Cellulose Blended Membranes for High-Salinity Water Pervaporation Desalination

In the current study, cellulose acetate (CA)/cellulose triacetate (CTA) nanocomposite membranes blended with zirconium dioxide (ZrO2) are prepared via phase inversion for pervaporation desalination performance. ZrO2 nanoparticles are added to enhance the hydrophilicity and porosity of the nanocomposite membranes. The fabricated nanocomposite membranes are characterized by SEM, FTIR, TGA, and DSC to study the surface morphology, chemical composition, thermal stability and strength. Nanocomposite membranes’ performance for pervaporation desalination is assessed as a function of feed concentration. Pervaporation results revealed that the nanocomposite membrane consisting of 2% ZrO2 achieved a maximum water flux of 6.5 kg/m2h, whereas the salt rejection was about 99.8%.

Removal of Copper, Nickel, and Zinc Ions from an Aqueous Solution through Electrochemical and Nanofiltration Membrane Processes

Heavy metal contamination in water is a major health concern, directly related to rapid growth in industrialization, urbanization, and modernization in agriculture. Keeping this in view, the present study has attempted to develop models for the process optimization of nanofiltration (NF) membrane and electrocoagulation (EC) processes for the removal of copper, nickel, and zinc from an aqueous solution, employing the response surface methodology (RSM). The variable factors were feed concentration, temperature, pH, and pressure for the NF membrane process; and time, solution pH, feed concentration, and current for the EC process, respectively. The central composite design (CCD), the most commonly used fractional factorial design, was employed to plan the experiments. RSM models were statistically analyzed using analysis of variance (ANOVA). For the NF membrane, the rejection of Zn, Ni, and Cu was observed as 98.64%, 90.54%, and 99.79% respectively; while the removal of these through the EC process was observed as 99.81%, 99.99%, and 99.98%, respectively. The above findings and a comparison with the conventional precipitation and adsorption processes apparently indicate an advantage in employing the NF and EC processes. Further, between the two, the EC process emerged as more efficient than the NF process for the removal of the studied metals.

Bimetallic Fe/Al-MOF for the Adsorptive Removal of Multiple Dyes: Optimization and Modeling of Batch and Hybrid Adsorbent-river Sand Column Study

Bimetallic Metal organic framework (MOF) has garnered interest over the years with its application in various environmental remediation. In this study, Fe-Al-1,4-Benzene di-Carboxylic acid (FeAl(BDC)) MOF was synthesized, and adsorptive removal of Rhodamine B dye in batch and unique hybrid FeAl (BDC)-River sand fixed-bed column was achieved. The experimental data from the batch studies corroborated well with the Pseudo second-order (PSO) and Freundlich adsorption isotherm models. Furthermore, a fixed-bed column study was conducted to assess the effect of varying flow rate (2, 5, 8 mL/min), bed height (5, 9, 13 cm), and feed concentration (10, 20, 30 mg/L) on the adsorption performance of FeAl(BDC) in continuous mode of operation. A uniform mixture of river sand and FeAl(BDC) by weight ratio (9:1) was achieved prior to packing the column. The column study reveals that Sand-FeAl(BDC) can achieve the maximum adsorption capacity of 113.05 mg/g at a flow rate of 5 mL/min, feed concentration of 20 mg/L, and bed height of 13 cm. The experimental data of the column study were successfully fitted with BDST, Thomas, Yoon-Nelson, and Dose-response models. The fitting parameter values from the BDST model raise the scope of possible upscaling of the fixed-bed column. Hence, it is proposed that these River sand-FeAl(BDC)-based filters can be widely used in areas facing critical contamination and in poor communities with a high demand for water.

Optimization of a High-Performance Poly(diallyl dimethylammonium chloride)-alumina-perfluorooctanoate Intercalated Ultrafiltration Membrane for Treating Emulsified Oily Wastewater via Response Surface Methodology Approach

This research aimed to investigate the ultrafiltration of water from emulsified oily wastewater through the application of surface-functionalized ceramic membrane to enhance its water permeability based on optimized parameters using a cross-flow filtration system. The interactive effects of feed concentration (10–1000 ppm), pH (4–10), and pressure (0–3 bar) on the water flux and oil rejection were investigated. Central composite design (CCD) from response surface methodology (RSM) was employed for statistical analysis, modeling, and optimization of operating conditions. The analysis of variance (ANOVA) results showed that the oil rejection and water flux models were significant with p-values of 0.0001 and 0.0075, respectively. In addition, good correlation coefficients of 0.997 and 0.863 were obtained for the oil rejection and water flux models, respectively. The optimum conditions for pressure, pH, and feed concentration were found to be 1.5 bar, pH 8.97, and 10 ppm, respectively with water flux and oil rejection maintained at 152 L/m2·h and 98.72%, respectively. Hence, the functionalized ultrafiltration ceramic membrane enables the separation efficiency of the emulsified oil in water to be achieved.

XÁC ĐỊNH MẬT ĐỘ NUÔI SINH KHỐI THÍCH HỢP VÀ ĐIỀU KIỆN THỨC ĂN TƯƠNG ỨNG CỦA TÔM TIÊN NƯỚC NGỌT, Branchinella thailandensis, LOÀI THỨC ĂN SỐNG TRIỂN VỌNG CHO ƯƠNG NUÔI THỦY SẢN Ở VIỆT NAM

Tôm tiên nước ngọt, Branchinella thailandensis, là một loài giáp xác nước ngọt có triển vọng sử dụng làm thức ăn cho con giống ở giai đoạn ấu trùng tại Việt Nam vì chúng có kích thước nhỏ, khả năng phát triển nhanh và hàm lượng carotenoid cao. Trong nghiên cứu này, B. thailandensis được nghiên cứu để xác định lượng thức ăn và mật độ nuôi thích hợp để nuôi sinh khối trong môi trường nước ngọt. Để đạt được mục tiêu này, 01 thí nghiệm 3 nhân tố được thực hiện: (i) mật độ nuôi tôm tiên với 3 mức (250, 500 và 1000 cá thể/L); (ii) mật độ thức ăn (tảo sống Spirulina platensis) với 3 mức(5 × 105 tế bào/mL, 1 × 106 tế bào/mL và 2 × 106 tế bào/mL); và (iii) mật độ vi khuẩn có lợi Bacillus subtilis với 2 mức (0 và 1 × 103 CFU/ mL). Kết quả nghiên cứu cho thấy, sau 72 giờ, để đạt được tỷ lệ sống cao nhất (68.33% ± 10.4%) và chiều dài tối đa (2.32 ± 0.23 mm), cần áp dụng mật độ thức ăn là 2 × 106 tế bào/mL với mật độ nuôi tối đa cần duy trì là 250 ấu trùng/L và có bổ sung vi khuẩn có lợi (1 × 103 CFU/ mL). Ở điều kiện nuôi này, 01 thí nghiệm 02 nhân tố được thực hiện để khảo sát nồng độ Carotenoid và khả năng lưu trữ vi khuẩn có lợi trong cơ thể của tôm tiên nước ngọt B. thailandensis. Nhân tố mật độ vi khuẩn có lợi B. subtilis với 2 mức (0 và 1 × 103 CFU/mL), nhân tố mật độ tảo với 3 mức: 5 × 105, 1 × 106, và 2 × 106 tế bào/mL. Kết quả nghiên cứu cho thấy B. thailandensis cũng có thể lưu giữ vi khuẩn có lợi trong cơ thể đến ít nhất là 48 giờ sau khi nở và đạt được hàm lượng carotenoid cao hơn hẳn lúc nuôi với nồng độ thức ăn thấp. ABSTRACT Freshwater fairy shrimp, Branchinella thailandensis, is a highly potential live feed for aquaculture species in Viet Nam, especially in their larval stages due to its small size, high growth and high carotenoid content. In this study, we aimed to identify the suitable feeding density and stocking density, which is inappropriate for mass production in freshwater. To attain these objectives, we conducted 01 three-factor experiment: (i) culture density with three levels (250, 500 and 1000 nauplii L-1); (ii) feed (live Spirulina platens) concentration with three levels (5 × 105 cells mL-1, 1 × 106 cells mL-1 and 2 × 106 cells mL-1); and (iii) beneficial bacteria Bacillus subtilis with two levels (0 and 1 × 103 CFU mL-1). The results indicated that after 72hrs, to the highest survival rate (68.33% ± 10.4%) and total length (2.32±0.23 mm) were obtained when shrimps were fed live S. platensis at 2 × 106 cells mL-1 with probiotics at 1 × 103 CFU/ mL, and density at 250 nauplii L-1. Under those culturing conditions, we conducted 01 two-factor experiment: feed (live Spirulina platens) concentration with three levels (5 × 105 cells mL-1, 1 × 106 cells mL-1 and 2 × 106 cells mL-1); and beneficial bacteria Bacillus subtilis with two levels (0 and 1 × 103 CFU mL-1). The results indicated that B. thailandensis could retain B. subtilis internally up to at least 48 hours and obtain significantly higher carotenoid content than at lower feed concentration.

A Systematic Approach to the Development of Cilostazol Nanosuspension by Liquid Antisolvent Precipitation (LASP) and Its Combination with Ultrasound

Nanosizing is an approach to improve the dissolution rate of poorly soluble drugs. The first aim of this work was to develop nanosuspension of cilostazol with liquid antisolvent precipitation (LASP) and its combination with ultrasound. Second, to systematically study the effect of bottom-up processing factors on precipitated particles’ size and identify the optimal settings for the best reduction. After solvent and stabilizer screening, in-depth process characterization and optimization was performed using Design of Experiments. The work discusses the influence of critical factors found with statistical analysis: feed concentration, stabilizer amount, stirring speed and ultrasound energy governed by time and amplitude. LASP alone only generated particle size of a few microns, but combination with ultrasound was successful in nanosizing (d10 = 0.06, d50 = 0.33, d90 = 1.45 µm). Micro- and nanosuspension’s stability, particle morphology and solid state were studied. Nanosuspension displayed higher apparent solubility than equilibrium and superior dissolution rate over coarse cilostazol and microsuspension. A bottom-up method of precipitation-sonication was demonstrated to be a successful approach to improve the dissolution characteristics of poorly soluble, BCS class II drug cilostazol by reducing its particle size below micron scale, while retaining nanosuspension stability and unchanged crystalline form.

Effect of Feeding on Juvenile Growth Rate of Wader Fish (Rashbora argyrotaenia)

Aquaculture is an activity to develop, obtain, reproduce and produce a fishery with the help of human resources. One of the cultivation practices is wader fish (Rashbora argyrotaenia) which is known for its very slow growth and relatively small size. This study aims to determine the growth rate of wader fish with different feeds in Blado Kulon Village, Tegalsiwalan, Probolinggo. The feed used was feed A in the form of fish pellets as a control, feed B consisting of a mixture of conch flour, soybean flour, bran, and tapioca flour, while feed C consisted of a mixture of conch flour, cassava leaf flour, bran and tapioca flour. The study was conducted for 42 days. The parameters measured in this study were temperature, DO, and pH, as well as observing the growth in absolute weight, specific growth rate (SGR), survival rate, and feed concentration ratio (FCR). Observations were analyzed using One Way Analysis of Variance (ANOVA) and further tests were carried out using the Duncan test. The results showed that different feeding did not have a significant effect on growth rate, absolute weight, feed conversion ratio, and survival of wader fish. Water quality parameters measured include temperature with an average of 28.42oC - 28.54 oC, while pH has an average of 7.42 - 7.50, and dissolved oxygen (DO) with an average of 5.54 - 6, 23 mg / L.

Modelling and Dynamic Simulation of One-Dimensional Isothermal Axial Dispersion Tubular Reactors with Power Law and Langmuir-Hinshelwood-Hougen Watson Kinetics

In this paper, the modelling, numerical lumping and simulation of the dynamics of one-dimensional, isothermal axial dispersion tubular reactors for single, irreversible reactions with Power Law (PL) and Langmuir-Hinshelwood-Hougen-Watson (LHHW)-type kinetics are presented. For the PL-type kinetics, first-order and second-order reactions are considered, while Michaelis-Menten and ethylene hydrogenation or enzyme substrate-inhibited reactions are considered for the LHHW-type kinetics. The partial differential equations (PDEs) developed for the one-dimensional, isothermal axial dispersion tubular reactors with both the PL and LHHW-type kinetics are lumped to ordinary differential equations (ODEs) using the global orthogonal collocation technique. For the nominal design/operating parameters considered, using only 3 or 4 collocation points, are found to adequately simulate the dynamic response of the systems. On the other hand, simulations over a range of the design/operating parameters require between 5 to 7 collocations points for better results, especially as the Peclet number for mass transfer is increased from the nominal value to 100. The orthogonal collocation models are used to carry out parametric studies of the dynamic response behaviours of the one-dimensional, isothermal axial dispersion tubular reactors for the four reaction kinetics. For each of the four types of reaction kinetics considered, graphical plots are presented to show the effects of the inlet feed concentration, Peclet number for mass transfer and the Damköhler number on the reactor exit concentration dynamics to step-change in the inlet feed concentration. The internal dynamics of the linear (or linearized) systems are examined by computing the eigenvalues of the linear (or linearized) lumped orthogonal collocation models. The relatively small order of the lumped orthogonal collocation dynamic models make them attractive and useful for dynamic resilience analysis and control system analysis/design studies.