【摘要】 以天然硅藻土为载体,制备了硅藻土负载无定形磷酸氢锡复合材料。利用该材料去除废水中的Pb(Ⅱ)、Cu(Ⅱ)和Zn(Ⅱ),研究了p H值、吸附时间、初始质量浓度对吸附性能的影响,探讨了材料的等温吸附规律,同时考察了材料在模拟海水中的吸附效果及再生能力。结果表明,硅藻土负载无定形磷酸氢锡对Pb(Ⅱ)、Cu(Ⅱ)和Zn(Ⅱ)的吸附量随p H值和吸附时间增大而逐渐增大并趋于平衡。等温吸附数据用Freundlich方程拟合效果最好,25℃时的饱和吸附量分别为27.54 mg/g、19.94 mg/g和16.33 mg/g。复合材料对3种离子的吸附机理均以化学吸附为主,在吸附Pb(Ⅱ)的过程中孔内扩散为速控步骤。高盐度对材料吸附Pb(Ⅱ)、Cu(Ⅱ)和Zn(Ⅱ)有一定的不利影响,但幅度不大,可以用于去除养殖海水中的Pb(Ⅱ)、Cu(Ⅱ)和Zn(Ⅱ)。吸附了重金属离子的复合材料可以用稀HCl再生,具有重复利用的潜能。更多还原

【Abstract】 In this paper,we have chosen natural diatomite as a kind of loading carrier of the amorphous tin(IV) hydrogen phosphate,with its content loaded on the diatomite being 170 mg / g.As a result of our experiments,we have found that it is possible for the total pore volume of diatomite to increase by 50. 99% and an astounding tenfold increase can be found in the specific surface area after loading the amorphous tin(IV) hydrogen phosphate,which indicates that the composite has successfully been prepared as the result of the experiment. The experimental results have also shown that the composite thus prepared can be used as adsorbent for removing Pb(II),Cu(II) and Zn(II) from the aqueous solution. In this paper,we have also investigated and found the extent of the adsorption as a function of p H,the contact time,and the adsorption concentrations. In addition,we have also made an exploration of the isothermal adsorption behavior,the adsorption capacity in the media of simulated seawater and the potential of the material regeneration. The experiment and investigation results show that the concentration of heavy metals to be adsorbed tends to increase with the increase of the solution p H within the examined range during the period of the reaction time and it would be possible to reach the state of equilibrium in 150 min later.Theoretically speaking,the kinetic analysis results show that the adsorption can be well described by using a pseudo-second-order model and the intra-particular diffusion as a reaction rate control step,however,we have also found that the liquid film diffusion can also play an important role in the absorptive process. The equilibrium data has been made known better fit for the Freundlich isotherm equation. In addition,the experimental facts show that,at the temperature of 25 ℃,the maximum sorption capacity can be made to reach 27. 54 mg / g,19. 94 mg / g,16. 33 mg / g for Pb(II),Cu(II) and Zn(II),respectively. What is more,the increase of the free energy Es(k J/mol) from the D-R isotherm proves that the adsorption process for Pb(II),Cu(II) and Zn(II) tends to reveal the chemical ion-exchange mechanism. In addition,the adsorption experiments we have done with the stimulated seawater(the p H value was adjusted as 5 in this study) also help to reveal the adsorption capacity of 13. 9 mg / g,3. 95 mg / g,and 3. 74 mg / g for Pb(II),Cu(II) and Zn(II),respectively,at the initial concentration of 50 mg / L. The result proves that it is feasible for tin(IV) phosphate to remove Pb(II),Cu(II) and Zn(II) from the hyper-saline media.更多还原