Novel iron-modified chitosan for effective demulsification and oil recovery of emulsified oily wastewater

Flocculation is considered an alternative, eco-friendly demulsification technology for treating emulsified oily wastewater. However, conventional flocculants produce a large amount of oily sludge, causing environmental risk as well as oil loss. To address this, we fabricated a demulsifying agent made of iron-modified chitosan (FeOX-CS) for demulsification and reducing the production of oily sludge. The hydrophilicity of the chitosan was enhanced after FeOX modification, which enhanced the hydrogen bond between the flocculant and the oil droplet, and improved the demulsification efficiency. The demulsification efficiency of the FeOX-CS for the oil-in-water (O/W) model emulsions is over 60% after 3 recycles. The demulsification efficiency of FeOX-CS excessed 97% within 60 min at the dosages of FeOX-CS 20 mg/L, initial model emulsion concentration of 200 mg/L, and pH of 7. The demulsified oil mainly exists in water surface and FeOX-CS surface. Thus, the synthesized FeOX-CS is a potential for treating emulsified oily wastewater.