SYNTHESIS AND CHARACTERIZATION OF HYDROXYL AMMONIUM IONIC LIQUIDS AS CORROSION INHIBITOR FOR CARBON STEEL UNDER ACIDIC MEDIA

The inhibition of carbon steel corrosion becomes of such interest because it is widely used as constructional materials in many industries, such as erecting boilers, drums, heat exchangers, pipe line, and many more. The acidization of oil and gas wells is probably the most widely used work over and stimulation practice in oil industry. HCl is widely used for stimulating carbonate-based reservoirs. Since HCl is strong aggressive medium for oil and gas well equipment, the effective way to protect these materials is to inject a suitable corrosion inhibitor. Accordingly, corrosion inhibitors must be injected with the HCl solution to avoid the destructive effect of acid on the surface of the pipe lines. Hence it is very important to measure the physical properties of the new corrosion inhibitor. A variety of organic additives as corrosion inhibitors have been tested in these processes. However, there are some disadvantageous with the current inhibitor such as toxic, difficult preparation method and the high material cost. Also it has been reported that the lack of their physical properties data, has limited the design and application of these corrosion inhibitors. Even though ionic liquids have been proven as a potential inhibitor on carbon steel corrosion in acidic media, their price is relatively higher compared to the commercially available corrosion inhibitor. An alternative way is to find cheaper ionic liquids that can be applied as corrosion inhibitor on carbon steel corrosion in acidic media. Hydroxyl ammonium ionic liquids are relatively cheap and easy to produce in purity greater than 99%. In order to develop low cost inhibitors, the recent investigations on application of the hydroxyl ammonium ionic liquids as inhibitor on corrosion of carbon steel in 1 M HCl, seem really worthwhile. The objectives of this research are to synthesis and characterize the range of ionic liquids, and to study their potential application as inhibitor on carbon steel corrosion in acidic media. For this study, sixteen hydroxyl ammonium ionic liquids were synthesized and characterized. The structures of synthesized ionic liquids were confirmed by infrared, 1H-NMR, and 13C-NMR spectra. Composition of synthesized ionic liquids was also confirmed from elemental analysis. Water content of these ionic liquids was found to be lower than 200 ppm. Physical properties of the ionic liquids such density, viscosity, and refractive index were measured at atmospheric pressure and temperature from 293.15 to 353.15 K, while refractive index was measured at temperature from (293.15 to 323.15) K. The coefficients of thermal expansions were calculated from experimental density data. In practical condition, corrosion inhibitors are mixture of active components, solvents, and surfactant. In this work, the effects of alcohol such as methanol, ethanol, and 1-propanol, as co-solvent on physical properties namely density, viscosity, and refractive index of the ionic liquids were also studied. The ionic liquids Bis(2-hydroxyethyl)ammonium formate, [BHEAF] was chosen as model due to the highest inhibition performance. The inhibition performance of the synthesized ionic liquids on carbon steel corrosion in 1 M HCl was measured within concentration range of ionic liquids from 0.02 to 0.08 M while temperature range from 298.15 – 343.15 K using two methods, weight loss and electrochemical. The obtained results showed that the inhibition performance increased with increasing concentration of ionic liquids and decreasing temperature of system. Tafel Plot analysis showed that these ionic liquids were mixed type inhibitor, which reduced the corrosion rate by blocking both cathodic and anodic site. Electrochemical Impedance Spectroscopy analysis showed that the addition of ionic liquids did not change the mechanism of corrosion of carbon steel. The synthesized ionic liquids reduced the corrosion rate of carbon steel by adsorbing themselves on the carbon steel surface. The adsorptions of the ionic liquids on the surface of carbon steel obey the Langmuir’s isotherm adsorption. The high values of equilibrium constant and standard free energy of adsorption indicated that the adsorption of ionic liquids on the surface of carbon steel was spontaneous and occurred only by physisorption. The apparent activation energy of corrosion of carbon steel in the presence of ionic liquids was higher compared to without ionic liquids. This result indicated that the addition of ionic liquids give energy barrier for corrosion. These results were also supported by their enthalpy and entropy of adsorption. Addition of alcohol on ionic liquids did not alter the inhibition efficiency. Thus, it can be concluded that these alcohols can be used as co-solvent with ionic liquids, without reducing the ionic liquids performance. The organic solvent is particularly helpful for reducing the viscosity of ionic liquids which is known to be highly viscous From these experimental results, it shows that hydroxyl ammonium ionic liquids have potential as inhibitor on corrosion of carbon steel in 1 M HCl. It suggests that all the synthesized hydroxyl ammonium ionic liquid in this work has the potential to be used as inhibitor on carbon steel corrosion in 1 M HCl

Ion speciation: A key for the understanding of the solution properties of ionic liquid mixtures

Recently, combinations of two (or more) ionic liquids, known as ionic liquid mixtures, have become popular and have a broad range of applications. However, the fundamental knowledge on the molecular interactions that exist in ionic liquid mixtures is far from being understood. In this work, the experimental measurement of the water activity coefficient and computational modelling using Conductor-like Screening Model for Real Solvent (COSMO-RS) were carried out to get an insight into the molecular interactions that are present in ionic liquid mixtures in aqueous solution. The results show that the combination of two ionic liquids of different basicity in aqueous solution allows fine tuning of the water activities, covering a wide range of values that could replace several pure fluids. This is an important feature resulting from the unexpected ion speciation of the ionic liquid mixtures in aqueous solution.We thank the CICECO – Aveiro Institute of Materials, POCI-01- 0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2019) and Associate Laboratory LSRE-LCM, POCI-01-0145-FEDER-006984 (Ref. FCT UID/ EQU/50020/2019), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDDER under the PT2020 Partnership Agreement.info:eu-repo/semantics/publishedVersio

Oxytetracycline Mineralization inside a UV/H2O2 System of Advanced Oxidation Processes: Inorganic By-Product

Oxytetracycline (OTC) was widely used antibiotic in agricultural industry. However, most of them were secreted from the body and entered the water stream, due to low absorption. The occurrence of the antibiotics in water stream may led to serious health hazards. Hence, finding the effective method that capable to achieve total mineralization of antibiotic-contaminated wastewater, followed by the production of benign inorganic and organic by-product, was necessarily deemed. Photochemical degradation method, such as: UV/H2O2 system, was capable to achieve total mineralization of OTC at its optimized condition. In this paper, inorganic by-products of OTC mineralization inside a UV/H2O2 system at its optimum condition were analyzed. The presence of nitrate, ammonium, chloride ions, and chlorine were detected at the sample solution after mineralization. The presence of these inorganic by-product has proven that the experimental setup chosen was capable to achieve total mineralization. In addition, possible routes of the inorganic by-products detachment from the OTC’s structure, were also presented. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Characterization Study of Dyes Photodegradation-Adsorption Products by TiO2-Chitosan Immobilized on Glass Beads using Flow System

Dyes have a complex molecular structure that is difficult to degrade and can persist for a long time in water bodies. This study examines more thoroughly the effectiveness of photodegradation-adsorption of dyes, kinetic aspects, isotherms, thermodynamics, identification of the structure of photodegradation products, and changes in environmental quality parameter values whose results are quite satisfactory. The combination of photodegradation-adsorption of dyes by TiO2-chitosan modified glass beads using a flow system has never been accomplished before. Flowing of the dye resulted in a dye degradation efficiency of 99%. The FESEM-EDX analysis shows that TiO2-chitosan has been coated onto the surface of the glass beads. R2 of kinetics MB, MO, RB are 0.99234, 0.9889, 0.9971, which were pseudo-first order. Qm, KL, R2 are 6.4382, 0.70533, 0.99923; 16.7364, 1.42059, 0.98816; 6.0078, 1.06973, 0.99889, respectively. The ∆H, ∆S, ∆S of -9.388, -0.024, -1.979; -27.182, -0.078, -3.592; -4.819, -0.017, 0.464 indicate the exothermic and spontaneous reaction. COD, TOC, pH, turbidity values have reached the threshold required by the government. The degradation products formed during the photodegradation-adsorption process were identified using LC-MS that the structure of the dye has been degraded to become simpler so that it is safely disposed of into the environment

A Study on The Healthy Rental-Housing for College Students According to World Health Organization: Evidence from Surabaya City in Indonesia

Introduction:Many college students live far from their parents to study to get a better higher education, so they occupy a rental-housing. However,many rental-housings do not meet the health standards according to the World Health Organization (WHO). Therefore, this study aiming at evaluating the rental-housing quality used by college students in Surabaya, Jawa Timur, Indonesia.Methods:This type of research is an observational study conducted with a descriptive observational design. The sample in this study was 52 college students who originated from outside Surabaya and currently living in the rental-housing in Mulyorejo, Surabaya, Indonesia.Results:The results present observational data from 52 student respondents who live in boarding houses including the overview of boarding houses condition, ventilation and air circulation condition, trash management, clean water and wastewater management, and toilet condition.Conclusion: Under the circumstance, this study was conducted to assess healthy rental-housing quality for college students, using the WHO's evaluation indicators. While some college students could afford to stay in proper and healthy rental-housing, some of them still suffer from lousy ventilation, the absence of clean water, and terrible trash management

Analytical Methods for Determination of Non-Nutritive Sweeteners in Foodstuffs

Sweeteners have been used in food for centuries to increase both taste and appearance. However, the consumption of sweeteners, mainly sugars, has an adverse effect on human health when consumed in excessive doses for a certain period, including alteration in gut microbiota, obesity, and diabetes. Therefore, the application of non-nutritive sweeteners in foodstuffs has risen dramatically in the last decade to substitute sugars. These sweeteners are commonly recognized as high-intensity sweeteners because, in a lower amount, they could achieve the same sweetness of sugar. Regulatory authorities and supervisory agencies around the globe have established the maximum amount of these high-intensity sweeteners used in food products. While the regulation is getting tighter on the market to ensure food safety, reliable analytical methods are required to assist the surveillance in monitoring the use of high-intensity sweeteners. Hence, it is also necessary to comprehend the most appropriate method for rapid and effective analyses applied for quality control in food industries, surveillance and monitoring on the market, etc. Apart from various analytical methods discussed here, extraction techniques, as an essential step of sample preparation, are also highlighted. The proper procedure, efficiency, and the use of solvents are discussed in this review to assist in selecting a suitable extraction method for a food matrix. Single- and multianalyte analyses of sweeteners are also described, employing various regular techniques, such as HPLC, and advanced techniques. Furthermore, to support on-site surveillance of sweeteners' usage in food products on the market, non-destructive analytical methods that provide practical, fast, and relatively low-cost analysis are widely implemented

Energy efficient harvesting of Spirulina sp. from the growth medium using a tilted panel membrane filtration

Membrane fouling is one of the main drawbacks in membrane-based microalgae harvesting. This study assessed the tilted panel to enhance filtration performance of Spirulina sp. broth. The influences of the operating parameters including the tilting angle, aeration rate and membrane materials on filtration performance and energy consumption were evaluated. Results showed that the system was effective and energy-efficient for membrane fouling control. The permeability peaked at a tilting of 45◦ thanks to combination of aeration and panel tilting. The microfiltration performed better than the ultrafiltration membrane due to the effective impact of air bubbles for foulant scouring that maximized the membrane intrinsic property. Small aeration rate of 1.0 L/min offered a high plateau permeability of 540 L/(m2⋅hr⋅bar) in which reversible fouling almost fully absent. The high permeability could be achieved under a low energy input of 0.2 kWh/m3

Predicting ionic liquid efficiency as steel corrosion inhibitor under static hydrochloric acid immersion using group contribution method

As a novel corrosion inhibitor, ionic liquid has garnered a growing amount of interest. Different electrodes, such as carbon steel, stainless steel, aluminium, copper, magnesium, and others; different electrolytes, such as hydrochloric acid, sulfuric acid, nitric acid, and seawater; different condition operations at different temperatures and tribological properties; and various techniques, such as weight loss (WL), potentiodynamic polarization (PDP), and electro impedance spectroscopy (EIS), have been investigated. Due to the large number of cations and anions, this conventional laboratory study may not be completed anytime soon. Therefore, IL as a corrosion inhibitor must be investigated further. The purpose of this study is to conduct a more comprehensive analysis of IL as a corrosion inhibitor in 1 M HCl immersion on carbon steel using the group contribution method. Cations and anions were divided into 29 functional groups (FG) of cations and 17 functional groups (FG) of anions using 74 IL and 760 WL data points collected from various studies. Training and test set results have R2 values of 0.639 and AARD values of 14.9%; validation set results have R2 values of 0.319 and AARD values of 14.4%; and the overall data point evaluation has R2 values of 0.324 and AARD values of 14.3%

Designing ionic liquids for absorptive cooling

A computational methodology for designing ionic liquids (ILs) with an enhanced water absorption capacity to be used in absorption-refrigeration systems is presented here. It is based on increasing the hydrogen bond (HB)-acceptor ability of the anion and combining it with a cation that presents a weak cation-anion interaction. Employing this strategy, we identified and prepared three novel dianionic ILs with an enhanced water absorption capacity, larger than LiBr