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"An anion exchange membrane, (AMX) that carries a quaternary ammonium functional group has been investigated for its adsorption of fluoride, nitrate and sulfate from aqueous solutions. Fitting of the Freundlich, Langmuir, and Dubinin–Radushkevich adsorption models to the equilibrium data was performed at different temperatures in the range of 283?313K. The sorption parameters of the studied models were determined by linear regression and discussed. Adsorption analysis results obtained at various temperatures showed that the adsorption pattern on the membrane followed Langmuir isotherms. Thermodynamic studies revealed that the adsorption of the AMX membrane to the studied ions was spontaneous. The 0 ?GT values suggested the affinity order of the membrane for the studied anions. At 283K and 298K, the affinity order was: ? ? ? SO ? NO3 ? F 2 4 . This order was: ? ? ? ? ? 3 2 F SO4 NO at 313K. The standard enthalpy change and the standard entropy change were found to be ?11.63 kJ/mol and ?9.93 J/mol. K for the adsorption of nitrate, 7.42 kJ/mol and 58,73 J/mol. K for the adsorption of sulfate, and 74.21 kJ/mol and 274.9 J/mol. K for the adsorption of fluoride, respectively. The negative values of standard free energy 0 ?GT indicate the spontaneous natures of adsorption of studied anions onto the AMX membrane."

"The isotherm adsorptions of Cu2+ ions in aqueous slutions by cross-linked chitosan-cellulose composite membranes were investigated...."

"ABSTRAKKekurangan utama dari membran kontaktor adalah penurunan performa membran ketika terbasahi oleh air limbah atau penyerap. Penelitian dilakukan untuk mengatasi masalah tersebut dengan menggunakan membran superhidrofobik. Penelitian ini dilakukan dengan memvariasikan konsentrasi (100, 200, 400, 800 ppm), pH air limbah (10, 11, 12), pH penyerap (0,5;1;2), laju alir, dean jumlah serat membran. Koefisien perpindahan massa menyeluruh tertinggi diperoleh ketika jumlah serat 2000, konsentrasi air limbah 200 ppm, pH air limbah 11, pH absorben 1, dan lajyu alir air limbah 60 rpm yaitu sebesar 0,018 cm/s.

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ABSTRACT

The main weakness in the membrane contactor is the decline in the performance of the membrane when wetted by wastewater or absorbent solution. The proposed research will try to overcome that weakness by using membranes that has superhydrophobic properties. This experiment is done with variety of feed concentration (100, 200, 400, 800 ppm), pH of feed (10,11,12), pH of absorben (0,5; 1; 2), flowrate feed, and the amount of stiff from the membrane. The highest mass transfer coeficients obtained in membrane with 2000 stifs, synthetic waste water concentration is 200 ppm, pH of waste water is 11, pH of absorben is 1, and the flowrate of synthetic waste water is 60 rpm, is 0,018 cm/s."

"ABSTRAKMicroreaktor telah menjadi teknologi yang menjanjikan dalam bidang bioteknologi dan teknik kimia. Dalam penelitian ini dikembangkan konsep baru biokatalis membran mikroreaktor (BMM) untuk reaksi transesterifikasi secara kontinyu dengan memanfaatkan pori-pori membran sebagai mikroreaktor. Poripori membran yang dilapisi dengan enzim lipase dari Pseudomonas sp dengan cara absorpsi sederhana dan dilanjutkan dengan filtrasi bertekanan. Suatu larutan lipase dibiarkan mengalir pada membran dan merembes melalui pori-pori dan molekul lipase molekul teradsorpsi pada dinding pori-pori bagian dalam.Membran yang terbuat dari mixed cellulose ester (MCE) dan polyetersulfone (PES) digunakan untuk studi immobilisasi lipase tetapi hanya PES membran digunakan sebagai mikroreaktor untuk studi transesterifikasi. Sifat katalitik biokatalis membran mikroreaktor (BMM) telah dipelajari dalam sintesis biodiesel melalui reaksi transesterifikasi triolein dengan metanol. Transesterifikasi dilakukan dengan melewatkan larutan triolein dan metanol melalui pori-pori membran yang telah dilapisi lipase. Konversi maksimum triolein dengan BMM sekitar 80% dengan waktu reaksi 20-30 menit. Sistem biokatalis membran mikroreaktor dengan lipase sebagai biokatalis menunjukkan aktivitas yang jauh lebih unggul dibandingkan dengan lipase bebas, yaitu 12-25 kali lipat. Tidak ada penurunan fluks dan aktivitas yang diamati selama 12 hari operasi terus-menerus. Biokatalis membran mikroreaktor memiliki potensi yang besar untuk diterapkan dalam proses transesterifikasi trigliserida pada produksi biodiesel komersial karena akan mengurangi limbah dalam skala besar dan memiliki waktu reaksi yang jauh lebih kecil.

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ABSTRACTMicroreactors have become a promising technology in the biotechnology and chemical engineering field. In this study a new concept of biocatalytic membrane microreactor was developed for continuous transesterification reaction by utilizing membrane pores as a kind of microreactor. The membrane pores were coated with lipase from Pseudomonas sp by simple adsorption and continues with pressure driven filtration. A lipase solution was allowed permeating through the membrane and lipase molecule adsorbed on the inner wall of the membrane pores. Membranes made of mixed cellulose ester (MCE) and polyethersulfone (PES) were used for lipase immobilization studies but only PES membranes were used as microreactor for transesterification studies.The catalytic properties of biocatalytic membrane microreactor (BMM) have been studied in biodiesel synthesis through transesterification of triolein with methanol. Transesterification was carried out by passing solution of triolein and methanol through pores of the membrane. The maximum conversion of triolein with lipasemembrane microreactor was approximately 80% with reaction time 20-30 minutes. The biocatalytic membrane microreactor system with lipase as biocatalysts showed far superior activities compared to those of free lipase, i.e. 12-25 fold. No decrease in flux and activities were observed over a period of 12 days of continuous operation. These biocatalytic membrane microreactor is of great potential to be applied in the process of transesterification of triglycerides for commercial biodiesel production since it would reduce waste in large scale and has a much smaller reaction time."

"The series of hybrid organic-inorganic silica materials have been prepared by introducing organic ligands materilas based on sol-gel processing of alkoxysilanes for potential applications in membrane design for pervaporation....."

"The study has been conducted to evaluate the effectiveness of the natural solvent from noni fruit for CO2 gas absorption from CH4 through hollow fiber membrane gas-liquid contactors. The solvent was made of 100 grams noni fruit per liter of water. In experiments, the solvent flowed to the shell side of the contactor, while the gas mixture flowed to the lumen fiber. The experimental results showed that mass transfer coefficients in the contactors increased with increasing liquid flow rate and decreasing number of fibers in the contactors. Mass transfer correlation indicated that the mass transfer in the contactor was dominated by turbulent flow. Hydrodynamics analysis of the contactors showed that at the same Reynolds number pressure drops increased with increasing packing density due to an increase in friction between fibers and water. The friction factor ratio data revealed that the fiber surface did not behave like a smooth pipe within the range of velocities in the experiments. Based on QI and Cussler coefficients, chemical absorption occurred during experiments, which might be indicated by the appearance of new compounds in the chemical analysis of the a queous extract from noni fruit after absorption."

"Kontaktor membran serat berongga dapat menutupi kerugian yang terjadi pada metode konvensional. Terdapat dua jenis konfigurasi aliran dari membran kontaktor serat berongga ini. Konfigurasi 1 ketika pelarut dialirkan ke bagian tube and gas di bagian shell, sedangkan konfigurasi 2 sebaliknya. Penelitian ini dilakukan untuk menganalisis efektivitas antara dua konfigurasi tersebut dengan menggunakan larutan Triethanolamine 10% berat sebagai pelarut dan membran PVC. Hasil penelitian ini menyatakan bahwa konfigurasi 1 menghasilkan kinerja yang lebih baik dalam menyerap CO2 dibandingkan dengan konfigurasi 2. Penggunaan Triethanolamine sebagai pelarut menunjukkan kinerja yang kurang optimal, ditunjukkan dengan persentase CO2 yang terserap sekitar 1.98%.

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The hollow fiber membrane contactor overcomes the disadvantages of the conventional method. There are two flow patterns: Case 1 operation where the liquid flows in tube and gas in shell. The case 2 operation where the liquid flows at shell side and gas at tube side. This study is conducted to analyze the effectiveness between both patterns using 10% weight of Triethanolamine as the solvent and PVC membrane. The result of this study: the case 1 provides more effective CO2 absorption performance rather than case 2. The use of triethanolamine shows suboptimal performance, because the maximum CO2 absorbed was 1.98%."

"Latar Belakang: Ulkus kornea bakteri merupakan penyebab utama buta kornea. Tatalaksana standar ulkus kornea bakteri hingga kini masih terfokus pada eliminasi infeksi melalui antibiotik. Meskipun amplifikasi bateri telah dihentikan, inflamasi sekunder kornea terus berlangsung dan mengakibatkan destruksi kornea lebih lanjut dan sikatriks yang tebal. Tujuan: Untuk mengevaluasi efektivitas dan keamanan terapi kombinasi keratektomi superfisial dengan transplantasi membran amnion dan plasma autolog topikal pada ulkus kornea bakteri sedang dan berat, dalam memfasilitasi penyembuhan dan meminimalisasi inflamasi sekunder kornea. Metode: Uji klinis terandomisasi terbuka. Pembedahan pada kelompok eksperimental dilakukan dalam 72 jam pasca pemberian tiga hari antibiotik inisial. Hasil: Enambelas mata dengan ulkus kornea bakteri diikutkan dalam penelitian ini. Seluruh ulkus sembuh dalam waktu 36 hari pada kelompok eksperimental, dan 54 hari pada kelompok kontrol. Kecepatan epitelisasi kelompok eksperimental lebih cepat dibandingkan dengan kontrol (1,82±1,11 vs 0,97±0,74 mm2/hari, p=0,04, uji t tidak berpasangan). Terdapat kecenderungan pembentukan sikatriks kornea yang lebih tebal pada kelompok kontrol. Pada akhir evaluasi, tajam penglihatan lebih baik didapatkan pada kelompok eksperimental (0,344 ± 0,15 vs 0,196 ± 0,12 pada ulkus sedang, p=0,2, uji t tidak berpasangan; dan 0,14 ± 0,05 vs 0,014 ± 0,02 pada ulkus berat, p<0,01, uji t tidak berpasangan). Tidak ada komplikasi pada kelompok eksperimental, namun terdapat dua komplikasi pada kelompok kontrol. Simpulan: Terapi kombinasi keratektomi superfisial dengan transplantasi membran amnion dan plasma autolog topikal pada ulkus kornea bakteri terbukti lebih efektif dan aman dibandingkan terapi antibiotik konvensional. Terapi ini mempercepat epitelisasi dan penyembuhan ulkus, sehingga membentuk sikatriks kornea yang lebih tipis dengan tajam penglihatan lebih baik.

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Background: Bacterial corneal ulcer is a leading cause of corneal blindness. Up to now, the standard treatment for bacterial corneal ulcer is limited to the elimination of infection with antibiotic. However, the secondary tissue inflammation may still persist, leading to further corneal tissue destruction and dense corneal scar.

Objectives: To evaluate the efficacy and safety of superficial keratectomy, freeze-dried amniotic membrane transplantation and topical autologous plasma as a novel combination therapy in moderate and severe bacterial corneal ulcer, for promoting corneal wound healing and minimizing second injury of the cornea.

Methods: An open randomized controlled trial. The operation in experimental group was performed within 72 hours after three days application of initial antibiotic.

Results: Sixteen eyes of bacterial corneal ulcers were enrolled. All ulcers were healed within 36 days in the experimental group, compared to 54 days in the control group. Epithelialization rate of the experimental group was significantly faster than the control group (1,82±1,11 vs 0,97±0,74 mm2/day, p=0,04, unpaired t-test). Dense corneal scarring was more likely marked in the control group. Higher visual acuity at the last follow-up was achieved in the experimental group (0,344±0,15 vs 0,196±0,12 for moderate cases, p=0,2, unpaired t-test; and 0,14±0,05 vs 0,014±0,02 for severe cases, p<0,01, unpaired t-test). None complication was found in experimental group, while two complications (impending perforation and limbal damage) were noted within the control group.

Conclusions: Combination of superficial keratectomy with amniotic membrane transplantation and topical autologous plasma shows its benefits and safety for bacterial corneal ulcers. It promotes early epithelialization and corneal wound healing, thus achieving less corneal scarring with better visual acuity than conventional antibiotic therapy."