Key Laboratory of Energy Thermal Conversion and Control of Ministry Education, School of Energy and Environment, Southeast University, Nanjing, China.
School of Energy & Mechanical Engineering, Nanjing Normal University, Nanjing, China.
Environ Sci Pollut Res Int. 2022 Mar;29(12):17964-17976. doi: 10.1007/s11356-021-16993-7. Epub 2021 Oct 22.
A novel adsorbent consisting of tannic acid (TA) immobilized on graphene oxide (GO) was proposed and used to remove Hg from desulfurization wastewater. The morphology and physicochemical properties of tannin-immobilized graphene oxide (TAIGO) were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The characterization results showed that TA was successfully immobilized on GO, and that new functional groups were introduced on TAIGO. The effects of contact time, adsorbent dose, pH, and ion components on removal efficiency were evaluated. The adsorption process was found to be complete within 15 min, and the removal efficiency increased with increasing adsorbent dosage. The pH value affected the protonation of TAIGO and the form of Hg in wastewater. High concentrations of Cl and SO hindered the adsorption performance, whereas SO and cations had a negligible effect. In addition, the excellent economic benefits of TAIGO were analyzed in an economic evaluation, and the Hg removal efficiency remained at 88% after three recycles. A pseudo-second-order kinetic model (R = 0.9995) was used to fit the adsorption process, and the oxygen-containing functional groups and chelation reaction played critical roles in adsorption. TAIGO is a low-cost adsorbent with high Hg removal efficiency and could be further used in practical desulfurization wastewater.
一种新型吸附剂由单宁酸（TA）固定在氧化石墨烯（GO）上制备而成，用于去除脱硫废水中的汞。单宁固定化氧化石墨烯（TAIGO）的形貌和理化性质通过扫描电子显微镜（SEM）、原子力显微镜（AFM）、傅里叶变换红外光谱（FTIR）、X 射线衍射（XRD）和 X 射线光电子能谱（XPS）进行了表征。表征结果表明 TA 成功地固定在 GO 上，并且在 TAIGO 上引入了新的官能团。考察了接触时间、吸附剂用量、pH 值和离子成分对去除效率的影响。吸附过程在 15 分钟内完成，去除效率随吸附剂用量的增加而增加。pH 值影响 TAIGO 的质子化和废水中汞的形态。高浓度的 Cl 和 SO 会阻碍吸附性能，而 SO 和阳离子的影响可以忽略不计。此外，还通过经济评估分析了 TAIGO 的优异经济效益，三次循环后 Hg 的去除效率仍保持在 88%。吸附过程用拟二级动力学模型（R²=0.9995）拟合，含氧官能团和螯合反应在吸附过程中起关键作用。TAIGO 是一种具有高 Hg 去除效率和低成本的吸附剂，可进一步用于实际脱硫废水处理。
