Study On The Treatment Of Thallium Wastewater With Thio-polystyrene Microspheres

Thallium in the environment with high toxicity,in recent years more thallium pollution incidents happened in our country,with the development of the society,thallium pollution has attracted people’s more and more attention.Therefore,the demand for efficient and low-cost treatment of thallium-containing wastewater is imminent.In this paper,the thio-polystyrene microspheres(TPM)with good adsorption properties of Tl+ were prepared with the high efficiency treatment of thallium wastewater.The TPM has the advantages of low cost and repeatability.The adsorption properties of the TPM on the Tl+ were studied,and the effects of adsorbents:reaction time,pH,temperature and heavy metal ions on their properties were determined.The coordination ability between Sulfhydryl pair and Tl+ was calculated by density functional theory.The mechanism of the TPM adsorption Tl+ is also discussed.The main findings are as follows:(1)A yellowish and smooth surface of sulfhydryl modified polystyrene microsp heres was prepared by hydrothermal method with Chloromethyl polystyrene mic rospheres and Thiourea as main materials.The thermogravimetric analysis show ed that the TPM had good chemical thermal stability.In the Tl+ solution of 1 mg/L,the removal rate of Tl+ by TPM is 99%,which has remarkable adsorpti on Tl+ property and can be used for adsorption treatment of thallium-containin g wastewater.(2)The effects of additive dosage,reaction time,pH,temperature and heavy metal ions on the adsorption of TPM were investigated.In 5mg/L of Tl+ solution,When the TPM dosage is 0.4L/g,Ph=6-10,the reaction temperature is 5-20 ℃ and the processing time of 640 min,the remaining Tl+ in the solution are lower than the 5μg/L emission standard.When heavy metal ions such as Pb2+ and Zn2+ are present in solution,the ability of TPM to absorb Tl+ is decreased.,The solution desorption of TPM by 0.5mol/1 dilute sulfuric acid can reach 99.96%,and the Tl+ adsorption ability of TPM is reduced by 0.1%after four repetitions,and has good regeneration performance.(3)According to the calculation results of density functional theory,the stable energies of mercapto group and Tl+ were up to 0.1043,and both of them had strong coordination ability.The modified polystyrene microspheres were characterized by EDS,FT-IR,Raman spectra and XPS,and it was proved that the modified polystyrene microspheres were ligated with Tl+ through the grafted mercapto group,so as to adsorb and remove Tl+ from the solution.According to the isotherm and kinetic model of TPM adsorption Tl+,the maximum saturated adsorption amount of TPM to Tl+ can reach 3.47mg/g,mainly chemical adsorption,and the membrane diffusion stage is the main control step of TPM adsorption Tl+.