Preparation of nanoscale zero-valent metal for catalyzed clean oxidation of hydroxypropyl guar gum at a wide pH range

Metal-persulfate is currently used for SO 4 •– generation and oxidation to remove organic contaminants. However, homogeneous metal-persulfate requires acidic pH conditions and metal ions cannot be separated from the bulk after the reaction. To address these issues, a heterogeneous nanoscale zero-valent metal catalyst was used to activate peroxymonosulphate for advanced oxidation of hydroxypropyl guar gum (HPG) and other polymers in oilfield wastewater. It was found that the nanoscale Cu(0) performed high catalytic activity in a wide pH range of 7.0–11.0. The viscosity of HPG can be reduced effectively from 24 to 2.5 with the 10.0% Na 2 S 2 O 8 (mass ratio to HPG) and 10.0% Cu(0) (mass ratio to Na 2 S 2 O 8 ), and the chemical oxygen demand of HPG solution can be decreased from 7,602 to 1,070 mg L –1 in presence of the nanoscale Cu(0). Furtherly, the morphology and pore structure of catalysts were characterized in detail by scanning electron microscopy, X-ray diffraction and Brunauer–Emmett–Teller.