SiO_(2)/PAA吸附剂的制备及其对Cu^(2+)、Pb^(2+)的吸附行为研究

Preparation of SiO_(2)/PAA and its adsorption behavior to CU^(2+) and Pb^(2+)

为了在吸附的同时使重金属离子与废水快速、有效分离,采用水溶液聚合法,将单体丙烯酸接枝在改性的SiO_(2)上,得到了SiO_(2)/聚丙烯酸(PAA)吸附剂。当引发剂过硫酸钾用量为单体质量的1%、反应温度为70℃、反应时间为4 h时,丙烯酸的单体转化率达到81.6%。当吸附剂质量分数为0.1%、振荡速率为80 r/min、pH值为6、温度为25℃、吸附时间大于2 h时,SiO_(2)/PAA吸附剂对Cu^(2+)的平衡吸附量达到12.03 mg/g,对Pb^(2+)的平衡吸附量达到14.97 mg/g。SiO_(2)/PAA吸附剂对Cu^(2+)、Pb^(2+)的吸附符合准二级动力学模型,化学吸附过程为速率决定步骤,吸附剂对Pb^(2+)的吸附速率及效果均优于Cu^(2+)。

In order to quickly and effectively separate heavy metal ions from wastewater during adsorption,SiO_(2)/PAA adsorbent was prepared by aqueous solution polymerization method which grafting monomer acrylic acid on modified SiO_(2).when the dosage of initiator:potassium persulfate was 1%of the weight of monomer,the reaction temperature was 70℃,the reaction time was 4 h,the monomer conversion rate of acrylic acid reached 81.6%.Under the condition that the mass fraction of adsorbent was 0.1%,the oscillation rate was 80 r/min,the pH value was 6,the temperature was 25℃,the adsorption time was over 2 h,the equilibrium adsorption capacity of SiO_(2)/PAA to Cu^(2+)and Pb^(2+)reached 12.03 and 14.97 mg/g respectively.The adsorption of SiO_(2)/PAA to Cu^(2+)and Pb^(2+)fit pseudo-second-order mode,indicating the chemical adsorption was rate-limiting step process.The adsorption rate and efficiency of Pb^(2+)by the said adsorbent was superior to Cu^(2+).