Cyanide removal from industrial praziquantel wastewater using integrated coagulation-gas-filled membrane absorption

摘要

Gas-filled membrane absorption has been used to remove cyanide from different cyanide containing wastewaters.In this study,cyanide removal from an industrial praziquantel wastewater has been investigated.The wastewater contained a high cyanide concentration and turbidity due to the presence of lipophilic colloids.During cyanide removal,the membrane was severely fouled by these lipophilic colloids.In order to overcome membrane fouling,an integrated coagulation-gas-filled membrane absorption process is proposed.Coagulation is used to remove the lipophilic colloids before cyanide removal in the subsequent gas-filled membrane absorption step.By using this integrated process,the turbidity of the wastewater was decreased from 100-800 NTU to 10-40 NTU.Further the cyanide concentration was reduced from 1000-3500 mg/L to below 0.5 mg/L.More than 98% of the cyanide could be recovered and reused.