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Title:	Nanofiltration separation process using modified nanoporous membrane for concentrated succinate recovery from fermentation broth
Authors:	Nadiah Khairul Zaman (P78154)
Supervisor:	Rosiah Rohani, Dr.
Keywords:	Membrane separation Succinic acid Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	14-Feb-2019
Description:	Nanofiltration (NF) Membrane is known as green technology with promising mechanism for effective salt separation of similar physicochemical properties. The flexibility of tailoring membrane properties has made it of high desirability to be further explored. In this study, a newly fabricated and modified polyimide (PI) membrane was introduced as an alternative to the commercial NF membranes for the recovery of concentrated succinate from fermentation broth, which has yet to be reported in the field of organic acid separation. This study involved investigating i) the effect of neat PI fabrication (polymer concentration and membrane thickness) and process parameters (feed concentration, pressure, stirring speed and concentration ratio) on succinate rejection and selectivity performances, ii) the membrane properties and performance with respect to few commercial membranes (NF1, NF2 and NF270) and iii) the effect of adding graphene oxide (GO) (of 0 - 3.5 wt%) and ethylenediamine (EDA) (at different crosslinking time between 0 - 2 h cross-linking) via blending and cross-linking, respectively, on the membrane performance. Response Surface Methodology (RSM) was also used to evaluate the effect of fabrication and process factors on the performance of the cross-linked membrane. The three factors set for the Box-Behnken design include different; (i) cross-linking time (0, 1, 2 h), (ii) membrane evaporation time (30, 45, 60 s) and (iii) feed concentration (10, 30, 50 g/L). Model solutions consisting of succinate, formate and acetate and Oil Palm Frond (OPF)-juice based fermentation broth were used throughout the study. For the characterization purposes, salt rejections, and various analytical tests were utilized. Based on the findings, 20 wt% PI membrane with 150 μm thickness was successfully fabricated in NF range with succinate rejection of 85 % at filtration pressure of 30 bar. Membrane also shows improved separation factor (SF) of succinate by 20 -50 % at increasing stirring speed from 300 -500 rpm and increasing ratio of succinate with respect to by-products. The PI membrane also demonstrated comparable performance as to the commercial membranes. However at increasing feed concentration from 20 to 50 g/L, a trade-off in membrane rejection and selectivity was observed. This has led to the incorporation of GO into the membrane matrix, which in the presence of GO, membrane exhibited enhanced hydrophilicity. 0.9 wt% PI/GO membrane concentration exhibited the best performance with only slight reduction in Na2SO4 rejection (> 98%) when concentration was increased from 5 to 150 mM. In contrast neat PI membrane exhibited 16% reduction in rejection. For long time application of real fermentation broth, EDA-modified PI/GO membrane was utilized. Optimization with RSM showed that the cross-linking time and feed concentration have significant effects on succinate rejection and selectivity. The membrane exhibited reasonably high succinate rejection of 86% and SF of 0.34 and 0.21 for succinate/formate and succinate/acetate, respectively. Low fouling tendency was also observed with Flux Recovery Ratio (FRR) of nearly 96 %. In conclusion, the modified-PI NF membrane has shown a great potential for the recovery of bio-based succinate. The modification of PI membrane with GO and EDA allows membrane to be utilized in concentrated solution without compromising the membrane rejection and selectivity performance.,Ph.D.,Certification of Master's / Doctoral Thesis" is not available"
Pages:	254
Call Number:	TP248.25.M46N345 2019 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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