摘要
以农业废弃物玉米(Zea mays L.)衣为吸附剂,研究其对水溶液中Pb(Ⅱ)的吸附作用,采用扫描电镜、红外光谱仪等对玉米衣的表面多孔性、吸附作用基团进行分析,并探究玉米衣的最佳吸附条件、吸附等温线、动力学模型。结果表明,当溶液Pb(Ⅱ)浓度为20 mg/L,p H为6.0,吸附剂投加量为0.10 g时,吸附率最高,达到94.77%;玉米衣对Pb(Ⅱ)的吸附动力学符合准二级动力学方程,以化学吸附为主;其吸附等温线符合Langmuir模型,为单分子层吸附;扫描电镜结果表明玉米衣表面覆盖大量绒毛,断裂形成小孔,有利于增加比表面积;红外光谱分析表明吸附过程中起主要作用的官能团有羧基、羟基等;当溶液中含有Ca2+、Mg2+等阳离子时,一定程度影响Pb(Ⅱ)的吸附。利用0.2 mol/L HCl解吸9.5 h解吸效果更好,其解吸率可达到48%。在众多吸附剂中,玉米衣最大吸附量可达32.468 mg/g,处于较好的吸附水平,因此,利用玉米衣作为吸附剂去除溶液中Pb(Ⅱ)具有潜在的应用前景。
Corn（Zea mays L.） clothing collected from land was investigated for their capacity for Pb（Ⅱ） adsorption from aqueous solution. The corn clothing was characterized by scanning electron microscopy,infrared spectroscopy,and batch experiments were carried out to analyse adsorption equilibrium,isotherm, kinetics. The results showed that in 20 mg / L Pb（Ⅱ） solution,the best removal rate of Pb（Ⅱ） reached 94.77%,when the pH value was 6.0 and the dosage of corn clothing was 0.10 g.Adsorption kinetics of Pb（Ⅱ） follow closely the pseudo-second-order kinetic model, and the adsorption isotherm fits Langmuir equation well. The breakage of tomenta on the surface of the corn clothing leads to the formation of micropores which is conducive to increasing the surface area. The functional groups that play major roles are carboxyl groups and hydroxyl groups.The potassium ions and magnesium ions from aqueous solution restrain the adsorption of lead ions. The better effect was found when hydrochloric acid of 0.2 mol / L was prepared for a 9.5 h desorption, and the ratio can reach 48%. Among many kinds of adsorbents, corn clothing gets a meglio capacity of 32.468 mg / g. Thus utilization of corn clothing for the removal of Pb（Ⅱ） from aqueous solution has potential prospects.
出处
《湖北农业科学》
2016年第17期4465-4471,共7页
Hubei Agricultural Sciences
基金
上海市自然科学基金项目(15ZR1401500)
