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In this study, a series of HZSM-5-X were prepared by acid modification, then Ce/HZSM-5-X (X = 0, 0.2, 0.4, 1.0, 2.0) were prepared by impregnation method. The catalytic performance of the catalysts on dichloromethane (DCM) oxidation was investigated. Through different characterizations, HZSM-5-X exhibit higher specific surface area, better redox ability, richer acidity and more suitable acidic site distribution after acid treatment. Among them, Ce/HZSM-5-0.4 shows better catalytic activity with the lowest by-product and the best CO2 yield, its T90 is 302 °C and the CO2 yield of T90 more than 80 wt%, which demonstrates that the acid modification of carrier plays the positive effect on the catalyst capacity for DCM oxidation.

Graphene oxide is successfully synthesized using Hummer’s method and Hummer’s method with additional KMnO4. Hummer’s method with additional KMnO4 shows higher oxidation of graphite as compared to Hummer’s method. The reduction of graphene oxide using sodium hydrosulfite shows some of functional group remains on the lattice of graphite as clear from FTIR spectra. Further, acid treatment of graphene is carried using H2SO4 at 90 °C for 90 min, showing removal of functional group of graphene from the surface revealed by XRD and obtaining more pure graphene.

The environmentally friendly nature of natural cellulose, as well as its excellent crystallinity and mechanical properties, have piqued researchers' interest. In this study, date palm seeds as agri...

The development of active oxidative desulfurization (ODS) catalysts is of practical importance. Recently, MOF-808(Zr) has been attempted to use as ODS catalyst due to its various advantages. However, generally MOF-808(Zr) prepared by conventional method was less active in the oxidation reactions due to the lack of defect sites in the structure. In this contribution, we report that the catalytic oxidative performance of MOF-808(Zr) can be enhanced by acid treatment due to the formation of defect sites resulting from the partial removal of organic linkers in the structure. During the experiment, the effect of acid concentration, treatment time, the addition amount of oxidant and reaction parameters on the performance of MOF-808(Zr) was studied. The catalytic results show that MOF-808(Zr) treated with 0.4 M HCl for 1h can catalyze the oxidation of dibenzothiophene completely at 60°C in 15 min. The activity (mole number of converted DBT per hour per unit mass) is 70 mmol h−1 g−1, which is much higher than that (45 mmol h−1 g−1) of parent MOF-808(Zr). In addition, the catalyst can be reused several times without obvious loss of catalytic performance.

La-deficient La1-xCexMnO3 mixed oxides, obtained by selective dissolution in 1 ​M nitric acid, were employed in methane complete oxidation. The majority of the La cations in these perovskites were removed, resulting in increased specific surface areas, better reducibility and greater activity. Incorporation of a small amount of Ce stabilized the structure and a perovskite phase persisted in La-deficient La1-xCexMnO3 mixed oxides after 12 ​h of acid dissolution. La0.95Ce0.05MnO3 after the acid treatment exhibited satisfactory catalytic activity, with T50 and T90 values of 365 and 459 ​°C, respectively, which was even comparable to that previously reported 1% Pd/Al2O3 catalysts. And it showed excellent long-term activity even in the presence of CO2 and H2O.

In the present study, municipal secondary sludge and purified glycerol (obtained after acid treatment of crude glycerol) were used together for lipid production using intermittent feeding strategy. Intermittent sludge feeding strategy (sludge SS 30 g/L) resulted in a higher biomass (54.99 g/L) and lipid concentration (25.35 g/L) at 96 h when compared to 35 g/L SS single sludge feeding or control strategy (45.67 g/L biomass & 19.16 g/L lipid). Moreover, the intermittent sludge feeding strategy significantly reduced foaming and requirement of anti-foam during fermentation when compared to control strategy. The energy balance of biodiesel production from lipid obtained by intermittent sludge feeding strategy (30 g/L SS) was energetically favorable. It was also revealed from yield coefficients and energy balance that sludge had an important contribution in microbial lipid and biodiesel production.

The use of hydrochloric acid treatment goes back a century. For the first time the company “Ohio Oil” applied acid for formation stimulation in 1895, and the patent for acidizing limestone was obtained by the company "Standard Oil". However, with a significant increase in production volumes, it turned out that acid solutions caused very strong corrosion of downhole equipment. Therefore, the hydrochloric acid treatment method had not been used for 30 years. The discovery by John Grib of “Dow Chemical” in 1931 – slowing down the effect of hydrochloric acid on the metal with arsenic – made it possible to return to this method, and three years later “Halliburton Oil Well Cementing” began to practice acidizing on an industrial scale. As the analysis of the field material has shown, there are many technologies with the use of modified acids intended for acidizing, which are characterized by a high degree of success. Nevertheless, according to the estimates of different authors, the treatments success varies in the range from 60 to 80%, and for repeated treatments – less than 50 %. The urgency degree of the problems associated with acid treatment of the bottomhole formation zone and the tendencies of its development was investigated. Analysis of patent information according to the International Patent Classification for 17 years (from 1997 to 2013 inclusive) for Russian patents and for 15 years (from 1999 to 2013 inclusive) – for American ones showed stable activity of Russian organizations, while foreign organizations showed in this respect a significant growth of interests and achievements. Foreign experts mainly investigated the modeling of acid treatment [6–11], while Russian specialists were more inclined towards service support of acid treatment. It was revealed that there were no methods for calculating the risks of falling out of heavy oil components during acid treatment, depending on the geological and physical conditions of the target.

Volatile organic compounds (VOCs) are one of the main sources of air pollution, which are of wide concern because of their toxicity and serious threat to the environment and human health. Catalytic oxidation has been proven to be a promising and effective technology for VOCs abatement in the presence of heat or light. As environmentally friendly and low-cost materials, manganese-based oxides are the most competitive and promising candidates for the catalytic degradation of VOCs in thermocatalysis or photo/thermocatalysis. This article summarizes the research and development on various manganese-based oxide catalysts, with emphasis on their thermocatalytic and photo/thermocatalytic purification of VOCs in recent years in detail. Single manganese oxides, manganese-based oxide composites, as well as improving strategies such as morphology regulation, heterojunction engineering, and surface decoration by metal doping or universal acid treatment are reviewed. Besides, manganese-based monoliths for practical VOCs abatementare also discussed. Meanwhile, relevant catalytic mechanisms are also summarized. Finally, the existing problems and prospect of manganese-based oxide catalysts for catalyzing combustion of VOCs are proposed.

In this post hoc study, arachidonic acid (AA)-induced platelet aggregation during pregnancy with and without acetylsalicylic acid (ASA) treatment was studied in 323 women with unexplained recurrent first-trimester miscarriage and in 59 healthy women with normal pregnancies. All women had normal AA-induced platelet aggregation in the non-pregnant state. Women with recurrent miscarriage were treated with 75 mg ASA or placebo daily. AA-induced platelet aggregation was measured with multiple electrode impedance aggregometry and presented in units (U), where 1 U = 10 aggregation units x minutes. There were no significant differences in platelet aggregation between placebo-treated women with recurrent miscarriage and healthy women. The mean differences were-0.7 (95%CI; -7.0; 5.6) U in the non-pregnant state, 3.8 (95%CI; -4.6; 12.2) U during the late first trimester and 1.7 (95%CI; -6.7; 10.3) U and 4.1 (95%CI; -3.9; 12.0) U during the early and late third trimester, respectively. ASA reduced platelet aggregation by median -84.0% (Q1; Q3; -89.8; -76.3), -79.9% (-84.7; -69.2) and -75.7% (-83.5; -49.5), respectively, during pregnancy. The degree of inhibition by ASA decreased during the third trimester (p

This study investigates, for the first time, the effects of steam heating of hierarchical porous-structured granular Y zeolite samples and of their subsequent treatment with aqueous nitric and citric acid solutions on the acid properties and porous structure characteristics of the samples. It was demonstrated that acid treatment of a sample not subjected to preliminary steam heating stabilization leads to its decationation, dealumination, and partial amorphization of its crystal lattice. In contrast, acid treatment of a steam-stabilized sample was found to mitigate the lattice destruction.

Consumer waste of cotton cellulose is receiving increasing attention. In this study, in order to recycle waste cotton cellulose fibre into ultrafine powder efficiently, a compact process containing sulfuric acid treatment and stone milling was examined. Scanning electronic microscopy (SEM) and atomic force microscope (AFM) were used to study the morphology of the original cellulose fibre, acid modified fibre and milled cellulose powder. The particle size, crystallinity and strength loss were also explored. The results illustrated that the fibre strength can be largely reduced by acid treatment and high temperature and the crystallinity of the fibre decreased after stone milling. Ultimately, the production efficiency and the output of the micron dry cellulose powder were greatly improved. About 1 kg dry ultrafine powder with particle size around 40 μm was achieved in 1.5 h by stone milling in laboratory. This method shows a great potential for industrial application in the future.

Introduction. Maltodextrins are a common dietary supplement with a number of positive properties. They consist of D-glucose units connected by a (1–4) glucoside bond. The research objective was to improve the existing technology of maltodextrin production based on potato and corn starch. Study objects and methods. Maltodextrins were obtained by enzymatic and acidic incomplete hydrolysis of potato and corn starch. Amilolux ATS and Glucolux A were used for enzyme hydrolysis, and sulfuric acid was used for acid hydrolysis. The finished product was obtained by spray drying. The sensory properties of the finished product were determined by standard methods. The method of high-performance liquid chromatography defined the hydrocarbon composition, while the method of dextrose equivalent helped to determine the reducing capacity of sugars. Results and discussions. The study improved the technique of the enzymatic breakdown of starch. Amylolysis ATS proved to be the optimal enzyme preparation in concentration of 0.5 mL/50 cm3). Other optimal parameters included the starch-splitting activity of 2,330.50 u/mL, temperature of hydrolysis of 65 ± 2°C, and pH reactions of pH 6.5. The method of spray drying proved most efficient for drying starch hydrolysates: the drying temperature and air flow was 100°C, while the flow rate of the solution was 12 mL/min). The experiment also established the dextrose equivalent of the finished product (12–13%) and the quantitative content of sugars in the obtained samples. For maltodextrins obtained from potato starch, the content of maltose and glucose was 16.73 ± 0.25% and 12.48 ± 0.050%, respectively; for corn maltodextrins – 40.22 ± 0.30% and 52.93 ± 0.040%. Conclusion. The market for food additives is developing rapidly. Maltodextrin is a natural food additive that can be used in various branches of food industry. The research made it possible to improve the technology of maltodextrin production in t dairy industry.

In this work, GdMnO3 material is successfully prepared using sol-gel method and GdMn2O5/GdMnO3 materials are in-situ generated by acid treatment. These materials are investigated and applied as catalysts for oxygenated VOC complete oxidation. The evaluation results show that GdMn2O5/GdMnO3-1.00 exhibits a remarkable increase in catalytic activity (T50% = 198 °C and T90% = 225 °C) of 2-ethoxyethanol oxidation when compared with the initial sample GdMnO3 (T50% = 223 °C and T90% = none). Characterization analyses show that acid treatment can result in the significant improvement of specific surface area from 20.502 m2·g−1 to 67.952 m2·g−1, abundant surface Mn4+ content and active oxygen, excellent reducibility at low temperature in GdMn2O5/GdMnO3-1.00 sample. In-situ DRIFTS results point out that the main functional groups such as νas(OCO), νas(COO), νs(C O) are formed in the process of 2-ethoxyethanol oxidation over GdMn2O5/GdMnO3-1.00 sample and some by-products including ethanol, 2-ethoxyethyl acetate, acetic acid, carbonic acid, 2-ethoxyethyl 2-methoxyethyl ester, ethane and 1,1′-oxybis[2-methoxy-] can be produced at a reaction temperature of 200 °C. Additionally, in-situ DRIFTS studies indicate the presence of gas-phase O2 plays a vital role in facilitating 2-ethoxyethanol deep oxidation to final products.

This paper aims to characterize a natural sediment from Bahía Blanca estuary (Argentina) as a new clay source and determine the catalytic capacity after its structural modification by an acid activation process. The acid treatment was performed by employing H2SO4 at different concentrations at 353 K and 60 min. The raw material and acid-activated samples were characterized by XRD, XRF, FTIR, N2 physisorption, TGA, SEM, EDX, potentiometric titration and pyridine adsorption monitored by FTIR. Moreover, the catalytic activity on lauric acid esterification with methanol was evaluated as a test reaction. From the structural characterization, it was determined that the material studied contains mainly Ca-montmorillonite, illite, albite and quartz. Likewise, the results obtained showed that the acid-treatment impacts the material characteristics, predominantly surface acidity and textural properties. Particularly, it was evidenced that the samples treated under medium acid activation conditions lead to an increase in acid site number and strength and specific surface area and consequently improve the catalytic activity. The results obtained evidenced that this low cost and widely available raw material presents an interesting mineralogical composition with a high clay mineral content. Additionally, the catalytic performance showed a good conversion in the test reaction regarding other heterogeneous catalysts. Hence, considering these results, this natural sediment merits further research on its purification and application. Fil: Reinoso, Deborath Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Angeletti, Sabrina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina Fil: Cervellini, Patricia Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina Fil: Boldrini, Diego Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina

Acid treatment of mordenite was conducted using acetic acid to increase the Si/Al ratio. The acid treatment of mordenite by acetic acid was performed using sonication. The various time of treatments was used to investigate the effect of sonication in acid treatment of mordenite. Mordenite and all samples after treatment were characterized by ICP, FT-IR, XRD, and ammonia adsorption to measure their acidity. The Si/Al ratio of mordenite was increased from 11.33 to 17.31, 19.47, and 20.58 respectively for 3, 6, and 9 h of sonication. This result was supported by the T‒O bond vibration of samples which shift to higher wavenumber. The increase of the Si/Al ratio was followed by the decrease of acidity. The XRD test result revealed partial loss of mordenite framework after acid treatment. The results indicated that the sonication method can be used for acid treatment of mordenite.

Acid-functionalized multi-walled carbon nanotube (MWCNTs-COOH) was prepared by acid treatment followed by decoration with magnetite (Fe3O4) nanoparticles (Fe3O4/MWCNTs-COOH) by co-precipitation of ...

The purpose of this study was to evaluate the ability of Lactobacillus rhamnosus to bind patulin (PAT) in the buffer solution and apple juice. The binding of L. rhamnosus to PAT was reversible, which improved the stability of the bacterial complex. The ability to bind PAT can be enhanced with the inactivation of the strain by high temperature and acid treatment. Acid-treated bacteria had the highest PAT binding rate of 72.73±1.05%. The binding rates of acid and high temperature (121 °C) treatments were increased by 21.37% and 19.15%, respectively. L. rhamnosus showed the best detoxification ability to PAT at 37 °C, where the binding rate reached 50.9±1.03%. When the dose of inactivated bacteria powder was 0.02 g ml−1, the minimum concentration of PAT in apple juice was 0.37 µg ml−1. The addition of the L. rhamnosus inactivated powder did not affect the quality of the juice product and effectively bound the PAT in apple juice.

In this study, acid fracturing treatments were simulated for a tight limestone reservoir within a shale formation using FRACPRO software. The purpose was to investigate the optimum acid fracturing design that leads to a higher fracture etched length and width, and higher fracture conductivity. Moreover, the impact of the rock-acid contact time and whether to consider a post-flush or fluids flowback, on the acid fracturing outcomes were also investigated. A simple geological model was constructed which consists of different lithological layers. Different acid fracturing design scenarios were considered starting from a single stage of acid injection to multi-stage treatment. In multi-stage acid treatment, alternate acid-slickwater injection was considered. Plain HCl acids with different concentrations and other acids that are already included in FRACPRO database were used. The results showed that the acid loss during post-flush is among the main problems of the acid fracturing in tight carbonate shale reservoir. For the single stage of acid injection, it is recommended to flow back the acid after well shut-in instead of considering a post-flush stage. The multi-stage alternate acid slickwater injection reduces or even eliminated the acid loss. However, it is recommended to inject a slickwater before well shut-in to reduce the rock-acid contact time, thus reducing the formation damage. The results also showed that the created fracture etched width decreases and the fracture etched length increases as the fracturing stages increase. In this study, because of the low carbonate layer permeability and compressive strength, a two-stage alternate 28% HCl and slickwater injection with a post-flush stage is recommended. Keywords: Acid fracturing, Tight carbonate, Acid loss, Low compressive strength, Single stage acid fracturing, Multi-stage acid fracturing

The effect of heat-moisture treatment (HMT) and acid hydrolysis (AH) on the properties of gorgon nut flour (GNF) were investigated. The flours were adjusted to 20%, 25% and 30% moisture levels, and heated at 107 °C for 3 h. The AH was carried out at 0.25, 0.5 and 1 M concentrations of hydrochloric acid. The water and oil absorption capacities of the AH GNF increased from 0.45–1.12 to 0.35–0.63 g/g respectively while for the HMT GNF water absorption capacity and solubility decreased from 0.45–0.25 to 26–20 g/g respectively. The ΔE values for the HMT and AT GNF increased from 4–5 to 5–7 respectively. The GNF displayed A-type structure as observed by X-ray diffraction. The HMT resulted in loss of granular integrity of GNF and AH made the surfaces rough. The HMT and AH, both resulted in an increase in peak intensities as observed by X-ray diffraction. HMT and AH both resulted in lowering of viscous properties as depicted by rapid visco-analysis.

In this work, multiple-wall carbon nanotubes (MWCNTs) were purified with an acid treatment and subsequently dispersed using commercial surfactants, such as amino trimethyl phosphonic acid and nonyl...

An effective method that combines solvent extraction with ultrasonic irradiation was developed to recycle spent bleaching clay (SBC) from modern oil refinery plants. The principle of ‘waste to treasure’ was used to achieve the regenerated SBC. Various characterization techniques were applied to analyse and compare regenerated SBC and commercial bleaching clay (CBC). The structure of the regenerated SBC did not show any obvious change compared with that of CBC, but the Brunauer–Emmett–Teller-specific surface area (SBET) and pore-volume values of the regenerated SBC increased. At the same time, the parameters of the regenerated SBC reached national standards. In addition, the samples were used as low-cost adsorbents for the adsorption of methylene blue (MB) from water. The regenerated SBC had greater adsorption efficiency and cycle performance for MB than CBC. Hence, the SBC may be treated by ultrasonic radiation combined with extraction, and the regenerated SBC has better properties than CBC. This work opens up a new approach to the regeneration and utilization of SBC and raises the potential of ultrasonic irradiation as an environmentally friendly method to be applied to various regeneration systems.

A series of modified montmorillonites were prepared by acid modification method prior to the organosilicon grafting. Aflatoxin B1, zearalenone and deoxynivalenol (DON) were selected to evaluated the mycotoxin adsorption performance of modified montmorrillonites. The experimental results suggest that under acidic conditions, the higher the charge density in the covalent orbital of the active group, the stronger the interaction between it and the DON molecule, and the better the corresponding modified montmorillonite adsorbs DON. Silicified montmorillonite with active groups of cyano group and methacryloyloxy group has the best adsorption performance for DON, and the adsorption degree are 51.6% and 39.0%, respectively. However, under alkaline terms, due to the hydrolysis of active groups, the adsorption degree of montmorillonite on DON dropped steeply.

The objective of this study was to investigate the effect of three different treatments on the morphology, microstructure, and the thermal characteristics of a montmorillonite (Mt) sample, by using hydrochloric acid (HCl), tributyl tetradecyl phosphonium chloride (TTPC) surfactant, and γ-methacryloxypropyltrimethoxysilane (γ-MPS). The resultant nanofillers were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption–desorption analysis, X-ray fluorescence spectrometry (XRF), and thermogravimetric analysis (TGA). The results showed that the amount of chemical grafting of the γ-MPS was increased after the acid treatment, whereas the amount of intercalation of the TTPC surfactant was decreased. The preintercalation of TTPC or silylation of γ-MPS, for the Mt sample, had a certain hindrance effect on its subsequent silylation or intercalation treatments. Furthermore, the effect of four different nanofillers on the thermal stability properties of the polystyrene (PS) matrix were also investigated. The results showed an increase in thermal stability for the triple-functionalized Mt, compared with the double-functionalized samples. The onset decomposition temperatures and the maximum mass loss temperatures of the PS nanocomposites were increased by 27 °C and 32 °C, respectively, by the incorporation of triple-modified Mt, as a result of the good exfoliation and dispersion of the nanolayers, more favorable polymer–nanofiller interaction, as well as the formation of a more remarkable tortuous pathway in the continuous matrix.

The increasing global population and the rapid industrial development associated therewith have increased the demand for fossil-derived fuel oils. The sources of fossil fuels are limited, and many studies have been being conducted to find alternative fuel sources. Waste tire pyrolysis oil (WTPO) attracts considerable attention as an alternative fuel because its properties are similar to those of diesel oil. However, WTPO has a high sulfur content of >1.0 wt%, which is above the environmental standard limit of 0.1 wt%; therefore, it cannot be used in engines directly. It is thus highly necessary to remove sulfur compounds from tire-derived oils. However, finding an appropriate and environmentally friendly process is proving difficult. This review article presents the various desulfurization methods used to removal sulfur from WTPO, such as hydrodesulfurization (HDS), oxidative desulfurization (ODS), ultrasound-assisted oxidative desulfurization (UAOD), and acid treatment. Of these, HDS is the most expensive as it involves high consumption of hydrogen, high temperature (~450 °C), and high pressure (~200 bar), whereas UAOD is an efficient and economic method of reducing the sulfur content of WTPO.

This article is about salt chemical treatment and hot acid treatment of wells. In this case, research has covered different points of theoretical and methodological the hydrochloric acid treatment of the well. Finally, research has pinpointed on various views of outcomes and shortcomings at all.

Waste lignin (WL) obtained from paper mills, was studied for its potential application in preparing carbon nanoparticles (CNPs) with high porosity. This was done by impregnation of 0, 5, 10 and 20% concentrations of phosphoric acid under various carbonization temperatures (600, 700, 800 and 900°C). The physicochemical properties of CNPs were characterized through nitrogen sorption, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Fourier transforms infrared spectroscopy (FTIR). Nitrogen sorption revealed that the condition using 10% concentration of phosphoric acid treatment at a carbonization temperature of 700°C formed carbon nanoparticles with a highly porous structure (Surface area 27.65 m2/g and pore volume 0.07 cm3/g). Additionally, in order to high surface area, porosity and concentrated carbon nanoparticle.

De-glycosylation could be an important process for enhancing the biological activities of flavonoids. In this study we investigated de-glycosylation of rutin by acid treatment by comparing hydrolysis of rutin to quercetin with two different solvents and acid concentrations. Antioxidant activity was measured using chemical methods and biological activities were examined in cell-based systems. Rutin hydrolysis occurred more rapidly when 80% ethanol was used as the reaction solvent (as compared to water), and the rate of hydrolysis accelerated as acid concentrations increased. In reactions of rutin with 0.5 M HCl in 80% ethanol for 3 h, almost all the rutin was converted into quercetin. 2,2-Diphenyl-1-picrylhydrazyl, 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activities, and reducing powers were correlated with conversion rate. Protective activity in HepG2 cells, anti-inflammatory activity in RAW264.7 cells, and antiadipogenic activity were increased with increased conversion of rutin to quercetin. This study suggests that de-glycosylation of glycoside flavonoids may increase physiological activity and, therefore, enhance its use in various fields.

Acid treatment is one of the main methods of stimulating the near wellbore area of the wells opening the carbonate reservoirs. Despite the extensive experience of using this technology both in Russia and abroad, as well as a significant number of studies, the success rate is hardly ever estimated at over 30%. One of the reasons for the low success rate is neglect to the changes in the physical properties of fluids during injection, interaction with the rock and the properties of the reaction products in the wellbore and the near wellbore area during the acid treatment planning. This paper discusses the main chemical reactions occurring during the interaction of hydrochloric acid with limestones and dolomites. The quantities of the substances resulting from a chemical reaction between 15% aqueous solution of acid and the carbonates have been determined. The properties (phase state, solubility, dependences of viscosity and density on pressure and temperature) of water, carbon dioxide, nitrogen, 15% aqueous solution of acid, solutions of calcium and magnesium chloride salts in the range of possible pressures and temperatures during the acid treatment were evaluated. Due to the diversity of additives used in acid solutions, the paper proves the necessity of conducting laboratory experiments to evaluate their properties under the conditions expected during the acid stimulation. Based on laboratory studies, the reaction time of 15% solution of hydrochloric acid with calcium carbonate was estimated. The impact of the chemical diverter used for primary treatments at the Badra oilfield (Iraq) on the properties of the acid solution and the reaction time was determined. The changes in the solution viscosity depending on the acid temperature and concentration were determined. The results provided in the work were used for the purposes of forecasting and evaluating the efficiency of acid treatment performed on the wells of the Badra oilfield.

Fusarium rot of muskmelon is a common and frequently-occurring postharvest disease, which leads to quality deterioration and neosolaniol (NEO) contamination. New strategies to control postharvest decay and reduce NEO contamination are of paramount importance. The effects of acetylsalicylic acid (ASA) treatment on the growth of Fusarium sulphureum in vitro, and Fusarium rot development and NEO accumulation in fruits inoculated with F. sulphureum in vivo were investigated. The results showed that ASA inhibited the growth of F. sulphureum, evident morphological and major cellular changes were observed under the microscope. In vivo testing showed that 3.2 mg/mL ASA significantly suppressed Fusarium rot development and NEO accumulation after 6 and 8 d of pathogen inoculation. Meanwhile, Tri gene expressions involved in NEO biosynthesis were down-regulated after treatment. Taken together, ASA treatment not only reduced Fusarium rot development by inhibiting the growth of F. sulphureum, but decreased NEO accumulation by suppressing NEO biosynthesis pathway.

Owing to the great importance of zeolite Y in industrial catalysis, the adsorption equilibrium and diffusion of toluene on a series of steaming and acid leaching Y zeolites were investigated to obt...

Enhancing the molecular loading capability of layer-by-layer(LbL) method holds high importance in environmental and biomedical application. Here, we reported a strategy to prepare highly loaded poly(acrylic acid)(PAA)/poly(allylamine hydrochloride)(PAH) LbL films by combining the particulate templating strategy and acid treatment film transformation and realized the efficient loading of hydrophilic small molecules. The loaded molecules can be released in a pH-controlled manner. A slow release speed was observed in the acidic solutions with pH value of 3. Abrupt releases were observed at higher pH values(5 or 7).

Here, we have studied the antibacterial effects of a newly synthesized carbon structure with excellent properties, named porous carbon cuboid (PCC) nanoparticles, upon Gram-negative Escherichia coli and Gram-positive Corynebacterium glutamicum bacterial cells and its algicidal effects upon Chlamydomonas reinhardtii microalgal cells. More specifically, the antibacterial properties of PCCs enriched with acid treatment (PCC-ox) or metal encapsulation (PCC-Cu and PCC-Ag) were investigated under various concentrations of PCCs and their interaction times. Additionally, the impact of PCCs upon microalgal growth was estimated by measuring the total chlorophyll level during their cultivation. As a result, E. coli and C. glutamicum were shown to be substantially inhibited by PCCs, depending on their special characteristics, dose, and bacterial strain. Moreover, it has been proven that the antibacterial effect is time-dependent. Growth of C. reinhardtii was inhibited by PCCs in a material-dependent manner, whereas P...

Concrete grinding from highway maintenance operations produces large amounts of a highly basic liquid residue, posing a significant challenge to proper disposal. To discard this residue with little risk to human health or the environment, it should be solidified and its pH should be neutralized. Herein we present the serendipitous discovery that both goals can be met by treatment with citric acid. Through the use of 13C and 29Si solid-state NMR we determined that such treatment removes the calcium from the concrete structure, thus allowing the solubilization of its one-dimensional silica chains. These silica chains then cross-link in solution forming a highly porous silica material that is able to absorb the water from the residue. This new waste treatment process, which may utilize other acids with low water content, promises to facilitate a significantly improved methodology for the disposal of concrete grinding residue in a safe and environmentally friendly manner.

Crushed stone powder and aluminum ash are industrial wastes, and effective utilization of these wastes has been highly expected. Since the main components of the two wastes are Si, Al and O, those wastes can be used as starting materials for synthesis of zeolites of which some types have been commercialized as catalysts and ion-exchangers. In this study, zeolites A and X well-known as practical materials were successfully synthesized with high purity using the two industrial wastes by a mild process based on two hydrothermal treatments with intermediate acid treatment. In the first hydrothermal treatment at 150 °C, quartz in the crushed stone powder was dissolved and acid-soluble hydroxysodalite (Na8(AlSiO4)6(H2O)2(OH)2) with Si/Al = 1 and sodium aluminosilicate (Na6(AlSiO4)6) were formed. Those compounds were dissolved with HCl aq. solution. The zeolites were successfully synthesized from the second hydrothermal treatment of the yellow dried filtrates at 80 °C in NaOH aq. solution. In the process proposed, removal of Ca from the crushed stone powder was effective to formation of zeolites A and/or X. Selective synthesis of zeolites A and X was achieved by controlling the acid treatment conditions. Furthermore, the effect of the drying condition of the filtrate obtained after the acid treatment was also investigated on the differences in the product phase.

In this study, removal of cadmium (Cd2+) from rice proteins (RPs) by soaking with hydrochloric acid (HCl) or ethylene diamine tetraacetic disodium (EDTA-2Na) solutions was reported. For HCl-soaking, Cd2+ removal reached equilibrium within 30-min treatment, and the size of RPs particles and reaction temperature had negligible effects on the Cd2+ removal rate (RCd). However, extra washing of HCl-treated RPs by distilled water or acid solution can further enhance RCd effectively. The reaction pH had a profound effect on RCd, and the reduction of pH values from 5.5 to 4 can boost RCd from 16.4% to 92.3%. On the other hand, by increasing the concentration of EDTA-2Na from 10 μg/mL to 40 μg/mL at pH 7, RCd increased from 69.1% to 92.0%. However, the reduction of pH resulted in the formation of insoluble conjugates consisting of RPs, EDTA and Cd2+, therefore lowering RCd. Both of the two methods reduced the mineral content in RPs, but had no significant impact on their amino acid compositions. Furthermore, compared to the soaking by EDTA-2Na, acid treatment weakened the emulsifying and foaming capabilities of RPs to a greater extent.

Two different approaches funded upon the intramolecular [4 + 2]-cycloaddition of in situ generated o-quinone methides have been explored to construct the central tetracyclic core of parvifolals A/B. At the outset, a cross-pinacol coupling of 2-formyl tri-O-methyl resveratrol with 4-methoxysalicylaldehyde followed by acid treatment was found to provide the desired tetracyclic core with an internal olefin. The requisite pendant aryl group has been introduced by a Pd-catalyzed direct coupling of corresponding diazonium salt.

Soybean residues were pretreated with 6% of HCl and NaOH, respectively, and then nanofibrillated cellulose (NFC) was prepared using the high pressure homogenization method. The effects of different pretreatment methods on the structure, properties, and NFC preparation of soybean residues were studied. Analysis of the X-ray diffraction, specific surface area, porosity, and thermal stability showed that pre-treatment of the soybean residues allowed the basic crystallinity to be maintained. Specific surface area, porosity, and thermal stability increased. Acid treatment led to the greatest increases. The soybean residues were treated with 6% hydrochloric acid at 80 °C for 1 h, and homogenized 15 times under a pressure of 60 MPa to obtain NFC.

Food processing might induce the transformation of hidden ZEN (zein-bound ZEN) in maize. The objective of this study was to assess the effect of processing factors on free ZEN and hidden ZEN. After zein was treated under different temperature and pH, ZEN was quantified in samples before and after in vitro digestion. The ratios of hidden to total ZEN in zein are decreased from 54.25% to 40.74% after thermal treatment and from 54.25% to 0 after alkaline treatment, respectively. Conversely, acid treatment increased the ratio of hidden to total ZEN from 54.25% to 100%. Thus, it can be concluded that thermal or alkaline condition induced the conversion of hidden ZEN to free ZEN while acid condition promoted the ZEN-zein interactions to form the hidden ZEN. Overall, temperature and pH values played a vital role in the conversion of hidden ZEN during food processing.

Matrix acidizing is a highly successful, effective, and relatively inexpensive approach to enhancing well productivity in carbonate formations. Accordingly, there has been little motivation to address the ways to optimize the acid stimulation process better. Acid-in-oil emulsions that form during this process cause one of the most challenging problems that negatively impact the performance and deliverability, especially when these emulsions are highly stable over extended periods. Such stable emulsions can plug the flow path of oil causing high resistance to flow and potentially reducing well productivity. De-emulsifiers are some of the most widely used acid additives targeting the reduction of emulsion stability. However, there is doubt in the research community on whether there is enough shear mixing that can cause the formation of emulsions inside the rock matrix. Besides, the effectiveness of de-emulsifiers in eliminating such emulsions in the pore space has not been investigated. In the current oil price market, there is a need to be more vigilant regarding the cost of well stimulation and the added value from the various additives. While laboratory work on matrix acidizing in carbonate formations is abundant, the work on oil-saturated samples is rare, and therefore, the effect of emulsions on the acidizing process has not been widely documented. In this work, we present a stacked study of bottle tests and core flooding tests designed to investigate the de-emulsifiers’ role in the rock matrix. The results reveal that (1) emulsion-risk in the pore space is real, and (2) the addition of de-emulsifiers to the acid allows for efficient backflow of oil, revealing an improvement in the performance of the acidizing treatment.

This work investigated the concept of preferential dissolution of copper in HNO3 10 M at 20 °C from two starting Cu-Mn oxides to acquire novel copper doped MnO2 like polymorphs. On purpose two starting Cu-Mn oxides were tested: a nanocristalline CuMn2O4 spinel phase with a SSA of 47 m2/g and a weak amorphous Cu-Mn oxide with a Mn/Cu atomic ratio of 4.8 (SSA: 166 m2/g). The physico-chemical properties of the final copper doped MnO2 like oxides were discussed in terms of the nature of the starting oxides and of the operating conditions applied for the acid treatment. Finally, these new copper doped γ/e MnO2 like oxides were assessed in toluene oxidation and their catalytic performances were compared with those of α-MnO2 and e-MnO2 catalysts. The copper doped MnO2 obtained from the weak amorphous Cu-Mn oxide exhibited the highest activity in terms of T50(CO2). This highest activity was related to a high density of Cu-O-Mn interactions at the outermost layers of the catalyst as assessed by ToF-SIMS results.

This study used the bark of the forest species Campomanesia guazumifolia modified with H2SO4 to absorb the anti-inflammatory ketoprofen from aqueous solutions. FTIR spectra confirmed that the main bands remained after the chemical treatment, with the appearance of two new bands related to the elongation of the carbonyl group present in hemicellulose. Micrographs confirmed that the surface started to contain a new textural shape after acid activation, having new pores and cavities. The drug adsorption’s optimum conditions were obtained by response surface methodology (RSM). The adsorption was favored at acidic pH (2). The dosage of 1 g L−1 was considered ideal, obtaining good indications of removal and capacity. The Elovich model very well represented the kinetic curves. The isotherm studies indicated that the increase in temperature negatively affected the adsorption of ketoprofen. A maximum adsorption capacity of 158.3 mg g−1 was obtained at the lower temperature of 298 K. Langmuir was the best-fit isotherm. Thermodynamic parameters confirmed the exothermic nature of the system (ΔH0 = −8.78 kJ mol−1). In treating a simulated effluent containing different drugs and salts, the removal values were 35, 50, and 80% at 15, 30, and 180 min, respectively. Therefore, the development of adsorbent from the bark of Campomanesia guazumifolia treated with H2SO4 represents a remarkable alternative for use in effluent treatment containing ketoprofen.

This study aim was to evaluate the influence of 37% hydrochloric acid (37% HCl) treatment of cobalt-chromium (Co-Cr) alloys on the metal-ceramic bond strength (MCBS). The specimens were sandblasted with 100-µm aluminum oxide particles and divided into four groups (n = 10) according to the surface treatment performed: control (C) - no treatment - and treated with 37% HCl for different times: 10 minutes (T1), 20 minutes (T2) and 30 minutes (T3). The samples were submitted to the 3-point bending test, and the type of failure was evaluated. Wald, Bonferroni and Pearson's tests were applied (α = 0.05). There was difference between the treatments (p = 0.019): T3 (61.57 MPa) had higher bond strength than C (51.96 MPa). The specimens presented 17.5% of adhesive and 82.5% of mixed failures. There was a weak correlation between the failure type and the MCBS. Co-Cr surface treatment with 37% HCl for 30 minutes is a promising protocol for an appropriate metal-ceramic bond strength.

Summary Climate change and global warming recently became significant concerns due to the massive emissions of greenhouse gases into the atmosphere, predominantly CO2 gases. Therefore, it is necessary to find sustainable and inexpensive methods to capture the greenhouse gasses and protect the environment for live species. The application of naturally available and cheap adsorbents of carbon such as clay minerals became a great interest. However, the minerals prone to low storage capacity despite their high affinity to adsorb carbon. This paper aims to explore ways to improve the pore volume and surface area of two selected clay minerals, ‘montmorillonite and kaolinite’ by acid treatment to overcome their low storage capacity.This study concludes that clay minerals are inexpensive and available material sources to model the realistic conditions and apply the results of carbon capture to prevent global warming, which is one of the most critical and urgent problems in the world.

In this work, peanut (Arachis hypogaea) skin, a by-product generated by the agricultural production of its seeds, was employed as a precursor in the preparation of an adsorbent for the 2,4-D removal in water. The skins were treated with sulfuric acid and characterized by different techniques. The adsorption was favored at acid pH = 2 with pHpzc = 6. The dosage of 0.9 g L-1 was considered ideal, obtaining satisfactory indications of removal and capacity. The kinetic curves were well represented by the general order model, with the equilibrium reached quickly in the first 30 min for all concentrations. Adsorption isotherm studies showed that the increase in temperature negatively affected the herbicide adsorption, obtaining a maximum capacity of 246.72 mg g-1, by the Langmuir isotherm at 298 K. The remarkable adsorption efficiency presented by the adsorbent can be associated with the presence of new functional groups on the adsorbent surface generated after the acid treatment. Thermodynamic parameters confirmed the exothermic nature of the adsorptive system. In the treatment of synthetic wastewater consisting of a mixture of herbicides and salts, a high removal efficiency (72%) of herbicides was obtained. Therefore, the development of an adsorbent derived from peanut (Arachis hypogaea) skin treated with sulfuric acid is an excellent alternative, generating remarkable removal results towards 2,4-D herbicide.

The design and development of highly efficient non-precious metal single-atomic ORR catalysts for proton exchange membrane fuel cells (PEMFCs) are highly desirable but challenging. Herein, we report a novel polydopamine (PDA)-metal complex-assisted pyrolysis strategy for producing zeolitic imidazolate framework-derived catalysts with a hierarchically porous carbon support and highly exposed dense-FeN4 sites (Z8@DA-FIP-950-C). The resultant Z8@DA-FIP-950-C catalyst shows remarkably enhanced performance for oxygen reduction reaction (ORR) with a half-wave potential (E1/2) of 0.828 V in 0.1 M HClO4 solution, which is close to commercial 20 wt% Pt/C catalyst. Impressively, the Z8@DA-FIP-950-C exhibits peak power densities of 982 and 454 mW cm-2 in H2/O2 and H2/air PEMFCs, respectively, which are superior to most of non-precious metal catalysts reported to date. In addition, we construct the quantitative relationship between the active site activity and ORR performance, and prove the dominating role of the FeN4 site density to the observed excellent PEMFC performance. This work demonstrates a facile strategy to prepare the 3D hierarchically porous carbons with a maximized exposure of high-dense FeN4 sites (without acid treatment), providing a useful guidance for the design and development of novel highly-efficient single-atom catalysts for the renewable energy applications.