Rate Of Acid Formation Research Articles

Stability of lipids during wet storage of the marine diatom Porosira glacialis under semi-preserved conditions at 4 and 20\xa0\xb0C

Cultivation of diatoms may help alleviate the pressure on wild fish stocks for marine nutrient availability in aquaculture feed and for human consumption. However, the lipids in microalgae biomass are easily deteriorated, both trough lipolysis and degradation of polyunsaturated fatty acids (PUFA). Proper storage conditions are therefore necessary to maintain the lipid quality. Additionally, the storage conditions must have a low cost and facilitate further processing of the biomass. In this study, we investigated the formation of free fatty acids, changes in lipid classes, and fatty acid composition of the psychrophilic marine diatom Porosira glacialis under storage. The wet biomass was stored for 14 days at 4 and 20 °C with either heat treatment, formic acid, or benzoic acid addition, and a control sample. Heat-treated and formic acid samples had the lowest rate of free fatty acid formation during storage. Mainly, polar lipids were hydrolyzed to free fatty acids and this occurred fastest at 20 °C. The fatty acid composition remained stable in heat-treated samples during storage, whereas a loss of PUFA was observed in the other treatments. The lack of effect from benzoic acid indicates that the loss of lipid quality stems from endogenous enzymes rather than exogenous organisms. Heat treatment and formic acid appeared to effectively reduce lipase activity, and potentially lipoxygenase and similar enzymes that affect the fatty acids. The low pH of the formic acid samples seems to have a negative effect on the PUFA content, in particular at 20 °C.

Gravistimulation effects on Oryza sativa amino acid profile, growth pattern and expression of OsPIN genes

Gravity is an important ecological factor regulating plant growth and developmental processes. Here we used various molecular and biochemical approaches to investigate artificial and normal gravistimulation’s effect on the early growth stages of rice (Oryza sativa L.) by changing the orientations of Petri dishes. Rate of amino acid formation, root and shoot growth, and OsPIN expression was significantly higher under gravistimulation compared with the control. Clinostat rotation positively affected plant growth and amino acid profile. However, under normal gravity, vertical-oriented seedlings showed high amino acid levels compared with clinostat, 90°-rotated, and control seedlings. Similarly, seedling growth significantly increased with 90°-rotated and vertical orientations. Artificial gravity and exogenous indole-3-acetic acid induced OsPIN1 expression in the roots, root shoot junction, and shoots of clinorotated seedlings. Phenyl acetic acid induced OsPIN1 expression in the roots and root shoot junction of clinorotated seedlings but not in the shoot. The current study suggests that OsPIN1 is differentially regulated and that it might be involved in the regulation of plant growth. Conversely, OsPIN2 and OsPIN3a are gravity sensors and highly induced in the roots and root shoot junctions of vertical and 90°-rotated seedlings and play an important role in stress conditions. Thus, on exposure to gravity, hormones, and UV-C radiation, these genes are highly regulated by jasmonic acid, 6-benzylaminopurine and gibberellic acid.

Electrocatalytic hydrogen production and carbon dioxide conversion by earth abundant transition metal complexes of the Schiff base ligand: (E)-1-((2-dimethylamino)-propylimino)methyl)naphthalene-2-ol

The present work describes an electrocatalytic study for the conversion of carbon dioxide to environmentally benign and industrially important products, as well as the production of hydrogen (green energy) from acids using earth abundant transition metal complexes as catalysts. One cobalt and one nickel complex of the Schiff base ligand (E)-1-((2-(dimethylamino)ethylimino)methyl)naphthalene-2-ol have been used. The cobalt complex (1) has been tested as an electrocatalyst for the reduction of protons in non-aqueous solvent using trifluoro acetic acid (TFA) as a substrate. Complex 1 catalyses the acid reduction at a relatively high potential (−0.7 V) with a turn over frequency of 7.05 s−1 at a 10:1 ratio of the acid to the catalyst. Production of hydrogen gas was detected by gas chromatography. The nickel complex (2) was examined for the electrocatalytic reduction of carbon dioxide. At an applied potential of −2.1 V, the main reduction product is oxalic acid. The acid produced was quantitatively determined by HPLC. The rate of oxalic acid formation is 1.3495 × 10−7 M/min. with a kcat value of 58.03 s−1.

Wet Air Oxidation of Oil Shales: Kerogen Dissolution and Dicarboxylic Acid Formation.

Until now, the oil shale kukersite has been used mainly for energy and oil production. To broaden the possible applications of oil shales, the wet air oxidation of kukersite (an organic-rich sedimentary rock from Estonia) was studied. Kukersite was oxidized with an oxygen-rich gas in water at temperatures up to 200 °C and pressures up to 60 bar. The efficiency of this batch process was evaluated from organic matter conversion, from the amount of solubilized organics obtained, and from the rate of dicarboxylic acid (DCA) formation. The effect of several reaction parameters—pressure, temperature, time, acid/base additives, substrate concentration, the origin of a substrate and its organic matter content, and so forth—was measured. A conversion of 91% in total organic carbon was achieved at 175 °C with 40 bar of the 1:1 oxygen/nitrogen mixture in 3 h without the presence of any additives. Under basic conditions, high yields (up to 50%) of dissolved organic matter were obtained with 8% of DCA; the best results are obtained with K2CO3 and KOH. The highest DCA outcome (12%) within the 3 h reaction time was obtained in the presence of acetic acid. It was found that temperatures higher than 185 °C, pressures over 30 bar of pO2, and long reaction times in the acidic media caused a considerable decrease in the DCA outcome. It was also found that the same process can be applied to shales of different origins, although with lower DCA yields.

Aromatic Ester-Functionalized Ionic Liquid for Highly Efficient CO2 Electrochemical Reduction to Oxalic Acid.

Electrochemical reduction of CO2 into valuable chemicals is a significant route to utilize CO2 resources. Among various electroreduction products, oxalic acid (H2 C2 O4 ) is an important chemical for pharmaceuticals, rare earth extraction, and metal processing. Here, an aprotic aromatic ester-functionalized ionic liquid (IL), 4-(methoxycarbonyl) phenol tetraethylammonium ([TEA][4-MF-PhO]), was designed as an electrolyte for CO2 electroreduction into oxalic acid. It exhibited a large oxalic acid partial current density of 9.03 mA cm-2 with a faradaic efficiency (FE) of 86 % at -2.6 V (vs. Ag/Ag+ ), and the oxalic acid formation rate was as high as 168.4 μmol cm-2 h-1 , which is the highest reported value to date. Moreover, the results of density functional theory calculations demonstrated that CO2 was efficiently activated to a -COOH intermediate by bis-active sites of the aromatic ester anion via the formation of a [4-MF-PhO-COOH]- adduct, which finally dimerized into oxalic acid.

High oxygen tension increases itaconic acid accumulation, glucose consumption, and the expression and activity of alternative oxidase in Aspergillus terreus

Itaconic acid is a five-carbon dicarboxylic acid with an unsaturated alkene bond, frequently used as a building block for the industrial production of a variety of synthetic polymers. It is also one of the major products of fungal "overflow metabolism" which can be produced in submerged fermentations of the filamentous fungus Aspergillus terreus. At the present, molar yields of itaconate are lower than those obtained in citric acid production in Aspergillus niger. Here, we have studied the possibility that the yield may be limited by the oxygen supply during fermentation and hence tested the effect of the dissolved oxygen concentration on the itaconic acid formation rate and yield in lab-scale bioreactors. The data show that a dissolved oxygen concentration of 2% saturation was sufficient for maximal biomass formation. Raising it to 30% saturation had no effect on biomass formation or the growth rate, but the itaconate yield augmented substantially from 0.53 to 0.85mol itaconate/mol glucose. Furthermore, the volumetric and specific rates of itaconic acid formation ameliorated by as much as 150% concurrent with faster glucose consumption, shortening the fermentation time by 48h. Further increasing the dissolved oxygen concentration over 30% saturation had no effect. Moreover, we show that this increase in itaconic acid production coincides with an increase in alternative respiration, circumventing the formation of surplus ATP by the cytochrome electron transport chain, as well as with increased levels of alternative oxidase transcript. We conclude that high(er) itaconic acid accumulation requires a dissolved oxygen concentration that is much higher than that needed for maximal biomass formation, and postulate that the induction of alternative respiration allows the necessary NADH reoxidation ratio without surplus ATP production to increase the glucose consumption and the flux through overflow metabolism.

Water Structure Controls Carbonic Acid Formation in Adsorbed Water Films.

Reaction pathways and kinetics in highly structured H2O adsorbed as Ångstrom to nanometer thick layers on mineral surfaces are distinct from those facilitated by bulk liquid water. We investigate the role of the interfacial H2O structure in the reaction of H2O and CO2 to form carbonic acid (H2CO3) in thin H2O films condensed onto silica nanoparticles from humidified supercritical CO2. Rates of carbonic acid formation are correlated with spectroscopic signatures of H2O structure using oxygen isotopic tracers and infrared spectroscopy. While carbonic acid virtually does not form in the supercritical phase, the silica surface catalyzes this reaction by concentrating H2O through adsorption at hydrophilic silanol groups. Within measurement uncertainty, we found no evidence that carbonic acid forms when exclusively ice-like structured H2O is detected at the silica surface. Instead, formation of H2C18O16O2 from H218O and C16O2 was found to be linearly correlated with liquid-like structured H2O that formed on the ice-like layer.

Mechanistic insight into the quantitative synthesis of acetic acid by direct conversion of CH4 and CO2: An experimental and theoretical approach

Conversion of CH4 and CO2 into value-added products has vital environmental and economic importance. Their direct conversion to acetic acid is challenging due to their high activation energy. Hence, kinetic and mechanistic information are crucial for the carbonylation of CH4 with CO2. Regarding this, single and dual component catalysts with different combinations of ZnO-, CeO2-, and MnO2- supported montmorillonite (MMT) were prepared and characterized by XPS, Raman, and XRD. Quick solid-state NMR, TGA, and FT-IR techniques were used and Langmuir-Hinshelwood model was considered to investigate mechanistic steps involved in the conversion of CH4 and CO2 to acetic acid. The obtained mechanistic and kinetic results were also theoretically proved by density functional theory (DFT) calculations. We found that ZnO and CeO2 dual active sites preferentially adsorb the CH4 and CO2, respectively that avoid surface adsorption competition. The rate of acetic acid formation was maximum when these sites exist at appropriate concentration (Ce: 0.44 wt%, Zn: 2.20 wt%). DFT calculations elucidated that the formation of acetic acid is strongly favored on ZnO catalyst with easier migration of the adsorbed CO2 from CeO2 to the ZnO side.

Study of Biogas Production from Cassava Industrial Waste by Anaerobic Process

Biogas production processes from tapioca wastewater have several problems that cause the biogas production is not optimal, such as pH drop at beginning of the process because the rate of acid formation is too fast and the rate of starch wastewater degradation is too slow. Therefore, to obtain optimal biogas production it is required two-stage reactor. The purposes of this research were to (i) study the influence of one stage fermentation and two stage fermentation on biogas production, (ii) study the effect of buffer Na2CO3 on biogas production, and (iii) study the effect of methanogenic bacteria concentration on biogas production from cassava starch effluent. The first method of our research was hydrolysis process by “Saccharomyces cereviceae” as substrate activator. The second is the arrangement of pH and the last is process of methane production. The results showed that the highest biogas production is achieved at concentration of methanogenic bacteria 20% (v/v) that is equal to 2458 ml. At concentration of 8% (v/v) and 15% (v/v), biogas production was 2105 ml and 2117 ml. The addition of Na2CO3 can extend to 16 days with accumulation of 372 ml. While without the addition of buffer, biogas production period was only 9 days with accumulation of 620 ml. In semi continuous process, the analysis carried out every 3 days. Highest biogas production achieved in the variable addition of yeast with the accumulation 9329 ml. Without yeast, accumulation of biogas was 6831 ml. Yeast is use as substrate activator so it can accelerate the hydrolysis process and increased biogas production. The addition of Na2CO3 is increase the alkalinity so the pH drop did not occur early in the process.

Screening of commercial enzymes for poly(ethylene terephthalate) (PET) hydrolysis and synergy studies on different substrate sources.

Poly(ethylene terephthalate) (PET) is one of the most consumed plastics in the world. The development of efficient technologies for its depolymerization for monomers reuse is highly encouraged, since current recycling rates are still very low. In this study, 16 commercial lipases and cutinases were evaluated for their abilities to catalyze the hydrolysis of two PET samples. Humicola insolens cutinase showed the best performance and was then used in reactions on other PET sources, solely or in combination with the efficient mono(hydroxyethyl terephthalate)-converting lipase from Candida antarctica. Synergy degrees of the final titers of up to 2.2 (i.e., more than double of the concentration when both enzymes were used, as compared to their use alone) were found, with increased terephthalic acid formation rates, reaching a maximum of 59,989µmol/L (9.36g/L). These findings open up new possibilities for the conversion of post-consumer PET packages into their minimal monomers, which can be used as drop in at existing industrial facilities.

Selective and Direct Hydrogenation of CO2 for the Synthesis of Formic Acid over a Rhodium Hydrotalcite (Rh‐HT) Catalyst

AbstractRhodium hydrotalcite (Rh‐HT), a heterogeneous catalyst was synthesized, characterized and investigated for CO2 hydrogenation. The catalyst was effectual for the CO2 hydrogenation and selective formation of formic acid at a moderate temperature and was efficiently recycled up to 5 times without any significant loss in activity. A TON of 15840 for formic acid was selectively obtained at 50 bar pressure (1:1, p/p, CO2 and H2) and 60 °C temperature in a mixture of methanol:water (5:1 v/v, 60 mL) as a solvent in 24 h with no additional base. The effect of various reaction parameters was investigated for the reaction rate and CO2 conversion. The formic acid formation rate follows the 1st order kinetic trend regarding the catalyst amount and partial pressure. The determined activation parameters from the temperature dependence rate of formic acid were Ea=33.5 ± 2.5 kJmol−1, ΔH#=30.9 ± 2.5 kJmol−1, ΔS#=‐275 ± 5 Jdeg−1mol−1. The presence of water as a solvent together with methanol have effectively enhanced the performance of the catalyst. The mechanistic routes for CO2 hydrogenation to formic acid are proposed and discussed by the kinetic and experimental observations.

Effect of gravistimulation on amino acid profile of pea, rice, corn, wheat during early growth stages

The amino acids are one of the major cellular components of plants, which are involved in different metabolic pathways. In present study, effect of artificial gravistimulation on amino acid profiles of pea, rice, corn, wheat during early growth stages was investigated. One-axis clinostat was used for gravistimulation application, which was applied at embryonic stage. Amino acid profile was measured in 10-days old seedlings of pea, rice, corn and wheat cultivars. The effect of clinostat rotation was also evaluated under salt stress and MS medium supplement. Germinated pea, rice, corn and wheat seedlings were grown under the gravity condition for specific time interval. Corn and wheat seeds showed slow germination as compared to pea and rice cultivars. The rate of amino acid formation under gravity condition was significantly higher than control (un-treated seedling). The variation in amino acid profile of pea, rice, corn and wheat cultivars vary deferentially. Results revealed that gravistimulation applied through clinostat has positive effect on amino acid profile in plant tissue and future studies should be focused on growth, biochemical, physiological at lateral stages of growth.

STUDY THE GROWTH KINETICS OF PEDIOCOCCUS ACIDILACTICI WITH ESTIMATION OF KINETIC PARAMETERS AND APPLIED IN LARGE SCALE PEDIOCIN PRODUCTION

ABSTRACTObjectives: The aim of the study was to determine the growth kinetics of Pediococcus acidilactici using a mathematical model for large scale pediocinproduction.Methods: Growth kinetics of P. acidilactici has been studied for pediocin production in small scale batch fermenter (Erlenmeyer flask) using meatprocessing waste medium. The experiments have been conducted with varying the concentrations of glucose, protein, and lactic acid. A mathematicalmodel has been developed to describe growth rate, products (pediocin and lactic acid) formation rate, and substrates (glucose and protein) utilizationrate. Monod model for dual substrates (glucose and protein) has been used with considering lactic acid inhibition. Luedeking-Piret model has beenintroduced to describe the production of pediocin and lactic acid.Results: The values of kinetic parameters have been determined using experimental data and model equations. The model prediction has beencompared satisfactorily with the experimental data for the validation of the model.Conclusions: The developed model was satisfactorily validated to scale up the production of pediocin.Keywords: Pediococcus acidilactici, Pediocin, Meat processing waste, Monod model, Luedeking-Piret model, Kinetic parameters.

Determination of Key Hydrocarbon Autoxidation Products by Fluorescence.

Hydroperoxides and carboxylic acids are key primary products that arise in the autoxidation of hydrocarbons. We have developed a simple approach to rapidly and simultaneously determine both types of products using hydroperoxide- and acid-sensitive moieties conjugated to nonpolar coumarin- and BODIPY-based fluorophores. The coumarin- and BODIPY-conjugated amine probes described here undergo 38- and 8-fold enhancement, respectively, upon protonation in a solvent system compatible with heavy hydrocarbons. The latter can be used directly with our previously described hydroperoxide-sensitive coumarin-conjugated phosphine probe to enable rapid quantification of both carboxylic acids and hydroperoxides in hydrocarbon samples. The utility of the approach is illustrated by the ready determination of the differing relative rates of hydroperoxide and acid formation with changes in hydrocarbon structure (e.g., n-hexadecane vs 1-hexadecene vs a lubricant base stock). The method offers significant versatility and automation compared with common but laborious titration approaches, and greatly improves screening efficiency and accuracy for the identification of novel radical-trapping antioxidants for high temperature applications. This application was demonstrated by the automated analysis of hydroperoxides and carboxylic acids (by microplate reader) in samples from 24 inhibited autoxidations of a lubricating oil, which were carried out on a parallel synthesizer at 160 °C in triplicate in a single day.

Study on Acid/Base Formation by Using Sulfonated Polyether Ether Ketone/Aminated Polysulfone Bipolar Membranes in Water Splitting Electrodialysis

The sulfonated polyether ether ketone (SPEEK) as a cation exchange polymer and aminated polysulfone (APSf) as an anion exchange membrane (AEM) were synthesized to prepare bipolar membranes (BPMs) through hot pressing. The water splitting electrodialysis (WSED) experiments were conducted to produce acids and bases by using the resulting SPEEK/APSf BPM. For comparative performance evaluation of the commercialized ASTOM membrane and the newly synthesized membranes in our lab, the acid/base production rate and the voltage changes according to the constant current were measured. The acid and base formation rates of the commercialized membrane from ASTOM were 2.3 and 2.7 g/L/h, respectively, whereas the rates of the membranes we developed were 1.0–2.4 and 1.5–2.7 g/L/h, respectively, depending on the amine contents in the AEM. The performance of the synthesized BPM in our lab was equivalent or higher than that of the commercialized membrane from the viewpoint of the acid/base production rates.

Oxidation Stability of Rapeseed Biodiesel/Petroleum Diesel Blends

The effects of fuels, including contaminants such as fuel oxidation products, on vehicle fuel system materials are important for vehicle durability and operation. Fuel oxidation is accelerated at the elevated temperatures and pressures of vehicle fuel systems. An extended time-course study of the oxidation of a biodiesel fuel blend consisting of 30% (v/v) rapeseed methyl ester in petroleum diesel (B30) was conducted at 70 and 90 °C with three aeration rates. Oxidation rates increased with increasing temperature as indicated by decreases in induction period (Rancimat), concentrations of unsaturated fatty acid methyl esters, and the time required to form hydroperoxides and acids. Peroxide values (PVs) rose to peak values in the range of 250–400 mequiv of O2/kg at 90 °C and 375–450 mequiv of O2/kg at 70 °C and then declined. Total acid number (TAN) increased rapidly as peroxides were formed after which the rate of TAN increase slowed, reaching values of up to 32 mg of KOH/g at 90 °C and 20 mg of KOH/g at 70 °C. The timing and maximum values of PV and TAN were somewhat dependent on aeration rate. Fuel mass decreased initially due to fuel volatilization, then increased as oxygen was incorporated, and then decreased reflecting volatilization of fuel and volatile oxidation products. Peroxide concentration showed a peak that coincided with the most rapid rate of oxygen incorporation, acid formation, and polyunsaturated FAME degradation. Net oxygen incorporation exhibited a plateau at approximately 5–6 wt % O above the 3.5 wt % O initially present in the FAMEs. This exceeds (by approximately 50%) the amount needed for incorporation of a single oxygen atom at every carbon atom allylic to carbon–carbon double bonds in the FAMEs that were oxidized.

Divergent utilization patterns of grass fructan, inulin, and other nonfiber carbohydrates by ruminal microbes

Fructans are an important nonfiber carbohydrate in cool season grasses. Their fermentation by ruminal microbes is not well described, though such information is needed to understand their nutritional value to ruminants. Our objective was to compare kinetics and product formation of orchardgrass fructan (phlein; PHL) to other nonfiber carbohydrates when fermented in vitro with mixed or pure culture ruminal microbes. Studies were carried out as randomized complete block designs. All rates given are first-order rate constants. With mixed ruminal microbes, rate of substrate disappearance tended to be greater for glucose (GLC) than for PHL and chicory fructan (inulin; INU), which tended to differ from each other (0.74, 0.62, and 0.33h−1, respectively). Disappearance of GLC had almost no lag time (0.04h), whereas the fructans had lags of 1.4h. The maximum microbial N accumulation, a proxy for cell growth, tended to be 20% greater for PHL and INU than for GLC. The N accumulation rate for GLC (1.31h−1) was greater than for PHL (0.75h−1) and INU (0.26h−1), which also differed. More microbial glycogen (+57%) was accumulated from GLC than from PHL, though accumulation rates did not differ (1.95 and 1.44h−1, respectively); little glycogen accumulated from INU. Rates of organic acid formation were 0.80, 0.28, and 0.80h−1 for GLC, INU, and PHL, respectively, with PHL tending to be greater than INU. Lactic acid production was more than 7-fold greater for GLC than for the fructans. The ratio of microbial cell carbon to organic acid carbon tended to be greater for PHL (0.90) and INU (0.86) than for GLC (0.69), indicating a greater yield of cell mass per amount of substrate fermented with fructans. Reduced microbial yield for GLC may relate to the greater glycogen production that requires ATP, and lactate production that yields less ATP; together, these processes could have reduced ATP available for cell growth. Acetate molar proportion was less for GLC than for fructans, and less for PHL than for INU. In studies with pure cultures, all microbes evaluated showed differences in specific growth rate constants (μ) for GLC, fructose, sucrose, maltose, and PHL. Selenomonas ruminantium and Streptococcus bovis showed the highest μ for PHL (0.55 and 0.67h−1, respectively), which were 50 to 60% of the μ achieved for GLC. The 10 other species tested had μ between 0.01 and 0.11h−1 with PHL. Ruminal microbes use PHL differently than they do GLC or INU.

Partial Oxidation of Propane Over Mo1V0.3Te0.23Nb0.12Ox Catalyst in a Fluidized Bed Reactor

A fluidized bed reactor, for the first time, was employed to investigate the partial oxidation of propane to acrylic acid over Mo1V0.3Te0.23Nb0.12Ox catalyst. Effects of temperature, oxygen concentration, steam concentration, space velocity, and dilution with different sizes of SiC were studied and discussed. The reaction in the fluidized bed was compared with the reaction in the classical fixed bed. The results indicated that at constant temperature propane conversion obtained in the fixed bed reactor was higher. But the fluidized bed recompensed it by higher acrylic acid selectivity leading to acrylic acid yields and formation rates considerably over the fixed bed. In the fluidized bed reactor, an enhancement in the acrylic acid selectivity was observed over fixed bed at similar conversions. It is suggested that passing a large portion of gas phase oxygen through bubbles allows operation under lower oxygen partial pressure, which favors the desired reaction path. With the heat sink feature of the diluent, the catalytic performance is more influenced by dilution in the fixed bed. However, hot spots are less likely to occur in the fluidized bed and dilution has little effect on the catalytic performance. However, propane conversion increases slightly by increasing SiC particle diameter due to better fluidization quality.

Effect of a novel induction food‐processing device in improving frying oil quality

SummaryProducing quality fried snacks involves monitoring the chemical processes that occur during frying to control oil degradation. Our objective was to evaluate the effects of a Novel Induction Food‐Processing Device (NIFPD) on the quality indices of frying oil. Under standard frying conditions, vegetable oil samples (corn and canola) were collected during a standardised frying cycle to test oxidative stability. Fourier transform infrared spectroscopy was used to evaluate and classify samples during the frying time, and standard reference methods used to monitor the oil stability included p‐anisidine value, free fatty acid content and CIELAB colour. The induction technology decreased the rate of free fatty acid and aldehyde formation. Tests also showed a marked effect on total colour difference between control and treatment (NIFPD), reducing colour degradation. Overall, our results showed that a patented induction device slows the rate of lipid degradation, resulting 7–20% reduction in formation rate of key quality parameters and significantly longer utilisation of frying oil.

Formation of Humic Substances in Weathered MSWI Bottom Ash

The study aimed at evaluating the humic substances (HSs) content from municipal solid waste incinerator (MSWI) bottom ash and its variation with time and the effect of temperature on HSs formation. The process suggested by IHSS was applied to extract HSs from two different bottom ash samples, and the extracted efficiency with NaOH and Na4P2O7 was compared. MSWI bottom ash samples were incubated at 37°C and 50°C for 1 year. HSs and nonhumic substances were extracted from the bottom ash sample with different incubated period by 0.1 M NaOH/Na4P2O7. Results show that the rate of humic acid formation increased originally with incubation time, reached a maximum at 12th week under 37°C and at 18th week under 50°C, and then decreased with time. More humic acid in MSWI bottom ash was formed under 50°C incubated condition compared with that incubated under 37°C. Also, the elemental compositions of HSs extracted from bottom ash are reported.