Corn stalk as starting material to prepare a novel adsorbent via SET-LRP and its adsorption performance for Pb(II) and Cu(II)

Abstract

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 (NH 2 OH · 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 –1 and 94.72 mg g −1 , 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.

Study on the Effect of the Copper Tailing Substrate with Different Treatments on the Growth of Tall Fescue (Festuca arundinacea)

“…Therefore, the treatment of different copper tailing sand substrates alleviated the stress of the copper tailing sand substrate on the tall fescue and improved the resistance of the tall fescue to the copper tailing sand substrate. The Cu content of tall fescue in the control group is higher than that in other groups, which may be due to the strong complexing ability of EM to dissolved Cu, while the loose and porous surface of sulfurized modified straw has a certain adsorption capacity for Cu, and the coverage of HDS sediment rebuilds an uncontaminated surface layer for the copper tailings matrix, causing the Cu in the copper tailings to be adsorbed and deposited in HDS sediment by the porous particles when it migrates to the plant roots, effectively reducing the tall fescue Cu absorption [40,41].…”