Effects Of Reaction Variables Research Articles

Adsorbents Characterization and Effect of Reaction Indices on The Uptake of Cadmium (II) and Chromium (VI) Ions From Wastewater

The effect of reaction variables on the uptake of heavy metals from wastewater using modified chitosan and plantain peels carbon based adsorbents was explored in this study. Plantain peels were carbonized, activated with phosphoric acid and the activated carbon was separated into various proportions and impregnated with various percentages of chitosan to make the composite biosorbents. Deproteinization, deminerization, and deacetylation techniques were used to extract chitosan from a snail shell. Fourier transform infrared (FTIR), energy dispersive X-ray (EDAX), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) techniques were used to analyze the adsorbents. Effects of process parameters: pH of wastewater, adsorbent dosage, temperature, initial concentration and contact time were determined. In the blending ratios of the biosorbents, 75% oxalic acid modified chitosan-25% activated plantain peel (CHT-APP5) was best blend and the optimum process variables for the removal efficiency were time (60-65mins), adsorbent dosage (2-2.125g/dm3), pH(6-6.5), initial concentration of wastewater(20-85mg/dm3) and temperature (308-325K). The results obtained showed that the maximum adsorption capacities of 90.9090, 55.5556 and 142.8571mg/g for Cr(VI) while 62.500, 83.3333 and 43.4783mg/g Cd(II) were obtained for CHT, APP1 and CHT-APP5 respectively. The results showed that blends have the potential to be used as alternative efficient low-cost biosorbent in the removal of heavy metals from wastewater.

Preparation of glycerides enriched with n-3 long-chain polyunsaturated fatty acids by Thermomyces lanuginosus lipase-catalyzed hydrolysis of tuna oil

n-3 Long-chain polyunsaturated fatty acids (LC-PUFAs) in glyceride form have attracted much attention due to their nutritional value and high bioavailability. In this work, Thermomyces lanuginosus lipase (TL 100 L) was used to selectively hydrolyze tuna oil for preparing glycerides enriched with n-3 LC-PUFAs. Effects of reaction variables on the hydrolysis reaction were optimized by response surface methodology, and the optimal conditions were as follows: reaction temperature 54 °C, enzyme load 3%, reaction time 6 h, mass ratio of water to tuna oil 1.5:1. Under these conditions, the resulting degree of hydrolysis was 55.01%, and the total content of eicosapentaenoic acid and docosahexaenoic acid in the glyceride fraction was found to be 46.39%. The final product was mainly composed of diacylglycerols (53.93%) and triacylglycerols (34.58%) after removal of the free fatty acids. This paper provides a simple and suitable method for industrial production of glycerides enriched with n-3 LC-PUFAs.

Catalytic gasification of textile wastewater treatment sludge for hydrogen production in supercritical water with K2CO3/H2O2: Reaction variables, mechanism and kinetics

As the main by-product, sludge was generated during the process of textile wastewater treatment. Due to containing organic compounds, textile sludge has great potential to be effectively reused for production of clean energy. In this work, gasification of textile sludge in supercritical water for hydrogen production was investigated. In order to improve hydrogen production, H2O2 and K2CO3 were used as catalysts. Effects of reaction variables (including temperature, retention time, oxidation coefficient and alkali catalyst dosage) on hydrogen yield were studied. Experimental results indicate that hydrogen yield increases with rise of temperature. When reaction temperature reaches 500 °C, the maximum value of hydrogen yield being 10.6 mol/kg was obtained. When excessive H2O2 was added, decrease of hydrogen yield was achieved. However, the addition of K2CO3 is favor to hydrogen yield, which is about 1.5 times as much as that of without catalyst. Meanwhile, reaction mechanism and kinetics of textile sludge gasification in supercritical water were explored. Reaction activation energy and Arrhenius constants were obtained in the established kinetic model.

Deacidification of Acidic Oil Catalyzed by Sulfonated Mesoporous Silica for Biodiesel Production: Optimization, Kinetic, and Enhancement by Using Calcined Kaolin

Acidified oil is characterized as high acid value. Hence, deacidification is indispensable in biodiesel production from acidic oil. Heterogeneous catalysts have many advantages over homogeneous counterparts in deacidification of acidic oil. Therefore, in the present work, sulfonated mesoporous silica (SMS) was prepared and characterized, followed by the systematical investigation on the effect of reaction variables on the deacidification rate (DR). Furthermore, response surface methodology (RSM) was employed to optimize the reaction parameters. Results showed that the optimal studied reaction variables for the deacidification process were as follows: reaction temperature 65 °C, methanol to oleic acid ratio 35:1, catalyst loading of 2%, in which, deacidification rate of 97.78% could be achieved. DR of 62.52% could still be obtained after catalyst had been used for four consecutive cycles. Finally, significant enhancement of DR could be achieved by using calcined kaolin to assist the deacidification of acidified oil with high water content, indicating that there is great potential in deacidification of acidic oil catalyzed by SMS with the assistance of calcined kaolin for biodiesel production.

Effect of reaction variables on facet-controlled synthesis of anatase TiO2 photocatalysts

Effect of reaction variables on facet-controlled synthesis of anatase TiO2 photocatalysts

Biodiesel production from non-edible high acid value phoenix seed oil using a cheap immobilized lipase

Fatty acid methyl ester (FAME) is one kind of renewable and biodegradable biodiesel energy. In this work, in order to decrease FAME production cost, a cheap immobilized lipase Lipozyme TLIM (Thermomyces lanuginosus lipase, 100$/kg) and waste phoenix seed (Firmiana platanifolia (L. f.) Marsili) oil with high free fatty acids (FFA) content (30.1 ± 0.4%) were used as catalyst and new feedstock, respectively. The effects of reaction variables were evaluated and optimized by response surface methodology. Results showed that Lipozyme TLIM can simultaneously catalyze the esterification and transesterification of high FFA phoenix seed oil to produce FAME. The conditions were optimized as follows: 11.8% water load added, 3.1:1 molar ratio of CH3OH to oil, and 7% lipase load at 33 °C for 6.47 h. High FAME yield (93.3 ± 1.6%) was achieved under the optimized conditions. Kinetic values (Vm and K’m) of FAME production were 2.66 × 10−2 mol/(L·min) and 7.4 mol/L, respectively, and the activation energy (Ea) was 42.62 kJ/mol. Therefore, a cheap immobilized lipase Lipozyme TLIM with a noted high level of tolerance of water could be useful in the industrial FAME production from phoenix seed oil with high FFA. After purified by molecular distillation, the contents of FAME, FFA, and water content of the final biodiesel product were 97.2%, 0.3%, and 0.04%, which were in accord with the quality standard of ASTM D6751 (>96.5%, <0.4%, and < 0.05%).

Yield and Selectivity Improvement in the Synthesis of Carbonated Linseed Oil by Catalytic Conversion of Carbon Dioxide.

Carbonation of epoxidized linseed oil (CELO) containing five-membered cyclic carbonate (CC5) groups has been optimized to 95% by reacting epoxidized linseed oil (ELO) with carbon dioxide (CO2) and tetrabutylammonium bromide (TBAB) as catalysts. The effect of reaction variables (temperature, CO2 pressure, and catalyst concentration) on the reaction parameters (conversion, carbonation and selectivity) in an autoclave system was investigated. The reactions were monitored, and the products were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), carbon-13 nuclear magnetic resonance (13C-NMR) and proton nuclear magnetic resonance (1H-NMR) spectroscopies. The results showed that when carrying out the reaction at high temperature (from 90 °C to 120 °C) and CO2 pressure (60–120 psi), the reaction’s conversion improves; however, the selectivity of the reaction decreases due to the promotion of side reactions. Regarding the catalyst, increasing the TBAB concentration from 2.0 to 5.0 w/w% favors selectivity. The presence of a secondary mechanism is based on the formation of a carboxylate ion, which was formed due to the interaction of CO2 with the catalyst and was demonstrated through 13C-NMR and FT-IR. The combination of these factors makes it possible to obtain the largest conversion (96%), carbonation (95%), and selectivity (99%) values reported until now, which are obtained at low temperature (90 °C), low pressure (60 psi) and high catalyst concentration (5.0% TBAB).

Optimization of Gold Nanoparticle Synthesis in Continuous‐Flow Micromixers Using Response Surface Methodology

AbstractGold nanoparticles (AuNPs) were synthesized in microfluidic mixers by means of response surface methodology (RSM). A reverse‐staggered herringbone micromixer was employed and reaction temperature, concentration ratio of reactants, Reynolds number, and pH of chloroauric acid were varied, with desired responses being particle size and peak intensity from UV spectroscopy. RSM was performed by simultaneously optimizing variable ranges to identify the best fit of polynomial equations to experimental data. Results revealed the individual and synergistic roles of each reaction variable on particle size and UV peak intensity, leading to identification of the largest design space. The effect of reaction variables on AuNP synthesis and particle size was confirmed in serpentine mixers.

Two-stage Enzymatic Hydrolysis of Soybean Concentrated Phospholipid to Prepare Glycerylphosphorylcholine: Optimized by Response Surface Methodology.

A two-stage enzymatic hydrolysis method, in which phospholipase A1 (PLA1) was added after phospholipase A2 (PLA2) was added for a certain time, was successfully carried out to prepare glycerylphosphorylcholine (GPC) from soybean concentrated phospholipid. Effects of reaction variables on hydrolysis reaction were optimized using response surface methodology, and the optimal conditions were as follows: PLA2 load of 1.25%, PLA1 load of 0.70%, substrate concentration of 13%, reaction temperature of 41°C, and stirring rate of 680 rpm. Under the optimal conditions, the GPC yield reached 83.07%, which is close to the predicted value by the fitted model. This paper not only provides an efficient and low-cost method to prepare GPC, but also improves the high-value utilization of soybean concentrated phospholipid.

Biodiesel preparation from Phoenix tree seed oil using ethanol as acyl acceptor

Fatty acid ethyl ester (FAEE) is one kind of renewable biodiesel, which has lower emissions of mono-nitrogen oxides, lower smoke opacity, higher energy contents, lower pour, and cloud points. In this work, phoenix (Firmiana simplex L.) tree seed oil (PTSO) from Sterculiaceae was used as the novel feedstock to produce FAEE. Ethanol was used as fatty acyl acceptor and sodium hydroxide was employed as a catalyst. Response surface methodology was used to evaluate and optimize the effect of transesterification variables on FAEE yield. The effect of reaction variables on the transesterification was as follows: catalyst concentration > transesterification temperature > substrate ratio. Transesterfication variables were optimized as follows: 0.3% catalyst concentration with 10.8:1 substrate ratio (ethanol to PTSO, mol/mol) at 52.7 °C for 20 min. Under these optimized transesterification variables, the maximum FAEE yield (97.4 ± 1.7%) was obtained. These can provide an efficient and effective information for biodiesel preparation using PTSO as the novel feedstock.

Amano Lipase PS-catalyzed Hydrolysis of Pine Nut Oil for the Fatty Acids Production Using Deep Eutectic Solvent as Co-solvent.

Free fatty acids (FFAs) are the important material used in food, personal care, emulsifiers, adhesives and surfactants. In order to enhance the preparation of FFAs, the effects of reaction variables, optimization, thermodynamic property for the Amano lipase PS catalyzed hydrolysis of pine nut oil (PNO) using deep eutectic solvents (DESs) as co-solvents were studied. The results showed that FFAs could be successfully prepared from pine nut oil through Amano lipase PS catalyzed hydrolysis using Choline chloride:Urea (ChCl:U, 1:2, mol/mol) as co-solvent. Under the optimal conditions (reaction temperature 46°C, water amount 38%, DES addition 43%, lipase dosage 7.6%, reaction time 13 h), the maximum content of FFAs in the products and degree of hydrolysis (DH) of oil were up to 89.1 ± 1.9% and 92.7 ± 2.2%, respectively. The effects of reaction variables on the hydrolysis increased in the order of DES addition < reaction temperature < reaction time < lipase dosage < water amount. The thermodynamics (Arrhenius equation) for the triglycerides hydrolysis was V = 4289.39·exp(-22942.09/RT) with the activation energy (Ea) of 22.94 kJ/mol. The Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were 81.50 ± 2.64 kJ/mol, 20.18 ± 0.12 kJ/mol and -184.59 ± 0.36 J/mol/K, respectively. The lipase in the aqueous DES could be directly re-used for 3 times.

Preparation of Structured Lipid Enriched with Medium Chain Triacylglycerol by Chemical Catalyzed Acidolysis of Coconut Oil: Optimized by Response Surface Methodology.

Medium chain triacylglycerols (MCTs) have gained wide attention due to its ability to induce the residual glyceride lipolysis and improve fat absorption. In this study, structured lipid enriched with MCTs was synthesized by chemical catalyzed acidolysis of coconut oil with the mixture of caprylic acid (Cy) and capric acid (Ca) in a solvent-free system. Three catalysts were compared for their efficiency in the production of MCTs yield. The results indicated that the highest yield of MCTs was achieved by H2SO4. Effects of reaction variables on the acidolysis reaction were optimized using response surface methodology, and the optimum conditions were as follows: molar ratio of Cy to Ca 1:1, reaction time 4 h, molar ratio of MCFAs to coconut oil 12:1, catalyst loading 12 wt%, reaction temperature 110℃. Under these conditions, the obtained structured lipid contained 89.5% of MCFAs and at least 82.0% of MCTs. This paper provides a simple and low-cost method for preparing structured lipid enriched with MCTs.

A novel and rapid method for fatty acid preparation by the lipase-catalyzed hydrolysis of Phoenix tree seeds.

Fatty acids are the precursors for the production of fuels, oleochemicals and special health care products. In this study, a novel rapid method for fatty acid (FA) preparation by the enzymatic hydrolysis of Phoenix tree seed, an undeveloped woody oil seed, was developed. High-temperature GC with flame ionization detector (FID) and the hydrolysis ratio were used to monitor reaction progress. Enzyme screening and the effect of reaction variables on the hydrolysis of seeds were evaluated and optimized by response surface methodology. The results showed that among the tested enzymes, Lipozyme TLIM showed the greatest amount of hydrolysis of Phoenix tree seed. FAs can be rapidly prepared by one-step hydrolysis of Phoenix tree seeds using Lipozyme TLIM as the biocatalyst. Under the optimized conditions (6% enzyme load, 1:8 mass ratio of seed to water, 47.7°C and 16min), the maximum hydrolysis ratio (96.4 ± 1.1%) can be achieved. The effect of reaction variables on the hydrolysis decreased in the following order: reaction time > enzyme load > substrate ratio of seed to water > reaction temperature. This work provides a novel and rapid method for FA preparation from oil seeds.

A cleaner approach for biodegradable lubricants production by enzymatic glycerolysis of castor oil and kinetic analysis

Abstract Monoricinolein (MRO) and diricinolein (DRO) were renewable and biodegradable lubricants. In this paper, MRO and DRO were prepared by the novel cleaner enzymatic glycerolysis of castor oil (CO) in solvent-free system. Three commercial immobilized lipases (Novozym 435, Lipozyme RM IM and Lipozyme TL IM) were screened and compared, and Novozym 435 showed the best catalysis performance among the tested lipases. Effects of reaction variables (reaction pressure, reaction time, temperature, enzyme load, substrate ratio and water content) on the enzymatic glycerolysis of CO were investigated. High conversion of CO (92.48 ± 1.02%) and the maximum bio lubricants yields (54.47 ± 0.58% MRO and 38.01 ± 0.50% DRO) were achieved under the following conditions: enzyme load 5% (w/w, based on the total mass), CO/glycerol ratio at 1:6, 90 °C, and 3 h. The activation energies (Ea) for CO conversion and the formation of MRO and DRO were calculated as 33.75 kJ/mol, 22.26 kJ/mol and 24.37 kJ/mol, respectively, and the process showed high selectivity toward the formation of MRO. Reaction kinetic agreed with the ping-pong Bi-Bi mechanism with the inhibition of CO, and the kinetic values ( V max , K m ′ and K IA ) were 0.0946 mol/(L·min), 1.6704 mol/L, and 0.89 mol/L, respectively.

Effect of ionic liquids on enzymatic preparation of lipophilic feruloylated structured lipids using distearin as feruloylated acceptor and kinetic analysis

Feruloylated acylglycerols (FAGs) are lipophilic structured lipids of ferulic acid (FA), which have antioxidant activities and UV-absorbing properties. In the paper, FAGs were prepared by the enzymatic transesterification of ethyl ferulate (EF) with distearin using ionic liquids (ILs) as the reaction media. The effects of ILs on the enzymatic transesterification and the selective formation of lipophilic FAGs or hydrophilic glyceryl ferulates (FGs) were investigated. The effect of reaction variables on the transesterification was optimized using response surface method (RSM), and kinetic analysis in the IL was also evaluated. Among the tested ILs, excellent FAGs selectivity (~0.63) was achieved using [Emim]TF2N as the reaction solvent. Moreover, [Emim]TF2N also showed protective effect on the enzyme stability at high temperature (110°C). High EF conversion (99.7±0.3%) and FAGs yield (68.7±1.0%) were also obtained at the optimized conditions (reaction temperature of 95°C, reaction time of 28h, and enzyme load of 15% (w/w, relative to the weight of substrates)). The activation energies (Ea) of EF conversion, FGs and FAGs formation were 44.4, 41.4, 59.9kJ/mol, respectively. KmA, KmB and Vmax were 0.02, 0.12mol/L, and 4.54mmol/(L·h), respectively. The kinetics of transesterification of EF with distearin in [Emim]TF2N agreed with the Ping-Pong Bi-Bi mechanism without substrates inhibition.

Bioactive paper by eugenol grafting onto cellulose. Effect of reaction variables

Abstract In this work, eugenol grafting onto cellulose is proposed as a strategy for developing a biodegradable active packaging material. Grafting reaction were performed according to Doehlert experimental design with temperature range fixed to 120–180 °C, time range 15–60 min and eugenol amount from 2 to 8 wt%. Reaction advances increases with three variables analyzed as expected, while paper mechanical properties decrease due to both grafting and secondary reactions (crosslinking and degradation). Also, color changes respect to virgin paper increases with the increment of the three variables although paper appearance is good for the most samples. Desirability function was used to determine optimal reaction conditions, looking for a trade-off between the paper properties (color and elongation at break) and reaction advance. The optimal conditions determined were 160 °C, 15 min and 2 wt% eugenol amount. Modified paper showed antioxidant activity and repellent and insecticide activity against Tribolium castaneum and Rhyzopertha dominica, making it a good material for active packaging applications.

Effect of Reaction Variables on Biodiesel Production from Canary Melon Seed Oil

Effect of Reaction Variables on Biodiesel Production from Canary Melon Seed Oil

Synthesis of glyceryl monocaffeate using ionic liquids as catalysts

Glyceryl monocaffeate (GMC) is the hydrophilic derivative of caffeic acid (CA), which can be used in cosmetic and food industries. In this paper, GMC was prepared by the reaction of glycerol with different caffeoyl donors (CA, or ethyl caffeic (EC)). Seven functionalized ionic liquids ([PSO3HMIM]HSO4, [BSO3HMIM]TS, [BSO3HMIM]OTF, [BSO3HMIM]HSO4, [AAMIM]HSO4, [BSO3HMIM]HPO4 and [HMIM]HSO4) were used as catalysts. Effects of reaction variables (reaction temperature, time, pressure, catalyst load and molar ratio of substrates) on CA conversion and GMC yield were investigated. For the esterification of glycerol with CA, high CA conversion (95.6±2.1%) and GMC yield (93.8±3.2%) were achieved using [BSO3HMIM]TS as catalyst under the following conditions: 90°C, CA/glycerol 1:10 (mol/mol), catalyst load 10% (relative to the weight of all substrates), 2h. Activation energies (Ea) of CA conversion and GMC formation were 84.53kJ/mol and 86.67kJ/mol, respectively, which were lower than those (111.79, 116.24kJ/mol) of EC as caffeoyl donor.

Effect of vanadium on the catalytic activity of ceria towards wet peroxide oxidation of persistent and biorecalcitrant chlorinated organics

Chlorinated aromatic compounds are recalcitrant to biodegradation and conventional treatment methods Herein, we investigate the efficiency of catalysts in the oxidation of 4-chlorophenol (4-CP) and 2,4-dichlorophenoxyacetic acid over CexV1-xO2 (x: 0, 0.25, 0.5, 0.75, 1) nano oxides with hydrogen peroxide in water. The catalysts were characterised by temperature programmed reduction (H2-TPR) and desorption (NH3-TPD and CO2-TPD) techniques. Effect of reaction variables like catalyst dosage, H2O2 and reactant concentrations and temperature, were investigated. The results show that 500mg/L 4-CP is completely removed with 0.13mol/L of H2O2 over 500mg/L Ce0.75V0.25O2, within 135min with the total organic carbon (TOC) removal of 21.56%. Within 75min, 250mg/L 2,4-D is completely degraded by 0.08mol/L H2O2 over 500mg/L Ce0.5V0.5O2 with 30.15% TOC removal. The major degradation intermediates are phenol, benzoquinone and 2,5-hexane dione as identified by gas chromatography mass spectrometry (GC–MS). Based on these, a possible reaction mechanism is proposed. The stability and reusability of the mixed oxides during five consecutive cycles was experimented by X-ray diffraction (XRD) and surface area measurements. The catalytic efficiency is retained after five successive runs and the catalysts are texturally stable Scavenging experiments revealed the activation of reaction through the formation of hydroxyl radicals.

Enzymatic production of sterculic acid from the novel Phoenix tree seed oil: Optimization and kinetic study

Phoenix tree (Firmiana simplex) seed oil is a novel oil which is rich in sterculic acid. Sterculic acid, a cyclopropene fatty acid, can be used as the inhibitor of the stearoyl-CoA desaturase system and mammary carcinomas growth. In this work, Lipozyme TLIM-catalyzed hydrolysis of the novel Phoenix tree seed oil was used to prepare sterculic acid. High temperature GC-FID and the degree of hydrolysis (DH) were used to monitor the reaction progress. Effects of reaction variables on the hydrolysis were evaluated and optimized using response surface methodology. Results showed that sterculic acid can be successfully prepared from the novel seed oil, and the effect of reaction variables on the hydrolysis decreased in the order of reaction time &gt; enzyme load &gt; temperature. A high yield of fatty acids (DH, 98.2±0.8%) can be obtained under optimized conditions (45 ºC, mass ratio of water to oil 10:1, enzyme load 10%, and 18 h). The Arrhenius equation for the hydrolysis was LnV0 = 9.12-4721/T. The activation energy was 39.25KJ/mol. The kinetic values for Vmax, K/m were 0.232mol/(L∙min) and 0.084 mol/L, respectively.