Solution Flow Rate Research Articles

Influence of alumina fixed-bed in steam reforming of glycerol for hydrogen production

In this study, hydrogen production by steam reforming was carried out in a tubular fixed-bed reactor. The influence of some operating variables such as temperature, flow rate of the feeding glycerol solution and space velocity on hydrogen production under a non-catalyzed reaction was analyzed. The results showed that the hydrogen yield increased with temperature and decreased with the space velocity. As the feedstock flow rate increased, the hydrogen yield decreased rapidly. Compared with a reference experiment without fixed-bed, the use of non-porous alumina fixed-bed showed better results. Under the best reaction conditions (900 °C and a feedstock flow rate of 0.85 g/min), 17 L/h of syngas were obtained, with a purity of about 55% of hydrogen and a production of 2.7 moles of hydrogen by mol of glycerol.

Synthesis of highly stable encapsulated astaxanthin/β-cyclodextrin microparticles using supercritical CO2 as an antisolvent

Although astaxanthin has promising physiological functions, its practical applications are limited by poor stability. Herein, astaxanthin was encapsulated in β-cyclodextrin (βCD) using CO2 as a supercritical antisolvent (SAS). The effects of process conditions, including temperature (313–333 K), pressure (12–18 MPa), solution concentration (3–5 wt%), solution flow rate (0.8–1.2 mL min−1), and astaxanthin-to-βCD mole ratio (1:50, 1:25, or 1:10), on the encapsulation efficiency, particle morphology, and residual solvent content were investigated. Astaxanthin–βCD complex spheres with an average diameter of 0.44 ± 0.08 µm were produced at 313 K and 15 MPa with a solution concentration and flow rate of 5 wt%, and 1.0 mL min−1, respectively. Under these optimal conditions, almost complete encapsulation (99.6% encapsulation efficiency) and residual organic solvent removal (0.22 ppm in the complex) were achieved. Density functional theory analysis of the configuration of the astaxanthin–βCD complex indicate that the hydroxyl hydrogen atoms on an ionone ring of astaxanthin interact with the oxygen atoms of βCD, but the ionone ring does not fit deeply within the βCD cavity. Notably, the astaxanthin–βCD complex exhibits higher thermal stability and antioxidant activity than free astaxanthin. The findings suggest that βCD encapsulation via the SAS process can produce astaxanthin microparticles with potential utility for food and pharmaceutical applications.

Neutralization Dialysis of Phenylalanine and Mineral Salt Mixed Solution: Effect of Concentration and Flow Rate of Acid and Alkali Solutions

Amino acids that are ampholytes can be effectively separated and purified by the method of neutralization dialysis (ND), whose advantage is the ability to control the pH value of the solution without adding reagents. An important task is to optimize the parameters of the ND process to ensure minimal losses of amino acids during their isolation from mixed solutions. An experimental study of the process of demineralization of the phenylalanine and sodium chloride equimolar mixture by the ND method was carried out. It is established that varying the concentration and flow rate of acid and alkali solutions in the corresponding compartments of the dialysis cell allows for regulating the pH value of the solution being desalted and controlling the amount of amino acid loss. Halving the acid concentration (from 0.10 to 0.05 M) allowed reducing the losses of phenylalanine from 18.3 to 16.4%, and using a lower solution flow rate in the acid compartment (0.75 instead of 1.50 cm s–1) made it possible to reduce these losses to 14.2%. At the same time, in all experiments, the electrical conductivity of the desalted solution decreased by 90%, which suggests a high degree of demineralization and the effectiveness of the method used to isolate phenylalanine from the mixed solution.

Bio-based synthesis of a sustainable Nano drag reducing agent for sprinkler irrigation systems

High-grade silica Nano particles were extracted from rice husk using a straightforward thermochemical method. The specifications of the isolated Nano particles were verified using a variety of material characterization techniques. Siloxane and silanol groups were notably visible in the spectra obtained using Fourier transform infrared spectroscopy. Scanning Electron Microscopy images revealed main Nano particles alongside secondary Micro particles. The size of the particles varied from 14.56 to 33.72 nm. The drag reduction experiments were took place in a facility that uses a forced closed loop. The extracted Nano silica was mixed with faucet water at a weight concentration of 50 to 400 mg/l to reduce drag. Records of pressure loss were obtained along a 186 cm carbon steel tube with internal diameters of 1.6 and 2.7 cm and variable flow rates of solutions at a comfortable temperature of 25 °C. The friction factor values were found to be around Blasuis asymptote for pure water but they were found to be near maximum drag reduction asymptotes when using the Nano material. A maximal drag reduction of nearly 68 % was achieved by using 400 ppm of Nano silica. It was observed that there is a crucial Reynolds number around 96000 that should not be surpassed since any additional increase results in a drop in drag reduction. Furthermore, a relationship between wall shear stress and velocity of the fluid was established.

Development of Novel Electrospun Fibers Based on Cyclic Olefin Polymer.

For the first time, a systematic study to investigate the electrospinnability of cyclic olefin polymer (COP) was performed. Different solvents and mixtures were tested together with different electrospinning parameters and post-treatment types to prepare bead-free fibers without defects. These were successfully obtained using a chloroform/chlorobenzene (40/60 wt.%) solvent mixture with a 15 wt.% COP polymer, a 1 mL/h polymer solution flow rate, a 15 cm distance between the needle and collector, and a 12 kV electric voltage. COP fibers were in the micron range and the hot-press post-treatment (5 MPa, 5 min and 120 °C) induced an integrated fibrous structure along with more junctions between fibers, reducing the mean and maximum inter-fiber space. When the temperature of the press post-treatment was increased (from 25 °C to 120 °C), better strength and less elongation at break of COP fibers were achieved. However, when applying a temperature above the COP glass temperature (Tg = 138 °C) the fibers coalesced, showing a mechanical behavior similar to a plastic film and a low elongation at break with a high strength. The addition of a high dielectric constant non-solvent, N,N-dimethylacetamide (DMAc), resulted in a considerable reduction in the COP fiber diameter. Based on the cloud point approach, it was found that the use of DMAc and the solvent chloroform or chlorobenzene improved the electrospinnability of COP polymer solution.

Performance of an air-cooled membrane based microchannel desorber-condenser working with LiBr-water

Absorption Refrigeration Systems can help to mitigate the environmental effect of the increasing energy demand in buildings. However, the size and the need of a cooling tower slow down their development. In the present study, a compact air-cooled desorber-condenser working with the LiBr-H2O solution is experimentally tested. The desorber is a stainless-steel plate provided with mini-channels. On one side water flows to heat the solution circulating in counter current flow through the other side of the plate. The vapour generated from the solution permeates through a flat membrane and directly enters the cavity of an air-cooled finned condenser. The membrane is a polytetrafluoroethylene (PTFE) membrane with a pore diameter of 45 μm. The assembly is tested for three different solution flow rates (40, 50 and 60 ml/min), three heating source temperatures (70 °C, 80 °C and 90 °C) and three inlet solution concentrations (43%, 46% and 50%wt). Measured desorption rates range from 3.10−3 to 14.10−3 kg/m2s. Heat and mass transfer in the desorber is characterized and pressure drop along the channels is also provided. Pressure drop along the solution channels varies from 70 to 105 Pa/m. The experimental results compare well with theoretical values calculated using correlations from the literature. The air-cooled condenser is able to condense the generated vapour at a rate ranging from 30 W to 100 W.

A conceptual evaluation of cross-flow membrane contactor for desalination process

The current work objectives are providing detailed understanding of heat and mass transport in a cross-flow membrane contactor for desalination process. The numerical code was developed using MATLAB software to investigate temperature and humidity distribution in the cross-flow membrane contactor at different operating parameters. Firstly, the developed model was successfully validated by experimental data. It was found that increase in saline solution inlet temperature from 40 °C to 80 °C can enhance solution outlet temperature, outlet air temperature, and humidity of outlet air from 37.38 °C to 56.79 °C, 39.48 °C–72.33 °C, and 0.0393 kg/kg to 0.2620 kg/kg respectively. Furthermore, the results showed that increase in saline solution flowrate and its inlet temperature has significant influence on the improvement of the process performance in terms of producing more pure water. However, there was no effect on temperature and humidity profiles, vapour transport though microporous membrane with the enhancement of inlet humidity of air. It was only had small positive influence on humidity humidification efficiency at inlet temperatures in the range of 40 °C–80 °C.

Energy, exergy, economic and environmental analysis of a solar-driven hollow fibre membrane dehumidification system

Solar-driven hollow fibre membrane dehumidification systems are already being used for air dehumidification, as they have the advantage of saving energy and preventing dehumidification solution droplets from entering the process air. Mathematical models of the system were built, which were validated with experimental data. An analysis of energy, exergy, economic and environmental was accomplished. Effects of critical parameters, including the flow rate of air, solution, hot-water and cold-water, and the cold-water temperature on the system's energy and exergy under the design conditions, were investigated theoretically. Economic and environmental aspects of the system were compared with a traditional refrigeration dehumidification system. The energy analysis indicates that the system has a higher coefficient of performance and dehumidification capacity in July and August. The exergy analysis indicates that the exergy efficiency is lower in May, June and July. The economic analysis shows the initial investment in the system is 641.65 $ higher than the traditional refrigeration dehumidification system, and the higher portion would be paid back with electricity savings in 6.08 years. The annual CO2 emissions of the solar-driven hollow fibre membrane dehumidification system is 0.2642 tCO2, which is 68.89% lower than the traditional refrigeration dehumidification system.

Improving surface characteristics and operational parameters of polyvinyl chloride ultrafiltration membranes: How to manipulate the performance of thin film composite forward osmosis membranes?

The environmental and economic costs are pivotal aspects that should be considered before the commercialization of any membrane separation-based process. Particularly, realizing this goal relies entirely on the key role played by fabrication and operational parameters. Herein, we introduced a systematic investigation for constructing thin-film composite (TFC) - forward osmosis (FO) membranes for direct fertigation applications. To the best of our knowledge, PVC membrane was rarely used as a porous top surface substrate for TFC-FO membranes. The PVC substrate porous structure and polyamide (PA) active layer were manipulated by variating their concentrations and reaction time to optimize the FO membrane performance. All necessary characterization tools were employed to visualize the fabricated TFC membrane's surface characteristics. The influence of feed solution concentration, membrane orientation, flow rate, and draw solutes on the FO work was also methodically tested. Results demonstrated that the porous structure-substrate membrane host polymer content had imparted a significant role in tailoring the TFC-FO performance concerning permeability and back-solute flux. The water flux was improved by 44.3 % with decreasing of the PVC amount, whereas water flux was improved by 48.13 % with decreasing of the M-phenylenediamine monomer (MPD) content from 3 to 1 wt% at constant tri-mesoylchloride monomer (TMC) content of 0.1 wt% in IP reaction conditions of a thin film. This was gone hand in hand with optimal operational conditions harnessed for optimizing the FO process.

Correlation between the Dimensions and Piezoelectric Properties of ZnO Nanowires Grown by PLI-MOCVD with Different Flow Rates

Zinc oxide nanowires (ZnO NWs) have gained considerable attention in the field of piezoelectricity in the past two decades. However, the impact of growth-process conditions on their dimensions and polarity, as well as the piezoelectric properties, has not been fully explored, specifically when using pulsed-liquid injection metal–organic chemical vapor deposition (PLI-MOCVD). In this study, we investigate the influence of the O2 gas and DEZn solution flow rates on the formation process of ZnO NWs and their related piezoelectric properties. While the length and diameter of ZnO NWs were varied by adjusting the flow-rate conditions through different growth regimes limited either by the O2 gas or DEZn reactants, their polarity was consistently Zn-polar, as revealed by piezoresponse force microscopy. Moreover, the piezoelectric coefficient of ZnO NWs exhibits a strong correlation with their length and diameter. The highest mean piezoelectric coefficient of 3.7 pm/V was measured on the ZnO NW array with the length above 800 nm and the diameter below 65 nm. These results demonstrate the ability of the PLI-MOCVD system to modify the dimensions of ZnO NWs, as well as their piezoelectric properties.

An efficient data-driven desalination approach for the element-scale forward osmosis (FO)-reverse osmosis (RO) hybrid systems

Freshwater shortages are a consequence of the rapid increase in population, and desalination of saltwater has gained popularity as an alternative water treatment method in recent years. To date, the forward osmosis-reverse osmosis (FO-RO) hybrid technology has been proposed as a low-energy and environmentally friendly next-generation seawater desalination process. Scaling up the FO-RO hybrid system significantly affects the success of a commercial-scale process. However, neither the ideal structure nor the membrane components for plate-and-frame FO (PFFO) and spiral-wound FO (SWFO) are known. This study aims to explore and optimize the performance of SWFO-RO and PFFO-RO hybrid element-scale systems in the desalination of seawater. The results showed that both hybrid systems could yield high water recovery under optimal operating conditions. The prediction of the system performance (water flux and reverse salt flux) by artificial intelligence was considerably better (R > 0.99, root mean square error <5%) than that of conventional mass balance models. A Markov-based decision tree successfully classified the water flux level in hybrid systems. An optimal set of operational conditions for each membrane system was proposed. For example, in RO, a combination of the feed solution (FS) flow rate (≥17.5 L/min), FS concentration (<17,500 ppm), and operation pressure (<35 bar) would result in high water permeability (>40 LMH). In addition, five SWFO elements and four PFFO elements should be the optimal numbers of FO membranes in the hybrid FO-RO system for effective seawater desalination, especially for long-term operation.

Research on Single Crystal Preparation via Dynamic Liquid Phase Method

Traditional liquid phase methods for growing single crystals are static growth methods, which include seed crystal sedimentation growth and seed crystal clamping growth using seed crystal holders. Single crystals grown via seed crystal sedimentation often have a flat and elongated shape, and the region in contact with the bottom of the container is restricted during growth, resulting in significant defects. Similarly, the seed crystal clamping growth method cannot avoid contact with external objects, leading to abnormal growth at the contact points and along the direction of the seed crystal holder, also resulting in certain defects. Both of these growth methods require processes, such as cutting and grinding, to remove defects, resulting in resource waste. To address the shortcomings of the static liquid phase single-crystal preparation mentioned above, this study successfully designed a dynamic liquid phase method for single crystal growth, which achieved the successful suspension of seed crystals in the mother solution and the growth of high-quality, large-sized single crystals, avoiding contact with the walls and the bottom of the container during the crystal growth process. Based on the dynamic liquid phase single crystal growth apparatus mentioned above, stable and dynamic liquid phase preparation was successfully achieved, ranging from seed crystals with a diameter of approximately 5 mm to single crystals with a diameter of approximately 20 mm, by controlling the cooling rate and adjusting the solution flow rate.

Techno-economic analysis of conversing the low-grade heat to hydrogen by using reverse electrodialysis – Air gap diffusion distillation coupled method for iron and steel industry

This study devotes to the reverse electrodialysis (RED) – air gap diffusion distillation (AGDD) coupled system of converting the low-grade waste heat recovered from the steel production to hydrogen for steelmaking. This approach not only recovers waste heat but also reduces carbon emissions. To assess the feasibility of the coupled system, a techno-economic model has been developed. The influences on the levelized cost of hydrogen (LCOH) of the ion exchange membranes (cost and lifetime), the operating condition of RED stack (current density and feed solution velocity), the AGDD unit (feed solution flowrate), and the numbers of RED stacks in a multistage series system are investigated. The high price of ion exchange membrane is currently the main factor causing non-commercialization, which is almost 6.63–19.9 times larger than the LCOH of hydrogen production from renewable electricity. The membrane lifetime is the critical factor in increasing the maximum permitted membrane cost. Assuming the membranes cost is 1 RMB/m2, the optimal current density, feed solution velocity (in RED stack), and the solution volume flowrate (in AGDD unit) of are 50 A/m2, 0.00075 m/s, and 0.7 m3/h, respectively. The series systems take a considerable advantage in reducing the required AGDD units compared with one stage.

Reduction of Concentrating Poisonous Metallic Radicals from Industrial Wastewater by Forward and Reverse Osmosis

The research aims to use a new technology for industrial water concentrating that contains poisonous metals and recovery quantities from pure water. Therefore, the technology investigated is the forward osmosis process (FO). It is a new process that use membranes available commercial and this process distinguishes by its low cost compared to other process. Sodium chloride (NaCl) was used as draw solution to extract water from poisonous metals solution. The driving force in the FO process is provided by a different in osmotic pressure (concentration) across the membrane between the draw and poisonous metals solution sides. Experimental work was divided into three parts. The first part includes operating the forward osmosis process using TFC membrane as flat sheet for NaCl. The operating parameters studied were: draw solutions concentration (10 – 95 g/l), draw solution flow rate (12-36 I/h), temperature of draw solution (30 and 40°C), feed solution concentration (10 -210 mg/l), feed solution flow rate (10 -50 l/h), temperature of feed solution (30 and 40°C) and Pressure (0.4 bar). The second part includes operating the forward osmosis process using CTA membrane as flat sheet for NaCl. The operating parameters studied were: draw solution concentration (15 – 95 g/l), feed solution concentration (10-210 mg/l). Constant temperature was maintained at 30°C. The last part includes operating the reverse osmosis process using TFC membrane as spiral wound module in order to separate NaCl salt from draw solution and obtain on pure water so as to usefully in different uses and also obtain on solution of NaCl concentrate which was recirculated to forward osmosis process. It is then used as draw solution. The operating parameter studied was: feed solution flow rate (15-55 l/h). The experimental results show that the water flux increases with increasing draw solution concentration, feed solution flow rate, temperature of draw solution and decreases with increasing feed solution concentration, draw solution flow rate and temperature of feed solution. The experiments also show that CTA membrane gives higher water flux than TFC membrane for forward osmosis operation.

Water Recovery from Brine Solution by Forward Osmosis Process

The present work aims to study the possibility of utilization a forward osmosis desalination process as an alternative method to extract water from brine solution rejected from reverse osmosis process. Experiments conducted in a laboratory–scale forward osmosis (FO) unit in cross flow flat sheet membrane cell yielded water flux ranging from (0.0315 to 0.56 L/m2 .min) when using CTA membrane,and ranging from (0.419 to 2.785 L/m2 .min) for PA membrane under 0.4 bar. Two possible membrane orientations were tested. Sodium chloride with high concentrations was used as draw solution solute. The effect of membrane orientation on internal concentration polarization (ICP) was studied. Two regimes of ICP; dilutive and concentrative were described and characterized and their governing equations were applied. Also the effect of draw and feed solution concentrations and flow rate were studied. It was found that the experimental water flux were lower than the theoretical water flux. Using of PA membrane under pressure was resulted in a higher flux of desalinated water than when CTA used alone without pressure under the same operating conditions.

MXene nanosheets woven in polyacrylonitrile nanofiber yarns aligned spider web as a highly efficient sorbent for in-tube solid phase microextraction of beta-blockers from biofluids

The use of electrospinning has received much attention in the production of nanofiber webs due to its advantages such as flexibility and simplicity. The direct electrospinning of nanofibers in an aligned or twisted form and the production of nanofiber yarns can turn nanofibers into woven fabrics, which leads to an increase in the diversity of nanofiber applications and improves their end-use possibilities. In this work, a victorious nanofiber yarn spinning system was used with the help of a rotating funnel. Yarn formation was studied using a composited polyacrylonitrile (PAN)/MXene polymer solution ejected from two oppositely charged nozzles. Finaly their application for packed-in-tube solid-phase microextraction of β-blocker drugs from biofluids was demonstrated. The separation and quantification of analytes were performed by HPLC-UV instrument. The 3D-yarn PAN/MXene sorbent exhibited high flexibility, porosity, sorbent loading, mechanical stability, and a long lifetime. The characterization of the final nanofiber was carried out utilizing Fourier-transform infrared spectroscopy, field emission scanning electron microscope, energy-dispersive X-ray mapping, transmission electron microscope and X-ray diffraction analysis. Various parameters that affect the extraction efficiency, such as extraction time, pH, ionic strength and flow rate of sample solution, and type, volume and flow rate of eluent, were investigated and optimized. Under optimized conditions, the limits of detection were obtained in the range of 1.5–3.0 μg L−1. This method demonstrated appropriate linearity for β-blockers in the range of 5.0–1000.0 μg L−1, with coefficients of determination greater than 0.990. The inter- and intra-assay precisions (RSDs, for n = 3) are in the range of 2.5–3.5%, and 4.5–5.2%, respectively. Finally, the validated method was put in an application for the analysis of atenolol, propranolol and betaxolol in human urine and saliva samples at different hours and acceptable relative recoveries were obtained in the range of 89.5% to 110.4%.

Natural extract-polymer monodisperse submicron particles from Plateau-Rayleigh microjets

Particles of interest in food, pharmaceutical, and nutraceutical sectors are often formulated with a polymer and one or more natural or synthetic active compound. The two components frequently have distinct hydrophilicity. Submicrometric particles with narrow size dispersion can be made by the droplet-to-particle route by electrospray. In the steady cone-jet mode a liquid Taylor cone (TC) continuously emits a Plateau-Rayleigh microjet which breaks up spontaneously and periodically into tiny droplets, which later dry up to form solid particles. To achieve a stable process of this kind, we argue that it is necessary to: (i) operate near the minimum solution flow rate compatible with TC stability, (ii) prevent the drying of the TC by surrounding it with a gentle gas stream saturated in solvent vapor, and (iii) monitor the electric current and image the TC. We demonstrate this process in the preparation of curcumin (CUR) loaded polyvinylpyrrolidone (PVP) submicrometric particles as a function of solution composition and ambient relative humidity. In the atomization step (jet and droplet formation), the initial droplet size and charge are determined by the liquid properties and flow rate. The particles’ shapes were spherical (with or without internal voids), corrugated due to shell buckling (with compact interiors), and filamented due to Coulombic instabilities, depending on the interplay of different factors at the droplet drying step. These included the droplet size and charge, solvent evaporation, solute diffusion, water uptake from the ambient, mechanical forces, and solution thermodynamics. The electric current and droplet size are suitably predicted by scaling laws developed for simple Newtonian fluids. Hence, our particle sizes lie always between the predicted droplet and compact-sphere sizes, at a distance which depends on the particle morphology. CUR-loaded PVP quasi-monodisperse submicron particles could be an interesting model for drug delivery and biomedical applications.

Rate-based modeling and energy optimization of acid gas removal from natural gas stream using various amine solutions

Reduction in energy consumption of industrial plants is always an essential need due to high cost, CO2 emissions and global warming caused by energy supply from fossil fuels for boilers and electricity consumers. Iran has been struggling to compensate the lack of gas supply for domestic and industrial demands in winter within the past decade despite of having large natural gas resources. One of the most economical methods to decrease energy requirements in hydrocarbon plants is process improvement and revamping by changing existing solvents. There are already 44 identical acid gas removal units under operation in the South Pars Gas Complex (located in Iran) with the same feed composition. The gas-sweetening unit in the Phase 12, operating with the solution of 45.5 wt% methyldiethanolamine (MDEA), was modeled by Aspen Plus for acid gas removal (CO2 and H2S) as a rate-based model with the application of electrolyte non–random two–liquid (E-NRTL) activity model and Peng–Robinson equation of state in addition to the actual characteristics of the absorber and regenerator, and the operational conditions of the gas and liquid streams. After validation of the model by the real data from the plant, the incumbent amine solution was replaced with five proposed amine solutions – one single and four blended amine mixtures – in the same mass concentration to select the most efficient alternative from the aspects of outlet acid gas concentration, H2S content in the treated flash gas, required total power, reboiler power supply, and regeneration heat duty. The simulation results revealed that H2S was sharply absorbed on the top of the column, while CO2 was smoothly removed from the gas phase to the MDEA and blended solutions along the absorber and it occurred at the bottom of the column for the DEA solution. The blended amine solution of 1.5 wt% sulfolane + 44 wt% MDEA (Sulfinol-M) has shown to be the most appropriate option instead of the solution of MDEA compared to other suggested absorbents, with several advantages such as higher selectivity of H2S over CO2, low temperature bulge, highest H2S loading, and outlet sweet gas flow rate while required total power, reboiler power supply, and regeneration heat duty were reduced by 21.19%, 21.26%, and 23.54% respectively. The operational conditions of the unit with the application of the Sulfinol-M solution were optimized to achieve three specifications (constraints) and the minimum required total power (objective function) through a sensitivity analysis and optimization using a genetic algorithm to assure the reliability of values for three independent parameters, namely, amine solution temperature, amine solution flow rate, and gas temperature. The optimum limits and values of these parameters were 47–50 °C, 220 – 240 ton/h, and 34 °C respectively.

Forward Osmosis Process for the Treatment of Wastewater from Textile Industries

This paper was aimed to study the efficiency of forward osmosis (FO) process as a new application for the treatment of wastewater from textile effluent and the factors affecting the performance of forward osmosis process.The draw solutions used were magnesium chloride (MgCl2), and aluminum sulphate (Al2 ( SO4)3 .18 H2O), and the feed solutions used were reactive red, and disperse blue dyes.Experimental work were includes operating the forward osmosis process using thin film composite (TFC) membrane as flat sheet for different draw solutions and feed solutions. The operating parameters studied were : draw solutions concentration (10 – 90 g/l), feed solutions concentration (5 – 30 mg/l), draw solutions flow rate (10 – 50 l/hr), feed solutions flow rate (20-60 l/hr), constant pressure and temperature were maintained at 0.5 bar and 30ºC respectively. And includes operating the forward osmosis process using cellulose triacetate (CTA) membrane as flat sheet for different draw solutions and feed solutions. The operating parameters studied were : draw solutions concentration (10 – 90 g/l), and feed solutions concentration (5 – 30 mg/l), constant temperature at 30ºC. It was found that water flux increases with increasing draw solution concentration, and feed solution flow rate and decreases with increasing draw solution flow rate and feed solution concentration for TFC and CTA. It was found MgCl2 given water flux larger than Alum. And also found that reactive red given water flux larger than disperse blue.The experiments also show that CTA membrane gives higher water flux than TFC membrane for forward osmosis operation. The increase in water flux for CTA is about 12.85% than TFC.

Amorphization versus cocrystallization of celecoxib-tramadol hydrochloride using CO2-assisted nano-spray drying

The manipulation of both solid-state form and particle size is a versatile means by which physicochemical properties of pharmaceutical drugs may be improved/fine-tuned. The work presented herein describes the solid-state and particle size control of the most recently FDA-approved pharmaceutical cocrystal, composed of two APIs, Celecoxib-Tramadol hydrochloride (Seglentis®), using a continuous atomization technique, namely supercritical CO2-assisted nano-spray drying. Using a three-factorial design of experiments, both (co)amorphous and cocrystalline samples were generated, depending on processing conditions. Mean particle sizes ranged from 120 nm to 1160 nm, with solution flow rate showing the most significant effect due to its impact on atomized droplet sizes. While all (co)amorphous samples displayed a similar morphology, one set of conditions produced a (co)amorphous sample with a larger degree of intermolecular interactions, comparable with the hydrogen bonding network observed in the cocrystalline samples. Tabletting of four formulations was carried out to investigate the impact of particle size and solid-state on tabletability, compactability and compressibility. While all formulations performed adequately in these critical quality attributes, the formulations which contained cocrystalline particles underperformed regarding tabletability and compactability due to their irregular shape and larger size. However, due to the increased prevalence of intermolecular interactions, the cocrystalline and (co)amorphous samples with a larger degree of hydrogen bonding led to improved compressibility.