Polyaniline composite membranes synthesis in presence of various acid dopants for pressure filtration

Polyaniline is a conductive polymer that is recently used as a material in producing a pressure filtration membrane. Polyaniline can be doped in various acids as dopants of different sizes and shapes to modify its inherent properties to produce membrane with high flux and rejection. This work is aimed to fabricate polyaniline composite membrane in presence of different acids as dopants namely hydrochloric acid, maleic acid, poly(methyl vinylether) acid (PMVEA) and polyacrylic acid (PAA). This polyaniline was coated onto microporous polyvinylidene fluoride (PVDF) support by using a specially fabricated two compartment cell. The field emission scanning electron microscope (FESEM) results show that the morphology of the coated polyaniline on PVDF membrane support is in globular shapes, which elongates at different sizes depending to the acid used. From the thermal analysis, the melting point of polyaniline coated PVDF membrane remains at 260°C, similar as obtained in the pristine microporous PVDF indicating no thermal change upon polyaniline coating. From all membranes prepared, the doped polyaniline membrane possessed a good conductivity value except for polyaniline-PMVEA membrane, which has the lowest value. In terms of the membrane filtration performance, which was measured based on the flux of pure water and polyethylene glycol (PEG) rejection, polyaniline-PMVEA membrane has a high flux and the highest PEG rejection. This result indicates that the conductivity does not influence much on the membrane filtration performance, but rather due to the physical coating itself. Different acid dopants present during polyaniline coating will lead to different filtration performance

Comprehensive evaluation of the integrated membrane contactor-microalgae photobioreactor system for simultaneous H2 purification and CO2 treatment from biomass fermented gases

Biohydrogen (H2) has been identified as a potential renewable energy source to substitute energy-based fossil fuel that can be produced from biomass fermentation. However, carbon dioxide (CO2) is also commonly present in the biogas mixture and must be properly treated as it could contribute to the climate change phenomenon. In this study, an integrated membrane contactor-microalgae photobioreactor system is applied to allow simultaneous H2/CO2 treatment from biomass fermented biogases. A comprehensive evaluation of the effectiveness of the integrated system was investigated by screening the essential operating parameters of the system using One Factor at a Time (OFAT) technique followed by optimization Response Surface Methodology (RSM). Serial investigations of the process parameters, the optimum condition was at a pH of 10 with gas and liquid flow rates at the respective levels of 0.1 L/min and 0.5 L/min, while the microalgae concentration was 0.6 g/L. At these optimum conditions, the H2 purity was found to have increased remarkably, from 69.4% to 83.2%. In a long-term separation performance using the optimized conditions, microalgae solution was found to be capable of sustaining its performance at a longer time with only 2% performance dropped observed within 540 min of the operational time. In conclusion, the use of microalgae in a membrane contactor system could be a promising technique for treating these fermented gases, in a move towards carbon neutrality

Comparison of separation performance of absorption column and membrane contactor system for biohydrogen upgraded from palm oil mill effluent fermentation

The adverse effects of ammonia found in wastewater streams lead to the development of advanced water treatment technology, i.e. membrane contactor (MC). In this study, single layer hollow fibre membrane (SLZK) and dual layer hollow fibre membrane (DLZK) were prepared from zirconia and kaolin and modified into hydrophobic membrane through simple grafting process via fluoroalkylsilane (FAS) agent. The properties of membranes such as morphology, surface roughness, mechanical strength, wettability and liquid entry pressure were analysed through scanning electron microscopy (SEM), atomic force microscopy (AFM), 3-point bending strength, contact angle and LEPw setup. Finally, the performance of the membranes was also investigated towards ammonia removal via membrane contactor system. Our findings showed that hydrophobicity properties significantly improved for both SLZK and DLZK membranes after grafting modification process as indicated by the increase of contact angle value from 5° and 1° to 132.7° and ~180.0° respectively. Based on the morphological analysis, the surface of DLZK showed more porous structure as compared to the SLZK. In addition, DLZK also displayed the highest mechanical strength and contact angle reading of 125 MPa and ~180° respectively. This suggests that the DLZK showed an excellent membrane contactor performance with highest value of mass transfer coefficient (3.77 x 10-5 ms-1) and almost complete removal of ammonia removal (91%). Overall, these results implied that dual layer ceramic membrane developed from kaolin and zirconia could provide the basis for the development of alternative ceramic membrane with excellent properties for membrane contactor system

Recent Advances for Wastewater Treatment on Polyvinylidene Fluoride-Based Membrane: A Review

The development of scalable membrane-based separation processes has attracted considerable interest on laboratory and industrial scales. Polyvinylidene fluoride (PVDF) is one of the most widely used fluoropolymer materials for membrane fabrication due to its excellent mechanical strength, good thermal stability and chemical resistance as well as aging resistance. However, the hydrophobic nature of PVDF has resulted in serious membrane fouling during the filtration process. From the past decade, the embedment of hydrophilic materials in/on PVDF-based membranes can significantly alter the membrane’s morphology and surface properties. Therefore, based on most articles retrieved from Web of Science, Scopus, Google Scholar, etc., this article provides the overview of the recent development of PVDF-based membranes during the recent several decades. The detailed information regarding PVDF as a polymer material as well as the main challenge in the development of PVDF-based membranes with better performance was summarised. Moreover, the factors influencing membrane fouling including surface hydrophilicity, roughness and charge are also addressed. Then, the PVDF-based membrane preparation and its recent modification via the blending method were discussed. Finally, the overview and future perspective of PVDF-based membrane development are reviewed. Overall, it can be concluded that PVDF-based membranes have great potential for further advances towards the development of membrane technologies for the future

A Review on Current Designation of Metallic Nanocomposite Hydrogel in Biomedical Applications

In the past few decades, nanotechnology has been receiving significant attention globally and is being continuously developed in various innovations for diverse applications, such as tissue engineering, biotechnology, biomedicine, textile, and food technology. Nanotechnological materials reportedly lack cell-interactive properties and are easily degraded into unfavourable products due to the presence of synthetic polymers in their structures. This is a major drawback of nanomaterials and is a cause of concern in the biomedicine field. Meanwhile, particulate systems, such as metallic nanoparticles (NPs), have captured the interest of the medical field due to their potential to inhibit the growth of microorganisms (bacteria, fungi, and viruses). Lately, researchers have shown a great interest in hydrogels in the biomedicine field due to their ability to retain and release drugs as well as to offer a moist environment. Hence, the development and innovation of hydrogel-incorporated metallic NPs from natural sources has become one of the alternative pathways for elevating the efficiency of therapeutic systems to make them highly effective and with fewer undesirable side effects. The objective of this review article is to provide insights into the latest fabricated metallic nanocomposite hydrogels and their current applications in the biomedicine field using nanotechnology and to discuss the limitations of this technology for future exploration. This article gives an overview of recent metallic nanocomposite hydrogels fabricated from bioresources, and it reviews their antimicrobial activities in facilitating the demands for their application in biomedicine. The work underlines the fabrication of various metallic nanocomposite hydrogels through the utilization of natural sources in the production of biomedical innovations, including wound healing treatment, drug delivery, scaffolds, etc. The potential of these nanocomposites in relation to their mechanical strength, antimicrobial activities, cytotoxicity, and optical properties has brought this technology into a new dimension in the biomedicine field. Finally, the limitations of metallic nanocomposite hydrogels in terms of their methods of synthesis, properties, and outlook for biomedical applications are further discussed

Pembangunan kursus elektif bermodul bagi pelajar Sarjana Muda Kejuruteraan Kimia KOHOT 2015 - 2020: kelebihan dan cabaran

Jabatan Kejuruteraan Kimia dan Proses (JKKP), Fakulti Kejuruteraan dan Alam Bina, Universiti Kebangsaan Malaysia telah mengambil initiatif semasa semakan kurikulum 2016 untuk melaksanakan Kursus Elektif secara bermodul bagi pelajar tahun IV sejak kohot kemasukan 2015/2016 sehingga 2019/2020. Kaedah pembangunan modul yang digunakan adalah melalui penanda-arasan bersama universiti terkemuka di dalam dan luar negara, serta melalui input daripada panel penilai industri yang dilantik dan menjalankan soal selidik bersama industri berkaitan. Pembangunan modul kursus elektif ini merupakan satu langkah untuk memberikan peluang kepada pelajar untuk mengambil kursus pengkhususan kejuruteraan kimia mengikut kombinasi kursus tertentu sahaja secara lebih berfokus. JKKP telah memperkenalkan 3 modul kursus elektif iaitu bioproses, kejuruteraan sistem proses dan proses industri. Pendekatan ini mampu untuk memberi pelajar pilihan yang lebih berstruktur dalam mengikuti kursus elektif yang wajib diambil pada semester akhir pengajian mereka. Amalan ini adalah sangat berbeza dengan amalan sebelumnya yang lebih terhad dan tidak berstruktur. Di dalam kurikulum terkini ini, terdapat lebih banyak pilihan kursus yang dibangunkan mengikut acuan terkini industri di dalam bidang-bidang utama yang dikenalpasti. Kajian ini dilakukan untuk membandingkan tentang penawaran kursus elektif di peringkat jabatan dalam tempoh sebelum dan selepas semakan kurikulum dilakukan. Kemudian, minat pelajar berdasarkan pemilihan modul yang dilakukan telah diselidiki. Didapati bahawa kebanyakkan pelajar sangat cenderung untuk memilih modul proses industri, diikuti dengan kejuruteraan sistem proses dan akhir sekali bioproses. Melalui amalan ini, dapat dilihat kecenderungan minat pelajar ke arah bidang pengkhususan tertentu. Maklum balas yang positif juga diperoleh daripada pelajar di mana mereka menyatakan bahawa kursus elektifbermodul ini perlu diteruskan di masa akan datang kerana pelajar dapat menentukan halatuju kerjaya yang lebih jelas melalui pengkhususan kursus yang dipilih. Namun, terdapat beberapa cabaran yang perlu ditangani oleh jabatan bagi memupuk lebih minat pelajar kepada bidang yang kurang diminati seperti bioproses. Antaranya adalah dengan meningkatkan kualiti pengajaran dan bahan pengajaran yang digunakan serta melibatkan industri di dalam pelbagai cara untuk menerapkan minat bidang-bidang tersebut. Dengan penghasilan graduat jurusan kejuruteraan kimia dari bidang yang pelbagai serta mencukupi dipercayai mampu untuk membekalkan tenaga kerja yang kompeten di dalam era revolusi industri 4.0 (IR 4.0) kini

Chlorine decay and formation of THM in Malaysia’s water distribution system

Chlorine is a popular disinfectant used in Malaysia in the treatment process of drinking water supply because of its effectiveness. The concentration of chlorine deteriorates upon travelling in the system due to its reaction with organic matter to produce carcinogenic substances known as disinfection by-products (DBP) such as trihalomethanes (THM). This study was conducted to investigate chlorine decay and THM formation in a state's drinking water distribution system in Malaysia specifically across a 24.9 km distance. EPANET 2.0 Software program was used to perform hydraulics and water quality analysis using the extended period simulation (EPS) for 24 hours demand pattern. A simulation of the water distribution system was performed to identify the formation of THM and its relationship between chlorine and total organic carbon (TOC). The value of THM was maintained at a lower level at the water treatment plant (WTP) than at the endpoint of the distribution system. At the endpoint, which was at the targeted industrial area, the level of THM was found to increase and the obtained data showed that its formation occurred along the investigated distribution system. THM formation manifested as the natural organic matter (NOM) presence along the pipe continuously reacted with chlorine which was dosed in the distribution system

Miscible-blend polysulfone/polyimide membrane for hydrogen purification from palm oil mill effluent fermentation

The biogas produced from the anaerobic fermentation of palm oil mill effluent (POME) contains equal amount of H2 and CO2, in which the biohydrogen (bioH2) is a prospective source of renewable energy. Therefore, the determination of an efficient H2 purification technique has been a major concern. Membrane separation technology is highly recommended due to its excellent purification performance with high permeation of H2 and H2/CO2 selectivity. Polymer blending is a favourable approach due to its simplicity to refine membrane inner structural properties by combining different polymers with complementary features. In this study, the synthesized polysulfone-polyimide (PSf/PI) membrane is an alternative polymeric membrane practicable for H2/CO2 separation due to its outstanding permeation properties, enhanced membrane properties as well as improved tolerance to plasticizing gases. The effect of evaporation time on PSf/PI membranes was further investigated and was thoroughly characterized by FTIR, TGA, DSC and SEM. The miscibility of the PSf/PI blending was proven by DSC with the detection of only single glass transition temperature value. The highest permeability of both H2 and CO2 gas were presented by PSf/PI-60 membrane with 348 GPU and 86 GPU, respectively, H2/CO2 selectivity of 4.4 and H2 purification efficiency of 80%. Hence, PSf/PI membrane is a high potential candidate with inherent properties for H2/CO2 separation from POME fermentation