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•Potentiometric method for TAN determination free of chloride salt interference.•Micellar solubilization of acidic compounds of crude oil in O/W nanoemulsions.•The potentiometric ...method was applied to different types of crude oil samples.•Ca, Mg, and Sr salts in crude oil did not affect TAN determination.
The determination of the total acid number (TAN) of crude oils is of great importance in the petroleum refining industry for evaluating the corrosion potentials of oils. The presence of salts CaCl2 and MgCl2 at concentrations higher than 100 mg kg−1 in crude oil can interfere with some standard methods used to measure the TAN; thus, CaCl2 and MgCl2 salts can hinder the accuracy of TAN determination. In this work, a new method based on the potentiometric titration of O/W nanoemulsions (NMS_TAN) was developed to eliminate the interference of CaCl2 and MgCl2 on TAN determination. This method is based on the potentiometric titration of oil-in-water (O/W) nanoemulsions formed via the micellar solubilization of the acidic compounds of crude oil with KOH in propan-2-ol. The O/W nanoemulsion was prepared using ultrasound and a nonionic surfactant (Tween 80). The accuracy of the method was evaluated by recovery tests, and the interferences of the mixture of salts NaCl, CaCl2, MgCl2, and SrCl2 in the determination of TAN using NMS_TAN were investigated. NMS_TAN was employed to determine the TAN of 15 oil samples (American Petroleum Institute gravity: 13.2–38.3), and the results were statistically compared with those of standard methods. The accuracy of the NMS_TAN method was not affected by the presence of salts in the crude oil samples. Recoveries from a sample spiked with hexanoic acid ranged from 95.0 % to 100.3 % of the theoretical values. The TAN of crude oil samples with CaCl2 and MgCl2 concentrations below 50 mg kg−1 determined using the potentiometric method were comparable to those determined by standard methods. The TAN of crude oil samples with high salt concentrations (>500 mg kg−1) obtained by the standard methods were 77 %–90 % higher than those determined by NMS_TAN. The potentiometric method is fast, simple, and accurate and allows for robust quantifications of the TAN of different crude oil samples without chloride salt interferences.
•Four novel pyrrolidinium-based amino acid ionic liquids (AAILs) were synthesized.•The physicochemical properties of these AAILs were investigated.•AAILs were used as a green chemistry approach for ...the deacidification of crude oil.•Extremely small amounts of ILs are sufficient to deacidify highly acidic crude oil.•Antimicrobial activity assay was performed to study its effect on aquatic system.
Four novel pyrrolidinium-based amino acid ionic liquids were synthesized and characterized. The physicochemical properties of these amino acid ionic liquids (AAILs), such as viscosity, density, thermal stability, and surface tension were investigated. These ionic liquids (ILs) were used as a green chemistry approach for the extraction of naphthenic acid from the model oil. The influence of amino acid anions on the de-acidification process was assessed by attaching prolinate, glycinate, alaninate and serinate. Extraction results show that very small amounts of ILs are sufficient to extract naphthenic acid from a model oil configuration with a high total acid number. The regeneration and reusability of the synthesized ILs have also been analysed in this work. Moreover, the antimicrobial activity assay was performed to ascertain the potential toxicological effect of the synthesized set on the aquatic system.
Corncob, an agricultural bio-waste, was used as adsorbent to remove organic and inorganic contaminants in waste lubricating oil (WLO) from diesel engine. To improve its adsorption capacity, corncob ...was modified with mixed solution of nitric acid, Hexadecyl trimethyl ammonium bromide and ethanol. Characterization results showed the crystallinity index of corncob enhanced 12%, which would be ascribed to the disruption of the dense lignin-carbohydrates structure in lignocellulose biomass by modification. The surface of modified corncob became smoother and porous. The adsorption results showed modified corncob had better removal rates to contaminants than raw corncob. For WLO with 80,000 km mileage, the removal rates to Fe, Al, Cu were enhanced from 19%, 6.4%, 48–27%, 27%, 53%, while that for oxide, sulphate, aromates, soot and insoluble resins were enhanced 1.7, 1.2, 3.0, 1.7 and 1.7 times. The reduction rate of total acid number to WLO with 40,000, 60,000, 80,000 km were enhanced 16%, 9%, 12% by modified corncob, respectively. The optimal adsorption condition was explored as adsorbing 60 min at 90 °C with 2% adsorbent. Corncob, with the advantages of low cost, good biodegradability and high adsorption capacity, could be used as alternative to conventional adsorbent for WLO.
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•The surface of modified corncob was more smoother and appeared obvious pores.•Modification gave corncob higher surface area and lower hemicellulose content.•The removal rate of corncob to Fe, Cu, Al from WLO were improved by modification.•Modified corncob showed higher removal rate to organic pollutants.•The reduction rate to TAN of lubricant improved after treatment by modified corncob.
•Oil chemistry and SAC type strongly influence the performance of CTWF and its underlying mechanisms.•Wettability alteration, SAC partitioning, adsorption and soap generation play a key role in CTWF ...performance.•TAN is not a sufficient oil descriptor for accurate CTWF performance prediction.•Carboxylic acid chain length exhibits an inverse relationship with oil recovery at lower PVIs, but not at higher PVIs.
Chemical enhanced oil recovery (cEOR) relies on the interactions between surface-active components (SACs) of the oil-in-place and injected chemicals to induce favorable physico-chemical changes. This study investigates the effect of oil chemistry on the performance of chemically-tuned waterflooding (CTWF) in carbonate rocks. Coreflood experiments were performed at 90°C using four model oils, each containing a single SAC (acetic acid, decanoic acid, stearic acid or quinoline) to evaluate the effect of oil composition on oil recovery. Complementary characterization techniques including thermal gravimetric analysis (TGA), attenuated total reflectance (ATR-FTIR) and zeta potential (ζ) were used to understand the underlying rock-oil-brine interactions that take place during CTWF, including SAC adsorption to the rock surface, strength of adsorption, partitioning into the brine phase, and electrostatic interactions, respectively. Sessile drop contact angle measurements were also performed to quantify the wetting behavior of the different SACs. Results of this study show that oil chemistry plays a significant role in triggering different oil-brine-rock interactions. Characterization of those interactions is crucial to explain the discrepancies in oil recovery observed in the CTWF literature. In this study, differences in the underlying oil-brine-rock interactions translated into significant variation in oil recovery ranging between 8.9 and 43.9 % after one pore volume injected (PVI). ATR-FTIR results showed that in-situ soap generation was detected for oils with longer chain carboxylic acids, whereas no soaps were observed for oils that have acetic acid or quinoline. Combined with sessile-drop contact angle measurements, a relationship is observed between SAC partitioning into the brine phase and water-wetting behavior. Additionally, TGA measurements suggested that long chain carboxylic acids chemisorb to the rock surface, making wettability alteration to a less oil-wetting state during CTWF more challenging, whereas intermediate chain carboxylic acids only physisorb leading to a more pronounced wettability alteration to a less oil-wetting state, ultimately yielding the highest recovery of ∼49.9 %. Finally, TAN was found to be an insufficient oil descriptor, where oils with the same TAN yielded different CTWF effects. Hence, a more robust oil analysis is crucial for more accurate prediction and modeling of CTWF behavior.
Oximata® jelly mix is a functional food rich in carotenoids and tocopherols from the
formulation of red palm oil, pumpkin juice, and red dragon fruit juice. This study was
conducted to determine the ...effect of increasing red palm oil concentration, temperature,
and storage time on vitamin C, total titrated acid, and antioxidant activity using the ABTS
method ((2,2-Azinobis (3-ethyl benzothiazoline) -6-sulfonic acid) and FRAP (Ferric
Reducing Antioxidant Power). The study used three factors with a combination of
treatments consisting of observation day (day 1, 7 and 14), storage temperature (28oC and
7
oC) and red palm oil concentration (0; 0.15%; 0.30% and 0.45%). The results showed
that Oximata® jelly mix powder added with 0.45% red palm oil and stored at 7°C for
seven days was the best treatment with vitamin C levels 5.83±0.24 µg/mL, antioxidant
activity 74.29±3.00% (ABTS) and 22.17±0.24 µg/mL (FRAP). The total titrated acid
value increased in the addition of Red Palm Oil by 0.15 and 0.3% and storage for 14 days
at 28oC, namely 1.54%. The concentration of red palm oil, temperature, and storage time
affect vitamin C, total titrated acid, and antioxidant activity.
•Full elemental and phase mass balances were conducted.•A detailed fats degradation mechanism was derived.•The highest hydrochar yield and energy yield were 84 % and 96 % respectively.•Hydrophobic HC ...with aromatic surface morphology and rich in inorganic compounds.•Liquid phase rich in fatty acids and the gas rich in CO2 and poor in hydrocarbons.
Batch hydrothermal carbonization (HTC) experiments were carried out using dissolved air flotation (DAF) dairy sludge in order to investigate the effects of changing temperature, residence time and water-sludge ratio on the yield and quality of the products. The highest solid hydrochar (HC) yield of 84 % (dry basis) and highest HC energy yield of 96 %, were achieved at a temperature of 250°C, a residence time of 4h and a water content of 96 wt.%. The wt.% of carbon and corresponding energy yield of HC increased with process severity while the oxygen and volatile matter contents decreased. Similarly, HC ash content and ash elemental composition increased and the resulting solid became more stable and hydrophobic. The majority of the compounds detected in the liquid product were acids, with carbon chain ranging between C1 and C10. The total acid-phenol concentrations increased with the severity of the HTC operating conditions, but remained around 2500 ppm. The hydrocarbon content of the gaseous product was low and a high CO2 concentration was observed, while H2S concentration increased significantly with the increase in temperature, residence time and water content. A degradation mechanism for proteins and fats was developed and a full elemental mass balance was performed.
This research aims to determine the effect of different kefir grain concentration to viscosity, total acid, protein and hedonic level of buffalo milk kefir and to determine the ideal kefir grain ...concentration for buffalo milk kefir. The basic ingredients used in this research were buffalo milk and kefir grain. Concentration of kefir grain at 2.5%, 5%, 7.5%, 10% (g/v) was used to measure viscosity, total acid, protein and hedonic level of buffalo milk kefir. Ostwald pipette and pycnometer were used to determine the viscosity, total acid used titration method with NaOH 0.1 N, destruction and distillation methods were used to determine the protein content and the hedonic test were done by 25 panelists. The results show that different levels of kefir grain concentration gave significant effect (p<0.05) on every parameter. Various levels of kefir grain concentration had highly significant effect (p<0.05) on kefir as a product. The conclusions from this study are the more addition of kefir grain, the more viscosity, total acid, and protein content. From the hedonic test gave specific results in sour taste, aroma, texture and overall.
Near-infrared spectroscopy (NIRS) calibrations were developed for the discrimination of spectra of the jujube (Zizyphus jujuba Mill.) fruit samples from four geographical regions. Prediction models ...were developed for the quantitative prediction of the contents of jujube fruit, i.e., total sugar, total acid, total phenolic content, and total antioxidant activity. Four pattern recognition methods, principal component analysis (PCA), linear discriminant analysis (LDA), least squares-support vector machines (LS-SVM), and back propagation-artificial neural networks (BP-ANN), were used for the geographical origin classification. Furthermore, three multivariate calibration models based on the standard normal variate (SNV) pretreated NIR spectroscopy, partial least squares (PLS), BP-ANN, and LS-SVM were constructed for quantitative analysis of the four analytes described above. PCA provided a useful qualitative plot of the four types of NIR spectra from the fruit. The LS-SVM model produced best quantitative prediction results. Thus, NIR spectroscopy in conjunction with chemometrics, is a very useful and rapid technique for the discrimination of jujube fruit.
By the aid of chemometrics, NIR spectroscopy calibrations were developed for the discrimination of the jujube fruit samples from four geographical regions, and quantitative prediction of their contents, i.e., total sugar, total acid, total phenolic content, and total antioxidant activity, were performed. Display omitted
•Evaluate the quality of jujube fruit samples by NIR spectroscopy and chemometrics•Quantitative analysis of sugar, acid, phenol and antioxidant activity in jujubes•Pattern recognitions were successfully applied for discrimination of jujube fruits.
In solar applications, the oxidation stability of heat transfer fluidsreducesthe thermal energy storage cost. In this work, the effect of new two azophenols, namely -2-sec-butyl-4-((3-chlorophenyl) ...diazenyl) phenol and 2-sec-butyl-4-((3-nitrophenyl) diazenyl)phenol, was studied to produce an oil that has good characteristics and is compatible with metals such asstainless steel, carbon steel, aluminum, and copper, which are generally used to manufacture pipes, heat exchangers, receivers, and storage tanks. The prepared compounds were characterized using spectroscopy analysis. The prepared compounds were added to a heat transfer fluid under operating conditions in the presence of iron and copper as catalysts. At different time intervals, the samples were tested by measuring the total acid number value. The results of this measurement show that compound II performed better than compound I. Additionally, the quantum chemical parameters were calculated. The theoretical calculations were compatible with the experimental results.
•Two new azophenols prepared.•These compounds were characterized using spectroscopy analysis.•The prepared compounds were added to a heat transfer fluid under operating conditions.•The performance of antioxidant around 200% compare with base oil.•The quantum chemical parameters were calculated. The theoretical calculations were compatible with the experimental results.
