Ceramic hollow fiber membrane derived from palm oil fuel ash for membrane distillation

Membrane distillation (MD) is an emerging desalination technology which separates vaporized solutes from the feed solution using a hydrophobic membrane at fairly high temperature. Ceramic membranes are known to have excellent chemical and thermal stability. However, their application in MD has not been well received as compared to their polymeric counterparts due to high cost and intrinsic hydrophilicity. This study focused on the development of novel cost-effective hydrophobic ceramic hollow fiber membranes (CHFMs) from an industrial waste, palm oil fuel ash (POFA), for direct contact MD (DCMD). POFA has high silica and potassium oxide content that could endow it with lower sintering temperatures during membrane fabrication than that of the widely used alumina membranes. However, POFA also exhibits a significant amount of carbon and organic impurities that could be detrimental to the mechanical properties of CHFM. Hence, in the first stage of the study, POFA was subjected to thermal pre-treatment at temperatures of 500–1,000°C, and the effect of pre-treatment temperature on the chemical and physical properties of POFA was correlated. It was found that the carbon content of POFA was eliminated after being pre-treated at =600°C, whereas the silica content was improved to >70 wt%. Moreover, the physical properties of POFA changed with increasing pre-treatment temperatures. In the second stage of the study, the high-strength POFA-derived CHFMs were fabricated through combined phase inversion/sintering technique. It was found that the pre-treatment temperature of POFA, POFA loading, phase inversion parameters (i.e.: air gap distance, bore fluid flow rate), and sintering temperature had substantial influences on the morphology and mechanical properties of CHFM. A high-strength CHFM (98.1 MPa) was acquired at the following conditions: 700°C POFA pre-treatment temperature; 55 wt% POFA suspension loading; 5 cm air gap distance; 9 mL/min bore fluid flow rate; 1,050°C sintering temperature. To attain hydrophobic properties, the surface of the CHFM was modified via dip-coating with polymethylhydrosiloxane/tetraethylorthosilicate (PMHS/TEOS) hybrid in the third stage of the study. A novel post-coating spinning technique has been developed to facilitate the pore formation on the coating layer. The effect of the number of coating layer on the morphology of the CHFM was studied. The concentrations of ethanol and PMHS were also found to affect the surface morphology and hydrophobicity of the CHFM. High water contact angle (WCA) of 108.2° and liquid entry pressure with water (LEPw) of 1.0 bar was achieved by the CHFM modified with the following conditions: TEOS/ethanol molar ratio: 1:45; PMHS/TEOS mass ratio: 1:10; the number of coating layer: 2; with post-coating spinning. An excellent DCMD desalination performance was achieved with a salt rejection of >99.98% and flux of 4.8 L/m2h at the feed salinity of 35,000 ppm. The outcomes of this study suggest that the hydrophobic POFA-derived CHFM could be an excellent low-cost alternative for MD desalination applications

Hydrophobic ceramic membrane for membrane distillation: A mini review on preparation, characterization, and applications

Membrane distillation (MD) is one of the emerging separation technologies with extremely high separation factor, especially in desalination application. MD utilizes the hydrophobic membrane which only allows the passage of vapor through the membrane pores. Recent years have witnessed great progress in the development of hydrophobic ceramic membranes for MD applications due to their superior properties over the polymeric counterparts. However, ceramic membranes are hydrophilic in nature; hence, membrane surface modification process is required to acquire hydrophobic properties for MD applications. Direct grafting using silane agents is the most widely used ceramic membrane hydrophobization method. Hence, this mini review provides a complete summary of the research progress on the preparation and characterization of the hydrophobic ceramic membranes through silane agent grafting, as well as their applications in MD. Finally, future research directions have also been addressed

Preparation and characterization of superparamagnetic magnetite (Fe3O4) nanoparticles: a short review

Magnetic magnetite (Fe3O4) nanoparticles have attracted a great deal of attention in both fundamental research and practical applications over the past decades. Down to the nanoscale, superparamagnetic Fe3O4 nanoparticles with only a single magnetic domain exhibit high magnetic susceptibility, which provides a stronger and faster magnetic response. Their superparamagnetic properties together with other intrinsic properties such as low toxicity, high surface area-to-volume ratio and simple separation methodology, making them ideal for environmental remediation, biomedical, and agricultural applications. This review discusses three conventional wet chemical methods, including chemical co-precipitation, sol-gel synthesis and thermal decomposition for the preparation of superparamagnetic Fe3O4 nanoparticles with controlled size and magnetic properties. Nowadays, with the growing research interest in Fe3O4 nanoparticles, there is a great amount of researches reported on efficient routes to prepare size-controlled magnetic nanoparticles. Thus, this review is designed to report the recent information from synthesis to the characterization of Fe3O4 nanoparticles as well as the discussion of future perspective in this research area

Development of hydrophobic metakaolin hollow fibre membrane for membrane distillation application

Metakaolin hollow fibre membranes (MHFM) was prepared by a combined phase inversion and sintering method for direct contact membrane distillation (DCMD) application. Four hydrophobic metakaolin hollow fibre membranes (h-MHFM) sintered at different temperatures (1200ºC to 1500ºC) were successfully prepared by grafting 1H,1H,2H,2H-perfluorodecyltriethoxysilane on the MHFM. Prior to the grafting process, the MHFM was hydrolysed with a mixture of ethanol and water with the ratio of 1:2 for 24 hours. The effectiveness of the hydrophobization on each MHFM was assessed using contact angle measurement, scanning electron microscopy (SEM) and three-point bending test. It was found that the increasing sintering temperature improved the mechanical strength from 117.6 MPa to 182.3 MPa. Further increment in mechanical strength was also observed after the modification with fluoroalkylsilane (FAS). The contact angle of the membrane was enhanced up to 120˚ after modification. In general, the membrane prepared at low sintering temperature of 1200°C exhibited the highest DCMD performance with the water vapor flux of 17.5 kg/m2h due to the sufficient pore size for the vapor to pass through the membrane structure

Research in advance for FMD Novel Vaccines

Foot-and-Mouth Disease (FMD), as a major global animal disease, affects millions of animals worldwide and remains the main sanitary barrier to the international and national trade of animals and animal products. Inactivated vaccination is the most effective measure for prevention of FMD at present, but fail to induce long-term protection and content new requires for production of FMD vaccines. As a number of Researchers hope to obtain satisfactory novel vaccines by new bio-technology, novel vaccines have been studied for more than thirty years. Here reviews the latest research progress of new vaccines, summarizes some importance and raises several suggestions for the future of FMD vaccine

A highly sensitive detection for foot-and-mouth disease virus by gold nanopariticle improved immuno-PCR

<p>Abstract</p> <p>Backgroud</p> <p>Foot-and-mouth disease (FMD) is one of the most contagious of all artiodactyl animal diseases, and its infection has an obvious ability to spread over long distances and to contribute to epidemics in FMD-free areas. A highly sensitive and specific method is required to detect FMDV. In this study, we evaluated the usefulness of a bio-barcode assay (BCA) technique for detecting clinical samples of FMDV.</p> <p>Methods</p> <p>Highly sensitive gold nanopariticle (GNP) improved immuno-PCR (GNP-IPCR) which derived from the bio-barcode assay (BCA) was designed for the detection of FMDV. The target viral particles were captured by a polyclonal antibody coated on ELISA microplate, followed by adding GNP which was dually modified with oligonucleotides and a FMDV specific monoclonal antibody (MAb) 1D11 to form a sandwiched immune complex. After the formation of immuno-complex, the signal DNA was released by heating, and consequently characterized by PCR and real time PCR.</p> <p>Results</p> <p>The detection limit of GNP-PCR could reach to 10 fg/ml purified FMDV particles, and the assay can detect clinical samples of FMDV with highly sensitivity, while detect limit of conventional ELISA is 100 ng/ml in this study.</p> <p>Conclusion</p> <p>GNP-IPCR may provide a highly sensitive method for the detection of FMDV.</p

Low cost palm oil fuel ash based ceramic membranes for oily water separation

Ceramic membranes have been gaining so much interest for oily water separation due to their superior characteristics such as good anti-fouling property, superhydrophilic, as well as excellent thermal and chemical stabilities. However, ceramic membranes are very expensive which hinders their uses in large scale applications. Therefore, the aim of our study is to develop a low cost palm oil fuel ash (POFA) based ceramic hollow fiber ceramic membrane for oily water separation application. An asymmetric membrane structure consisting of sponge-like and macrovoid layers were acquired using a combined phase inversion and sintering technique. The membranes were sintered at different temperatures ranging from 1000 to 1150 °C. The sintered membranes were characterized in terms of morphology, mechanical strength, porosity, permeate flux and oil rejection performance. A high oil rejection efficiency of up to 96.0% was obtained for the membrane sintered at 1050 °C with the permeate flux of 185.42 L/m2h at the applied pressure of 3 bar. Based on the comparison with other ceramic membranes reported in the literature, it can be concluded that POFA based ceramic hollow fiber membrane showed a comparable performance and thus can be a promising low cost alternative ceramic membrane for oily water separation application

Analysis of codon usage and nucleotide composition bias in polioviruses

<p>Abstract</p> <p>Background</p> <p>Poliovirus, the causative agent of poliomyelitis, is a human enterovirus and a member of the family of Picornaviridae and among the most rapidly evolving viruses known. Analysis of codon usage can reveal much about the molecular evolution of the viruses. However, little information about synonymous codon usage pattern of polioviruses genome has been acquired to date.</p> <p>Methods</p> <p>The relative synonymous codon usage (RSCU) values, effective number of codon (ENC) values, nucleotide contents and dinucleotides were investigated and a comparative analysis of codon usage pattern for open reading frames (ORFs) among 48 polioviruses isolates including 31 of genotype 1, 13 of genotype 2 and 4 of genotype 3.</p> <p>Results</p> <p>The result shows that the overall extent of codon usage bias in poliovirus samples is low (mean ENC = 53.754 > 40). The general correlation between base composition and codon usage bias suggests that mutational pressure rather than natural selection is the main factor that determines the codon usage bias in those polioviruses. Depending on the RSCU data, it was found that there was a significant variation in bias of codon usage among three genotypes. Geographic factor also has some effect on the codon usage pattern (exists in the genotype-1 of polioviruses). No significant effect in gene length or vaccine derived polioviruses (DVPVs), wild viruses and live attenuated virus was observed on the variations of synonymous codon usage in the virus genes. The relative abundance of dinucleotide (CpG) in the ORFs of polioviruses are far below expected values especially in DVPVs and attenuated virus of polioviruses genotype 1.</p> <p>Conclusion</p> <p>The information from this study may not only have theoretical value in understanding poliovirus evolution, especially for DVPVs genotype 1, but also have potential value for the development of poliovirus vaccines.</p

Fabrication of magnesium bentonite hollow fibre ceramic membrane for oil-water separation

In this study, low-cost magnesium bentonite (MB) was used for the fabrication of bentonite hollow fibre (BHF) membrane with high pure water flux. MB powder was initially characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size distribution (PSD) analyser, Brunnauer -Emmett- Teller (BET) method, and field emission scanning electron microscope (FESEM). The BHF membrane obtained was then fabricated through dope suspension mixing, phase inversion and sintering process. The dope suspension was prepared by mixing MB, dispersant, polymer binder, and solvent using a planetary ball mill. While the spinning process was carried out at the extrusion rate of 8 mL/min, a fluid bore rate of 10 mL/min and air gap of 5 cm, and this was followed by sintering operation at 950 °C, 1000 °C, 1050 °C, and 1100 °C. The resulting BHF membrane was characterized by scanning electron microscopy (SEM) and XRD; the porosity test, water flux and oil rejection were also examined. The SEM surface morphology of BHF at sintering temperature of 950 °C showed spongy-like and nested macrovoids structure; the porosity was 49.09% with a mean pore size of 3.9 µm. The performance test on the bentonite-based hollow fibre membrane showed that the membrane prepared at 20 wt% and sintering temperature of 1000 °C, which induced high and stable permeate water flux and oil rejection of BHFC membrane were 544 L/m2 h and 97%, respectively. The results have shown that the presence of magnesium in bentonite can enhance and promote the needed support material for the fabrication of hollow fibre ceramic membrane