Recovery and application of heavy metals from pickling waste liquor (PWL) and electroplating wastewater (EPW) by the combination process of ferrite nanoparticles

Heavy metal contamination in wastewater poses a severe threat to the environment and public health. Magnetic iron-based materials are effective for heavy metal wastewater treatment, resources conservation, and recycling of metal ions. In the present work, two kinds of heavy metal wastewater were used to fabricate magnetically separable MnFe2O4 and CuFe2O4 as catalysts. The obtained catalysts were characterized by scanning electron microscopy, X-ray diffractometry, vibrating sample magnetometer, and X-ray photoelectron spectroscopy. Results showed that MnFe2O4 and CuFe2O4 MNPs could effectively activate peroxymonosulfate (PMS) to generate powerful sulfate radicals for Rhodamine B (RhB) removal. More than 99% of RhB (10mg/L) was degraded within 20min using 0.4g/L MnFe2O4 MNPs and 0.2g/L PMS. The most effective pH for RhB degradation by PMS/WB-MnFe2O4 was 3. And under the condition of catalysts loading (0.40g/L), dye concentration (10mg/L), PMS=0.2g/L and T=25 degrees C, the stability and reusability of MnFe2O4 and CuFe2O4 MNPs was investigated. Recycled WB-MnFe2O4 MNPs showed strong activity in RhB degradation and its activity remained almost unchanged in eight cycles, while the activity of WB-CuFe2O4 MNPs dropped down after three cycles.