Greener Surface Active Reagents: Structure, Property and Performance Relationships

Surfactants are used in many industrial applications, such as flotation, flocculation, water treatment, enhanced oil recovery, emulsification, drug delivery, personal care, detergency, chemical mechanical polishing, etc. The design, development, and characterization of greener surfactants in their applications are required to meet the increasing requirements for environmental protection and an escalating demand from the society for sustainable development. It is a challenge currently to develop structure-property-performance relationships for surfactant mixtures containing greener reagents to obtain maximum efficiency with minimum environmental damages. Even though conventional surfactants and their mixtures are well studied, the fundamental studies of the structure, property and performance relationships for greener surfactants when used individually or in combination with others are just started as more and more attentions are focusing on this area. In this work, solution behaviors of surfactant systems containing several amino acid based greener surfactants have been systematically investigated using various techniques, including surface tensiometry, fluorescence spectroscopy, analytical ultracentrifugation, viscometry and computer simulation to obtain information of the structures of the aggregates formed by greener surfactants or their mixtures with conventional ones in solutions. This comprehensive study helps to elucidate the mechanism of micellization behaviors of the greener surfactant mixtures and understand the roles of molecular structures and interactions in determination of system properties and performance. The colloidal and interfacial properties of a series of lipopeptides synthesized by chemo-enzymatic reactions were studied. They were found very surface active, especially C12/oligo(L-Glu). The effects of chain length of hydrophobic moiety, composition of oligopeptide as well as aqueous chemical conditions, such as pH, on the interfacial properties of the lipopeptides were studied. Results showed the mechanism of how the interfacial and colloidal properties of amino acid based surfactants can be fine tuned by adjusting structures of the molecules. Two new surfactants, Surfactin and FA-Glu, synthesized by genetically engineered bacteria were also evaluated. Both of them showed exceptional surface activity. Genetic engineering also showed its advantages when it was found that Surfactin was limited by its solubility. Quick modifications were made in the bacteria and better option FA-Glu was produced with improved structure for better solubility. The results provide fundamental knowledge of those greener surfactants on their structure-property relationships. A number of amino acid based greener surfactants with systematic structural variations, including sodium lauroyl glutamate (C12Glu), sodium lauroyl alaninate (C12Ala), sodium lauroyl sarcosinate (C12Sar), and sodium lauroyl glycinate (C12Gly), were tested as triblend mixtures with dodecyl glucoside (C12G1) and lauramidoproply betaine (LAPB) to evaluate their performance as a function of their molecular structures. The C12Gly/C13G1/LAPB system was confirmed to have very high viscosity compared to the other systems. It was found the following micellar evolution processes happened in this system that delivered the high viscosity: small spherical micelles evolved into elongated rod-like micelles in the low concentration range, and networks of worm-like micelles formed in the high concentration range. The unique properties achieved by this system were attributed to the packing of the surfactant molecules in the system. Further results confirmed that C12Gly has a desired structure with a packing parameter of 0.4 which favors formation of worm-like micelles. Foaming performance of the selected greener surfactant was also evaluated to compare with commercial benchmark system. Even though sodium dodecyl glycinate itself is not a good foaming agent as the petroleum based non-green surfactant sodium lauryl ether sulfate, when it is mixed with the other two ingredients, significant improvement can be achieved for both foamability and foam stability due to strong synergistic interactions among them. The mixture of sodium dodecyl glycinate, dodecyl glucoside and lauramidopropyl betaine actually can deliver equal viscosity, foamability and foam stability as the benchmark system, which makes this system a leading option for the future formulations in personal care industry. Computer simulation as a powerful tool was used to understand the mechanism how greener surfactant molecules interacted with each other and how they aggregated into micelles from molecular level. Simulation found that when different surfactant molecules were mixed together, the synergistic interaction reduced the electrostatic repulsion between molecules, which led to reduction of the effective space occupied by head groups making the two head groups overlapping on each other partially. The overlapping led to a close packing of molecules. The results suggest that geometry of molecules and the interactions among them play equally important roles in determining the packing of surfactants and in turn the packing controls properties and performance of the whole system. Thus a new formula for effective packing parameter of surfactant mixtures was proposed, in which not only the geometries of molecules but also the interactions among them were included to calculate the effective packing parameter for surfactant mixtures for better predictions of the properties and performance of surfactant mixture systems. The fundamental and systematical work accomplished through this work will have a profound impact on the understanding of greener surfactant mixture systems, as structure, property and performance relationships developed herein will in turn direct the use of greener surfactants in future applications for efficiency and low chemical footprin

A comparative study of the antimicrobial and antioxidant activities of Inonotus hispidus fruit and their mycelia extracts

Inonotus hispidus (Bull.) P. Karst. has been used as traditional medicine for the treatment of dyspepsia, cancer, and diabetes. Numerous studies have confirmed the antimicrobial, antiviral, antioxidant, anti-inflammatory, immunomodulatory, antiproliferative and cytotoxic biological activities of extracts from this species. The purpose of this study was a comparative analysis of the antioxidant and the antimicrobial activities of methanol extracts from fruit and liquid-cultured mycelia. Four compounds (N-butylbenzenesulfonamide, lauramidopropyl betaine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, and uplandicine), determined by hybrid HRMS, were found only in mycelia culture extracts. Free radical scavenging, measured by DPPH assay on methanol extracts, showed an activity of about 17.2% and 22.1% of Trolox in fruiting bodies and mycelia, respectively. The I. hispidus methanol extracts from fruit and mycelia culture were found to have varying degrees of antibacterial and antifungal effects against the pathogenic microorganisms tested (minimum inhibitory concentration from 0.17 to 2.56 μg mL−1)

Effects of formulation conditions on micellar interactions and solution rheology in multi-component micellar systems

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, June 2011.Cataloged from PDF version of thesis. "June 2011."Includes bibliographical references (p. 98-100).Surfactants are crucial to the personal care industry due to their unique surface activity, cleansing, and self assembly properties. Typically, multi-component systems are used in order to maximize mildness, hard water tolerance, and foaming. System morphology and viscosity are controlled through chemistry and solution conditions. An experimental study was conducted to determine how variations in solution chemistry (surfactant headgroup and blend stoichiometry) and solution conditions (pH and [NaCl]: [anionic + zwitterionic surfactant] ratio) affect the structure and rheology of surfactant solutions. This study examined binary systems of Sodium Laureth Sulfate (SLES) and Lauramidopropyl Betaine (LAPB) or SLES and Lauramidopropyl Hydroxysultaine (LAPHS) as well as ternary systems of SLES/LAPB/PEG-80 Sorbitan Laurate (PEG-80 SL) and SLES/LAPB/Polysorbite-20 (Tween-20). Using dynamic light scattering and rheometic measurements, system morphology was determined. In the SLES/LAPB system, it was found that there was a break in system viscosity at a critical [NaCl]: [anionic + zwitterionic surfactant] ratio, 0.16:1 (R*). Micelles only had the ability to entangle, thus increasing viscosity, above this ratio. When the system pH decreased such that pH ~ pKa of LAPB, all [NaCl]:[anionic + zwitterionic surfactant] ratios had the ability to entangle, and entanglement began at lower surfactant concentrations. At these pH values, LAPB protonated and created a pseudo-ternary system with SLES, LAPB0 , and LAPB*. There was no measured variation in system morphology in the SLES/LAPHS system with [NaCl]: [anionic + zwitterionic surfactant] ratio, most likely because the minimum ratio achievable was above R* due to a high salt content in the raw materials. In addition, there was no measured variation in system morphology in the SLES/LAPHS system with variation in pH, most likely because the system was not tested at pH ~ pKa of LAPHS. The addition of a third surfactant drastically decreased the system viscosity and drove the system towards the formation of spherical micelles because the nonionic surfactant of choice decreased the packing parameter due to its relatively large size as compared to that of SLES and LAPB.by Leslie Sarah Nachbar.S.M

Development and Application of Suspect and Nontarget Screening to Characterize Organic Micropollutants in Aquatic Environments of New York State

Organic micropollutants (OMPs) have presented a global challenge to water resources management due to concerns over their adverse impacts on aquatic biota and human health at low exposure concentrations (e.g., at ng/L to μg/L levels in aquatic systems). OMPs encompass an extensive array of synthetic organic compounds (e.g., pharmaceuticals, pesticides, personal care products, household chemicals, industrial additives) and their transformation products. My research has been centered around establishing analytical methods based on liquid chromatography-high-resolution mass spectrometry (LC-HRMS), with a focus on the development and application of suspect and nontarget screening workflows for the identification and prioritization of OMPs in inland lakes, streams, and urban wastewater in New York State. In Chapter 1, I collaborated with volunteers from the Citizens Statewide Lake Assessment Program and scientists at the Upstate Freshwater Institute to conduct the first statewide investigation of OMP occurrence in New York inland lakes. Through this project, I developed a suspect screening method based on LC-HRMS to identify and quantify 65 OMPs in 314 lake water samples collected by volunteers from 111 lakes, ponds, and reservoirs across the state. I also performed partial least squares regression and multiple linear regression analyses to prioritize total dissolved nitrogen, specific conductance, and a wastewater-derived fluorescent organic matter component as the best combination of explanatory predictors for the inter-lake variability in OMP occurrence patterns. I further applied the exposure-activity ratio approach to estimate the potential for biological effects associated with OMPs. My work demonstrated that engaging an established network of citizen volunteers offers a viable approach to increasing the spatiotemporal coverage of OMP monitoring while raising public awareness of their prevalence. In Chapter 2, I collaborated with Drs. Christa Kelleher and Rebecca Schewe to investigate the occurrence patterns of OMPs in streams draining mixed-use watersheds in central New York. I combined the use of polar organic chemical integrative samplers (POCIS) with suspect screening and nontarget screening based on LC-HRMS to identify and quantify 133 OMPs in samples collected from 20 stream sites over two sampling seasons. I also performed hierarchical clustering to establish the co-occurrence profiles of OMPs in connection with watershed attributes indicative of anthropogenic influences. I further evaluated the feasibility of deploying POCIS for estimating daily average loads of OMPs and their potential for biological effects in streams via screening-level risk assessments. My work supported the prospect of combining passive sampling with high-resolution accurate mass screening for the multi-watershed characterization of OMP contamination status in streams. In Chapter 3, I collaborated with colleagues from the School of Public Health to pursue one of the earliest wastewater-based epidemiology studies on population-level substance use during the COVID-19 pandemic. I developed and validated an online solid-phase extraction method for sample preconcentration before LC-HRMS analyses to achieve rapid screening of health and lifestyle-related substances in urban wastewater. I applied this method to quantify the levels of 26 pharmaceuticals and lifestyle chemicals in wastewater influent samples collected from six sewersheds in central New York over a period spanning the rising and falling of COVID-19 prevalence. I back-calculated the population-level consumption rates of antidepressants, antiepileptics, antihistamines, antihypertensives, and central nervous system stimulants and further identified their co-variation with disparities in household income, marital status, and/or age of the contributing populations as well as the detection frequency of SARS-CoV-2 RNA in wastewater and the COVID-19 test positivity within the sewersheds. My work highlighted the utility of high-throughput wastewater analysis for assessing substance use patterns during a public health crisis such as COVID-19

Amélioration des techniques d’identification en spectrométrie de masse et étude de la transformation de contaminants organiques

On comptait en 2020 plus de 350 000 composés organiques en circulation, dont un grand nombre mal défini et dans des mélanges chimiques complexes. Il y a un manque de connaissance majeur sur la présence environnementale et la stabilité des contaminants organiques dans les milieux aquatiques et encore plus pour leurs produits de transformation (PTs) qui y sont formés. Les méthodes de monitoring de contaminants sont spécifiques à quelques dizaines de composés et ne fournissent pas un tableau suffisant de la contamination. Les analyses non ciblées cherchent à pallier ce problème, mais obtenir une identification conclusive est complexe en raison de la taille limitée des banques de données et des faibles concentrations des contaminants. Les PTs sont particulièrement difficiles à élucider comme leur identité est généralement inconnue. Cette thèse en trois axes tente d’abord d’améliorer et développer des techniques et méthodes d’identification de contaminants organiques et de leurs PTs dans les eaux de surface. Puis, elle se penche sur l’identification des PTs stables de quatre contaminants organiques préoccupants après une exposition simulant la photolyse solaire pour ensuite les retrouver dans des échantillons environnementaux. Finalement, dans le troisième axe, on cherche à identifier des PTs et des composés issus de mélanges chimiques complexes directement depuis des échantillons d’eaux de surface sans avoir recours à des études de dégradation de contaminants en laboratoire. Dans le premier axe, une méthode d’échange hydrogène-deutérium permettant de distinguer des composés similaires a d’abord été développée. Puis, un outil de génération de formules moléculaires a été évalué puis adapté à des conditions environnementales ; il s’est avéré supérieur aux autres méthodes avec lesquelles il a été comparé. Finalement, un flux de travail non ciblé a été développé avec des outils de correspondances de spectres de masse in silico et de réseaux moléculaires. Plus de 250 contaminants ont été identifiés dans la rivière Yamaska à Granby dont plusieurs jamais reportés au Canada. Dans le deuxième axe, des PTs de quatre contaminants préoccupants ont été générés puis identifiés en laboratoire avec les méthodes développées dans l’axe 1. Ces PTs ont ensuiteii été recherchés et détectés dans des échantillons réels. Dans le troisième axe, le flux de travail développé dans l’axe 1 a été amélioré en incorporant des outils regroupant des spectres de masse en tandem similaires en réseaux. Cela a permis d’identifier plus de 400 contaminants. Plusieurs PTs de composés pharmaceutiques et de pesticides auparavant inconnus ont été identifiés ainsi que plus d’une centaine de congénères d’additifs de produits de consommation. Ce flux répond à des besoins importants en analyse environnementale en ce qui a trait à l’identification d’homologues et de produits de transformation divers. Cependant, les PTs des composés étudiés en laboratoires n’ont pas pu être identifiés directement par le flux de travail, soulignant l’importance des méthodes de contrôle en laboratoire. Cette thèse joint les approches ascendantes où l’on génère en laboratoire des produits de transformation et les approches descendantes où ceux-ci sont identifiés directement à même l’échantillon avec le flux de travail. D’une part, elle a accru notre compréhension sur le devenir de plusieurs contaminants particulièrement préoccupants avec les études en laboratoire puis a poussé le cheminement en les retrouvant dans échantillons réels et en simulant leur toxicité pour une approche ascendante totale. Parallèlement, elle consiste une preuve de principe sur comment mener une analyse non ciblée selon l’état de l’art. Les outils ont été validés en fournissant des informations précieuses aux élaborateurs de programmes de monitoring et de suivi de toxicité sur l’occurrence locale de nombreux contaminants organiques et leurs PTs

Transport of Components and Phases in a Surfactant/Foam

The transport of components and phases plays a fundamental role in the success of an EOR process. Because many reservoirs have harsh conditions of salinity, temperature and rock heterogeneity, which limit process options, a robust system with flexibility is required. Systematic experimental study of formulations capable to transport surfactant as foam at 94°C, formulated in sea water, is presented. It includes methodology to conduct core floods in sand packs using foaming surfactants and to develop “surfactant blend ratio- salinity ratio maps” using equilibrium phase behavior to determine favorable conditions for oil recovery in such floods. Mathematical model able to reproduce the foam strength behavior observed in sand packs with the formulations studied is presented. Visualization of oil recovery mechanism from matrix is realized using a model system of micro-channels surrounded by glass beads to mimic matrix and fractures respectively. The observations illustrate how components may distribute within the matrix, thereby releasing oil into the fractures. The use of chemicals to minimize adsorption is required when surfactant adsorption is important. The presence of anhydrite may limit the use of sodium carbonate to reduce adsorption of carbonates. A methodology is presented to estimate the amount, if any, of anhydrite present in the reservoir. The method is based on brine software analysis of produced water compositions and inductively coupled plasma (ICP) analysis of core samples. X-ray powder diffraction (XRD) was used to verify the mineralogy of the rock. X-ray photoelectron spectroscopy (XPS) was used to obtain surface composition for comparison with bulk composition of the rock. Adsorption of surfactants was measured using dynamic and static adsorption experiments. Determining the flow properties of the rock samples via tracer analysis permitted the simulation of the dynamic adsorption process using a mathematical model that considers the distribution of adsorbed materials in the three different regions of pore space. Using this method allows one to predict adsorption in a reservoir via simulation

FOAM LIFT EFFICIENCY FOR GAS WELL DELIQUIFICATION IN PRESENCE OF CONDENDATES

Over the life of Natural Gas wells, as the formation pressure declines, they face the issue of liquid loading. Liquid loading or inability of gas to carry the accumulated liquids along the wellbore shortens the life of gas wells, costing the operators in revenue. One of the common gas-well deliquification techniques is surfactant injection or foam lift. This method is proven very beneficial especially at low-pressure gas reserves, where the required critical gas velocity to avoid liquid loading gets reduced to around 20% of its original value. However, it is known that the presence of condensed hydrocarbons lowers the surfactant’s efficiency in foam lift operations. In this study experimental evaluation of the performances of various surfactants in presence of both water and hydrocarbon condensates with regards to unloading the liquids is carried out. Experimental work includes characterization of surfactants based on static and dynamic surface tension measurements and liquid unloading tests with varying surfactants and concentrations, changing liquid column water cuts and a fixed Nitrogen gas injection rate to generate foam at room temperature and at high temperature. The results are recorded in terms of unloaded liquid, liquid drainage rate, foam quality, foam density, and foam half-life. A noticeable drop is observed in liquid unloading as the water cut is reduced showing the diminishing foam lift efficiency at room temperature and at high temperature as well. However, the significance of this drop is different for different surfactant types