Coskun Aydiner

Biodiesel production from sunflower, soybean, and waste cooking oils by transesterification using lipase immobilized onto a novel microporous polymer.

This study aims at carrying out lipase-catalyzed synthesis of fatty acid methyl esters (biodiesel) from various vegetable oils using lipase immobilized onto a novel microporous polymeric matrix (MPPM) as a low-cost biocatalyst. The research is focused on three aspects of the process: (a) MPPM synthesis (monolithic, bead, and powder forms), (b) microporous polymeric biocatalyst (MPPB) preparation by immobilization of lipase onto MPPM, and (c) biodiesel production by MPPB. Experimental planning of each step of the study was separately carried out in accordance with design of experiment (DoE) based on Taguchi methodology. Microporous polymeric matrix (MPPM) containing aldehyde functional group was synthesized by polyHIPE technique using styrene, divinylbenzene, and polyglutaraldehyde. Thermomyces lanuginosus lipase was covalently attached onto MPPM with 80%, 85%, and 89% immobilization efficiencies using bead, powder, and monolithic forms, respectively. Immobilized enzymes were successfully used for the production of biodiesel using sunflower, soybean, and waste cooking oils. It was shown that immobilized enzymes retain their activities during 10 repeated batch reactions at 25 degrees C, each lasting 24h. Since the developed novel method is simple yet effective, it could have a potential to be used industrially for the production of chemicals requiring immobilized lipases.

Investigation of process performance and fouling mechanisms in micellar-enhanced ultrafiltration of nickel-contaminated waters.

Nickel removal from aqueous solution by micellar-enhanced ultrafiltration (MEUF) with relatively low transmembrane pressures was investigated at varying conditions of sodium lauryl ether sulfate (SLES) and nickel concentrations, transmembrane pressure and sodium chloride content. Process employed in continuous filtration mode, could be operated within a short time of 30 min presenting high rejection of nickel and SLES at high transient fluxes. Under the effect of increasing transmembrane pressure, the rejection of nickel and SLES increased, but the transient flux decreased. The existence of salt caused to decrease both rejections and flux. Nickel rejection, SLES rejection and flux were established as 98.6%, 75.7% and 0.304 m(3)/m(2)h, respectively, for the conditions of surfactant to metal (S/M) ratio of 10 (SLES = 2 mM), transmembrane pressure of 250 kPa without NaCl content at the end of 90-min operation time. The analyses related to the membrane fouling were carried out using adsorptive fouling models. It has been determined that, the fouling occurs as a dynamic function of various process conditions studied, and depends strongly on mechanisms controlled by the formation of gel layer and its bridging over the pore entrances simultaneously together with partial constriction of membrane pores by surfactant adsorption.

Techno-economic investigation of water recovery and whey powder production from whey using UF/RO and FO/RO integrated membrane systems

AbstractAs a by-product of dairy industry with high pollutant capacity, uncontrolled discharges of cheese whey result in serious pollution problems in the environment. Besides, recovery of water and whey powder in a whey stream has come to the fore as an important one of whey control strategies in environmental pollution. In that sense, the feasibility of water recovery and whey powder production from whey using integrated membrane processes was techno-economically investigated in this study. The study was focused on three case studies including different process scenarios were executed with laboratory-scale experiments in order to determine the technical performances of processes. The process scenarios were selected as following: the ultrafiltration/reverse osmosis (UF/RO), the forward osmosis/reverse osmosis (FO/RO) with NaCl draw solution and forward osmosis/reverse osmosis including thermolysis (FO/T/RO) at 60°C for concentrating NH4HCO3 draw solution. The real-scale costs for the processes were estim...

Water recovery from treated urban wastewater by ultrafiltration and reverse osmosis for landscape irrigation

Techno-economic feasibility of water recovery from secondary effluents of an urban wastewater treatment plant (WWTP) for landscape irrigation was investigated considering two distinctive strategies: ultrafiltration (UF)/chlorination and UF/reverse osmosis (RO). Experimental performance evaluations were conducted separately for UF membranes and for different RO trans-membrane pressures. The quality of the effluent recovered by the UF/RO system was in accordance with the national and international guidelines. The produced reuse water was first class quality according to the national guideline for all parameters except sodium adsorption ratio (SAR), which can be eliminated readily by direct addition of KCl into the recovered water. Estimated field-scale costs indicated that UF/RO yielded a total cost of US

A novel implementation of water recovery from whey: “forward–reverse osmosis” integrated membrane system

12,500,000–13,600,000 with annual operating cost being US

Interrelated Analysis of Performance and Fouling Behaviors in Forward Osmosis by Ex-Situ Membrane Characterizations

482,000–533,000 at 5–20 bar. The economic estimations guaranteed reimbursement with US

Effect of pretreatment and membrane orientation on fluxes for concentration of whey with high foulants by using NH3/CO2 in forward osmosis

7,600,000–7,400,000 net present value, 0.22–0.39 year payback time, US

Kâğıt atıksularından bütünleşik membran sistemi ile su geri kazanımı ve konsantre atık minimizasyonu

0.44–0.49/m3 treatment cost, and a benefit/cost ratio of 0.57.

Adsorption of reactive dyes from aqueous solutions by fly ash: Kinetic and equilibrium studies

Abstract As a result of its emerging contribution to water recovery and clean water production, forward osmosis (FO) in integrated membrane system has recently especially been preferred by research communities on membrane science and desalination technology. In this study, the effectiveness of FO reverse osmosis (RO) integrated membrane system in whey dewatering was investigated in laboratory scale experiments in which FO and RO were utilized for whey concentration and water recovery, respectively. FO experiments were carried out at different conditions of cross-flow rate, temperature, membrane kind, membrane orientation mode, and microfiltration (MF) pretreatment. A single-step RO system was applied for water recovery from the FO draw solution. In the FO process, about 1.6 L water of 3 L whey was withdrawn into 3 M NaCl draw solution during 6 h operating time, and a sufficiently high performance in whey concentration was obtained, with the solid content being increased from 6.8 to 14.3%. However, the pro...

Treatment of potato chips manufacturing wastewater by electrocoagulation

In membrane processes, flux decline takes place as an inherent result of membrane fouling that varies with specificity in their implementations. The membrane fouling having uncontrollable or unexplainable complexity in many cases leads to somewhat loss of process efficiency which results mainly in costly pretreatment, higher operating pressure requirement, limited recoveries, feed water loss, frequent chemical cleaning and short lifetimes of membranes as the factors increasing the water and energy costs (Aydiner, 2010, as cited in Tu et al., 2005; Hoek et al., 2008; Van der Bruggen et al., 2008). In recent years, more economical operation of membrane processes is to be taken into account based on lower energy and membrane costs in practice. At this point, understanding the reasons lying under the fouling phenomena as related with a membrane’s performance is to be rather valuable task in terms of scientific and technological developments of these processes (Danis & Aydiner, 2009). However, non-generalization course of the fouling during a membrane filtration necessitates the use of either modeling tools or specific analyses for clarifying meaningful performance-fouling relationships in each specific application. The modeling solutions are widely utilized not only to expose these relations but to put forward performance dynamics intended for a main aim of systematic representation and reasoning. A specific modeling study for lab-scale researches mostly results in simulation deficiencies or key limitations in attainment of a definitive solution when compared to that for realworld implementations. As a matter of fact, the development of simple, accurate and effective models needs to produce a solution relying on a “solution-directed focus” approach which includes full-scale consideration of theoretical and practical issues of the events. But, it is explicit that successive synchronization of model assemblies with real-time could not be entirely accomplished by the community of membrane scientists and technologists at this time. In that sense, it can be said that specific membrane analyses based on either in-situ or ex-situ characterizations could be foreseen as a progressive tool on the purpose of obviating interruption or non-coordination of transition among small and large