Recovery of silk sericin from the filature wastewater by using a novel foam fractionation column

Silk industry was an important mainstay of Asian textile industry. However, a large volume of filature waste water is produced during the cocoon cooking step and it might lead to severe environment pollution without effective treatment. In fact, the wastewater contained an important and valuable protein, silk sericin. In this work, foam fractionation was purposed to recover silk sericin (SS) from the filature wastewater. A novel column with groined internal component (GIC) was developed for strengthening foam fractionation at room temperature. Compared with the control column, the collected foam from the experimental column possessed of a low liquid holdup because the low gas-liquid weakened the viscous effect caused by the rising velocity of the bubbles, when the rising foam passed through the corner channels creased by GIC. Under the suitable operating conditions of pH 4.0, length of GIC 400 mm, volumetric air flow rate 200 mL/min and pore diameter of gas distributor 180 gm, the enrichment ratio and the recovery percentage of SS reached 6.77 and 80.29%, respectively. This work is expected to provide a cost-effective technique to recover SS from the filature wastewater, and to facilitate the industrialization of foam fractionation in wastewater treatment.