ZHANG Li-juan, FAN Wen-li, WEN Xue-han

(Textile Footwear and Apparel Engineering College of Liming Vocational University, Quanzhou 36200, China)

Abstract: The combined flocculation-adsorption process has been applied to treat the complex jewelry and jade processing wastewater which is rich in suspended solid particles and high chemical oxygen demand (COD). The anionic polyacrylamide (HPAM) with limiting viscosity number of 1 760 mL/g is used as a linear macromolecule flocculant to treat wastewater. The addition of HPAM with mass concentration of 40 mg/L into the jewelry and jade processing wastewater has resulted in the decrease of wastewater turbidity to 0.9 FTU. In order to overcome deficiency of the flocculation which is unable to reduce COD in water, porous polymer adsorption substance (PAS) was selected to remove COD in the water by adsorption. Under the condition at the PAS dosage of 2 g/L, the adsorption time of 110 min, and the adsorption temperature of 288.15 K, the removal rate of COD was up to 95%. Its adsorption kinetics is accorded with pseudo-second-order kinetic equation (R2=0.99) and internal diffusion model (R2=0.95). Its isothermal adsorption process is accorded with Freundlich model (R2=0.91－0.98). The enthalpy change of adsorption process is less than 0 (ΔH<0). These indicate that the adsorption process of the system was controlled by external diffusion and internal diffusion, the adsorption substance occurred in the form of multi-molecular layer in the adsorption site, and the adsorption process is an exothermic one. The combined treatment process has not only flocculated solid suspended particles but also effectively reduced COD content in the jewelry and jade processing wastewater. It is a green treatment process for treating the jewelry and jade processing wastewater.

Keywords: The jewelry and jade processing wastewater; flocculation; adsorption; high turbidity wastewater.

ACTA MINERALOGICA SINICA Vol. 39, No. 6, 2019, page 745