Minutes Of Reaction Time Research Articles

RESPONSE SURFACE METHODOLGY (RSM) OPTIMIZATION AND CHARACTERIZATION OF SILICA PRODUCTION FROM BIDA RICE HUSK

Due to the fact that the compositions of silica derived from rice husk depends on the soil type and composition, type of fertilizer and chemicals used during planting and climate or geographical factors. In this particular research, the production of silica from rice husk obtained from Bida was optimized using Response Surface Methodology (RSM). The final silica produced at optimum conditions was characterized using XRF, XRD, SEM/EDX and BET. Preliminary investigations were conducted on the reaction variables which include: NaOH concentration, volume of NaOH, reaction temperature and reaction time. The results obtained were used to generate a design matrix using design expert 13.0 software via Box-Behnken Design (BBD). The software suggested a quadratic model that predicted the optimum yield of 7.655 g at optimum conditions of 3.0 M NaOH, 250 ml NaOH, 90 minutes reaction time and 100 OC reaction temperatures. The model fit statistics also shows that the predicted R2 value of 0.9141 is in agreement with the adjusted R2 value of 0.9654. The adequate precision of the model is 28.558 with an insignificant lack of fit P-value of 1.71. The experimental optimum yield recorded is 7.30 g with a standard deviation of 0.251. The XRF analysis reveals 71.415 % and 79.120 % silica in the rice husk and final silica respectively. The XRD results shows predominance of amorphous silica while the SEM image shows that the silica possesses agglomerates particles of irregular shapes that are jagged and porous. The elemental analysis from the EDX is in accord with the XRF result. The BET results showed that the silica has a surface area of 314 m2/g, pore volume of 0.1761 cm3/g and pore size of 2.128 nm. From all the results gathered, silica of significant quality and characteristics can be successfully produced from Bida rice husk.

Optimization of Biodiesel Production from Thevetia Peruviana Seed Oil using Transesterification Method

Globally there is a rekindled interest to find alternative fuels to fossil fuel because of the issues of pollution and climate change associated with fossil fuels. Therefore, one of the alternatives is plant oil from non-edible sources. So, this study investigated the synthesis and optimization of biodiesel production from a novel non-edible feedstock (Thevetia Peruviana Seed Oil) using NaOH catalyst and methanol through transesterification route. The influence of parameters catalyst loading and alcohol-to-oil molar ratios on the yields of the biodiesel was checked. A mixture method of experimental design was adopted for the study. The results showed an optimal biodiesel yield of 98.87 % comprising of 80.02 % methyl esters and 18.85 % ethyl esters from the experiment with the reaction conditions; concentration of catalyst 0.25%, 9:1 methanol/oil molar ratio, 60 0C reaction temperature, 60 minutes reaction time and 150 rpm agitation speed. This study developed an optimal catalyst concentration, alcohol-to-oil molar ration, reaction temperature, reaction time and agitation speed for synthesizing biodiesel from Thevetia Peruviana Seed Oil and it also identifies the methyl esters %, ethyl esters % and free fatty acid (FFA) % present in the biodiesel. The study showed biodiesel can be produced from Thevetia Peruviana Seed Oil with a very high yield, this is a potential alternative to diesel fuel and can be applied to diesel engines to produce power for use in automobiles, farm machineries and electricity generation.

Fast biodiesel production via potassium ferrate catalysis at room temperature using used cooking oil and refined canola oil

Abstract As biodiesel is continuously aimed to be a better alternative to petroleum-based diesel fuel, the University of the Philippines Los Baños – Interdisciplinary Biofuels Research Studies Center (UPLB-IBRSC) continues to explore process conversion techniques to improve efficiencies in biodiesel production. In this study, the catalytic activity of potassium ferrate in the transesterification of canola oil and used cooking oil for biodiesel production at room temperature was examined for potential reduction in energy consumption. Parameters such as methanol-to-oil molar ratio, catalyst loading, and reaction time were varied to determine their effects on biodiesel yield and purity. Thin layer chromatography was applied to qualitatively analyze the biodiesel, while ImageJ software was used for purity determination. The characterization analysis confirmed that the refined canola oil used in the study has an acceptable FFA content of 0.06%. On the other hand, the used cooking oil showed an FFA content of 3.71%, which is beyond the desired limit of 2%. Hence, neutralization through the addition of potassium hydroxide was performed, resulting in a lowered FFA content of 0.86%. Experimental results of the parametric and optimization study on used cooking oil showed that an optimum conversion of 86.55% was achieved at a 2:1 methanol-to-oil molar ratio, 5 wt% catalyst loading, and 90 minutes reaction time. Consequently, a yield of 83.21% was attained using refined canola oil at the optimum conditions of 6:1 methanol-to-oil molar ratio, 3 wt% catalyst loading, and 69 minutes reaction time. Generally, findings show that catalyst loading and reaction time significantly affect the biodiesel yield and purity only up to a certain optimum value. The methanol-to-oil ratio, on the other hand, showed to have a significant inverse relationship on yield and purity. Compared to the typical biodiesel production process at 60 °C with up to two hours of reaction time, this study which describes a catalytic process at room temperature and a relatively shorter reaction time, showed the potential to reduce significantly the high energy consumption in biodiesel production.

Fast biodiesel production via potassium ferrate catalysis at room temperature using refined coconut oil and vegetable oil

Abstract Traditionally, the transesterification reaction for biodiesel production takes place at elevated temperatures, around 60-65°C, for up to two hours of reaction time, entailing a high energy consumption. As the University of the Philippines Los Baños – Interdisciplinary Biofuels Research Studies Center (UPLB-IBRSC) continuously aims to conduct studies on improving process efficiencies in biofuels production, this research investigated the potential of potassium ferrate as a catalyst for fast biodiesel production at room temperature. Particularly, the catalytic activity of potassium ferrate in the transesterification of refined coconut oil and vegetable oil was examined. The effects of the parameters such as methanol-to-oil molar ratio, catalyst loading, and reaction time on biodiesel yield and purity were studied. Thin layer chromatography, with the aid of ImageJ software, was applied to analyze the purity of the biodiesel through the developed spots’ area estimation. Characterization experiments in terms of free fatty acid (FFA) content and acid value were performed to confirm the low FFA content of the feedstocks prior to transesterification. Results of the parametric and optimization study revealed that a biodiesel yield of 87.67% using vegetable oil was experimentally achieved at the optimum conditions of 6.75 wt% catalyst loading, 6:1 methanol-to-oil molar ratio, and 30 minutes reaction time. Using coconut oil, on the other hand, resulted in a higher biodiesel yield of 94.90% at a catalyst loading of 6 wt%, a methanol-to-oil molar ratio of 6:1, and a reaction time of 60 minutes. Generally, findings show that catalyst loading has a positive effect on biodiesel yield and purity only up to a certain optimum amount. Among all the parameters analyzed, the methanol-to-oil molar ratio was found to have the most significant effect as an individual factor. Given the results of this study, it can be concluded that the potassium ferrate-catalyzed transesterification reaction at room temperature can potentially reduce the energy consumption in biodiesel production and the production cost in general.

SYNTHESIS OF PRECIPITATED CALCIUM CARBONATE IN THE FORM OF CALCITE CRYSTALS AS A VALORIZATION OF LIME CARBIDE SLAG WASTE

The presence of high level of calcium oxide (CaO) has been detected in lime carbide (LC) slag waste generated form the acetylene gas industry. There is untapped potential for the valorization of LC-slag waste, where the calcium oxide content can be converted into Precipitated Calcium Carbonate (PCC/CaCO3) which is valuable and can contribute to carbon dioxide sequestration. Calcium carbonate has unique advantages as a carrier, but some critical problems need to be addressed, such as low productivity, disordered structure, and weak adsorption ability. In this study, the desired type of crystal is calcite which has the most stable characteristics from the other types of crystals. Micro-bubble reactor is used as a method of dispersing CO2 in converting CaO to PCC/CaCO3. This method has the advantage of being able to maintain CO2 gas bubbles longer in solution so that the reaction time that occurs can also be optimize. The LC-Slag valorization process was carried out by varying the LC-slag concentration between 3-7% w/w and the reaction time between 15 - 35 minutes. The dispersion of CO2 gas is fixed at a flow rate of 2.5 L/m. From the yield, it can be seen that the longer the reaction time, the yield of PCC/CaCO3 produced is also greater. At 35 minute reaction time and concentration LC-Slag Waste varied 3, 5, and 7% w/w, the produced yields were 89.44, 95.00, and 93.76%, respectively. This is evidenced by the results of SEM and XRD analysis. In the future, this treatment method is expected to provide more insight and guidance for the valorization of LC-slag waste and CO2 mineralization in the acetylene gas industry.

Influencing Factors and Stimulus-Sensitivity of Chitosan/Polymethacrylic Acid (CS/PMAA) Nanogels as Nanocarriers

ABSTRACT Nanogel, nanosized hydrogel, can contribute to biomedical and pharmaceutical, especially in drug delivery, due to its enthralling properties. Small size, large surface area, hydrophilicity, and stimulus responsiveness of nanogel ameliorate tissue penetration, drug loading capacity, and targeted drug delivery. The current study prepared nanosized, pH-sensitive, biocompatible, and stable chitosan/polymethacrylic acid (CS/PMAA) based nanogels using MBA as a crosslinker and APS as an initiator. FTIR confirmed the reaction between functional groups to synthesize nanogels sufficiently in a spherical shape, as affirmed by a FESEM. DLS data revealed nanosized particles with a size range of 70–170 nm and a range of 6–13 for polydispersity index (PDI). A study showed that 2% of MBA crosslinker is sufficient to achieve the desired crosslinking in 60 minutes reaction time (RT) with nanogel size ~ 92 nm. Increasing RT from 30 to 80 minutes during nanogel synthesis demonstrated a decrease in nanogel sizes from 186–73 nm. Synthesized nanogels have shown pH sensitivity (stimuli responsiveness) in acidic and alkaline mediums with an increase in particle size in pH-2 (~144 nm) and pH-8 (~280 nm) compared to intermediate pHs. The pH sensitivity of nanogels by changing the size per the suspended medium’s pH is crucial for prolonged systemic circulation and targeted drug delivery. Moreover, nanogels have shown good colloidal stability with zeta potential (ZP) +28 mv in acidic and −38 mv alkaline mediums. DSC and XRD results demonstrated thermal stability and amorphous morphology of nanogels, respectively. BET surface analysis revealed the surface area of nanogels in the range of 65–68 cm2/g with an average pore size of 28–32 nm. In-vitro cytotoxicity in the L-929 cell line by MTT assay established the cell viability (>70%) after 24 hours of incubation, substantiating the non-toxicity and biocompatibility of nanogels as nanocarriers for drug delivery.

Production of biosurfactant sodium lignosulfonate (NaLS) using elephant grass based lignin (Pennisetum purpureum) and NaHSO3

Elephant grass (Pennisetum purpureum) is an animal feed ingredient, especially ruminants with a lignocellulose content of 40.85% and lignin of 21.5% and can be used as a raw material for making biosurfactant sodium lignosulfonate. Biosurfactant is an amphiphilic molecule and has biodegradability. This study aims to obtain data on the effect of NaHSO3 concentration, reaction time, and the ratio of elephant grass: NaHSO3 on the sodium lignosulfonate content, yield, degree of sulfonation, and physico-chemical properties of sodium lignosulfonate obtained. This study consists of 3 treatment factors, namely NaHSO3 concentration, reaction time, and mass ratio of elephant grass : NaHSO3. The results showed that sodium lignosulfonate can be produced from elephant grass using direct sulfonation process. The best treatment combination was 80% concentration and 155 minutes reaction time which produced sodium lignosulfonate content of 20.619 mg/L and 65.83% yield. The physicochemical properties are: density 1.4061 g/mL, degree of sulfonation 57.73%, completely soluble in water, smells a little sulfur, has a brownish yellow color, pH 5, and the results of functional group analysis showed a change in functional groups.

Effective degradation of recalcitrant naphthenic acids by the Fe(III)/peroxymonosulfate oxidation enhanced by molybdenum disulfide: Degradation performance and mechanisms

In this study, molybdenum disulfide (MoS2) has been investigated as a catalyst to boost the redox cycle of Fe(III)/Fe(II) to activate peroxymonosulfate (PMS) to effectively break down cyclohexanecarboxylic acid (CHA), which is a model naphthenic acid (NA) pollutant. The optimum conditions of pH 3, MoS2 concentration of 0.4 g/L, Fe(III) concentration of 0.3 mmol/L, and PMS concentration of 2 mmol/L has been applied for complete degradation of 0.1 mmol/L CHA in 10 minutes reaction time. Based on results of electron paramagnetic resonance analysis, chemical probe and quenching experiment, it was found that all of •OH, SO4•−, 1O2, and Fe(IV) contributed to the MoS2/Fe(III)/PMS oxidation system. Eighteen CHA byproducts and three primary CHA degradation pathways were revealed according to the results of UHPLC-QTOF-MS analysis. By using XPS, SEM, and XRD to characterize the MoS2 powders before and after the reaction, MoS2 was found with high stability and the oxidation of Mo(IV) on the surface was negligible. The impacts of background anions on CHA degradation were found to be nonimportant, and commercial NAs mixture were verified to be efficiently degraded in current system. Overall results indicate the capacity and potential of MoS2/Fe(III)/PMS system to be utilized for future treatment of authentic oil and gas field wastewater.

Influence of Temperature and Blending Ratio on Product Yield for Co-gasification of Torrefied Palm Kernel Shell (TPKS) and Low-Density Polyethylene (LDPE)

This study investigated the product yields produced from the co-gasification of torrefied palm kernel shell (TPKS) and low-density polyethylene (LDPE). Prior co-gasification, PKS was undergo pre-treatment process at different temperature. The optimum parameter for torrefaction was found at 250 oC for 60 min reaction time with 4.89 wt.% moisture content and 10.48 wt.% fixed carbon. Thus, the result indicated that TPKS a suitable fuel feedstock for further thermal conversion. Then, TPKS and LDPE were gasified at different temperature and blending ratio for 60 min reaction time. The results showed that, Co-gasification is significantly influenced by temperature. A higher gasification temperature improves the gasification rate by increasing carbon conversion. By varying temperature from 600 to 1000 oC, the tar production dropped significantly from 49.61 to 35.03 wt.%, while the gas yield grew significantly from 25.88 to 45.94 wt.%. However, as temperature increased from 800 to 1000 oC, tar yield increased from 26.58 to 35.03 wt.%. Meanwhile, char yield decreased from 24.50 wt.% to 19.02 wt.% when the temperature from 600 to 1000 oC. For the effect of blending ratio, through blending of TPKS and LDPE, the gas and char yield increase, while tar decrease with increase torrefied TPKS ratioAdditionally, it was found that the highest gas yield with low tar and char yield was obtained from the co-gasification of TPKS and LDPE at 50:50 blending ratios produce the than another blending ratio. Therefore, based on the effect of temperature and blending ratio on product yield shows that the optimum parameter to produce maximum gas yield with minimum tar and char yield are at 50:50 (TPKS: LDPE) blending ratio at 800oC for 60 minutes reaction time. The gas analysis exhibited in increasing H2 composition when the reaction time increase for TPKS: LDPEcompared than UnPKS:LDPE.

Optimization of biodiesel production parameters for hybrid oil using RSM and ANN technique and its effect on engine performance, combustion, and emission characteristics

The increased need for renewable energy sources and growing concerns about environmental pollution has driven the need for alternative fuels (particularly biodiesel) in the transportation industry. The most used technique for producing biodiesel is transesterification, which involves the oil reacting with alcohol in the presence of a catalyst. This study looks at the usage of artificial neural network (ANN) and response surface methodology (RSM) to optimize biodiesel synthesis factors for a hybrid oil feedstock (30% cottonseed and 70% spirulina microalgae oil). The parameters that were optimized were the methanol/oil ratio, reaction time, and catalyst concentration. Cottonseed oil was combined with spirulina microalgae oil to minimize its higher free fatty acid content to less than 1% and prevent soap formation during the transesterification process. The optimal biodiesel production was 94.37%, with 106.4 minutes of reaction time, 1.612% catalyst loading, and a methanol/oil ratio of 20:1. The optimized findings, when confirmed with experiments, gave a biodiesel yield of 91.03% with an error of 3.6%. To provide vital insights into the potential environmental benefits of using this alternative fuel, the study further investigates how the optimized biodiesel blend influences engine performance and emission characteristics. Testing was done at 1500 RPM and 17.5 CR for maximum loading conditions, diesel, HBD20, and HBD fuel produced 0.2746, 0.2805, and 0.288 kg/kWh of specific fuel consumption (SFC), respectively. The CO2 emissions of HBD and HBD20 were 2.49% and 8.30% lower, respectively, than pure diesel. NOx emissions increased by 14% and 18.3%. The highest cylinder pressure was 66.87 at 363 °C.

Triplet Energy Transfer Mechanism in Copper Photocatalytic N- and O-Methylation.

Methylation reactions are chemically simple but challenging to perform under mild and non-toxic conditions. A photochemical energy transfer strategy was merged with copper catalysis to enable fast reaction times of minutes and broad applicability to N-heterocycles, (hetero-)aromatic carboxylic acids, and drug-like molecules in high yields and good functional group tolerance. Detailed mechanistic investigations, using kinetic analysis, aprotic MS, UV/Vis, and luminescence quenching experiments revealed a triplet-triplet energy transfer mechanism between hypervalent iodine(III) reagents and readily available photosensitizers.

Influence of Temperature and Blending Ratio on Product Yield for Co-gasification of Torrefied Palm Kernel Shell and Low-Density Polyethylene

This study investigates the product yields produced from the co-gasification of torrefied palm kernel shell (TPKS) and low-density polyethylene (LDPE). Prior co-gasification, PKS was undergo pre-treatment process at different temperature. The optimum parameter for torrefaction was found at 250 °C for 60 min reaction time with 4.89 wt. % moisture content and 10.48 wt.% fixed carbon. Thus, the result indicated that TPKS a suitable fuel feedstock for futher thermal conversion. Then, TPKS and LDPE were gasified at temperature of 600, 800 and 1000 °C and blending ratio of 10:90, 50:50, 90:10 (TPKS:LDPE) for 60 min reaction time. Based on the findings found that, temperature plays an important role in co-gasification. Higher gasification temperature increases the carbon conversion which improves gasification rate. By varying temperature from 600 to 1000 °C, the gas yield increased whilst tar yield decreased sharply. For the effect of blending ratio, through blending of TPKS and LDPE, the gas and char yield increase, while tar decrease with increase torrefied TPKS ratio. Furthermore, it was observed that the product yields obtained from the co-gasification of TPKS and LDPE at 50:50 blending ratios produce the highest gas yield with low char and tar yield than another blending ratio. Therefore, based on the effect of temperature and blending ratio on product yield shows that the optimum parameter to produce maximum gas yield with minimum tar and char yield are at 50:50 (TPKS:LDPE) blending ratio at 800 °C for 60 minutes reaction time.

The employing of pure calcium sulfate extracted from phosphogypsum for composing highly pure ammonium sulfate and calcium carbonate

ABSTRACT The phosphoric acid wet process waste stream provided the phosphogypsum (PG). Phosphogypsum waste is environmentally harmful and economically valuable. However, processing phosphogypsum to produce (NH4)2SO4 and CaCO3 can solve these environmental and economic issues. ICP-OES, XRD, SEM-EDS, FTIR, and TGA were used to characterize PG, purified CaSO4, (NH4)2SO4, and CaCO3. Herein, PG is treated with different HNO3 concentrations and 0.5M NH4NO3 to eliminate most impurities for gaining a highly purified CaSO4. The factors affecting CaSO4 purification were studied. These aspects include HNO3 and NH4NO3 concentration, the S/L ratio, time spent on treatment, temperature, and grain size. According to the findings, the ideal working conditions for extracting 98.71% of CaSO4 from PG are as follows: 149 µm grain size, 0.5M NH4NO3, 2M HNO3, 1/4 S/L, 30 minutes reaction time, 300 rpm, and 80°C. Using a pure CaSO4 suspension as the raw material, CO2, and a mechanical stirring method, the (NH4)2SO4 solutions crystallized by heating and CaCO3 precipitate were investigated through several trials. The preparation method was investigated by changing variables such as the NH4 +/Ca2+ molar ratio, reaction time, CO2 flow rate, and temperature. Finally, (NH4)2SO4 (98.25%) and CaCO3 (98.5%) are produced from the slurry of pure CaSO4.

Synergistic potency of ultrasound and solar energy towards oxidation of 2,4-dichlorophenol: a chemometrics approach.

Industrial units based on chemical processes-the textile and paper industries-are major sources of chlorophenols in the environment, and chlorophenolic compounds persist within the environment for a long time with high toxicity levels. The photo-assisted Fenton's and photocatalysis processes were investigated for the degradation of chlorophenols in the present study. Response surface methodology was employed to get optimised conditions for photocatalysis and photo-Fenton process-governing factors, thus, yielding a profound removal efficiency. Under optimised conditions, with a photocatalyst dose of 0.2 g/L, oxidant concentration of 10.0 mM and pH 5.0, complete removal of 2,4-dichlorophenol (2,4-DCP) was observed in 210 minutes in photocatalytic treatment. In the case of the photo-Fenton process, at an H2O2 dose of 5.0 mM and Fe2+ concentration of 0.5 mM, the organic pollutant was eliminated within 5 minutes of reaction time under acidic conditions (pH 3.0). The RSM model reported the perfect fit of experimental data with the predicted response. Among different isotherm models, the Langmuir isotherm was the best fit. The process followed pseudo-first order rate kinetics among various kinetics models. For the obtained optimised conditions, sonication and solar energy-driven processes were incorporated to study enhanced mineralisation. The solar-assisted Fenton process reported maximum mineralisation (90%) and cost-effective ($0.01/litre for 100 mg/L 2,4-DCP) treatment among different hybrid oxidation processes. The work provides insight into harnessing the naturally available solar energy, reducing the overall treatment cost and opting for a sustainable treatment method.

Formal Radical Deoxyfluorination of Oxalate‐Activated Alcohols Triggered by the Selectfluor‐DMAP Charge‐Transfer Complex

AbstractWe present a photon‐ and metal‐free approach for the radical fluorination of aliphatic oxalate‐activated alcohols. The method relies on the spontaneous generation of the N‐(chloromethyl)triethylenediamine radical dication, a potent single electron oxidant, from Selectfluor and 4‐(dimethylamino)pyridine. The protocol is easily scalable and provides the desired fluorinated products within only a few minutes reaction time.

Hetero-Alkali Catalyst for Production of Biodiesel from Domesticated Waste: (Used Waste oil)

Biodiesel, a fuel derived from renewable sources, has garnered significant attention from energy researchers over the past two decades as a clean alternative to diesel fuel. This increased interest can be attributed to the alarming impact of climate change caused by the use of traditional diesel fuel. This paper focuses on showcasing the qualities of biodiesel produced from used waste oil and the positive impact on the alarming change in climate today. The observable characteristics of used waste oil for the synthesis of biodiesel in the presence of an ethanolic CaO-K2 O-SiO2 base catalyst created from leftover palm kernel empty bunches was rigorously explored in this study. The catalyst obtained from Palm Kernel Bunch Stem (PKBS) was characterized using Scanning Electron Microscope (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), Extended Range Spectroscopy - Flame Photometry (XRS-FP), Brunauer-Emmett-Teller analyzer (BET) isothermal adsorption and qualitative analysis. Reusability of catalyst and economic evaluation of the synthesized biodiesel were also evaluated. The quality of the Oil was identified through standard techniques by examining its physicochemical characteristics as well as other elements. According to the findings, the improved Used Waste Oil (UWO) characteristics met the specifications for oil required to produce biodiesel. The Used Waste Oil’s physicochemical properties included the oil’s physical condition as liquid/dark brownish at 28, acid value of 0.96 (mg KOH/g oil), FFA (% oleic acid), 0.48, iodine value of 152.00 (I2g/100g), and peroxide value of 5.1 milli-equivalent of peroxide/kg of oil, among others. The obtained catalyst demonstrated high basic strength with potassium oxide (61.63 wt/%) being the predominant component. At run 5 with 98.52 (%wt /wt), 65 minutes reaction time, 4.0 (%wt) catalyst amount, reaction temperature of 70 , and a 7:1 ethanol to oil ratio produced the highest biodiesel yield. The study concluded that, UWO can possibly be utilized as an economically benign feedstock for the production of biodiesel, and the resultant catalyst could potentially be employed in industries as bio-base.

Partial wet oxidation of dairy manure as a pretreatment process to produce acetic acid 'a Source Growth of Methanogens'.

Wet oxidation can be an effective process for the pretreatment of complex biomass such as lignocellulose. However, studies on the use of wet oxidation for treating solid waste such as dairy manure are limited. The use of partial wet oxidation to convert dairy manure into low molecular weight carboxylic acids as final products were investigated. This work focuses on the performance of the sub-critical wet oxidation treatment of dairy cattle manure as a conversion/pretreatment process to release matter from the lignocellulosic fraction rather than a destructive process. The operating conditions were controlled at the short residence time and optimal temperature in the presence of oxygen under a pressure of 120 psi. The thermal hydrolysis under wet oxidation significantly affected conversion manure slurry into organic acids. The concentration of acetic acid reached 1778 mg L-1, achieved at 190°C (60 minutes reaction time) as the reaction temperature increased within the range of 150°C-200°C, total organic carbon was reduced and monomers in the process liquids decreased. On the other hand, soluble COD in process liquids increased with an increment in reaction temperature. The results provide insights into technical options to pretreat dairy manure to improve biochemical conversion yield.

Treatment of net washing wastewater by Fenton process

<p>The discharge of wastewater from net washing is one of the most significant problems in the marine ecosystem because of its high organic and saline content. Sea water quality is deteriorated every day due to the high amount of organic matter produced in the aquaculture sector. The aim of this study was to investigate the treatability of net washing wastewater by Fenton process. The efficiency of advanced oxidation processes (AOPs) in the treatability of net washing wastewater was evaluated through chemical oxygen demand (COD) and color removal. The effects of H2O2, and Fe (II) dosages, pH and reaction time were investigated, and the parameters were optimized by 23 full factorial design principles and variance analysis (ANOVA). The results showed that H2O2 dosage was the most effective parameter for Fenton process. The maximum COD removal was found at Fe (II)/H2O2 concentration ratio of 1/5 and the 180 minutes reaction time. The COD removal increased from 77 % to 88 % by increasing the peroxide dose from 80 mM to 400 mM. The total R2 for the three factors was calculated to be 59.67%. According to the experimental results, in the factor analysis between the three variables and COD removal, only the variation in peroxide concentration was statistically significant. Since the efficiency of biological treatment is unstable in treating of high organic matter and saline wastewaters, the Fenton process has great potential in the treatment of net washing wastewater.</p>

The Study on the Effect of Acid Concentration, Temperature, and Time on the Dehydration of Xylose to Furfural in Ethanol Solvent

The development of the palm oil industry is followed by the increased amount of lignocellulosic biomass waste. Lignocellulosic biomass waste contains cellulose and hemicellulose which are potential sources of C6 and C5 sugars. C5 or pentose can be hydrolyzed into furfural through the hydrolysis process and then dehydration reaction using the acid catalyst in various kinds of solvent. At this moment, the highest yield of furfural in the acid-catalyzed hydrolysis of xylose in water resulted in only about 50.0w-%. Other methods such as salt addition or the use of various organic solvents lead to new challenges both in purification and environmental issues. Therefore in this study, 70.0w-% ethanol in water was utilized as the solvent in a range of temperatures (140-170°C) and concentration of sulfuric acid (0.1-0.5M) up to 120 minutes reaction time. As the outcomes, the shorter time was needed to achieve maximum furfural yield with the increase of temperature and acid concentration with the water and the ethanol as the solvent. Improvement was shown in the highest furfural yield achieved up to 70.0-72.0mol-% (after 15 min at 170°C, 0.2-0.5 M concentration of H2SO4). The results showed the potential use of ethanol as a green solvent to produce furfural from xylose.

Heterogeneous Reaction Model for Evaluating the Kinetics of Levulinic Acid Synthesis from Pretreated Sugarcane Bagasse

The abundance of sugarcane bagasse, a by-product of sugarcane juice extraction in sugar factories, serves as an advantage of its potential for producing chemicals such as levulinic acid (LA). Levulinic acid contains carbonyl and carboxyl groups that can be utilized for many applications, such as pharmacies, cosmetics, and solvents. Bagasse hydrolysis into LA was preceded by alkaline-acid pretreatment to separate cellulose from hemicellulose and lignin. This treatment could minimize the disturbance of these unwanted components, so that LA synthesis would be more optimal. Pretreated bagasse contained 82.64% cellulose, about two-fold from the non-pretreated one. It was hydrolyzed with hydrochloric acid (HCl), which acts as a catalyst (a Bronsted acid), at 150-170 oC, 0.1-1 M catalyst concentration, 1-10% solid-to-liquid (cellulose:catalyst-solution) ratio, and 0-200 minutes reaction time. The range of LA yield values obtained in the study were between 15-64.05%. The maximum LA yield was obtained at a temperature of 160 oC, 1 M catalyst concentration, and 1% solid-to-liquid ratio. The high LA yield indicates the importance of pretreatment supported by optimal conditions of synthetic reaction. The reaction route involved in hydrolysis was cellulose-glucose-levoglucosan (LG)-hydroxymethylfurfural (HMF)-LA. The result exhibits that temperature and catalyst concentration do not significantly affect the maximum potential LA yield. However, higher temperatures and catalyst concentration can accelerate the time to achieve the maximum potential LA yield. Meanwhile, the LA yield increases with a lower solid-to-liquid ratio. In contrast to previous studies, this study evaluated the reaction model in a more precise way using combination of models, considering that the reaction occurs between solid and liquid. The heterogeneous reaction model, namely the shrinking core model (SCM) for cellulose conversion to glucose and the first-order homogeneous reaction model for glucose to LA reaction, give good fitting results. The more appropriate reaction model is expected to be the basis of scale-up process carried out for industry one day. The results of this research have the potential to be applied for various other biomass raw materials with some improvements based on their characteristics which can be studied in the future.