration experiment showed that the adsorption-desorption performance of the resin was stable.The dynamic adsorption of D301-TETA resin on the actual wastewater of acrylic acid showed that the wastewater flowed at 4 mL/min through a resin column with a height-to-diameter ratio of 4.5,and the COD removal rate before the break was 80%.No acrylic acid content was detected,and the residue was not detected.It is mainly a neutral substance such as esters and alcohols.The penetration volume of acrylic acid is 210 mL,and the saturated adsorption capacity is 190 mg/g.After the resin is saturated,the 2 mol/L NaOH desorbed solution is passed to the saturated resin column at a flow rate of 2 mL/min.After the elution,the resin regeneration adsorption rate is over 90%,and the resin column can be adsorbed in series to improve the resin utilization rate.The resin regeneration rate is reproducible 20 times and the recyclability is good.Thermodynamic studies show that the Langmuir equation can better fit the adsorption process of acrylic acid on D301-TETA resin than the Freundlich equation,with R~2 above 0.992 and RL at 0~1.In between,it indicates that the adsorption process of acrylic acid is a preferential adsorption of monolayer.The thermodynamic parameter?G~0 is about-1.51 KJ/mol,?H~0 is-7.21 KJ/mol,and?S~0 is-19.13J/(mol·K),indicating that the reaction is a spontaneous,exothermic,entropic reduction process.The kinetic study showed that the process of adsorption of acrylic acid by D301-TETA resin accorded with the quasi-secondary kinetic model,R~2 was above 0.999,and the rate controlling step was intraparticle diffusion. |
PDF Full Text Request