污泥酸提液/Fe^(2+)改性活性炭纤维对氨氮的吸附

Activated Carbon Fiber Modified with Sludge Acid Extract and Fe^(2+)for Ammonia Nitrogen Adsorption

以活性炭纤维(ACF)为载体,以给水厂污泥酸提液(Sae)与氯化亚铁混合溶液为改性溶液,制备氨氮吸附材料Fe/Al-ACF。实验结果表明:Fe/Al-ACF在水中稳定性良好,在中性和碱性条件下对氨氮具有较好的去除效果。当温度为25℃、氨氮为20 mg/L、Fe/Al-ACF为2.0 g/L、pH=7、反应240 min时,Fe/Al-ACF对氨氮的去除率为90.52%,且在经过4次循环再生后去除率仍可达59.16%。Fe/Al-ACF对氨氮的吸附符合准二级动力学模型、Elovich模型以及Langmuir等温吸附模型,吸附过程为自发吸热的化学单分子层吸附,涉及静电吸引,吸附速率与表面吸附量有关。扫描电子显微镜(SEM)、X射线衍射仪(XRD)、傅里叶红外光谱仪(FTIR)结合热力学分析结果表明:Fe/Al-ACF纤维束表面的沟壑间生长有大量呈针状和钟乳石状的铁铝氧化物晶体(Fe_(3)O_(4)、γ-Fe_(2)O_(3)和Al2O3),其参与了吸附,吸附过程存在络合反应与N、O之间的氢键结合作用。

The ammonia nitrogen adsorption material Fe/Al-ACF was prepared by using activated carbon fiber(ACF)as the carrier and sludge acid extract(Sae)and ferrous chloride mixture as the modifier.Fe/Al-ACF had good stability in water and good ammonia nitrogen removal performance under neutral and alkaline conditions.When the temperature was 25℃,ammonia nitrogen was 20 mg/L,Fe/Al-ACF dosage was 2.0 g/L,pH was 7,and the reaction time was 240 min,the removal rate of ammonia nitrogen by Fe/Al-ACF was 90.52%,and the removal rate was still 59.16%after 4 cycles of regeneration.The adsorption of ammonia nitrogen by Fe/Al-ACF conformed to the quasi‑second‑order kinetic model,Elovich model and Langmuir isotherm adsorption model.The adsorption process was a spontaneous endothermic chemical monolayer adsorption involving electrostatic attraction,and the adsorption rate was related to the surface adsorption capacity.The results of scanning electron microscope(SEM),X‑ray diffractometer(XRD)and Fourier transform infrared spectroscope(FTIR)combined with thermodynamic analysis showed that there were a large number of acicular and stalactites shaped iron and aluminum oxide crystals(Fe_(3)O_(4),γ‑Fe_(2)O_(3)and Al2O3)growing between the ravines on the surface of Fe/Al-ACF,which participated in the adsorption process,and the adsorption process involved complex reaction and hydrogen bonding between N and O.