Browsing by Author "Yagcioglu, Meltem"

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    Recovery of succinic acid from whey fermentation broth by reactive extraction coupled with multistage processes
    (Science Direct, 2020-06) Omwenea, Philip Isaac; Yagcioglu, Meltem; Sarihan, Zehra Betül Ocal; Karagunduz, Ahmet; Keskinler, Bülent
    Fermentative production of succinic acid (SA) from renewable resources such as whey is environmentally sustainable compared to petroleum-based synthesis. However, a major drawback of fermentation is the concurrent production of SA with byproducts such as lactic acid (LA), formic acid (FA) and acetic acid (AA). Therefore, appropriate downstream SA recovery and purification steps are significant in ensuring sustainable SA production. In this study, SA was fermented by Actinobacillus succinogenes and recovered in an integrated process consisting of ultrafiltration, vacuum distillation and reactive extraction. The extractant used was tri-n-octylamine (TOA) with 1-octanol as a diluent for both liquid-liquid (LLE) extraction and supported liquid membrane (SLM). The produced SA titer and yield was 11.16 g/L and 0.44 g/g, respectively. The steady state ultrafiltration permeate flux ranged from 31.18 to 33.42 L/m2h, and complete decolorization of the fermentation broth was achieved with 10 % (w/v) of powdered activated carbon. The extraction efficiency for LLE was 51.5 %, whereas SLM achieved 57.3 % recovery. SA exhibited transport and permeability coefficient of 0.00697 h−1 (R2 > 0.92) and 0.08605 cm h−1, respectively. Extraction of SA tremendously decreased as the aqueous pH was increased from 2 to 5. In SLM, initial SA flux was calculated as 9.65 g/m2h and doubled that of lactic acid. Selective extraction of only SA was not achieved; however, residue biological material and macromolecular substances were effectively removed. Herein, we clearly demonstrated that process integration applied in reactive extraction is a promising approach for recovery of SA from fermentation broth.
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    Treatment of organized industrial zone wastewater by microfiltration/reverse osmosis membrane process for water recovery: from lab to pilot scale
    (Science Direct, 2020-09-21) Ozbey-Unal, Bahar; Omwene, Philip Isaac; Yagcioglu, Meltem; Balcik-Canbolat, Çigdem; Karagunduz, Ahmet; Keskinler, Bulent; Dizge, Nadir
    The global increase in industrialization has resulted into water scarcity. Research on water use efficiency and water reclamation is paramount in addressing this scarcity. In this study, laboratory and on-site pilot scale tests were conducted for water recovery from an industrial wastewater treatment plant. Different RO membranes (BW30, HP, and LE) were investigated with chemical treatment and ceramic microfiltration (MF) as pretreatment steps. Laboratory studies were conducted in dead-end filtration mode, whereas pilot scale studies were performed in cross flow mode with two spiral wound membranes. The removal efficiencies ranged from 40.0-86.3% for COD, 97.6- 99% for SO42-, 69.2-94.9% for Cr ion, 89.3-100% for Pb ion, 66.3-98.2 for Fe ion, 97.5- 99.7% for Zn ion, 95.1-99.5% for Si ion, and 79.1-100% for total phosphorus (TP). For the laboratory studies with 80% water recovery, the permeate flux reduced from 27.2 to 7.1 L/m2h, 35.7 to 1.3 L/m2h and 25.6 to 0.8 L/m2h for BW30, LE, and HP, respectively. On the other hand, four different operation modes were investigated to determine the effect of each mode on membrane performance and fouling properties. Average permeate flux of 18.7 and 21.3 L/m2h, 12.7 and 12.8 L/m2h, 13.4 and 14.6 L/m2h, 12.5 and 14.1 L/m2h were recorded for LE and BW30 membranes in the first, second, third, and fourth modes, respectively. Membrane autopsies were performed by atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-rays (EDX). The system was effective in recovering the permeate to required industrial cooling and boiler water quality.