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 (FeO X -CS) for demulsification and reducing the production of oily sludge. The hydrophilicity of the chitosan was enhanced after FeO X modification, which enhanced the hydrogen bond between the flocculant and the oil droplet, and improved the demulsification efficiency. The demulsification efficiency of the FeO X -CS for the oil-in-water (O/W) model emulsions is over 60% after 3 recycles. The demulsification efficiency of FeO X -CS excessed 97% within 60 min at the dosages of FeO X -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 FeO X -CS surface. Thus, the synthesized FeO X -CS is a potential for treating emulsified oily wastewater.