In this paper, an effective and sustainable treatment method for recycling chromium from sludge produced by magnetic flocculation was established. Chromium was extracted from sludge with hydrogen peroxide and sodium hypochlorite, and then, superparamagnetic ferroferric oxide nanoparticles (MPs) were recovered by magnetic separation. The recovery percentage of chromium with sodium hypochlorite was higher than that with hydrogen peroxide, and the maximum was 99.12%. With increasing MPs use times, the adsorption percentage of chromium decreased, but there was no significant change in the recovery percentage of chromium in sludge. The purity of the recovered sodium chromate crystals was 96.28%. The back-propagation algorithm was used to model chromium recovery. The correlation coefficient between the model prediction data and experimental data was 0.9990, and the average absolute error was 0.51. The maximum recovery percentage of chromium obtained from model prediction was 99.27%, and the corresponding optimal conditions were consistent with those of experiments.

本文建立了一种从磁絮凝污泥中回收铬的有效且可持续的处理方法。用过氧化氢和次氯酸钠从污泥中提取铬，然后通过磁分离回收超顺磁性四氧化三铁纳米颗粒（MPs）。次氯酸钠对铬的回收率高于双氧水，最高可达99.12%。随着MPs使用次数的增加，铬的吸附率下降，但污泥中铬的回收率没有明显变化。回收的铬酸钠结晶纯度为96.28%。反向传播算法用于模拟铬回收。模型预测数据与实验数据的相关系数为0。9990，平均绝对误差为0.51。模型预测得到的铬最大回收率为99.27%，相应的优化条件与实验一致。