【摘要】 研究了纳米无定型TiO2颗粒对饮用水中低浓度的三价砷As(Ⅲ)吸附行为。纳米TiO2颗粒吸附剂的BET表面积为205 m2/g,计算的BJH吸附平均孔径为4.02 nm(4 V/A)。对起始As(Ⅲ)浓度为150μg/L的模拟含砷水,经过5h的吸附处理后残余浓度不足4μg/L,As(Ⅲ)去除率达到97%。反应起始阶段吸附速率较快,84%的As(Ⅲ)能够在20min内去除。As(Ⅲ)吸附动力学较好地符合拟二级动力学模式。最佳As(Ⅲ)吸附pH为9.3,低于此值,随酸性增加吸附速率有所降低;而高于此值的强碱性pH对吸附有强烈抑制作用。在平衡浓度较低的情形下(10～220μg/L),Lang-muir,Freundlich和Dubinin-Radushkevich(D-R)吸附等温式均可较好拟合吸附行为,但中性和弱碱性条件下更符合Fre-undlich吸附等温式;平衡浓度大于220μg/L,吸附容量随平衡浓度增加而迅速增加,最大吸附容量在低浓度下达到4.79 mg/g。更多还原

【Abstract】 Arsenite(Ⅲ) removal from low-arsenic concentration drinking water by adsorption with nano-scale hydrous amorphous TiO2 prepared from hydrolysis of tetrabutyl titanate(Ti(OC4H9)4) solution were researched.The amorphous TiO2 nanoparticles size ranged from 1.9 to 6 nm with BET surface area of 205 m2/g.The nanoparticles adsorbent size calculated by BJH adsorption average pore diameter(4 V/A) was 4.02 nm.As(Ⅲ) adsorption kinetics data were found to be well described by the pseudo-second order model.Most of As(Ⅲ) in the solution can be adsorbed onto amorphous hydrous TiO2 adsorbent in a very short time even less than 20 min,which is beneficial to engineering application of the materials for purification water.Constant of the adsorption rate of As(Ⅲ) removal increased from 0.018 to 0.027 L/(mg·min) with the pH increased from 3.04 to 9.3,but dramatic decreased to 0.0101 L/(mg·min) with increasing pH from 9.3 to 12.11.The maximum adsorption pH value at 9.3 was coincident with the first dissociation constant of pK1 of H3AsO3 at 9.22.Adsorption data obtained were fitted to Langmuir,Freundlich and Dubinin-Radushkevich models well if the equilibrium concentration of As(Ⅲ) was less than 220 μg/L.更多还原