改性水稻秸秆对溶液中Cd^(2+)的吸附机制研究  

Adsorption mechanism of Cd^(2+)in solution by modified rice straw

作　　者：吴伟健 唐云鹏 马桥 赵颖玥 邓潇 曾清如[1] WU Weijian;TANG Yunpeng;MA Qiao;ZHAO Yingyue;DENG Xiao;ZENG Qingru(College of Environment and Ecology,Hunan Agricultural University,Changsha 410000)

机构地区：[1]湖南农业大学环境与生态学院,长沙410000

出　　处：《环境科学学报》2023年第12期276-286,共11页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.U20A20108)。

摘　　要：选用水稻秸秆作为原料,采用强氧化剂和氢氧化物(KMnO_(4)、KOH和H_(2)O_(2))进行改性.通过静态吸附试验,研究了改性秸秆的表面特性以及初始镉(Cd)浓度、pH值和固液比等因素对其吸附性能的影响.同时,运用电位滴定、等温吸附模型和吸附动力学模型来深入探讨其吸附机制.结果表明,KMnO_(4)为最佳改性试剂,改性后显著增强了秸秆对Cd^(2+)的吸附性能,较原始秸秆提高了1.19~3.46倍.KMnO_(4)改性导致秸秆表面负载更多的锰氧化物,增加了其表面的羧基、羟基、氨基及总官能团数量.原始秸秆和KMnO_(4)改性秸秆对Cd^(2+)的吸附过程均符合准二级动力学方程和Langmuir模型,这表明秸秆吸附以单分子层化学吸附为主导.此外,KMnO_(4)改性秸秆对Cd^(2+)的吸附性能受pH影响较小,且具备出色的抗离子干扰性能,在不同pH值和复杂离子共存条件下,能够高效去除重金属污染废水中的Cd^(2+).Rice straw was selected as the raw material and modified using potent oxidants and hydroxides(KMnO_(4),KOH,and H_(2)O_(2)).To investigate the surface characteristics of modified straw and the influence of initial cadmium(Cd)concentration,pH value,and solid-liquid ratio on its adsorption performance,static adsorption experiments were conducted.Furthermore,potentiometric titration,isothermal adsorption models,and adsorption kinetic models were employed to investigate the adsorption mechanisms.The results revealed that KMnO_(4) was the optimal modification reagent,markedly enhancing the adsorption performance of straw for Cd^(2+)by 1.19 to 3.46 times compared to untreated straw.Modification with KMnO_(4) resulted in an increased loading of manganese oxides on the surface of the straw,simultaneously augmenting the quantity of carboxyl groups,hydroxyl groups,amino groups,and total functional groups.Both untreated and KMnO_(4)-modified straw followed pseudo-second-order kinetic equations and the Langmuir model,suggesting that straw adsorption was primarily governed by monolayer chemical adsorption.Furthermore,KMnO_(4)-modified straw exhibited minimal sensitivity to pH,demonstrated excellent ion interference resistance,and efficiently removed Cd^(2+)from heavy metal-polluted wastewater under varying pH conditions and in the presence of complex ions.

关 键 词：水稻秸秆 CD 改性 高锰酸钾 吸附 

分 类 号：X703[环境科学与工程—环境工程]