Regression Analysis for the Adsorption Isotherms of Betacyanin Extracts from the Dragon Fruit Peel onto the Spun Silk Yarn

The betacyanin pigment extracted from the dragon fruit peel has a potential to be a natural dye as an alternative to replace the synthetic dyes. To investigate the dyeability of spun silk with betacyanin pigment, the adsorption isotherm models were performed. The equilibrium adsorption data were analyzed using the Langmuir, Freundlich, and Temkin isotherm models. In order to determine the best-fit isotherm for each system, three error analysis methods were used to evaluate the data, namely the sum of the squares of the errors, residual root mean square error and chi-square test. On the basis of low three error analysis and high correlation of determination, it was found that the Langmuir isotherm model fitted well with the experimental data. Therefore, it can be concluded that the adsorption process of betacyanin pigment onto the spun silk followed the Langmuir isotherm model. Moreover, the adsorption features of the experimental system might be caused by the monolayer adsorption

Surface modification of polyethersulfone membrane via uv-grafting for forward osmosis technology = Modifikasi permukaan membran polyetersulfon melalui cantuman-uv untuk teknologi osmosis ke hadapan

In this study, UV-grafting was used in surface modification of polyethersulfone membrane (UFPES50) for forward osmosis (FO) application. Using two parameters, namely monomer concentration (acrylic acid) and grafting time, the modified membrane was characterised by attenuated total reflectance-Fourier transform infrared (ATR-FTIR), field emission scanning electron microscope (FESEM) and contact angle. The membrane was evaluated for its water permeability, solute permeability, and structural parameter. The water permeability increases as the grafting parameters increases; however, at the highest (50 g/L) of monomer concentration, a sudden drop occurred due to the thickening of the grafted layer. Focusing on this monomer concentration, the grafting time was increased up to 60 minutes and it was successfully demonstrated that the modification using UV-grafting on PES membrane involved both effective grafting and chain scission. In addition, negative rejection on the modified membrane was observed

Mesoporous Ce-doped Ti:Ash Photocatalyst Investigation in Visible Light Photocatalytic Water Pretreatment Process

The treatment of organic pollutants in water including semiconductor photocatalysis is a promising approach to disinfect water. The objective of this study is to investigate the effect of Ce loaded on mesoporous Ti:Ash catalyst for water pretreatment process. The mesoporous Ti:Ash catalyst that doped with Ce was synthesized through wet impregnation method with 5%, 10%, and 15% weight percentage of Ce doped on 40:60 Ti:Ash. The photocatalytic properties were characterized through X-ray powder diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy, N2 adsorption-desorption studies and diffuse reflectance UV–vis absorption spectroscopy. It is found that the Ti:Ash nanocomposites doped with Ce shifted the light absorption band-edge position to the visible region. Moreover, the Ce doped Ti:Ash has large surface area and pore diameter. The Ce doping could significantly improve the absorption edge of visible light and adjust the cut-off absorption wavelength from 404 nm to 451, 477 and 496 nm for 5%, 10% and 15% Ce-doped mesoporous Ti:Ash catalysts, respectively. As the Ce doping ratio increased, the band gaps decreased from 3.06 eV to 2.53 eV. The most contaminant reduction up to 45% was achieved when Ti:Ash:Ce 40:55:5 was used. Higher Ce loading on the photocatalyst may reduce the photocatalyst performance because supernumerary metal loading on TiO2 can block TiO2 defect sites which are necessary for the adsorption and photoactivation. The OPFA also acts as an adsorbent for some pollutants besides, reducing the water salinity. It can be deduced that the hybrid TiO2 photocatalyst that synthesized with OPFA and doped with Ce has huge potential to treat seawater prior to commercial seawater desalination process. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Application Of Factorial Design To The Stress Phenomenon Of Bacillus Cereus (Atcc 14579) Growth

Background: A two level (23) factorial design of experiment (DOE) was employed to investigate the influence of nutrients concentrations and main operational parameters on the growth of Bacillus cereus (ATCC 14579) in a shake flask. The factorial models have been established from experimental design to study the individual and interactions effects toward the response within the selected variables nutrient concentration (4-16gl-1), temperature (300C – 420C), agitation (140rpm-200rpm) and acclimatization time (24hours-72hours). These were statistically validated using analysis of variance (ANOVA). Objective: The present study aimed to use fractional factorial design of experiment to investigate the influence of growth limiting factors to the bacterial growth in a fermenting medium of orbital shaker. Results: The results revealed that the model terms were all significant with F-value of 251.07 at (p temperature > acclimatization time. The analysis of the experimental response indicated that the interaction of nutrient concentration and temperature had the highest influence on the response. Whereas the interaction effects of nutrient and acclimatization time was found to be statistically insignificant. Based on the R2 and adjusted R2 the estimated model terms spell high degree of relationship between observed and predicted values, thus the prediction ability of the models is maintained. Conclusion: Although the interaction models terms have significant effects, their levels were only less likely comparable to linear effects. It could therefore concluded that nutrient concentration, temperature and to some extend acclimatization time were four to greatly limit growth at a specific ranges. In general, the predicted value was in reasonable agreement with the experimental data, further confirming the very good prediction ability of the model

Effect of methacrylic acid monomer on the reverse salt diffusion in chemical grafted forward osmosis membrane

Reverse salt diffusion (RSD) is a common issue in forward osmosis (FO) membrane normally contribute to substantial fouling and lead to a lower water flux. Commercial nanofiltration (NF) membrane surface was grafted using chemical grafting for controlling this RSD issue. Different concentrations of 0.3, 0.6, and 1.0 M of methacrylic acid (MA) were selected as main monomer while potassium persulfate and sodium metabisulfite (K2S2O8/Na2S2O5) with concentration of 0.01 M as pair of initiators were used for the grafting modification. Then the grafted membrane was evaluated in term water flux (Jw) and RSD using 1 M sodium chloride (NaCl) as draw solution. The result shows that, the highest Jw (0.7534 L/m2.h) and the lowest RSD (4.272 g/m2.h) both were recorded at the grafting of 30 min with 1.0 M concentration of MA. Both performance increase with the increasing in the MA concentration and grafting time. Therefore, modification of the commercial NF membrane using chemical grafting can therefore be used as an alternative technique for enhancing the performance of commercial membrane in the application of FO

Hydrogen Sulphide (H2S) Awareness Training for Process 3 Services Solution Sdn Bhd

Hydrogen Sulphide (H2S) is one of the major polluting substances found in petroleum refinery wastewater as well as other industrial and domestic sludge. Sulfide build up may cause several side effects like corrosion of concrete sewer pipes, releasing unpleasant odors, toxicity due to sulfide gas and negative effect to subsequent wastewater. Early detection and accurate quantification of hydrogen sulphide is necessary to assure equipment integrity, to comply with regulations and to ensure safety of workers. Routine maintenance and inspection activities become non-routine when hydrogen sulphide present in the workplace is above the Permissible Exposure Limit (PEL) 10 mg/L and become problematic when hydrogen sulphide concentrations are above the PEL level. Occupational Safety and Health Administrations (OSHA) enforceable ceiling limit for workplace exposure is set at 20 parts per million (ppm). The National Institute of Occupational Safety & Health (NIOSH) Permissible Exposure Limit (PEL) for hydrogen sulphide is set at 15 mg/m3 (10 ppm) averaged over a 10 minute period, and that work areas in which the concentration of hydrogen sulfide exceeds 70 mg/m3 be evacuated . P3SS Sdn. Bhd. is one of the petrochemical based industries which facing direct hydrogen sulphide exposure in their jobs. The objective of this program is to conduct workshops as part of development process to generate a training methodology in hydrogen sulphide handling, hydrogen sulphide monitoring and hydrogen sulphide surveillance, to apply the knowledge of mercury awareness and proper personal protective equipment (PPE) used while handling hydrogen sulphide

Water flux prediction of UV-photografted nanofiltration membrane for forward osmosis application

In the application of forward osmosis, commercial nanofiltration (NF) membrane was modified via ultraviolet(UV)-photografting technique at different grafting parameters; monomer concentration (acrylic acid) and grafting time. However, the performance of the modified membrane measured at the osmotic pressure of 1M NaCl as draw solution limits their applications. In this research, the mathematical modelling was applied to predict the water flux at different osmotic pressure. The mathematical modelling indicated that the generated water flux follows the osmotic pressure but strictly affected by the grafting parameters. The result shows that at grafting time of 3min, the monomer concentration of 15 g/L generates the highest water flux followed by the membrane modified at the monomer concentration of 30 g/L. High water flux was attributed to the presence of strongly hydrophilic groups at new carboxyl layers leading to improved membrane properties. The approach of theoretical modelling on the membrane that is reported in this work allows estimating the water flux at different grafting parameter

Influence of Polyethersulfone substrate properties on the performance of thin film composite forward osmosis membrane: Effect of additive concentration, polymer concentration and casting thickness

This research seeks to optimize the impact of substrate parameters such as polyvinylpyrrolidone (PVP) additive concentration (3–11 wt%), polyethersulfone (PES) concentration (11–17 wt%), and casting thickness (100–250 μm) on the overall performances of (PES) thin film composite (TFC) FO membrane. Non-solvent induced phase separation (NIPS) method was used to fabricate the substrate membrane, which was then followed by the interfacial polymerization of m-phenylene diamine (MPD) in aqueous solution and trimesoyl chloride (TMC) in hexane-organic solvent to form the active polyamide (PA) layer. Analyses of contact angle, porosity, pore size, functional group, morphology, and surface roughness were performed on membrane substrates and TFC membrane. Membrane performance parameters such as water flux (Jw), reverse salt diffusion (RSD), and specific reverse flux (SRF) were evaluated for the fabricated TFC membranes using the FO filtration system (pure water as feed solution and NaCl as draw solution). In addition, the water permeability coefficient (A), the solute permeability coefficient (B), and the structural parameter (S) were computed mathematically. Optimized membranes were chosen using the specific reverse flux (SRF) as the principal performance indicator. The optimal membranes for each parameter were then evaluated for their antifouling and rejection properties using humic acid (HA) solution. Among the optimized membranes, 15%PES/5%PVP/100 μm membrane exhibited the best performance with high rejection and antifouling properties towards HA

Factorial screening on the development of cellulose nanocrystal/ carboxylated multi-walled carbon nanotube polyethersulfone membrane for humic acid rejection

A two-level factorial experimental design was used to formulate the dope composition of cellulose nanocrystal (CNC) multi-walled carbon nanotube (MWCNT) polyethersulfone (PES) membrane for humic acid (HA) rejection. Four factors were screened, which are the composition of PES (1517 wt.%), polyvinylpyrrolidone (PVP, 1-4%), CNC (0.01-0.75%), and carboxylated MWCNT (00.025%). The membranes were evaluated based on HA rejection from a 10-ppm aqueous feed solution. The percentage of MWCNT was the most significant factor, accounting for 72.31 % of the contribution. The highest HA rejection of 90% was obtained from the membrane fabricated using 17 % PES, 1% PVP,0.01 % CNC, and 0.025% MWCNT. The predicted values generated from the model agreed reasonably with the experimental data, demonstrating the model's validity

Tetrabutylphosphonium trifluoroacetate ([P4444]CF3 COO) thermoresponsive ionic liquid as a draw solution for forward osmosis process = Larutan ionik responsif haba tetrabutilfosfonium trifluoroasetat ([P4444]CF3 COO) sebagai larutan penarik untuk proses osmosis kehadapan

Forward osmosis (FO) is recognized as a potential membrane technology that utilizes low energy for water desalination. It is driven by natural osmotic pressure difference between feed solution and draw solution across semipermeable membrane. Pure water will permeate from the salinity feed water to the draw solution side. In order to produce pure water, it is necessary to find the best draw solute that exhibits high draw ability and can separate the permeated water efficiently from the draw solution. In the current study, lower critical solution temperature (LCST) thermoresponsive ionic liquid (IL) of tetrabutylphosphonium trifluoroacetate ([P4444]CF3COO) was synthesized as the draw solute for FO process. ([P4444]CF3COO) is dissolved in water below its critical temperature of 29°C and becomes two layered above this critical temperature. [P4444]CF3COO IL showed high water flux of 0.44 ± 0.007 LMH compared to the water flux of 0.32 ± 0.049 LMH for the NaCl draw solute at the same draw solution concentration. Applying thermoresponsive IL as the draw solute in FO process has the potential to treat high salinity of feed stream with ease of water recovery and draw solute regeneration