CO\u3csub\u3e2\u3c/sub\u3e-Selective Membranes Containing Amino Groups

Novel compositions suitable for fabrication of CO2-selective membranes are disclosed. In one aspect, the present invention is directed to compositions comprising polyimide/polyamine blends and copolymers, and to compositions comprising interfacially polymerized polyamides. In another aspect this invention is directed to novel CO2-selective membranes comprising such polyimide/polyamine blends and copolymers, and to novel CO2-selective membranes comprising interfacially polymerized polyamides. In yet another aspect, the present invention is directed to a novel water-gas-shift (WGS) reactor comprising the novel CO2-selective membranes. Advantageously, the use of the novel CO2-selective membrane allows alteration of the normal WGS reaction equilibrium, shifting the reaction towards production of H2. Carbon dioxide on the high pressure, feed gas side of the membrane reactor reacts with the novel membranes of the present invention at the interface between the feed gas and the membrane. The reaction product permeates through the membrane to the interface between the feed gas and the low pressure side of the membrane, where the CO2 desorbs into the low pressure side and is removed

New facilitated transport membranes for CO2 capture and separation

We have synthesized new facilitated transport membranes comprising high-molecular-weight polyvinylamine (PVAm) as the fixed site carrier and aminoacid salt (e.g., piperazine glycinate (PG) or lithium glycinate (LG)) as the mobile carrier for facilitated transport of CO2. PVAm samples with different molecular weights were synthesized through free radical polymerization by adjusting the monomer concentration and initiator amount. The synthesized PVAm showed both a higher molecular weight and a higher solution viscosity than the commercially available PVAm (Lupamin® 9095 from BASF Corporation). The high viscosity of the PVAm solution at a low concentration allowed for the preparation of much thinner membranes. It could also help reducing penetration of the polymer solution into the pores of the substrate, further minimizing the mass transfer resistance. Consequently, a high CO2 permeance could be obtained from thin membranes with the thicknesses of 100 – 200 nm. The PVAm/PG blend solution was coated onto different substrates including polyethersulfone (PES) and polysulfone (PSf) substrates. Sodium dodecyl sulfate (SDS) surfactant was incorporated in the coating solution to improve the adhesion between the membrane layer and the substrate in some cases. The resultant PVAm/PG membranes exhibited a high CO2 permeance of about 1100 GPU and a high CO2/N2 mixed gas selectivity of more than 140 at the typical flue gas temperature of 57°C along with 17% water vapor, which is the desirable performance for post-combustion CO2 capture from coal-fired power plants

Oxidatively stable membranes for CO2 separation and H2 purification

CO2-selective facilitated transport membranes are well-known for providing remarkably high CO2/H2 selectivity along with high permeance at high temperatures (100 – 120oC). In some cases, it is desirable to use air as the sweep gas to enhance the driving force and membrane performance, and the membrane should be stable in the presence of oxygen. This work demonstrates the development of a new class of facilitated transport membranes containing quaternaryammonium hydroxide small molecules and quaternaryammonium hydroxide- and fluoride-containing polymers as mobile carriers and fixed-site carriers, respectively, for CO2 separation and H2 purification. The active nature of tetramethylquaternaryammonium hydroxide (TMAOH) as a mobile carrier was successfully demonstrated with the high CO2 permeance obtained by the TMAOH-containing membranes. However, the membrane performance was improved significantly by the incorporation of quaternaryammonium hydroxide- and/or fluoride-containing polymers in the membrane. The resulting hydroxide- and fluoride-containing membranes exhibited CO2 permeance \u3e 100 GPU and CO2/H2 selectivity \u3e 100 at 120oC using humid air as the sweep gas. The membrane composition was optimized, and the transport stability of the membrane was investigated. The membrane showed oxidatively stable during the 145-hour transport measurement at 120oC using air as the sweep gas. Furthermore, the effects of sweep steam content and membrane thickness were investigated. As the sweep steam content was increased (especially for steam content \u3e 50%), both CO2 permeance and CO2/H2 selectivity increased. As the membrane thickness was reduced from 15 µm to 2 µm, a sharp drop in the CO2/H2 selectivity was observed whereas the CO2 permeance did not seem to increase as prominently as the H2 permeance. In addition, the membrane was successfully scaled up using a roll-to-roll continuous membrane fabrication machine, and the scale-up membrane showed similar performance as the lab-scale membrane

Development, Characterization and Cross-species Transferability of Expressed Sequence Tag-simple Sequence Repeat (EST-SSR) Markers Derived from Kelampayan Tree Transcriptome

Neolamarckia cadamba (or locally known as kelampayan) is an important fast growing plantation tree species that confers various advantages for timber industry as a strategy for reducing the logging pressure on natural forests for wood production to an acceptable level. Hence, attempts were made to develop a set of EST-SSR markers for kelampayan trees based on the EST sequences of kelampayan (NcdbEST) and further assessed the polymorphisms and transferability of the markers to other species. In this study, 155 (2.34%) out of 6,622 EST sequences which contain 232 SSRs were mined from NcdbEST. Of these, 97 ESTs were assigned with putative functions and gene ontology terms. Eighteen EST-SSR markers were developed according to the criteria, and further characterized and validated by using 50 individuals of kelampayan from two selected mother trees. The markers exhibited a considerable high level of polymorphism in kelampayan trees with an average of 4.17 and 4.11 alleles per locus, and PIC values of 0.465 and 0.537, respectively for mother trees T1 and T2. Parentage assignment analysis suggests a high probability for kelampayan trees to be predominantly outcrossed. The transferability rate was ranging from 16.7-94.4% among the five cross-genera species of kelampayan. The present study is the first report of the development of EST-SSR markers in kelampayan. These markers will be valuable genomic resources that could pave the way for exploiting the genotype data for comparative genome mapping, association genetics, population genetics studies and molecular breeding of kelampayan and other indigenous tropical tree species in future

Resequencing And Nucleotide Variation Of Sucrose Synthase (Nmsusy1) Gene In A Tropical Timber Tree Neolamarckia Macrophylla

Sucrose synthase (SuSy) is a key enzyme that catalyses the reversible synthesis and degradation of sucrose. It provides greater impact in regulating the photosynthetic processes and environmental stresses in plants. Thus, the nucleotide variation of partial NmSusy1 genomic DNAs (750 bp) generated through PCR amplification was examined in this study, and this followed by resequencing from 15 selected Neolamarckia macrophylla clones. The consensus sequences were aligned to detect the presence of single nucleotide polymorphisms (SNPs). In total, five SNPs were detected at nucleotide 1, 2, 34, 35 and 397. Of these, four SNPs were located at the predicted coding region while one SNP was located at the predicted non-coding region. Interestingly, one single base pair InDel polymorphism was also detected at nucleotide 17. On average, one SNP at every 150 bp was detected based on the 15 NmSusy1 sequences. There was one non-synonymous mutation detected, whereby amino acid glutamic acid (E) was replaced by arginine (R) in one of the 15 samples tested. This non-synonymous SNP might change the structural, functional or biochemical properties of the enzyme being produced and therefore possibly lead to changes in phenotypic characteristic of the trees. Overall, this study has demonstrated that resequencing is an effective technique for classifying molecular diversity or nucleotide variation in the Susy gene of N. macrophylla. Those SNPs, once validated, could potentially be used as a tool in marker-assisted selection (MAS) that enables more precise and accurate in the selection and prediction of yield or performance at the early developmental stages, such as at the seedling stage

Optimal Biomethane Injection into Natural Gas Grid – Biogas from Palm Oil Mill Effluent (POME) in Malaysia

The Malaysian government aims to facilitate the renewable energy (RE) sector by introducing the National Renewable Energy Policy and Action Plan during 2010. 4,000 MW of installed RE capacity is targeted by 2030, with 410 MW biogas capacity. Palm oil mill effluent (POME), agro-based industries and farming industries are identified as potential sources of biogas. It was studied that more than 500 kt of biomethane could be produced yearly if all the POME is treated anaerobically. The utilization of biomethane has remained unexplored for its injection into natural gas grid. This papers aims to identify the potential of POME biomethane injection into natural gas grid by using the BeWhere model, a techno-economic spatial explicit model. The locations, capacity and technology of biogas refinery plants will be identified based on cost minimization of the full supply chain of biogas production. The result shows that 135 - 227 biogas plants were selected, supplying 40% - 67% residential fossil gas demand, under different carbon price implementation and fossil gas subsidy scenarios

The normal ranges of cardiovascular parameters measured using the ultrasonic cardiac output monitor

The ultrasonic cardiac output monitor (USCOM) is a noninvasive transcutaneous continuous wave Doppler method for assessing hemodynamics. There are no published reference ranges for normal values in adults (aged 18– 60 years) for this device. This study aimed to (1) measure cardiovascular indices using USCOM in healthy adults aged 18–60 years; (2) combine these data with those for healthy children (aged 0–12), adolescents (aged 12–18), and the elderly (aged over 60) from our previously published studies in order to present normal ranges for all ages, and (3) establish normal ranges of USCOM-derived variables according to both weight and age. This was a population- based cross-sectional observational study of healthy Chinese subjects aged 0.5–89 years in Hong Kong. USCOM scans were performed on all subjects, to produce measurements including stroke volume, cardiac output, and systemic vascular resistance. Data from previously published studies (children, adolescents, and the elderly) were included. Normal ranges were defined as lying between the 2.5th and 97.5th percentiles. A total of 2218 subjects were studied (mean age = 16.4, range = 0.5–89; 52% male). From previous studies, 1197 children (aged 0–12, 55% male), 590 adolescents (aged 12–18, 49% male), and 77 elderly (aged 60–89, 55% male) were included. New data were collected from 354 adults aged 18–60 (47% male). Normal ranges are presented according to age and weight. We present comprehensive normal ranges for hemodynamic parameters obtained with USCOM in healthy subjects of all ages from infancy to the elderly

Nano Fe3O4-activated carbon composites for aqueous supercapacitors

In this study, a symmetric supercapacitor has been fabricated by adopting the nanostructured iron oxide (Fe3O4)-activated carbon (AC) composite as the core electrode materials. The composite electrodes were prepared via a facile mechanical mixing process and PTFE polymeric solution has been used as the electrode material binder. Structural analysis of the nanocomposite electrodes were characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The electrochemical performances of the prepared supercapacitor were studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 1.0 M Na2SO3 and 1.0 M Na2SO4 aqueous solutions, respectively. The experimental results showed that the highest specific capacitance of 43 F/g is achieved with a fairly low Fe3O4 nanomaterials loading (4 wt. %) in 1 M Na2SO3. It is clear that the low concentration of nanostructured Fe3O4 has improved the capacitive performance of the composite via pseudocapacitance charge storage mechanism as well as the enhancement on the specific surface areas of the electrode. However, further increasing of the Fe3O4 content in the electrode is found to distort the capacitive performance and deteriorate the specific surface area of the electrode, mainly due to the aggregation of the Fe3O4 particles within the composite. Additionally, the CV results showed that the Fe3O4/AC nanocomposite electrode in Na2SO3 electrolyte exhibits a better charge storage performance if compared with Na2SO4 solution. It is believed that Fe3O4 nanoparticles can provide favourable surface adsorption sites for sulphite (SO32-) anions which act as catalysts for subsequent redox and intercalation reactions

Genetic diversity of Neolamarckia cadamba using dominant DNA markers based on inter-simple sequence repeats (ISSRs) in Sarawak

Neolamarckia cadamba or commonly known as kelampayan has been selected as one of the important plantation tree species in Malaysia. Thus, the molecular characterization of this indigenous tropical tree species is needed to maintain its high quality. Inter simple sequence repeats (ISSR) markers were used in this study to determine the genetic diversity and relatedness of N. cadamba in two planted forests and six natural forests in Sarawak. Three ISSR primers had generated atotal of 239 loci, of which 32.6% - 59.4% of the loci were polymorphic among236N. cadamba treesin eight populations. The mean Shannon’s diversity index (I)ranged from 0.1399 to 0.2354. The coefficient of population differentiation was low for planted forests (Gst = 0.0871) and natural forests (Gst = 0.2013`). Both UPGMA dendrogram and NJ-tree generated by ISSR markers had divided natural forests and planted forests into two distinct clusters. Natural forests were grouped in one cluster while planted forests were grouped in another cluster. This study shows that N. cadamba trees are closely related within its own population and its designated forest type. In future, several specific loci can be sequenced and developed into SCAR (sequence characterized amplification region) markers for tree improvement and conservation programme of N. cadamba

Toward Green Synthesis of Graphene Oxide Using Recycled Sulfuric Acid via Couette-Taylor Flow

Developing eco-friendly and cost-effective processes for the synthesis of graphene oxide (GO) is essential for its widespread industrial applications. In this work, we propose a green synthesis technique for GO production using recycled sulfuric acid and filter-processed oxidized natural graphite obtained from a Couette-Taylor flow reactor. The viscosity of reactant mixtures processed from Couette-Taylor flow was considerably lower (???200 cP at 25 ??C) than that of those from Hummers' method, which enabled the simple filtration process. The filtered sulfuric acid can be recycled and reused for the repetitive GO synthesis with negligible differences in the as-synthesized GO qualities. This removal of sulfuric acid has great potential in lowering the overall GO production cost as the amount of water required during the fabrication process, which takes a great portion of the total production cost, can be dramatically reduced after such acid filtration. The proposed eco-friendly GO fabrication process is expected to promote the commercial application of graphene materials into industry shortly