Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, People's Republic of China.
Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.
Environ Sci Pollut Res Int. 2023 Dec;30(57):120030-120043. doi: 10.1007/s11356-023-30771-7. Epub 2023 Nov 7.
Elevated Sb(V) concentration in textile wastewater is a growing environmental concern worldwide and has received wider attention in recent years. Iron oxides possess appealing characteristics as efficient and cost-effective adsorbents in large-scale applications. In the present study, Sb(V) adsorption capacity of α-FeO, γ-FeO, and FeO was compared under experimental conditions close to the practical textile wastewater treatment. Results demonstrated that α-FeO performed better under different pH values, reaction times, dye compounds, and co-existing ions as compared to γ-FeO and FeO, and the adsorption equilibrium was achieved within 8 h. Sb(V) adsorption is found to be highly pH dependent, and higher removal was achieved in lower pH, indicating the involvement of electrostatic interactions. The pH value of α-FeO was 7.15, which favored Sb(V) adsorption in practical wastewater having neutral pH value (pH ~ 7). Pseudo-first- and pseudo-second-order described the data and the simulated values of q fitted well with the experimental values, indicating that pseudo-second-order model described the adsorption kinetics better with R (> 0.95) higher than of pseudo-first-order plots. The Langmuir and Freundlich models both described well the sorption data of all the adsorbents, where the R values were > 0.90 with a better fit in the Freundlich model for α-FeO, suggesting that the adsorbent has heterogeneous surface characteristics. Similarly, characterizations revealed that the specific surface area, pore volume, and hydroxyl group content in α-FeO were higher than others, making it easier for contaminants to bind on to the active sites. Furthermore, the effect of dyes and co-existing anions on Sb(V) adsorption was negligible, except for SO, CO, and PO by the formation of inner-sphere complexes with iron oxides through competitive adsorption with [Sb(OH)]. Findings from the present study suggested that α-FeO effectively reduced Sb(V) in textile wastewater and could be a promising alternative for practical textile wastewater treatment.
纺织废水中 Sb(V) 浓度升高是一个全球性的环境问题，近年来受到了更广泛的关注。氧化铁作为高效、经济实用的吸附剂，在大规模应用中具有吸引力。本研究在接近实际纺织废水处理的实验条件下，比较了α-FeO、γ-FeO 和 FeO 对 Sb(V) 的吸附能力。结果表明，α-FeO 在不同的 pH 值、反应时间、染料化合物和共存离子下的性能均优于γ-FeO 和 FeO，吸附平衡在 8 小时内达到。Sb(V) 的吸附高度依赖于 pH 值，在较低 pH 值下去除率更高，表明静电相互作用的参与。α-FeO 的 pH 值为 7.15，有利于实际废水中性 pH 值（pH~7）下的 Sb(V) 吸附。准一级和准二级动力学模型都能很好地描述数据，拟合值与实验值吻合较好，表明准二级动力学模型更好地描述了吸附动力学过程，拟合值的 R (>0.95) 高于准一级动力学模型。Langmuir 和 Freundlich 模型都很好地描述了所有吸附剂的吸附数据，R 值均>0.90，其中 Freundlich 模型对α-FeO 的拟合更好，表明吸附剂具有非均相表面特性。同样，表征结果表明，α-FeO 的比表面积、孔体积和羟基含量均高于其他物质，使得污染物更容易结合到活性位点上。此外，除 SO、CO 和 PO 外，染料和共存阴离子对 Sb(V) 吸附的影响可以忽略不计，这是因为它们通过与[Sb(OH)]的竞争吸附形成内圈络合物，与氧化铁相互作用。本研究结果表明，α-FeO 能有效降低纺织废水中的 Sb(V)，是一种很有前途的实际纺织废水处理方法。
