生物炭负载羧甲基纤维素钠稳定化纳米铁对水中六价铬的去除

利用液相还原法，通过先负载再包裹的方式制备了4种不同炭铁质量比的生物炭负载羧甲基纤维素钠稳定化纳米铁(BC-nZVI-CMC)材料，并将其用于对水中Cr(Ⅵ)的去除，使用扫描电镜、X射线衍射和傅里叶红外等技术对BC-nZVI-CMC的结构与性质进行了表征。结果表明：BC-nZVI-CMC具有较好的分散性，粒径为纳米级且被CMC完全包覆，抗氧化能力得到较大提升，可有效去除水中Cr(Ⅵ)；投加1 g·L⁻¹的BC-nZVI-CMC对含有30 mg·L⁻¹的Cr(Ⅵ)去除率达99.83%；pH越小，越有利于BC-nZVI-CMC对水中Cr(Ⅵ)的去除，最高去除率可达100%；BC-nZVI-CMC的抗氧化能力明显高于商品纳米铁和生物炭负载纳米铁；含有8 g·L⁻¹ C/Fe=1∶1的BC-nZVI-CMC对电镀废水中Ni、Zn、Cu、总铬、Cr(Ⅵ)的去除率可达39.60%、91.70%、100%、91.69%、100%。上述研究结果对水中Cr(Ⅵ)去除新技术的开发有重要的参考价值。

Removal of hexavalent chromium from water by biochar supported with sodium carboxymethyl cellulose-stabilized nano-iron

In this study, biochars supported with sodium carboxymethyl cellulose-stabilized nano-iron (BC-nZVI-CMC) with four different carbon-iron mass ratios was prepared though liquid-phase reduction method and first supporting and then covering way, which were used to remove Cr(Ⅵ) from water. The structure and properties of BC-nZVI-CMC were characterized by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The results showed that BC-nZVI-CMC presented good dispersion, nano-sized distribution, complete CMC coating and greatly improved anti-oxidation ability, it could effectively remove Cr(Ⅵ) from water. At the dosage of 1 g·L−1 BC-nZVI-CMC, 99.83% Cr(Ⅵ) could be removed from water with the initial concentration of 30 mg·L−1. The lower the pH, the higher removal efficiency of Cr(Ⅵ) by BC-nZVI-CMC, and the highest removal efficiency could reach 100%. The anti-oxidation ability of BC-nZVI-CMC was significantly superior to that of commercial nano-iron and biochar-loaded nano-iron. At the dosage of 8 g·L−1 BC-nZVI-CMC with C/Fe=1∶1, the removal efficiencies of Ni, Zn, Cu, total chromium and Cr(Ⅵ) in electroplating wastewater could reach 39.60%, 91.70%, 100%, 91.69% and 100%, respectively. The result provides important reference for the development of new Cr(Ⅵ) removal technology from water.