P.T.P. Aryanti

LTA zeolite membranes: current progress and challenges in pervaporation

Linde Type A (LTA) zeolite-based membranes have demonstrated excellent selectivity in pervaporation due to their unique structural framework and interaction with water. The development of LTA zeolite membranes for commercial application is limited by some parameters, particularly the complexity of the membrane preparation required to produce reproducible defect-free membranes and the high costs required for the membrane materials. In addition, the high content of Al in the zeolite framework makes the LTA zeolite membrane unsuitable for acidic conditions. A number of modification techniques have been proposed to produce a thin, defect-free, and high permselectivity LTA zeolite membrane with high reproducibility. Two major approaches are generally used to produce defect-free zeolite membranes, i.e. modifying either the seeding step or the synthesis process. Since the self-supported zeolite membrane has low mechanical stability, the LTA zeolite membrane is usually synthesized on an inorganic support to give better properties. Zeolite membrane costs can be reduced by several methods such as replacing the support, manufacturing a higher flux zeolite membrane, and fabricating a polymer–zeolite membrane. One should consider, however, that changing the support can dramatically influence and even reverse the obtained separation behavior. Despite various techniques used to prepare dense LTA zeolite membranes, a facile mass production technique with a highly reproducible result remains a significant challenge. To present a clear background for LTA zeolite and its performances in pervaporation, this paper includes a brief discussion on the recent trends related to LTA zeolite membranes. Some topics are discussed, including the features inherent to LTA zeolite, the transport phenomena in zeolite structures, preparation methods of LTA zeolite membranes, and the challenges associated with preparation. Furthermore, critical issues related to LTA zeolite membranes in pervaporation will be discussed to develop the topic further.

The role of ion-exchange membrane in energy conversion

Ion-exchange membrane (IEM) may play an important role in the future of electrical energy generation which is considered as renewable and clean energy. Fell cell (FC) is one of the promising technologies for solving energy issues in the future owing to the interesting features such as high electrical efficiency, low emissions, low noise level, and modularity. IEM-based processes, such as microbial fuel cell (MFC) and reverse electrodialysis (RED) may be combined with water or wastewater treatment into an integrated system. By using the integrated system, water and energy could be produced simultaneously. The IEM-based processes can be used for direct electricity generation or long term energy storage such as by harnessing surplus electricity from an existing renewable energy system to be converted into hydrogen gas via electrolysis or stored into chemical energy via redox flow battery (RFB). In this paper, recent development and applications of IEM-based processes in energy conversion are reviewed. In add...

Determination of thermodynamic properties of polysulfone/PEG membrane solutions based on Flory-Huggins model

Flory-Huggins (F-H) model was used to study thermodynamic properties of polysulfone-based membrane solution that consists of water, dimethylacetamide (DMAC), polysulfone (PSf), and polyethylene glycol (PEG400). The thermodynamic properties of membrane solution were examined based on equilibrium composition in a ternary diagram of the membrane system, which known as binodal curve. The binary interaction parameters of each component in F-H model were predicted based on cloud point experiment at various PSf and PEG400 concentrations and used to calculate the binodal curve in ternary diagram. It was obtained that the binary interaction parameters in the membrane solution are: X13 (water–PSf) = 6.76, g14 (water–PEG400) = 0.51, g23 (DMAc–PSf) = 0.46, g24 (DMAc–PEG400) = 0.46, and g34 (PSf–PEG400) = −0.53. Based on the thermodynamic analysis in the ternary diagram, low solubility of membrane solution was achieved when 20 wt% of PSf was blended with a high concentration of PEG400 (20–30%). It means that the membr...

Membrane-based zero-sludge palm oil mill plant

Abstract The palm oil industry is one of the most important agro-industries for tropical countries because of the unique properties and wide range of uses of palm oil for various end products. In a palm oil extraction process, a large quantity of water is required, of which half the quantity will end up as effluent. This palm oil mill effluent (POME) has an extremely high content of organic matter, which can cause severe pollution of waterways and other environmental problems. Disposal of this highly polluting effluent has become a major problem for the palm oil mills. Therefore, several methods have been proposed either to treat the POME so it could comply with environmental regulation while discharged or to recover water and other valuable components from the effluent. Membrane technology has emerged as a feasible alternative to conventional treatment in vegetable oil processing because of its attractive features such as low energy consumption, reduction in the number of processing steps, high separation efficiency, and improvement of the final product quality. In the case of POME treatment, an integrated membrane-based process promises efficient water recycling and total solid recovery from the effluent, thus eliminating the environmental problem. Recently, a novel concept combining oil–oil extraction and continuous filtration using a superhydrophobic membrane has been proposed to achieve a zero-sludge palm oil mill. In this concept, the huge wastewater effluent generated from the conventional process can be eliminated and the palm oil milling process simplified. Furthermore, the superhydrophobic membrane enables the production of high-purity palm oil. In this paper, we review the prospect of a zero-sludge palm oil mill concept and strategies to achieve the proposed concept. In addition, we also highlight the development of the superhydrophobic membrane and phytonutrient recovery.

Recent progress and challenges in membrane-based O2/N2 separation

Abstract Compared with current conventional technologies, oxygen/nitrogen (O2/N2) separation using membrane offers numerous advantages, especially in terms of energy consumption, footprint, and capital cost. However, low product purity still becomes the major challenge for commercialization of membrane-based technologies. Therefore, numerous studies on membrane development have been conducted to improve both membrane properties and separation performance. Various materials have been developed to obtain membranes with high O2 permeability and high O2/N2 selectivity, including polymer, inorganic, and polymer-inorganic composite materials. The results showed that most of the polymer membranes are suitable for production of low to moderate purity O2 and for production of high-purity N2. Meanwhile, perovskite membrane can be used to produce a high-purity oxygen. Furthermore, the developments of O2/N2 separation using membrane broaden the applications of oxygen enrichment for oxy-combustion, gasification, desulfurization, and intensification of air oxidation reactions, while nitrogen enrichment is also important for manufacturing pressure-sensitive adhesive and storing and handling free-radical polymerization monomers.

The effect of polymer concentration on flux stability of polysulfone membrane

The influence of various polymer concentrations on flux stability of polysulfone membranes was investigated. The polysulfone membrane was prepared by blending polysulfone in DMAc with 25%wt concentration of PEG400 and 4% wt concentration of acetone. It was found that the pure water flux was sharply decreased from 1230 to 7 Lm-2h-1, when the polysulfone concentration was increased from 14% to 24%wt. Furthermore, the increase of polysulfone concentration also affects the fouling behavior of the membranes, in which almost of 90% of FRR was achieved by the addition of 18 %wt of polysulfone concentration. It was suggested that fouling formed on the membrane surface was dominated by reversible fouling, thus it could be easily cleaned by flushing method. In addition, the applied transmembrane pressure (TMP) also plays an important role in fouling behavior of polysulfone membrane. It was observed that irreversible fouling of organic matter was deteriorated by the increase of TMP, which contributed to the reduction of water flux. More stable membrane flux performance was achieved although it was operated at high TMP, when 20% wt concentration of polysulfone was added into membrane solution.The influence of various polymer concentrations on flux stability of polysulfone membranes was investigated. The polysulfone membrane was prepared by blending polysulfone in DMAc with 25%wt concentration of PEG400 and 4% wt concentration of acetone. It was found that the pure water flux was sharply decreased from 1230 to 7 Lm-2h-1, when the polysulfone concentration was increased from 14% to 24%wt. Furthermore, the increase of polysulfone concentration also affects the fouling behavior of the membranes, in which almost of 90% of FRR was achieved by the addition of 18 %wt of polysulfone concentration. It was suggested that fouling formed on the membrane surface was dominated by reversible fouling, thus it could be easily cleaned by flushing method. In addition, the applied transmembrane pressure (TMP) also plays an important role in fouling behavior of polysulfone membrane. It was observed that irreversible fouling of organic matter was deteriorated by the increase of TMP, which contributed to the reductio...