Wang Yazhen, Li Shuang, Ma Liqun, Dong Shaobo, Liu Li
College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006, Heilongjiang, People's Republic of China.
College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, Heilongjiang, People's Republic of China.
R Soc Open Sci. 2020 Mar 11;7(3):191811. doi: 10.1098/rsos.191811. eCollection 2020 Mar.
Corn stalk was used as the initial material to prepare a corn stalk matrix-g-polyacrylonitrile-based adsorbent. At first, the corn stalk was treated with potassium hydroxide and nitric acid to obtain the corn stalk-based cellulose (CS), and then the CS was modified by 2-bromoisobutyrylbromide (2-BiBBr) to prepare a macroinitiator. After that, polyacrylonitrile (PAN) was grafted onto the macroinitiator by single-electron transfer living radical polymerization (SET-LRP). A novel adsorbent AO CS-g-PAN was, therefore, obtained by introducing amidoxime groups onto the CS-g-PAN with hydroxylamine hydrochloride (NHOH · HCl). FTIR, SEM and XPS were applied to characterize the structure of AO CS-g-PAN. The adsorbent was then employed to remove Pb(II) and Cu(II), and it exhibited a predominant adsorption performance on Pb(II) and Cu(II). The effect of parameters, such as temperature, adsorption time, pH and the initial concentration of metal ions on adsorption capacity, were examined in detail during its application. Results suggest that the maximum adsorption capacity of Pb(II) and Cu(II) was 231.84 mg g and 94.72 mg g, and the corresponding removal efficiency was 72.03% and 63%, respectively. The pseudo-second order model was more suitable to depict the adsorption process. And the adsorption isotherm of Cu(II) accorded with the Langmuir model, while the Pb(II) conformed better to the Freundlich isotherm model.
以玉米秸秆为初始原料制备了玉米秸秆基质接枝聚丙烯腈基吸附剂。首先，用氢氧化钾和硝酸处理玉米秸秆以获得玉米秸秆基纤维素（CS），然后用2-溴异丁酰溴（2-BiBBr）对CS进行改性以制备大分子引发剂。之后，通过单电子转移活性自由基聚合（SET-LRP）将聚丙烯腈（PAN）接枝到大分子引发剂上。因此，通过用盐酸羟胺（NHOH·HCl）在CS-g-PAN上引入偕胺肟基团，得到了一种新型吸附剂AO CS-g-PAN。采用傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和X射线光电子能谱（XPS）对AO CS-g-PAN的结构进行了表征。然后将该吸附剂用于去除Pb（II）和Cu（II），并对Pb（II）和Cu（II）表现出优异的吸附性能。在其应用过程中，详细考察了温度、吸附时间、pH值和金属离子初始浓度等参数对吸附容量的影响。结果表明，Pb（II）和Cu（II）的最大吸附容量分别为231.84 mg/g和94.72 mg/g，相应的去除效率分别为72.03%和63%。准二级模型更适合描述吸附过程。Cu（II）的吸附等温线符合Langmuir模型，而Pb（II）更符合Freundlich等温线模型。
