摘要
As a novel electric demulsification method,bidirectional pulsed electric field(BPEF)was employed to demulsify the surfactant stabilized oil-in-water(SSO/W)emulsion for oil/water separation in this work.The demulsification behavior,characteristics,and stages under BPEF were explored.It was discovered that BPEF drove SSO/W emulsion to move and form vortexes,during which the oil droplets aggregated and accumulated to generate an oil droplet layer(ODL).ODL subsequently transformed into a continuous oil layer(COL)leading to the demulsification and separation of SSO/W emulsion.The conversion rate of ODL to COL was defined and used to evaluate the demulsification process and reflect the coalescence ability and transformation efficiency of dispersed oil droplets into COL.Furthermore,the effects of BPEF voltage,frequency,duty cycle,ratio of pulse output time,and surfactant type and content on the demulsification performance were examined.The optimal values of BPEF parameters for demulsification operation were 400 V,25 Hz,50%,and 4:1.O/W emulsion containing anionic surfactant was apt to be demulsified by BPEF,nonionic surfactant took the second place and cationic surfactant was the most difficult.A high surfactant content was not conducive to the BPEF demulsification.This work is anticipated to provide useful guidance for oil/water separation and oil recovery from actual emulsified oily wastewater by BPEF.
基金
Scientific Platform Project of the Ministry of Education(fykf201907)
the Postdoctoral Science Foundation Project of the Natural Science Foundation of Chongqing Municipality(cstc2021jcyjbshX0194)
Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202100820 and KJZD-K201900804)
Science and Technology Innovation Project of the Construction of the Chengdu-Chongqing Economic Circle of Chongqing Municipal Education Commission(KJCX2020036)
Scientific Research Project of Chongqing Technology and Business University(2152016 and 2056006)
Chongqing Technical Innovation and Application Project(cstc2019jscx-msxmX0275).
