Membrane pervaporation performance applied for brackish water prepared by vacuum impregnation method

Coating method and number of membrane layer are crucial factors on membrane performance. Through a vacuum impregnation method allows a sol solution uniformly fill into membrane support and it is required only less solution. The aim of this study is to apply vacuum impregnation method through vacuum calcination and air calcination during fabrication of silica membranes and to investigate the effect of layer variations on silica membranes performance to apply for brackish water. The sol solution was made from TEOS as silane precursor, ethanol and dual catalysts (citric acid + ammonia). Alumina membrane support was coated by vacuum impregnation method and calcined the membrane under air and vacuum condition. From the FTIR result, it indicates that silica membranes calcined in air and vacuum calcination have Si-O-Si and Si-OH. The vacuum impregnation obtained smoother surface membranes. The silica membrane calcined via vacuum calcination performs excellent water fluxes and salt rejection of 22.01 kg.m− 2.h−1 and 98.98 %. If compare to silica membranes calcined in air, the water flux (19.11 kg.m− 2.h−1) and salt rejection (98.75 %). It also found the two layers silica membrane is better than three layers for the membrane performance result.

Yielding quality viral RNA by using two different chemistries: a comparative performance study

Purity and integrity are two important criteria for any RNA extraction process to qualify the RNA for meaningful gene expression analysis. This study compares four commercially available RNA extraction kits using silica membrane and magnetic bead separation methods. The performance was evaluated in terms of both quantity (total RNA amount in μg/μl) and purity (260/280 ratio). The concentration and purity of each kit was significantly different from those of the others (p < 0.001). Although quantity obtained from Mag MAX is comparatively lower than QIAGEN, the quality is comparable as evident from real-time PCR performance. This study suggests that there are practical differences between these RNA extraction kits that should be taken into account while isolating RNA required for gene expression analysis.

EVALUASI KINERJA MEMBRAN SILIKA PEKTIN UNTUK DESALINASI AIR PAYAU TERHADAP SUHU KALSINASI MEMBRAN

Krisis air bersih khususnya di Kalimantan Selatan pada musim kemarau sering terjadi karena adanya intrusi air laut yang mengakibatkan air menjadi payau. Konsentrasi garam tinggi yang tidak sesuai baku mutu air bersih mengharuskan perlu adanya pengolahan. Oleh karena itu, proses desalinasi melalui pervaporasi menjadi pilihan untuk memisahkan kadar garam yang terlarut dalam air. Proses desalinasi dilakukan menggunakan membran silika yang dimodifikasi dengan menambahkan karbon dari pektin pisang untuk memperkuat struktur pori dan meningkatkan hidrostabilitas membran. Penelitian ini bertujuan untuk mengetahui kinerja membran silika-pektin pisang dengan metode pervaporasi (PV) menggunakan umpan air payau (NaCl 0,3 wt%) pada suhu ruang (~25°C). Bahan utama pada pembuatan membran ini adalah tetraethyl orthosilicate (TEOS). Membran silika-pektin pisang dengan konsentrasi 1% dikalsinasi pada suhu 300°C dan suhu 400°C melalui teknik RTP (Rapid Thermal Processing). Nilai fluks membran pada suhu kalsinasi 300°C sebesar 4,5 kg.m-2.jam-1 dengan nilai rejeksi garamnya sebesar 99,64 %. Sedangkan pada membran dengan suhu kalsinasi 400°C menghasilkan nilai fluks sebesar 13,2 kg.m-2.jam-1 dengan nilai rejeksi garam sebesar 99,78%. Kinerja kedua membran menunjukkan hasil yang sangat baik pada suhu kalsinasi 400°C dikarenakan adanya pengaruh penyisipan karbon dalam matriks silika sehingga pori yang terbentuk lebih kuat. Kata kunci: air payau, desalinasi air payau, membran silika-pektin, pektin pisang, pervaporasi. South Kalimantan during the dry season has been clean water scarcity, due to the sea water intrusion which formed brackish water. High salt concentration in brackish water is does not meet with clean water quality standards that necessary to processing before used. Therefore, the desalination process via pervaporation has chosen to separate the dissolved salt ions in water. The desalination process was carried out using a modified silica membrane by carbon templated from banana pectin to strengthen the pore structure and increase membrane hydro-stability. This work aims to determine the performance of banana silica-pectin membrane by pervaporation (PV) method, using brackish water (NaCl 0,3 wt%) at room temperature (~25°C). The main ingredient to make this membrane is tetraethyl orthosilicate (TEOS). Banana silica-pectin membrane with a concentration of 1% was calcined at 300 ° C and 400°C via RTP (Rapid Thermal Processing) technique. The water flux of membrane calcined at 300°C is 4,5 kg.m-2.h-1 with the salt rejection of 99,64%. Whereas the membrane in calcined temperature of 400°C produced a water flux of 13,2 kg.m-2.h-1 with a salt rejection of 99,78%. An excellent performance of both membranes showed at calcination temperature of 400°C due to the influence of carbon template in the silica matrices that makes the pores more robust. Keywords: banana pectin, brackish water, brackish water desalination, pervaporation, silica-pectin membrane.

Bench-Scale Membrane Reactor for Methylcyclohexane Dehydrogenation Using Silica Membrane Module

Methylcyclohexane-toluene system is one of the most promising methods for hydrogen transport/storage. The methylcyclohexane dehydrogenation can be exceeded by the equilibrium conversion using membrane reactor. However, the modularization of the membrane reactor and manufacturing longer silica membranes than 100 mm are little developed. Herein, we have developed silica membrane with practical length by a counter-diffusion chemical vapor deposition method, and membrane reactor module bundled multiple silica membranes. The developed 500 mm-length silica membrane had high hydrogen permselective performance (H2 permeance > 1 × 10−6 mol m−2 s−1 Pa−1, H2/SF6 selectivity > 10,000). In addition, we successfully demonstrated effective methylcyclohexane dehydrogenation using a flange-type membrane reactor module, which was installed with 6 silica membranes. The results indicated that conversion of methylcyclohexane was around 85% at 573 K, whereas the equilibrium conversion was 42%.

Organo-Silica Membrane Prepared from TEOS-TEVS Modified with Organic-Acid Catalyst for Brackish Water Desalination

The sol gel process is one of the processes used in the manufacture of thin films on membranes because it can control the pore size in the resulting silica matrix. In addition, another way to build membrane size can be done by adding catalysts and precursors to be used. In this study, using a combination of tetraethyl ortho silicate (TEOS) and triethoxy vinyl silane (TEVS) precursors and citric acid as a catalyst to produce a silica matrix with mesoporous size so that it is suitable for application in the desalination process. The organo silica membrane was calcined at 350 ° C for 1 hour using the RTP calcination technique under vacuum, thus preventing the decomposition of carbon in the silica matrix. The membrane was dipcoated 4 times to obtain 4 layers. The FTIR (Fourier-transform Infrared Spectroscopy) test was carried out to see the functional groups on xerogel, namely silanol, siloxane and carbon. In addition, the performance of this membrane is carried out by desalination through pervaporation using 0.3% NaCl feed water with variations in feed air temperature, namely 25 ℃, 40 ℃ and 60 ℃. The resulting flux of air value increased with increasing feed water temperature, namely 6.1; 11.2; and 12.1 kg.m-2h-1 while the resulting salt rejection was 99.72; 99.64 and 99.23%. So that the organo silica membrane is suitable when applied to the desalination process through pervaporation.

Synthesis of Chitosan-Chitosan Composite Silica by Gamma Irradiation and Multi-Stage Deacetylation

The Study on synthesis of chitosan prepared by gamma irradiation and multi-stage deacetylation as chitosan-silica membrane has been carried out. Synthesis of chitosan is carried out by deproteination with papain, demineralization, and deacetylation. Deacetylation of chitosan using gamma irradiation with 0, 5, 10, 15, 20, and 25 kGy and two and multi-stage deacetyllation. The synthesis of chitosan silica composite using sol gel method with the ratio of 1:1; 1:2; and 1:3. Based on the study, gamma irradiation increase deacetylation degree of chitosan and minimize the sodium hydroxide needed for deacetylation chitosan. The multi stage deacetylation increase the efficiency procedure for increase deacetylation degree of chitosan. Chitosan-silica composite has been synthesized by sol gel method. The gamma radiation doses have significantly influence on the deacetylation degree of chitosan. Gamma irradiation and multi stage deacetylation increase the efficiency procedure for preparation chitosan and chitosan-silica composite.

Procedures for DNA Extraction from Opium Poppy (Papaver somniferum L.) and Poppy Seed-Containing Products

Several commonly used extraction procedures and commercial kits were compared for extraction of DNA from opium poppy (Papaver somniferum L.) seeds, ground seeds, pollen grains, poppy seed filling from a bakery product, and poppy oil. The newly developed extraction protocol was much simpler, reduced the cost and time required for DNA extraction from the native and ground seeds, and pollen grains. The quality of extracted DNA by newly developed protocol was better or comparable to the most efficient ones. After being extended by a simple purification step on a silica membrane column, the newly developed protocol was also very effective in extracting of poppy DNA from poppy seed filling. DNA extracted from this poppy matrix was amplifiable by PCR analysis. DNA extracted from cold-pressed poppy oil and suitable for amplifications was obtained only by methods developed previously for olive oil. Extracted poppy DNA from all tested matrices was analysed by PCR using primers flanking a microsatellite locus (156 bp) and two different fragments of the reference tubulin gene (553 bp and 96 bp). The long fragment of the reference gene was amplified in DNA extracted from native seeds, ground seeds, and pollen grains. Poppy DNA extracted from the filling of bakery product was confirmed only by amplification of short fragments (96 bp and 156 bp). DNA extracted from cold-pressed poppy oil was determined also only by amplification of these two short fragments.