Abstract:

Vanadium slag, derived from converter vanadium slag, contains a large amount of iron, and its secondary utilization has significant economic value and practical significance. In this paper, H₂SO₄ was used as the acid leaching solution, and the response surface method was used to optimize the acid leaching process parameters. Subsequently, the α-Fe₂O₃/Bi₂WO₆ composite photocatalyst was successfully prepared by the calcination-hydrothermal method for the photodegradation of methyl orange (MO), a dye wastewater, under simulated visible light. The results showed that the optimal process parameters for acid leaching were as follows: H₂SO₄ concentration of 2.8mol/L, acid leaching temperature of 98℃, acid leaching time of 138min and solid-liquid ratio of 1∶4.2. Under these optimal parameters, the iron leaching efficiency from vanadium slag was 71.0%. After preparing α-Fe₂O₃ from vanadium slag using a precipitation-calcination method, the photodegradation performance of the VS-Fe₂O₃/Bi₂WO₆ composite synthesized via hydrothermal treatment was found to be significantly superior to that of the commercial Fe₂O₃/Bi₂WO_6. The optimal doping amount of VS-Fe₂O₃ was 10%. When the H₂O₂ dosage was 19.58mmol/L, pH was 6.5, catalyst dosage was 0.4g/L, initial concentration of wastewater was 10mg/L and photoreaction was carried out for 6h, the removal rate of MO was 96% and the COD removal rate was 88.4%. The effluent COD concentration of 13.34mg/L met the requirements of the “Integrated Wastewater Emission Standard” level A standard and the rate constant ofthe photoreaction was 4.8 times that of the pure Bi₂WO₆ phase. The degradation mechanism of MO was primarily due to the photo-Fenton reaction under the action of H₂O₂ synergistic VS-Fe₂O₃/Bi₂WO₆. This paper can provide a reference for the efficient and clean resource utilization of vanadium slag and its resource utilization in photocatalysis.

Key words: vanadium slag, acid leaching, response surface, photocatalysis, Bi₂WO₆

摘要：

钒渣来自转炉钒渣，含有大量铁元素，它的二次利用具有重大的经济价值与现实意义。本文以H₂SO₄为酸浸液，利用响应面法优化酸浸工艺参数，后通过煅烧-水热法成功制备出ɑ-Fe₂O₃/Bi₂WO₆复合光催化剂，在模拟可见光作用下光降解染料废水甲基橙（MO）。结果表明，响应面优化酸浸实验的最佳工艺参数为H₂SO₄浓度2.8mol/L、酸浸温度98℃、酸浸时间138min、固液比1∶4.2，钒渣中Fe的浸出率为71.0%；以钒渣为铁源，采用沉淀-煅烧法制备出α-Fe₂O₃后，通过水热法合成VS-Fe₂O₃/Bi₂WO₆，其光降解性能明显优于商业Fe₂O₃/Bi₂WO₆，VS-Fe₂O₃的最佳掺杂量为10％，当H₂O₂投加量为19.58mmol/L、pH=6.5、催化剂投加量为0.4g/L、MO初始浓度为10mg/L、光反应6h时，MO去除率达96%，COD去除率为88.4%，出水COD为13.34mg/L，符合《污水综合排放标准》一级标准，光反应速率常数为纯相Bi₂WO₆的4.8倍；MO的降解机理主要为H₂O₂协同VS-Fe₂O₃/Bi₂WO₆作用下的光芬顿反应。本文可为钒渣高效、清洁的资源化利用及其在光催化领域的资源化利用提供参考。

关键词: 钒渣, 酸浸, 响应面, 光催化, 钨酸铋