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Journal : Reaktor

COMBINATION OF REVERSE OSMOSIS AND ELECTRODEIONIZATION FOR SIMULTANEOUS SUGAR RECOVERY AND SALTS REMOVAL FROM SUGARY WASTEWATER I.N. Widiasa; I Gede Wenten
Reaktor Volume 11, Nomor 2, Desember 2007
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (216.327 KB) | DOI: 10.14710/reaktor.11.2.91-97

Abstract

An integrated membrane system combining reverse osmosis (RO) and electrodeionization (EDI) is used for simultaneous sugar concentration and salts removal from a synthetic dilute sugar solution as a model of sugar-containing wastewater. The RO system uses a thin film composite RO membrane (Saehan CSM, RE1812-60). Meanwhile, the EDI stack has two diluted compartments, one concentrated compartment, one anode compartment, and one cathode compartment. Commercially available cation exchange membrane (MC-3470) and anion exchange membrane (MA-3475) are used as ionic selective barriers of the EDI stack. Both diluate and concentrate compartments are filled with mixed ion exchange resins (purolite strong acid cation exchange, C-100E and strong base type I anion resins, A-400). Two different operation modes, i.e. RO-EDI and EDI-RO, were assessed. The experimental results show that the observed sugar rejection of RO membrane is more than 99.9% and there is no sugar loss in the EDI stack. This indicates that the hybrid process allows almost total sugar recovery. In addition, significant reduction of salts content from the concentrated sugar solution is obtained. From permeate flux and permeate purity points of view, however, the EDI-RO configuration seems superior to the RO-EDI configuration. It should be emphasized that scale formation on the membrane surface of the concentrate compartment side has to be controlled.
PERFORMANCE OF NEWLY CONFIGURED SUBMERGED MEMBRANE BIOREACTOR FOR AEROBIC INDUSTRIAL WASTEWATER TREATMENT I Gede Wenten
Reaktor Volume 12, Nomor 3, Juni 2009
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (270.034 KB) | DOI: 10.14710/reaktor.12.3.137 – 145

Abstract

The application of membrane to replace secondary clarifier of conventional activated sludge, known as membrane bioreactor, has led to a small footprint size of treatment with excellent effluent quality. The use of MBR eliminates almost all disadvantages encountered in conventional wastewater treatment plant such as low biomass concentration and washout of fine suspended solids. However, fouling remains as a main drawback. To minimize membrane fouling, a new configuration of submerged membrane bioreactor for aerobic industrial wastewater treatment has been developed. For the new configuration, a bed of porous particle is applied to cover the submerged ends-free mounted ultrafiltration membrane. Membrane performance was assessed based on flux productivity and selectivity. By using tapioca wastewater containing high organic matter as feed solution, reasonably high and stable fluxes around 11 l/m2.h were achieved with COD removal efficiency of more than 99%. The fouling analysis also shows that the newly configured ends-free membrane bioreactor exhibits lower irreversible resistance compared with the submerged one. In addition, the performance of pilot scale system, using a membrane module  with 10 m2 effective area and reactor tank with 120 L volume, was also assessed. The flux achieved from the pilot scale system around 8 l/m2.h with COD removal of more than 99%. Hence, this study has demonstrated the feasibility of the newly configured submerged ends-free MBR at larger scale.
NON-DISSOLVED SOLIDS REMOVAL DURING PALM KERNEL OIL ULTRAFILTRATION Mubiar Purwasasmita; Petrus Benny Juwono; Aysha Mareta Karlina; Khoiruddin Khoiruddin; I Gede Wenten
Reaktor Volume 14, No. 4, OKTOBER 2013
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (300.96 KB) | DOI: 10.14710/reaktor.14.4.284-290

Abstract

Performance of polypropylene hollow fiber ultrafiltration membrane during non-dissolved solids (NDS) removal from palm kernel oil is investigated. The filtration is operated at difference feed temperature and pressure to study the effect of both parameters on membrane performance. From the experimental results, it can be concluded that polypropylene hydrophobic hollow fiber membrane can be used for palm kernel oil NDS removal. Temperature and trans-membrane pressure have proportional effect to permeate flux. In contrast, they have inverse effect to rejection of NDS. During the experiment, permeate fluxes and rejections of NDS varied from 3.4 to 8.7 L/m2.h and from 51% to 94%, respectively. The best operating conditions suggested are feed temperature of 30°C and TMP of 1 bar which produce the highest NDS rejection. In addition, the permeate quality can meet the requirement of standard NDS content even at its lowest rejection level which shows the remarkable performance of membrane filtration.
SACCHARIFICATION OF NATIVE CASSAVA STARCH AT HIGH DRY SOLIDS IN AN ENZYMATIC MEMBRANE REACTOR I Nyoman Widiasa; I Gede Wenten
Reaktor Volume 12, Nomor 3, Juni 2009
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (217.143 KB) | DOI: 10.14710/reaktor.12.3.129 – 136

Abstract

This study is aimed to develop a novel process scheme for hydrolysis of native cassava starch at high dry solids using an enzymatic membrane reactor (EMR). Firstly, liquefied cassava starch having solids content up to 50% by weight was prepared by three stage liquefactions in a conventional equipment using a commercially available heat stable a-amylase (Termamyl 120L). The liquefied cassava starch was further saccharified in an EMR using glucoamylase (AMG E). By using the developed process scheme, a highly clear hydrolysate with dextrose equivalent (DE) approximately 97 could be produced, provided the increase of solution viscosity during the liquefaction was precisely controlled. The excessive space time could result in reduction in conversion degree of starch. Moreover, a residence time distribution study confirmed that the EMR could be modelled as a simple continuous stirred tank reactor (CSTR). Using Lineweaver-Burk analysis, the apparent Michaelis-Menten constant (Km) and glucose production rate constant (k2) were 552 (g/l) and 4.04 (min-1), respectively. Application of simple CSTR model with those kinetic parameters was quietly appropriate to predict the reactor’s performance at low space time.
Heterogeneous Polypropylene-Based Cation-Exchange Membrane Modified by Functionalized Zinc Oxide Particles for Vanadium Redox Flow Battery Khoiruddin, Khoiruddin; Firmansyah, Rizky W.; Yulanda, Nanda; Wardani, Anita K.; Wenten, I Gede
Reaktor Volume 24 No.2 August 2024
Publisher : Department of Chemical Engineering, Faculty of Engineering, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/reaktor.24.2.58-67

Abstract

This work presents the synthesis and characterization of heterogeneous cation-exchange membranes based on polypropylene (PP) and cation-exchange resin (IER) powder, developed via melt spinning. The membranes were modified with zinc oxide (ZnO) nanoparticles functionalized with polydopamine (PDA) to enhance their electrochemical properties. The effects of varying IER content and ZnO/PDA loading on key membrane properties, including ion-exchange capacity (IEC), water uptake (WU), water contact angle (WCA), proton conductivity, water permeability, and vanadium permeability, were systematically investigated. The results demonstrated that increasing IER content improved proton conductivity and IEC, but also increased vanadium permeability. The PP/ZnO-PDA (Z-2.5) membrane, with 2.5%-wt. ZnO/PDA, showed reduced water permeability (0.46 L·m⁻²·h⁻¹·bar⁻¹) and vanadium permeability (5.67 × 10⁻⁵ cm² min⁻¹), while maintaining moderate proton conductivity (13.17 mS/cm). However, increasing ZnO/PDA content beyond 2.5%-wt. led to declines in WU, IEC, and proton conductivity, likely due to nanoparticle aggregation reducing access to ion-exchange sites.