12 research outputs found
Влияние химического строения катионных ПАВ на процессы смачивания породообразующих минералов
Interfacial interactions of cationic surfactants of various chemical structures at the solution / finely dispersed mineral material (quartz and dolomite) interface were studied. It is established that the modification of the surfaces of quartz and dolomite with cationic surfactants leads to a change in the structure and radius of the capillaries due to the formation of adsorption-solvate shells. The hydrophobic ability of cationic surfactants is determined by the structure of the hydrophilic part of their molecules – the balance of amino groups in the alkyl chains and the absence of steric hindrances during adsorption interaction with the surface of mineral materials. The mixture of surfactants containing six amino groups and a polyhydric alcohol glycerin has an effective hydrophobic ability from both aqueous and highly mineralized solutions.Изучены межфазные взаимодействия катионных ПАВ различного химического строения на границе раздела раствор/тонкодисперсный минеральный материал (кварц и доломит). Установлено, что модифицирование поверхностей кварца и доломита катионными ПАВ приводит к изменению структуры и радиуса капилляров вследствие образования адсорбционно-сольватных оболочек. Гидрофобизирующая способность катионных ПАВ определяется строением гидрофильной части их молекул – сбалансированностью аминогрупп в алкильных цепях и отсутствием стерических затруднений при адсорбционном взаимодействии с поверхностью минеральных материалов. Эффективной гидрофобизирующей способностью как из водных, так и высокоминерализованных растворов обладает композиция из аминопроизводных жирных кислот рапсового масла, содержащая шесть аминогрупп и многоатомный спирт глицерин
Регулирование межфазных процессов поверхностно-активными веществами и их композициями при разработке технологий нефтеотдачи
Physicochemical aspects of the regulation of interfacial processes occurring at the oil-water-rock interface in the presence of ionic surfactants and their compositions are considered with the goal of developing efficient, scientifically grounded innovative technologies ensuring enhanced oil recovery and refining. A complex of studies of surface phenomena in the presence of ionic surfactants made it possible to identify criteria for evaluating the effectiveness of their action at the oil-water-rock interface, which makes it possible to predict the behavior of surfactants in real conditions of oil production and to use them purposefully in various enhanced oil recovery technologies.Рассмотрены физико-химические аспекты регулирования межфазных процессов, протекающих на границах раздела нефть–вода–порода в присутствии ионогенных ПАВ и их композиций, с целью разработки эффективных, научно обоснованных инновационных технологий, обеспечивающих повышение нефтеотдачи и нефтепереработки. Проведенный комплекс исследований поверхностных явлений в присутствии ионогенных ПАВ позволил выявить критерии оценки эффективности их действия на границах раздела нефть–вода–порода, что дает возможность прогнозировать поведение ПАВ в реальных условиях нефтедобычи и целенаправленно использовать их в различных технологиях повышения нефтеотдачи
Адсорбционная способность бинарных смесей ПАВ на межфазных границах раздела
The adsorption capacity on the interphase surfaces of solution / air and solution / mineral material of binary mixtures of anionic (alkylbenzenesulfonic acid and its sodium salt (ABSCNa)) and nonionic surfactants (Tween-80) was studied. It has been established that the adsorption interaction of binary mixtures of surfactants with the surface of quartz and dolomite is affected by the presence of potential-determining ions that activate the surface of mineral materials, the charge and hydration of the anionic antagonists, the nature of the intermolecular interactions between the surfactant-components of the mixture. It was shown that the ABSCNa / Tween-80 mixture, characterized by low adsorption capacity to the mineral materials under study and absence of interaction between the surfactant components of the mixture, has a maximum oil displacement capacity from the surface of dolomite and quartz.Изучена адсорбционная способность на межфазных поверхностях раствор/воздух и раствор/минеральный материал бинарных смесей анионного (алкилбензолсульфокислота и ее натриевой соли (АБСКNa)) и неионогенного ПАВ (Твин-80). Установлено, что на адсорбционное взаимодействие бинарных смесей АПАВ/НПАВ с поверхностью кварца и доломита оказывает влияние наличие потенциалопределяющих ионов, активирующих поверхность минеральных материалов, заряд и гидратированность противоионов АПАВ, характер межмолекулярных взаимодействий между ПАВ-компонентами смеси. Показано, что смесь АБСКNa/Твин-80, характеризующаяся низкой адсорбционной способностью к исследуемым минеральным материалам и отсутствием взаимодействия между ПАВ-компонентами смеси, обладает максимальной нефтевытесняющей способностью с поверхности доломита и кварца
СТАБИЛИЗАЦИЯ НЕФТЯНЫХ ДИСПЕРСИЙ КОМПОЗИЦИЯМИ ПОВЕРХНОСТНО-АКТИВНЫХ ВЕЩЕСТВ
Colloid-chemical properties of water solutions of compositions of surfactants of different nature are studied. The synergetic effects for the compositions of cationic/anionic surfactants and cationic/non-ionized surfactants at micellization and adsorption are found. It has been found that the maximal synergism of action, showing up in a decrease of surface tension, is offered by the composition of cationic/anionic surfactants in the component 4 : 1. This fact stipulates the efficiency of its dispersive action and its capacity of forming on the surface of particles the dispersible phase of oil slime of the structured layer, possessing maximum elasticity and mechanical strength, as compared to the molecules of cationic and non-ionized surfactants. Water dispersions of oil slime obtained with the use of the composition of cationic and anionic surfactants are the aggregative and kinetically stabilized dispersions of direct type.Изучены коллоидно-химические свойства водных растворов композиций поверхностно-активных веществ (ПАВ) различной природы: катионные ПАВ (КПАВ), анионные ПАВ (АПАВ), неионогенные ПАВ (НПАВ). Обнаружены синергетические эффекты для композиций КПАВ/АПАВ и КПАВ/НПАВ при мицеллообразовании и адсорбции. Установлено, что максимальным синергизмом действия, проявляющимся в снижении поверхностного натяжения, обладает композиция КПАВ/АПАВ при соотношении компонентов 4 : 1. Этот факт обуславливает эффективность ее диспергирующего действия и способность к формированию на поверхности частиц дисперсной фазы нефтешлама структурированного слоя, обладающего максимальной упругостью и механической прочностью по сравнению с молекулами КПАВ/НПАВ. Водные дисперсии нефтешлама, полученные с использованием композиции КПАВ/АПАВ, являются агрегативными и кинетически устойчивыми дисперсиями прямого типа
МЕЖФАЗНЫЕ ВЗАИМОДЕЙСТВИЯ НА ГРАНИЦЕ РАЗДЕЛА НЕФТЬ–ВОДА В ПРИСУТСТВИИ АНИОННЫХ ПОВЕРХНОСТНО-АКТИВНЫХ ВЕЩЕСТВ
The effect of anionic surfactant alkyl chain structure on the processes occurring at oil–surfactant solution interface and structure formation in water solution, has been studied. The criteria for evaluating anionic surfactants҆ efficiency have been formulated. It has established that their behavior at the oil–water interface is governed not only by the linearity and saturation of the alkyl group, but also by its length and presence of aromatic ring in its structure. The regularities found are in agreement with the data on the ability of anionic surfactant solutions to wash off oil from metal surface, structural and rheological properties of their water solutions. It has been shown that anionic surfactants effectively reduce the interfacial tension at the oil – water and stabilize the drops of oil thus improving the processes of recovery, preparation and transportation of heavy oil.Изучено влияние строения углеводородного радикала АПАВ на процессы, происходящие на межфазной границе нефть–раствор АПАВ, и структурообразование в их водных растворах. Выявлены критерии оценки эффективности действия АПАВ, заключающиеся в том, что их поведение на границе нефть–вода зависит от строения углеводородного радикала молекулы АПАВ и определяется линейностью, насыщенностью, а также при уменьшении длины радикала наличием ароматического кольца в его структуре. Полученные закономерности изменения межфазного взаимодействия на границе свободная нефть–вода в присутствии АПАВ коррелируют с результатами исследования их нефтеотмывающей способности с металлической поверхности и структурно-реологическими свойствами водных растворов.
Влияние природы функциональных групп химических модификаторов на термическую стабильность нефтяного битума
It has been established that introduction of adhesives, containing groups reactive towards asphaltens, into the bitumen causes its colloid structure change. This in turn affects the irreversible change processes caused by air oxygen and elevated temperature. Maximal deceleration of thermo-oxidative destruction processes is effected by additives containing phosphate groups, either individually or together with amino groups, as the result of their interaction with bitumen asphaltens.Исследовано влияние адгезионных добавок, содержащих аминогруппы, свободные кислотные группы фосфорной кислоты, а также композицию этих групп, на изменение коллоидной структуры битума и оценена возможность ее стабилизации к процессам термоокислительной деструкции. Установлено, что максимальным модифицирующим эффектом, проявляющимся в повышении структурирующего и термостабилизирующего действия для нефтяного битума, обладают добавки, в состав которых входят фосфорсодержащие группы как в индивидуальном виде, так и в композиции с аминогруппами, что обусловлено их взаимодействием с асфальтенами битума
Mатричный синтез многомерного пористого кремнезема
Isothermal data of superficial tension of solutions of surfactant mixture and low-temperature nitrogen sorption of multidimensional porous silica received by template synthesis prove complementarity of its properties and properties of SAA micelles. The measured isotherms of gas sorption belong to IV Type inherent in mesoporous adsorbents. The BET specific surface area is 600–800 m2/g, and the Gurvich pore volume is 0.7–1.0 cm3/g. With increase in mole fraction of nonionic component these values decrease, the ordered texture of SiO2, characteristic of MCM-48 mesoporous molecular sieve, collapses, d211-spacing becomes < 3.31 nm, and NLDFT distribution is transformed from monomodal to polymodal one.Изотермические данные поверхностного натяжения растворов смеси поверхностно-активных веществ и низкотемпературной сорбции азота многомерным пористым кремнеземом, полученным путем матричного синтеза, доказывают комплементарность его свойств и свойств мицелл ПАВ. Измеренные изотермы газовой сорбции относятся к типу IV, присущему мезопористым адсорбентам. Удельная поверхность по БЭТ составляет 600–800 м2/г, а объем пор по Гурвичу – 0,7–1,0 см3/г. С увеличением молярной доли неионного компонента значения данных величин уменьшаются, упорядоченная текстура SiO2, характерная для мезопористого молекулярного сита МСМ-48, разрушается, межплоскостное расстояние d211 становится < 3,31 нм, и NLDFT-распределение из мономодального трансформируется в полимодальное
Влияние комплексных парафиносодержащих добавок на свойства портландцементных мелкозернистых бетонов
The composition of complex hydrophobic plasticizer for portland cement concretes has been developed on the basis of wax-bearing emulsion and the hardening accelerator, and its behavior in portland cement mixtures has been studied.Разработаны комплексные добавки для портландцементных мелкозернистых бетонов, содержащие парафиновые эмульсии и ускорители твердения, выбраны их оптимальные дозировки и изучено влияние на удобоукладываемость цементно-песчаных смесей, степень гидрофобизации и кинетику набора прочности бетонов. Изучены их плотность, водопоглощение, коэффициенты водо- и солестойкости, марка водонепроницаемости. Установлено, что при экспонировании бетонов с парафиносодержащими добавками в воде и в растворах солей наблюдается продолжение процесса гидратационного твердения с кольматацией крупных пор кристаллами соли и труднорастворимыми продуктами твердения, приводящее к росту прочностных показателей бетонов
Влияние модифицированных парафиновых эмульсий на свойства портландцементных бетонов
Structural and rheological properties of paraffin emulsions based on sorbital C-20 surfactant and its mixtures with concrete polycarboxylate superplasticizer, kinetics of durability improvement and behavior of portland cement concretes containing these emulsions, in water and salt solutions have been studied.Получены парафиновые эмульсии, содержащие поликарбоксилатный суперпластификатор бетонов, исследованы их коллоидно-химические свойства. Установлено, что введение суперпластификатора в эмульсии приводит к росту размера их частиц и снижению показателя прочности структуры. Модифицированные эмульсии вводились в портландцементные песчаные бетоны, их использование приводило к увеличению воздухововлечения и подвижности смесей, росту показателей ранней прочности бетонов, уменьшению их водо- и солепоглощения и повышению прочности бетонов после хранения в растворах солей
Social and demographic characteristics, features of disease course and treatment options of inflammatory bowel disease in Russia: results of two multicenter studies
Background: Epidemiological studies performed in different countries have identified a number of trends that allow to predict the problems related to the prevalence of inflammatory bowel diseases (IBD), their severity and healthcare resources utilization. Aim: To present comparative results of two large epidemiological studies of IBD in the Russian Federation (RF), i.e. ESCApe and ESCApe-2. Materials and methods: Two multicenter cross-sectional cohort studies with a similar design were performed at three-year interval. The studies had the common aim: to identify social and demographic and clinical particulars of ulcerative colitis (UC) and Crohn’s disease (CD) in RF, as well as treatment options. Twenty (20) centers of gastroenterology from 17 RF regions participated in the ESCApe (2010–2011) and 8 centers from 7 RF regions in the ESCApe-2 study (2013–2014). Results: The ESCApe study included 1797 patients (1254 UC and 543 CD), whereas the ESCApe-2 included 1000 patients (667 UC and 333 CD). Patient demographic and social characteristics: In both studies, female: male ratio was similar in UC and CD. Patients’ age was almost identical: in UC, median age was 38 years and 40 years in ESCApe and ESCApe-2, respectively; in CD the corresponding values were 36 and 35 years. In ESCApe, the peak UC onset was at the age of 21 to 40 years, whereas in CD it was shifted towards younger age (22.5% of the patients manifested before 20 years) and the peak incidence was in three age groups (below 20 years, 21 to 30 and 31 to 40 years). A statistically significant difference between CD and UC was found only in the age group of 11 to 20 years (22.5% vs. 13.6%, respectively, p < 0.01). In ESCApe-2, median age of disease onset in UC and CD was approximately 30 years. In both studies, urban:rural ratio for UC and CD was 4:1. In ESCApe, the proportion of current smokers among CD patients was almost two-fold higher than among those with UC (15.6 and 8.8%, respectively, p < 0.001); the same trend was found in ESCApe-2 (15 and 7.3%, p < 0.001). Socioeconomic characteristics of patients in both studies were similar: 50 to 60% were at work (professional occupation and income levels were not studied); in ESCApe 30.9% of UC patients and 40.9% of CD patients had legal disability due to various reasons (including that related to UC and CD in 12,6 and 14.9%, respectively), whereas in ESCApe-2 the respective proportions were 35.7 and 51.1%. Clinical characteristics of patients: The time from the first UC symptoms to diagnosis was similar in both studies (median, 5 months in ESCApe and 4 months in ESCApe-2); in CD patients these parameters were significantly different in both studies (12 vs. 1 month). As for the severity of the disease, the UC patients in ESCApe had mild disease in 16%, moderate in 53%, and severe in 31%, whereas the respective proportions among the CD patients were 21, 44, and 35%. In ESCApe-2, there were no patients with severe disease; mild and moderate UC were diagnosed in 51.3 and 46.6% of the patients, respectively, and mild and moderate CD, in 52.3 and 47.3%. The frequency of left-side UC was similar: 38% in ESCApе and 34% in ESCApе-2. Proctitis was more frequent in the first study (33 vs. 11%, p < 0.01), and total UC was more frequent in the second study (29 vs. 55%, p < 0.02). There were no significant differences between ESCApe and ESCApe-2 in the main CD localizations: terminal ileitis was seen in 31.3 and 35.4% of the patients, respectively, ileocolitis in 33.4 and 37.8%, colitis in 25.6 and 32.1%. The upper gastrointestinal involvement In ESCApе was found 4.4%, and mixed involvement in 5.3%. In both studies, extra-intestinal manifestations were more frequent in CD, than in UC: in ESCApe, 33.1% and 23% (р < 0.05), and in ESCApe-2 in 41.7 and 29.4%, respectively (р < 0.05). Peripheral arthropathies were most frequent. Ankylosing spondylitis was found in CD only, and primary sclerosing cholangitis, only in UC. Aphthous stomatitis was significantly more prevalent in CD in both studies. There were no significant differences in all other extra-intestinal symptoms (eye and skin involvement). Treatment characteristics: Treatment options before the study entry, as well as at the study inclusion visit were analyzed. In ESCApe, the majority of the patients had not been given any treatment before the study entry (49.1% with UC and 40.5% with CD). Three years later the situation was changing: in ESCApe-2, the proportion of treatment-naïve patients was 2.5 to 3-fold lower (15.3% with UC and 14.4% with CD), which was most probably related to increasing awareness of physicians. Before the study entry, most patients (40 to 70%) had been treated with 5-aminosalicylic acid (5-ASA). Before the second study, the patients were more frequently treated with glucocorticosteroids (GCS), immunosuppressors and genetically engineered biological agents (GEBA), but with no significant differences from the first study. 5-ASA prevailed also among the agents that were administered during the inclusion visits in both studies (80 to 90% UC patients and about 70% of CD patients). Compared to ESCApe, in ESCApe-2 there was a trend towards lower rate of GCS administration in UC and CD, but the differences did not reach the significance level. It may be explained by the absence of severe IBD types in ESCApe-2. In ESCApe, immunosuppressors were rarely used (in 14.4% of the UC patients and in 26.8% of the CD patients); however, in ESCApe-2 there were administered more frequently: up to 35.9% of the UC patients and 55.1% of the CD patients (р < 0.01 for both cases). It was unknown if immunosuppressors were used as monotherapy or in combination with GCS. Three years later, the rate of GEBA administration was also higher, but this increase was significant only in CD: 28.3% in ESCApe-2 vs. 9.2% in ESCApe (р < 0.01). According to the results of ESCApe, in the UC patients steroid resistance was seen in 23% and steroid dependency in 21%, whereas in the CD patients these values were 24 and 27%, respectively. In ESCApe-2 these parameters were not assessed. Conclusion: Both studies showed a number of patterns coinciding with the world trends, such as age and gender distribution of UC and CD patients, age at manifestation, the proportion of urban to rural residents, smoking status, prevalence and types of extra-intestinal symptoms. Unlike in European countries, moderate and severe forms of UC with extensive involvement are prevalent in RF. Low prevalence of mild and limited types of IBD is to be explained by underdiagnosis. Of note is the high proportion of patients with UC and CD treated with 5-ASA, although in CD these agents have demonstrated low efficacy. The rates of immunosuppressors and GEBA administration significantly increased in the second study, most likely, due to the implementation of a system of educational measures. Nevertheless, the rate of GEBA use in IBD remains low, which is to be related to their insufficient availability. In total, steroid resistance / steroid dependency rate amount to almost half of UC and CD cases. In general, some positive changes in the patient management are obvious in the second study. However, monitoring these changes over time could only be possible if similar studies would be performed at regular intervals