오는 3월 15일 금요일 재미한인과학기술자협회 (KSEA) 기술 세미나가 계획되어 있습니다!

KSEA 학술세미나의 행사목적은 발표하시는 분의 연구 분야에 대해서 좀 더 친숙해 지고, 또한 맛있는 저녁 식사와 함께 멤버간 좋은 네트웍을 쌓을 수 있는 기회로 삼을 수 있는 행사입니다.

당일 세미나 뿐만 아니라 맴버쉽 가입과 리뉴얼도 진행할 예정이니 새로 멤버쉽을 가입하시고자 하시는 분들은 꼭 참석하시여 해택을 받으시기 바랍니다.

Time and Date: 6:30 PM, Friday, March 15, 2019
Place: Neural Molecular Science Building, Room 1.120., University of Texas, 2506 Speedway, Austin


Speaker: Soyoon Kum, Ph.D. candidate, Civil, Architectural and Environmental Engineering, The University of Texas at Austin

 

Title: A Hybrid (ED-NF) Membrane System to Remove NOM and Reduce DBPs

Soyoon Kum*, Desmond F. Lawler, Lynn E. Katz

Natural organic matter (NOM) complicates virtually all water treatment processes. Of particular import is that NOM reacts with disinfectants to form disinfection byproducts (DBPs) that increase the risk of cancer. Removal of NOM prior to disinfection reduces DBPs, but the conventional treatment (enhanced coagulation) rarely removes more than 40%. Nano-filtration (NF) can remove more than 80% of NOM, but fouling by NOM is extensive, especially in the presence of divalent cations. Therefore, the temporary removal of divalent cations prior to NF could improve performance. Ion removal can be accomplished by electrodialysis (ED); ED removes ions by passing electric current across alternating pairs of cation and anion exchange membranes, but achieves little separation of NOM because of the slow diffusivity of NOM. The hybrid membrane system developed in this research takes advantage of these characteristics of NF and ED. ED removed most inorganic ions while achieving minimal removal of NOM. Then the diluate from ED, containing NOM at nearly the original concentration but few inorganic ions was treated by NF. Subsequently, the small volume of ED concentrate and the large volume of NF permeate were combined to yield a water with nearly the original ion concentration but dramatically lowered NOM. Disinfection of the resulting water would result in very low DBP concentrations. The objective of this study was to develop a thorough understanding of the removal characteristics of NOM and ions in both ED and NF; a matrix of conditions were evaluated including different ED and NF membranes, different sources of NOM (Suwannee River NOM (SRNOM) and Leonardite Humic Acid (LHA)), and different solution conditions (ion makeup and concentration).

All ED membrane pairs achieved excellent removal of inorganics in NOM-containing water. NOM did not pass through the ED membranes (as desired) but the different membrane pairs had remarkably different affinity for NOM. Of the three membrane pairs tested, the CMX/AMX pair had less than 5% loss of either NOM tested whereas both other sets had significantly higher adsorptive loss (7% of SRNOM and 16% of LHA for PCSK/PCSA; 38% of SRNOM and 27% of LHA for CR67-HMR/AR204-SZRA). The CMX/AMX membrane pair was also easily cleaned. Therefore, the CMX/AMX were determined to be the appropriate ED membranes for the hybrid system. NF 90 and NF 270 membranes both removed more than 90% of NOM from feed solutions, but NF 90 showed less fouling.  The reduced fouling resulting from incorporation of ED allowed the NF system to maintain high fluxes for extended periods. Results to date are very promising, with >80% NOM and <20% inorganic ions removal, and approximately 95% water recovery.