Independent Process Variables Research Articles

WITHDRAWN: Optimization of wear parameters of aluminium composites (AA7010/15wt%MoO3) utilizing taguchi technique

In this analysis, an investigation was carried out on the wear properties of AA7010/15%MoO 3 AMCs. The key focus was on optimizing processing parameters to evaluate prepared composites employing the Taguchi response study. Experimental runs are organized using the Taguchi system. The experiment was carried out by considering independent process variables such as applied load, operating temperature and rotating distance at three different speeds. Wear rate (gram) is chosen for this research as output characteristics. Each particular process variable's effect on the optimal response parameters has been studied from this observational investigation.

Simultaneous isolation and selective encapsulation of volatile compounds from essential oil during electrospraying of β-Cyclodextrin

This study's primary purpose was to develop a new technique to stabilize high value-added bioactive volatile compounds present in essential oils to ensure their usability as chemical raw materials with enhanced stability. Selective isolation and encapsulation of various volatile compounds by changing the electrospraying process parameter, including voltage, flow rate, and β-Cyclodextrin concentration, were attributed to the formation of inclusion complexes between β-cyclodextrin and volatile compounds. Investigations regarding the effects of independent process variables on simultaneous isolation and selective encapsulation of volatile compounds during electrospraying of β-cyclodextrins were carried out mainly with TLC analyses. The TLC analyses were confirmed with GC, GC–MS, and 1H NMR analyses. It was possible to obtain nanoparticles with an average particle size between 25–160 nm with the designed system. Obtained data revealed that isolation and encapsulation of cumin aldehyde, camphene, isoborneol, and hexadecanoic acid, benzyl benzoate from labdanum essential oil were successfully achieved.

Statistically optimized charcoal production from Prosopis juliflora for use as alternative fuel in cement factories

Prosopis juliflora is an invasive species, which is spreading at an alarming rate in Ethiopia. Cement factories in the country are using fossil fuels contributing to the global greenhouse gas emission. The present study has aimed at utilizing Prosopis juliflora charcoal as a carbon-neutral alternative fuel for cement factories with the objectives of reducing CO2 emission and controlling the spread of the plant to arable areas. The study focused on optimizing the charcoal preparation conditions using central composite design response surface methodology. The independent process variables were carbonization temperature and time, which were investigated in the temperature and time ranges of 300–600 °C and 60–180 min, respectively. The response variables were charcoal yield, calorific value, and volatile matter content. Quadratic model equations were selected for all responses based on analysis of variance. The respective regression analyses have demonstrated that the model equations can be used to predict the charcoal yield, calorific value, and volatile matter content in the investigated range with 99.85%, 99.9%, and 99.9% variability, respectively. For the predicted optimal carbonization condition, charcoal yield, calorific value, and volatile matter content were found to be 47.52%, 24.43 MJ/kg, and 56.58%, respectively. The charcoal prepared at the optimized condition was subjected for elemental and proximate analysis and compared with other alternative fuels that are in use in the industry. Results show that the charcoal has better desirable properties such as less moisture and volatile matter and higher fixed carbon content and calorific value.

Optimization of tocols and γ-oryzanol extraction from rice bran using ultrasound and soybean oil as a green solvent

A new process was developed to extract tocols and γ-oryzanol from rice bran using ultrasound with soybean oil as a natural solvent. Results were compared to the conventional solvent method. The extraction process was optimized using response surface methodology (RSM) with three independent process variables as amplitude level (A) (20-60%), extraction temperature (B) (25-65°C) and time (C) (20-60 mins). Statistical analysis indicated that models developed for all responses were significant. Linear terms of all process variables had significant effects on α-tocopherol, γ-tocopherol, and γoryzanol, while quadratic effects of amplitude level (A2), temperature (B2) and time (C2) on all responses were highly significant. Optimal process conditions for maximum yield of tocopherols and γ-oryzanol were 40% amplitude level, 65°C solution temperature and 40 mins. Yields of α-tocopherol and γ-oryzanol in oil extracted under the optimal conditions or ultrasound-assisted soybean oil extraction (O-UASO) were comparable to oil yield produced by conventional solvent extraction (O-CSE). Interestingly, O-UASO showed higher total antioxidant activities compared with O-CSE. Extraction using ultrasound with soybean oil was proposed as an effective alternative green process to improve oil functionality without the need for separating environmentally hazardous organic solvents.

EVALUATION OF MASS TRANSFER DURING OSMO-CONVECTIVE DRYING OF BENINCASA HISPIDA CUBES IN SALT SOLUTION USING REGRESSIONAL-DESIRABILITY METHOD

Regressional-desirability approach in Box-Behnken response surface design was employed in this study to examine and optimize the osmotic dehydration process of Benincasa hispida cubes by impregnating in salt solution as an osmotic agent. The effect of independent parameters such as, concentration of solution (1-5%), sample to solution ratio (1:5-1:15 g/ml), temperature of osmotic solution (30-50℃) and time of immersion (30-180 min) on the weight reduction (WR), solid gain (SG), water loss (WL), rehydration ratio (RR) and shrinkage (SH) were studied. Second order polynomial mathematical models were developed for the responses and all the independent process variables have considerable consequence on the responses. The optimal dehydration process condition was found by regressional-desirability method and were: osmotic solution concentration of 2.73%, sample to solution ratio of 1:14 g/ml, osmotic solution temperature of 50℃ and osmotic dehydration time of 179 minutes with the mass transfer and quality properties such as weight reduction of 24.59%, solid gain of 7.69%, water loss of 32.28%, rehydration ratio 11.43%, shrinkage 8.58% and overall acceptability 8.19. The optimized samples were subjected to convective drying in cabinet tray dryer at different drying air temperatures (40, 50 and 60℃). The results indicated that the osmotic pre-treatment of the samples using salt solution was better in terms of water removal and reduction in the processing time when combined with convective drying process. Also, the quality of the final product was found to be good for the osmo-convective dried product using salt solution.

Barium Hydrogen Phosphate Electrodes for High Electrocatalytic and Photoelectrocatalytic Degradation of Rhodamine B in Neutral Medium: Optimization by Response Surface Methodology

Barium hydrogen phosphate (BaHPO4) thin films were electrodeposited on fluorine-doped tin oxide (FTO) and used as electrocatalysts for organics degradation. The effects of applied current density and deposition time on the phase and morphology of electrodeposited films were analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflectance-Fourier-transform infrared (ATR-FTIR) spectroscopy, Raman spectroscopy, electrochemical impedance spectroscopy (Mott–Schottky) plots, and photocurrent response. The electrodeposited BaHPO4 films crystallize in the orthorhombic structure and form platelets on the FTO substrate. Response surface methodology (RSM) was used to optimize the operational conditions. Four independent process variables were considered: NaCl concentration, rhodamine B (RhB) initial concentration, applied current density, and reaction time. Based on the model prediction, the optimum conditions for RhB degradation were determined with the maximum RhB degradation of 98.78%. The corresponding experimental value of RhB degradation under the optimum conditions was determined as 99%, which is very close to the optimized one, implying that RSM is a powerful strategy for the process optimization. The photoelectrochemical degradation of RhB, performed at optimal operational conditions, allowed the very fast degradation rates of almost 99% during 7 min due to the synergic effect while combining photocatalysis and electrocatalysis.

Exploitation of Kiwi Juice Pomace for the Recovery of Natural Antioxidants through Microwave-Assisted Extraction

In a completely green approach to the exploitation of kiwi juice pomace (KP), a microwaved-assisted extraction (MAE) process was performed to extract antioxidant compounds present in KP, evaluating the influence of four independent process variables (temperature (T), extraction time (E), solvent composition (C), and solid-to-solvent ratio (R)) on the response of total phenolic content (TPC). The optimal conditions for the green extraction of total polyphenols from KP were obtained using a three-level fractional factorial design under response surface methodology (RSM) coupled with desirability optimization, and a feed-forward multilayered perceptron artificial neural network (ANN) with a back-propagation algorithm. Data were analyzed by ANOVA and fitted to a second-order polynomial equation using the regression method. Results showed that T was the most influential factor, followed by R and C, whereas the extraction time (E) was not shown to have a significant linear effect on the extraction yield of total polyphenols (TPs). The optimal conditions based on both individual and combinations of all responses were found out (T: 75 °C; E: 15 min; C: 50% ethanol:water; R: 1:15), and under these conditions the obtained extract showed both a high bioactive compound content and a high antioxidant potential, pointing out how this by-product could become an inexpensive source of compounds with high added value. A very good agreement was observed between experimental and calculated extraction yields, thus supporting the use of these models to quantitatively describe the recovery of natural antioxidants from KP. Finally, the ANN model exhibited more accurate prediction and better generalization capabilities than the RSM model (R2: 0.90 and 0.99, for RSM and ANN, respectively).

Optimization of Polyphenols and Carotenoids Extraction from Leaves of Cassia auriculata for Natural Health Products

Aims: C. auriculata leaves contains polyphenols and carotenoids and also it posses various antioxidant activities towards free radical scavenging, lipid peroxidation inhibition and reducing potential. The present study investigated the optimization of polyphenols and carotenoids extraction from Cassia auriculata leaves by response surface methodology (RSM).
 Study Design: A three-factor, three-levels central composite design (CCD) was performed to determine the effect of solvent concentration (30-100%), extraction temperature (30-60°C) and extraction time (30-90 min) to obtain the best extraction parameters.
 Place and Duration of Study: Fresh C. auriculata leaves were collected from home gardens in Makandura area of Sri Lanka and the experiments were conducted at the Department of Food Science and Technology of Wayamba University of Sri Lanka between June 2016 and August 2016.
 Methodology: Total polyphenol and carotenoid contents of the ethanolic extracts of the C. auriculata leaves were determined. Total polyphenols and carotenoids content in the extracts were used as the response variables. According to the design used, twenty randomized experiments including six replicates as the center points were assigned based on the combinations of extraction variables used CCD and the values of independent process variables considered, as well as response variables. The optimal value of these factors was determined suing response surface methodology. Predicted values were compared with experimental values.
 Results: The optimum extraction conditions for phenolics and carotenoids were 45.4% ethanol; 19.8°C; 110.5 min and 100% ethanol; 70.2°C; 9.5 min respectively. The optimal predicted contents for total polyphenols and carotenoids were 13.08 mg GAE/g-DW and 17.31 mg/g-DW respectively. Validation experiments results had good agreement with the predicted responses by RSM.
 Conclusion: Ethanol concentration was the most significant factor affecting on total polyphenols and carotenoids extraction. Extraction temperatures and time did not significantly influence on carotenoids and polyphenols extraction from leaves of C. auriculata. The estimated optimum extraction conditions; were established and they were very close to the experimental values. These parameters can be used as the guidelines for scale-up extraction of bioactives from the leaves of C. auriculata.

Optimization and modeling of ethanol–alkali pulping process of bamboo (Yushania alpina) by response surface methodology

Response surface methodology based on the central composite design was used to investigate modeling and optimizing the individual and interactive effects of independent process variables (temperature, pulping time, ethanol concentration and alkali concentration) on the yield, kappa number and brightness of the pulp produced from the bamboo species Yushania alpina. Based on the central composite design, quadratic models and two-factor interactions were developed and correlated the pulp yield, kappa number and brightness of the pulps. The most significant parameters that affect the pulp yield, kappa number and brightness of the pulp were found to be temperature, ethanol concentration and alkali concentration, respectively. The optimum process variables were found at a cooking temperature of 162.30 °C, cooking time of 180 min, ethanol concentration of 60% and alkali concentration of 18.03% producing maximum pulp yield of 53.56% and brightness of 63.85%, and minimum kappa number of 11.65, and desirability of 0.882. In addition, the chemical analysis of Y. alpina chips was compared with different bamboo species. The predicted optimum conditions provided tensile index, burst index and tear index of 48.25 kN m/kg, 2.95 kPa m2 and 2.80 N m2/kg, respectively, and were experimentally confirmed. In general, the findings of the study show that pulp produced from the bamboo species Y. alpina is a suitable raw material for the paper and pulp industry.

Nonlinear scheduling with time‐variable electricity prices using sensitivity‐based truncations of wavelet transforms

AbstractWe propose an algorithm for scheduling subject to time‐variable electricity prices using nonlinear process models that enables long planning horizons with fine discretizations. The algorithm relies on a reduced‐space formulation and enhances our previous work (Schäfer et al., Comput Chem Eng, 2020;132:106598) by a sensitivity‐based refinement procedure. We therein expose the coefficients of the wavelet transform of the time series of independent process variables to the optimizer. The problem size is reduced by truncating the transform and iteratively adjusted using Lagrangian multipliers. We apply the algorithm to the scheduling of a multi‐product air separation unit. The nonlinear power consumption characteristic is replaced by an artificial neural network trained on data from a rigorous model. We demonstrate that the proposed algorithm reduces the number of optimization variables by more than one order of magnitude, whilst furnishing feasible schedules with insignificant losses in objective values compared to solutions considering the full dimensionality.

Optimization of glycerol etherification with ethanol in fixed bed reactor under various pressures

Abstract The objective of this paper was to study the glycerol etherification with ethanol in a fixed bed reactor catalyzed by Amberlyst 15. We analyzed through a four factor central composite design the influence of independent process variables including pressure (7–103 MPa), temperature (180–290 °C), ethanol/glycerol molar ratio (4–30/1) and amount of catalyst (0–0.95 g). Special interest was taken in evaluating the effect of pressure, since this reaction mixture can be one or two phase depending on this variable. The results showed that for this system it is not necessary to keep all the reaction mixture in just one phase to obtain good results in terms of glycerol conversions and ether yields. For the glycerol conversion, a maximum of 97% was obtained and the optimum conditions were temperature (269 °C), ethanol/glycerol molar ratio (12:1), catalyst amount (0.78 g) and pressure (2.5 MPa). In terms of ether yield, the optimization study using canonical analysis predicted the following optimal levels were predicted: pressure (7.1 MPa), temperature (242 °C), ethanol/glycerol molar ratio of (22:1) and catalyst amount (0.63 g). Under these operating conditions, the experimental value for ether yield obtained was 69%, confirming the result predicted by the optimization study. These results indicated that the equations were effective in describing the actual experimental data. Reaction conditions in which glycerol-ethanol form two phase mixtures still presented excellent results on the responses.

Spray drying of organic strawberry extract

In this study, the effects of spray drying parameters on organic strawberry extract were investigated. Response surface methodology was applied to optimize spray drying conditions. Air inlet temperature (120-150°C), extract mass percentage in the feed mixture (m/m in dry basis 15-50%) and solid content of feed (20-40 Brix) were the independent process variables and maltodextrin was used as encapsulating agent. The responses of model were operational efficiency (yield) and phenolic retention. The optimum temperature, extract mass percentage and solid content of feed were estimated as 120°C, 23.26% (m/m) extract, and 20.00 Brix. The maximum levels of responses under optimum conditions were obtained as operational efficiency of 91.95% and phenolic retention of 79.62%. It was found that the most important variable was extract mass percentage in production of strawberry extract powders. As a result, organic strawberry extract powder can be effectively produced by spray drying.

Desulfurization of di-benzothiophene from gasoil model using Ni-Co2, Ni-Fe2 and Co-Fe2 nano layered-double hydroxides as photocatalysts under visible light

The synthesis and the development of Ni-Co2, Ni-Fe2, and Co-Fe2 layered double hydroxides (LDHs) with Co32− interlayer anion as novel photo-catalysts at photo-desulfurization of dibenzothiophene (DBT) from Gasoil is investigated. All LDHs exhibited the photocatalytic activity in the desulfurization of the Gasoil under visible light at the same conditions. Among them, Ni-Co2 LDH exhibited the highest activity and supported on Fe3O4 to get a high surface magnetic nanocomposite as photocatalyst. The photocatalytic tests showed a good correlation between the bandgap values, cation size in LDH and the photocatalytic activity. The physical–chemical properties of the Ni-Co2 LDH and the related magnetic catalyst were further characterized by X-ray diffraction (XRD), BET, Fourier Transform Infrared (FTIR), Field-Emission Scanning Electron Microscope (FESEM), Elemental mapping, Uv–Vis diffuse reflectance spectroscopy (UV–Vis DRS), Transmission electron microscopy (TEM), vibration sample magnetometer (VSM) and thermal gravimetric analysis (TGA). The desulfurization process using Ni-Co2 LDH/Fe3O4 photocatalyst was modelled and optimized by Box-Behnken method of response surface methodology and considering DBT concentration, photocatalyst dosage and reaction time as three independent process variables. Besides, the interactions between the process factors were investigated. The optimum conditions resulted for a Gasoil containing 65 ppm DBT, which was desulfurized by 0.0895 g of Ni-Co2 LDH/Fe3O4 under visible light for 222 min. Under these conditions, 74.6% of DBT was removed whereas the RSM model predicted the 76% removal of DBT. The study indicated that the magnetic Ni-Co2 LDH/Fe3O4 could be the promising catalyst for the photo- desulfurization of diesel.

Evaluation and Optimization of Kraft Delignification and Single Stage Hydrogen Peroxide Bleaching for Ethiopian Sugarcane Bagasse

ABSTRACT The current study investigated the Ethiopian sugarcane bagasse during its delignification using the Kraft pulping process and bleaching by single stage hydrogen peroxide process. The multilevel categoric experimental design was used to appraise the effects of the independent process variables (temperature, NaOH concentration, and time) on the pulp yield and kappa number during the Kraft pulping process. The central composite experimental design of response surface methodology was used to appraise the effects of independent bleaching variables (bleaching temperature, H2O2 concentration, and time) on the pulp yield, brightness, and whiteness during the bleaching process. The optimal pulp yield was 38.41% with 17.68 kappa number. The bleached pulp yield for the pulp with kappa number of 17.68 and the pulp with kappa number of 8.41 were 84.12% and 83.91%, respectively. The brightness and whiteness for the pulp with kappa number of 17.68 were 61.92% and 85.36%, respectively. Similarly, for the pulp with a kappa number of 8.41, the brightness and whiteness were 68.35% and 91.43%, respectively. Paper from the pulp with kappa number of 17.68 has higher tensile, burst, and tear strength. The study shows the promising utilization of the Ethiopian sugarcane bagasse for paper production via the Kraft delignification and single stage hydrogen peroxide bleaching.

Insights into endocrine-disrupting Bisphenol-A adsorption from pharmaceutical effluent by chitosan immobilized nanoscale zero-valent iron nanoparticles

Bisphenol A (BPA) in the aquatic environment have adverse effects on human health and other living organisms. BPA at low traces can lead to cardiovascular disease, type II diabetes, and impaired hepatic enzymes. For efficient BPA removal, chitosan immobilized nanoscale zero-valent iron (nZVI-chitosan) nanoparticles were synthesized and used as adsorbent. Since the BPA removal efficiency depends on independent process variables like nZVI-chitosan dosage, initial BPA concentration, pH and contact time, experiments were conducted systematically. To characterize the interaction effect of these variables, the experimental matrix is designed using response surface methodology (RSM). The isothermal and kinetic model parameters are estimated using differential evolution optimization (DEO), and these parameters better represent adsorption behaviour. The batch adsorption experiments indicated that the BPA adsorption on to nZVI-chitosan follows pseudo 1st order kinetic models. The maximum extent of BPA adsorption was 65.16 mg/g based on the Langmuir isotherm model. DEO based model parameters better fit the non-linear models with high R2 and lower RMSE. The regenerability experiments indicate that synthesized nZVI-chitosan adsorbent can be used up to three cycles with removal efficiency over 50%. The thermodynamic studies indicated that ΔG° is negative signifying a favourable and spontaneous adsorption process. The inhibition effects of coexisting ions on BPA adsorption followed the order of Mn2+ > Ca2+ > Mg2+ > Fe2+ for cations and of SO42− > NO3− > Cl− for anions. The BPA removal from real pharmaceutical wastewater is 93.8% obtained for optimal initial BPA concentration of 6 mg/L, an adsorbent dosage of 1.5 g/L, with solution pH of 3 and adsorption time of 1 h, whereas this removal efficiency is 95% for synthetic wastewater.

Optimization of xylanase production using ragi (Eleusine coracana) husk as a substrate by Aspergillus fumigatus JCM 10253 through response surface methodology

Hydrolytic enzymes play a significant role in hydrolyzing lignocellulosic polysaccharides into fermentable sugars. Due to the complex structure of lignocellulosic materials, developing robust processes for high titer production is a major challenge. The present study was investigated on xylanase production by filamentous fungi Aspergillus fumigatus strain JCM 10253 using agricultural residue ragi husk as a substrate for microbial fermentation. Central composite design (CCD) was employed to optimize the independent process variables and their effect on xylanase activity. Experimental results with optimized process variables showed 156.7 IU/mL activity under 1.24% substrate concentration and pH 2.0 at 49.9 °C after 120 h of the incubation period. The morphological study of isolate JCM 10253 was observed by scanning electron microscopy analysis and Fourier transform infrared spectroscopy was used to characterize the crude enzyme for secondary protein helical structures. Thus, this study demonstrates that ragi husk could be a potential substrate for xylanase production and can be further used as value-added industrial products.

Micronutrients, antinutrients composition and sensory properties of extruded snacks made from sorghum and charamenya flour blends

The effect of process variables (feed composition, feed moisture, and exit barrel temperature) on the vitamins, antinutrients, and sensory profile of extruded snacks produced from sorghum and charamenya flour blends using response surface methodology were investigated in this study. Feed composition (FC, 10-30%), feed moisture content (FMC, 25-30%) and exit barrel temperature (EBT, 110-130°C) were the independent process variables considered while vitamins, anti-nutrients and sensory evaluation were the response variables. Flour produced from sorghum (SF) and charamenya (CF) seeds were blended in the ratio of 3.2:96.8, 10:90, 20:80, 30:70 and 36.8:63.2%. The blends were conditioned to desired moisture content and allowed to equilibrate overnight in a refrigerator (4°C). Feeding temperature, cooking temperature, screw speed, and pressure of the extruder were set at 90 and 100°C, 250 rpm, and >300 psi, respectively. Extruded snacks from each run were collected when steady state extrusion conditions were attained and dried overnight at 40°C in a cabinet dryer. The vitamins (A, B1, B2, B6, B12, C, and D) and antinutrients (phytate, oxalate and tannin) content reduced post extrusion when compared with the flour blends prior to extrusion. They were significantly (p 0.05), indicating the extrusion process’s ability to reduce the beany flavor associated with legumes. Key words: Extrusion, snacks, micronutrient, antinutrients, sensory, cereal-legume.

Modeling and optimization by particle swarm embedded neural network for adsorption of methylene blue by jicama peroxidase immobilized on buckypaper/polyvinyl alcohol membrane

Jicama peroxidase (JP) immobilized functionalized Buckypaper/Polyvinyl alcohol (BP/PVA) membrane was synthesized and evaluated as a promising nanobiocomposite membrane for methylene blue (MB) dye removal from aqueous solution. The effects of independent process variables, including pH, agitation speed, initial concentration of hydrogen peroxide (H2O2), and contact time on dye removal efficiency were investigated systematically. Both Response Surface Methodology (RSM) and Artificial Neural Network coupled with Particle Swarm Optimization (ANN-PSO) approaches were used for predicting the optimum process parameters to achieve maximum MB dye removal efficiency. The best optimal topology for PSO embedded ANN architecture was found to be 4-6-1. This optimized network provided higher R2 values for randomized training, testing and validation data sets, which are 0.944, 0.931 and 0.946 respectively, thus confirming the efficacy of the ANN-PSO model. Compared to RSM, results confirmed that the hybrid ANN-PSO shows superior modeling capability for prediction of MB dye removal. The maximum MB dye removal efficiency of 99.5% was achieved at pH-5.77, 179 rpm, ratio of H2O2/MB dye of 73.2:1, within 229 min. Thus, this work demonstrated that JP-immobilized BP/PVA membrane is a promising and feasible alternative for treating industrial effluent.

Evaluation of Soda Delignification and Single-Stage Hydrogen Peroxide Bleaching for the Ethiopian Sugarcane Bagasse for Paper Production

The present study investigated the Ethiopian sugarcane bagasse during its delignification via the sulfur-free soda pulping process and bleaching by the single-stage hydrogen peroxide process. The multilevel categoric experimental design was used to assess the effects of the three independent process variables (pulping temperature, NaOH concentration and time) on the pulp yield and kappa number, during the soda pulping process. The effect of the independent bleaching variables (bleaching temperature, time and H2O2 concentration) on the pulp yield, brightness and whiteness was assessed by using the response surface methodology (central composite experimental design). The soda pulps from the Ethiopian sugarcane bagasse were of varying yield and kappa number and hence were classified according to the sugarcane bagasse providing the highest pulp yield (pulp-SA) with 88.07% and that providing the lowest pulp yield (pulp-SB) with 85.17%. Their corresponding kappa numbers were 16.73 and 8.27, respectively. The brightness and whiteness for the pulp-SA were 62.02% and 84.43%, respectively, whereas for the pulp-SB, the corresponding values were 71.86% and 90.47%, respectively. The study further shows that the paper produced from the pulp-SA had higher mechanical properties. Thus, the promising valorization of the Ethiopian sugarcane bagasse for paper production using the adopted methodology, namely the soda pulping and single-stage hydrogen peroxide bleaching routes, is validated.

Reactive extraction of propionic acid using trioctylamine in 1–decanol by response surface methodology optimization technique

Abstract Reactive extraction, a novel technique, was experimentally investigated for the removal of propionic acid, which is usually present in low concentrations in aqueous solutions. The experiments were conducted according to statistical design to develop an appropriate regression model. This was aimed at analyzing and optimizing the process variables and extraction efficiency for propionic acid reactive extraction from dilute aqueous streams using trioctylamine as extractant and 1-decanol as organic diluent. Response surface methodology in combination with Box–Behnken design involving 17 experimental runs was utilized for the propionic acid reactive extraction in this study. Three independent process variables were chosen as temperature (T), initial propionic acid concentration (CPAO) in the aqueous phase and trioctylamine composition (CTOA) in the organic phase. The statistical design analysis demonstrated that the propionic acid concentration and TOA composition had a significant effect while temperature had an insignificant effect on the response value as well as an interactive and quadratic effect on the response. The optimum conditions for propionic acid extraction were established as T = 300.752 K, CTOA = 18.252 %v/v, CPAO = 0.408 kmol/m3. Under these optimum conditions, the propionic acid experimental extraction yield was 89.788 %, which was in close conformity with the predicted yield value of 91.939 %.