纳米羟基铁改性阳离子树脂制备及去除Cd(Ⅱ)

采用乙醇分散浸渍法对大孔强酸性阳离子树脂(D001)进行改性,制备了纳米羟基铁改性树脂复合材料(nFeOOH@D001),并考察其去除饮用水中Cd(II)的性能。研究结果表明,羟基铁以20~150 nm的粒径均匀负载到D001的表面。与D001相比,nFeOOH@D001对Cd(II)的吸附性能提高了13%,反应过程符合Langmuir吸附模型和准2级动力学,最大吸附量和反应速率常数分别为282 mg/g和0.042 g/(g·h)。nFeOOH@D001具有更强的抗钙镁离子干扰能力,且吸附后的nFeOOH@D001可用醋酸脱附,经5次脱附-吸附循环使用后再生率依然可达77%。失效的nFeOOH@D001可使用1 mol/L的HCl洗脱并重新负载nFeOOH,再生率可达86%,比D001提高了57%。该改性方法在提高树脂吸附Cd(II)性能的同时,增强树脂抗钙镁离子干扰能力并延长其使用寿命。

Preparation of Cationic Resin Modified with Nano-Sized Goethite and Its Application for Cd(Ⅱ) Removal

Macroporous strong cation resin(D001) was modified with an ethanol dispersion and impregnation method to prepare nano-sized-goethite modified resin composite(n Fe OOH@D001). The performance of this composite for Cd(II) removal from drinking water was investigated. The results showed that Fe OOH particles with a diameter of 20~150 nm were homogeneously distributed on the surface of the D001. Compared to the D001, the Cd(II) removal efficiency by n Fe OOH@D001 improved 13%, this adsorption process confirmed to the Langmuir adsorption model and the pseudo-secondorder kinetics. The maximum adsorption and the reaction rate constant were 282 mg/g and 0.042 g/(g·h), respectively. Besides, the nFeOOH@D001 had stronger anti-calcium-magnesium inhibition capacity. The adsorbed nFeOOH@D001 could be desorbed by acetic acid and the regeneration efficiency reached 77% after 5 desorption-adsorption cycles. The spent n Fe OOH@D001 could be eluted with 1 mol/L HCl and reloaded with n Fe OOH, the regeneration efficiency reached 86%, 57% higher than that of D001. This modification method not only improves the capacity of resin for Cd(II) removal, but also enhances its resistance to the inhibition of calcium and magnesium ions and extends its life-span.