Antifoam Research Articles

PH level has a strong impact on population dynamics of the yeast Yarrowia lipolytica and oil micro-droplets in multiphasic bioreactor.

The oleaginous yeast Yarrowia lipolytica has the ability to use oils and fats as carbon source, making it a promising cell factory for the design of alternative bioprocesses based on renewable substrates. However, such a multiphasic bioreactor design is rather complex and leads to several constraints when considering emulsification of the oil-in-water mixture, foaming and cell growth/physiology on hydrophobic substrate. This study aims to shed light on the effect of pH changes on the physico-chemical properties of the cultivation medium and on cell physiology. It was indeed observed that at a pH value of 6, cell growth rate and intracellular lipid accumulation were optimized. Additionally, foaming was significantly reduced. In order to avoid over foaming in bioreactor, without impairing cell physiology, the use of alternative processes that can only act on the physical structure of culture medium, seems to be an effective alternative to usual chemical anti-foam agents.

Magic Bullet! Rebamipide, a Superior Anti-ulcer and Ophthalmic Drug and Its Large-Scale Synthesis in a Single Organic Solvent via Process Intensification Using Krapcho Decarboxylation

Rebamipide (1) is a superior drug compared to existing drugs for use in healing of peptic ulcers, gastrointestinal bleeding, and dyspepsia. It is also useful as an ophthalmic drug for the treatment of dry eye syndrome. Process intensification for its synthesis was achieved by (i) averting uncontrollable frothing using Krapcho decarboxylation instead of conventional acid hydrolysis, where uncontrollable frothing became chaotic, (ii) minimizing organic waste generation by using a single organic solvent, and (iii) avoiding anti-foaming agents (n-octanol, acetophenone) and acetic acid. With these trifling modifications, the overall yield of active pharmaceutical ingredient (API) was ≥83% with excellent purity (≥99.89%), and the process meets the metrics of “green” chemistry with an E-factor = 11.5. The developed hassle-free commercial process is viable for multi-kilogram synthesis of Rebamipide (1) as the key step, Krapcho decarboxylation is safe to run at 130–140 °C in DMSO, and it was proved to be effective...

Analysis of antifoam agent degradation products in an evaporator

ABSTRACTA wetting agent used to control foaming in the Chemical Processing Cell at the Defense Waste Processing Facility degrades to form compounds that could volatilize to form vapor exceeding the lower flammability limit. Three identified components of concern were hexamethyl disiloxane, trimethyl silanol, and propanal. Analytical methods were developed and implemented on a real waste sample to monitor degradation products. Using standards, an extraction method with dichloromethane and analysis by gas chromatography-mass spectrometry and hydrogen nuclear magnetic resonance was developed. Both methods had detection limits less than 1 mg/L for the analytes.

The Effects of Antifoam Agent on Dead End Filtration Process

The formation of foam as a result from introducing gases during cell culture process in the bioprocess industry has indirectly affected the throughput of the product of interest. Due to that, antifoams were developed and established as one of the means to minimize the formation of foam in the cell culture. There are many types of antifoams but the silicone-type of antifoams are widely used in the bioprocess industry. Although the establishment of antifoam has aided the cell culture process, the impacts of its presence in the cell culture to the downstream process especially the dead end filtration is not widely discussed. The findings in the study emphasized on the dead end filtration performance that includes flux rate profile and the resulted filtration capacity. In this study, the concentrations of antifoam injected into the solution were varied from 0.2% v/v – 1.0% v/v and the solutions were filtered using constant flow method. The resulted maximum pressure readings and final flux rates indicated that the resistance exerted to the feed flow rate increased as the concentration of antifoam loaded in the solution increased. This later has led to the decline in the flux rates with percentage reduction between 32 – 68%. The calculated filter capacity for flux rate of 1000LMH ranged from 53 – 63L/m2 while it is in the range of 40 – 43L/m2 for flux rate of 2000LMH. The presence of antifoam agents in the feed load was determined to have negative effects on the dead end filtration performance and it may reduce the efficiency of the dead end filtration process.

Effect of Select Surfactants on Activities of Soil Enzymes Involved in Nutrient Cycling

ABSTRACTExperiments were conducted to investigate the impact of commonly used herbicides and surfactants on the activity of acid phosphatase, β-glucosidase, arylsulfatase, β-glucosaminidase, and dehydrogenase, using two soils (silt loam and silty clay loam) from Mid-Missouri, USA. The surfactants used in this study were alkylphenol ethoxylate + alcohol ethoxylate (ACTIVATOR 90), polyethoxylate (Agri-Dex®) and a blend of ammonium sulfate, drift reduction/deposition polymers, and an antifoam agent (THRUST®). The herbicides were glyphosate, atrazine, and bentazon. Surfactants and herbicides were applied to soils at the label rate, either alone or combined. In general, enzyme activity was enhanced more in silt loam soil than in silty clay loam soil. Acid phosphatase displayed the greatest amount of enzymatic activity within soils; dehydrogenase displayed the most inhibition, whilst β-glucosidase and β-glucosaminidase fluctuated based on treatment. ACTIVATOR 90 appeared to have the most inhibitory effect on enzymatic activity within soils compared to the control.

Ignoring Adjuvant Toxicity Falsifies the Safety Profile of Commercial Pesticides.

Commercial formulations of pesticides are invariably not single ingredients. Instead they are cocktails of chemicals, composed of a designated pesticidal “active principle” and “other ingredients,” with the latter collectively also known as “adjuvants.” These include surfactants, antifoaming agents, dyes, etc. Some adjuvants are added to influence the absorption and stability of the active principle and thus promote its pesticidal action. Currently, the health risk assessment of pesticides in the European Union and in the United States focuses almost exclusively on the stated active principle. Nonetheless, adjuvants can also be toxic in their own right with numerous negative health effects having been reported in humans and on the environment. Despite the known toxicity of adjuvants, they are regulated differently from active principles, with their toxic effects being generally ignored. Adjuvants are not subject to an acceptable daily intake, and they are not included in the health risk assessment of dietary exposures to pesticide residues. Here, we illustrate this gap in risk assessment by reference to glyphosate, the most used pesticide active ingredient. We also investigate the case of neonicotinoid insecticides, which are strongly suspected to be involved in bee and bumblebee colony collapse disorder. Authors of studies sometimes use the name of the active principle (for example glyphosate) when they are testing a commercial formulation containing multiple (active principle plus adjuvant) ingredients. This results in confusion in the scientific literature and within regulatory circles and leads to a misrepresentation of the safety profile of commercial pesticides. Urgent action is needed to lift the veil on the presence of adjuvants in food and human bodily fluids, as well as in the environment (such as in air, water, and soil) and to characterize their toxicological properties. This must be accompanied by regulatory precautionary measures to protect the environment and general human population from some toxic adjuvants that are currently missing from risk assessments.

Activated sludge foaming: can phage therapy provide a control strategy?

Foaming in activated sludge systems is a global problem leading to environmental, cosmetic and operational problems. Proliferation of filamentous hydrophobic bacteria (including the Mycolata) are responsible for the stabilisation of foams. Currently no reliable methods exist to control these. Reducing the levels of the filamentous bacteria with bacteriophages below the threshold supporting foaming is an attractive approach to control their impact. We have isolated 88 bacteriophages that target members of the foaming Mycolata. These double stranded DNA phages have been characterised and are currently being assessed for their performance as antifoam agents.

Integrated Approaches forExtinguishing the Fire of Coal Pillars in Contiguous Coal Seams

The fire of coal pillars caused by spontaneous combustion in contiguous coal seams at the Dongrong2# colliery in China was examined. The reasons of spontaneous combustion of coal pillars in 16# coal seam were investigated. Based on testing results, the scope of high temperature was judged. To deal with the problem of significant air leakage together with a large fire area and the hidden fire source easily re-ignite, a series of key techniques for extinguishing the fire of coal pillars was put into practice. These mainly included plugging air leakage channel, high-flow injection of liquid nitrogen, and infusion of a large quantity of foam inhibitor into flame locations by drillings. The results showed that these integrated measures rapidly extinguish the fire of coal pillars, reduce carbon monoxide (CO) concentration from 1.6% to about 0.001% and temperature in the closed area of 16# coal seam from 81℃ to less than 20℃. In a word, the fire of coal pillars is successfully controlled in contiguous coal seams, which protect the safety of personnel and equipment.

Factors affecting the suitability of superplasticiser-amended cement for the encapsulation of radioactive waste

Organic superplasticisers improve the flow properties of cement, offering operational advantages for the disposal of radioactive wastes. However, there are concerns that they could increase the mobility of encapsulated contaminants significantly. The effect of polycarboxylate ether superplasticisers on the solubility of Ni(II), Am(III), Pu(IV) and U(VI) in two cement-equilibrated waters (ordinary Portland cement/pulverised fuel ash (OPC/PFA) and OPC/ground granulated blast-furnace slag (GGBS)) has been assessed. The study included four commercial superplasticisers, three adjuncts (a de-foaming agent, biocide and viscosity modifier) and a bespoke, synthesised superplasticiser from which residual monomer had been removed by dialysis. The commercial products (0·5% w/w dosage) had a much greater effect on metal solubility than the dialysed equivalent, increasing solubility by 2–3 orders of magnitude. As the adjuncts alone showed no effect, the difference between the commercial and synthesised superplasticisers is attributed to small molecules, primarily residual monomers, in the commercial formulations owing to incomplete polymerisation. The distribution of radionuclides in hardened cement pastes corresponds closely to the distribution of superplasticiser, as shown by 14C-labelling in combination with digital autoradiography and accounting for the bleed observed for certain slag-rich formulations.

Industrial antifoam agents impair ethanol fermentation and induce stress responses in yeast cells

The Brazilian sugarcane industry constitutes one of the biggest and most efficient ethanol production processes in the world. Brazilian ethanol production utilizes a unique process, which includes cell recycling, acid wash, and non-aseptic conditions. Process characteristics, such as extensive CO2 generation, poor quality of raw materials, and frequent contaminations, all lead to excessive foam formation during fermentations, which is treated with antifoam agents (AFA). In this study, we have investigated the impact of industrial AFA treatments on the physiology and transcriptome of the industrial ethanol strain Saccharomyces cerevisiae CAT-1. The investigated AFA included industrially used AFA acquired from Brazilian ethanol plants and commercially available AFA commonly used in the fermentation literature. In batch fermentations, it was shown that industrial AFA compromised growth rates and glucose uptake rates, while commercial AFA had no effect in concentrations relevant for defoaming purposes. Industrial AFA were further tested in laboratory scale simulations of the Brazilian ethanol production process and proved to decrease cell viability compared to the control, and the effects were intensified with increasing AFA concentrations and exposure time. Transcriptome analysis showed that AFA treatments induced additional stress responses in yeast cells compared to the control, shown by an up-regulation of stress-specific genes and a down-regulation of lipid biosynthesis, especially ergosterol. By documenting the detrimental effects associated with chemical AFA, we highlight the importance of developing innocuous systems for foam control in industrial fermentation processes.

Impact of preprocedure simethicone on adenoma detection rate during colonoscopy: a multicenter, endoscopist-blinded randomized controlled trial.

Ideal bowel preparation for colonoscopy requires complete removal of fluid and foam from the colon. Polyethylene glycol (PEG) is widely used for bowel preparation, with antifoaming agents such as simethicone commonly used in combination with PEG. Data on the effect of simethicone on the adenoma detection rate (ADR) were limited. This study therefore aimed to investigate whether preprocedure simethicone could increase the ADR. This was a prospective, multicenter, endoscopist-blinded randomized controlled trial involving consecutive patients who underwent colonoscopy in six centers in China. Patients were randomly assigned to one of two groups: PEG plus simethicone or PEG alone. The primary outcome was ADR; secondary outcomes were quality of bowel preparation, measured by the Boston bowel preparation scale (BBPS) and bubble scores. 583 patients were included. More adenomas were detected in the PEG plus simethicone group than in the PEG alone group (ADR 21.0 % vs. 14.3 %, P = 0.04; advanced ADR 9.0 % vs. 7.0 %, P = 0.38). The mean number of adenomas detected was 2.20 ± 1.36 vs. 1.63 ± 0.89 (P = 0.02). Patients in the PEG plus simethicone group showed better bowel cleansing efficacy: BBPS ≥ 6 in 88.3 % vs. 75.2 % (P < 0.001) and bubble scores of 1.00 ± 1.26 vs. 3.98 ± 2.50 (P < 0.001). Abdominal bloating was reported less frequently in the PEG plus simethicone group (7.8 % vs. 19.7 %, P < 0.001) than in the PEG alone group. Combined use of PEG and simethicone is associated with a significantly increased ADR in a Chinese population.

Role of large inhomogeneities in initiating liquid sheet breakup in agricultural atomisation

It is known that agricultural emulsifiable concentrate (EC) formulations reduce the fraction of fine spray produced during atomisation when compared with water. In recent years researchers inferred why EC formulations spray differently when multiple phases are present. The dispersed phase (e.g., oil drops/solid particles) is responsible for creating holes within the sheet, where the holes grow and merge to form liquid bridge ligaments which stretch and then breakup into droplets. Creating an inhomogeneous formulation of water and oil is a necessary, but not sufficient condition, to reduce the fine droplets produced during atomisation. The dispersed phase must also be of sufficient size and wettability (hydrophobicity) to create holes within the spray sheet emanating from agricultural nozzles. This manuscript describes the mechanics of creating perforations in liquid sheets using inhomogeneities within the spray solution. Perforations alter the sheet breakup mechanism leading to a reduction of very small drops (e.g., driftable fines) when atomised. Therefore, the number and location of perforations within the sheet can be used to control sheet breakup and droplet size distribution upon atomisation, based upon proof-of-concept experimental observations, surface energy minimisation principles, an overview of the various antifoaming agents that have been reported in literature (solids, oil globules, micelles), along with physical mechanisms for hole growth. Understanding the multiphase fluid parameters and atomisation process conditions that lead to hole perforation in liquid sheets (i.e., inhomogeneities) provides the basis for a priori formulation design based solely on physicochemical properties of formulation components.

Effect of polymer addition on air void content of fine grained concretes used in TRCC

Textile Reinforced Cementitious Composite (TRCC) became the most common construction material lately and have excellent properties. TRCC can be employed in the manufacture of thin-walled facade elements, load-bearing integrated formwork, tunnel linings or in the strengthening of existing structures. These composite materials are a combination of matrix and textile materials. There isn\'t much research done about the usage of polymer modified matrices in textile reinforced cementitious composites. In this study, matrix materials named as fine grained concretes (dmax 1.0 mm) were investigated. Air entraining effect of polymer modifiers were analyzed and air void content of fine grained concretes were identified with different methods. Aim of this research is to study the effect of polymer modification on the air content of fine grained concretes and the role of defoamer in controlling it. Polymer modifiers caused excessive air entrainment in all mixtures and defoamer material successfully lowered down the air content in all mixtures. Latex polymer modified mixtures had higher air content than redispersible powder modified ones. Air void analysis test was performed on selected mixtures. Air void parameters were compared with the values taken from air content meter. Close results were obtained with tests and air void analysis test found to be useful and applicable to fine grained concretes. Air void content in polymer modified matrix material used in TRCC found significant because of affecting mechanical and permeability parameters directly.

Wacker unveils novel silicone solution for defoaming applications

Wacker unveils novel silicone solution for defoaming applications

Enhanced entrainment of fine air bubbles in self-compacting concrete with high volume of fly ash using defoaming agent for improved entrained air stability and higher aggregate content

This paper presents an experimental study on the use of a defoaming agent (DA) to promote entrainment of fine air bubbles for improved volumetric stability of entrained air in self-compacting concrete (SCC) with fly ash. The possibility of increasing the aggregate content of self-compacting concrete with fly ash through the ball-bearing effect of fine entrained air bubbles is also investigated. Lower water retention and the ball-bearing effect of both fly ash and entrained air bubbles are considered to affect the self-compactability of fresh concrete. The results suggest that, generally, the employment of DA improves the stability of entrained air bubbles owing to the reduced entrainment of large air bubbles. The self-compactability of fresh concrete with fly ash is found to improve as dosage of DA increases, due to the ball-bearing effect of fine entrained air bubbles. Evidently, a higher aggregate content is also made possible through use of a certain type of air-entraining agent (AEA), due to the lower amount of large entrained air bubbles.

Improvement in Self-compacting Properties of Fresh Concrete by Eliminating Large Air Bubbles using an Antifoaming Agent

Improvement in Self-compacting Properties of Fresh Concrete by Eliminating Large Air Bubbles using an Antifoaming Agent

Filtration Effects on Foam Inhibitors and Optically Detected Oil Cleanliness

ABSTRACTFoam inhibitors (FIs) are effective at reducing foam in lubricants but can be detected by optical particle counters as contaminants. Filtration can decrease the particle counts but will also adversely affect foam performance because the additive is filtered out of the fluid. In this research, we explore the opposing effects of filtration on optically detected particle counts due to foam inhibitors and foam performance. A custom-built test rig is used to filter fluid consisting of polydimethylsiloxane foam inhibitors in base oil and to measure particle counts per ISO 4406. Foam tests are then performed per ASTM D892 on samples taken during filtration. In order to meet both particle count and foam performance specifications, we find that the following three variables must be carefully optimized: FI treat rate, filter pore size, and number of filtration passes.

Foamed emulsion drainage: flow and trapping of drops.

Foamed emulsions are ubiquitous in our daily life but the ageing of such systems is still poorly understood. In this study we investigate foam drainage and measure the evolution of the gas, liquid and oil volume fractions inside the foam. We evidence three regimes of ageing. During an initial period of fast drainage, both bubbles and drops are very mobile. As the foam stabilises drainage proceeds leading to a gradual decrease of the liquid fraction and slowing down of drainage. Clusters of oil drops are less sheared, their dynamic viscosity increases and drainage slows down even further, until the drops become blocked. At this point the oil fraction starts to increase in the continuous phase. The foam ageing leads to an increase of the capillary pressure until the oil acts as an antifoaming agent and the foam collapses.

Policies Regarding Industrial Wastewater Ocean Discharge in Korea

In August 2016, Korean press media released the news on the discharge of hazardous chemicals from power plant into surfaces waters of the sea in Ulsan area. The power plant used antifoaming agent which contains hazardous substance (Polydimethylsiloxane) to reduce the formation of foam for cooling system. Ministry of Maritime Affairs and Fisheries (MMAF) in Korea announced that the plant violate the law (Marine Environment Management) because Polydimethylsiloxane (PDMS) is a prohibited substance to discharge into the sea as a Noxious Liquid Substances by MARPOL 73/78. However, there is no standard to apply as a noxious liquid substance and no one knows the power plant is in the scope of Marine facilities of that law. ME (Ministry of Environment) and MOTIE (Ministry of Trade, Industry and Energy) argued it is uncertain how to discharge and there is no standards to apply. In this reason, MOTIE started feasibility study research of the regulations. This follow up study investigated how treat and discharge wastewater containing hazardous chemicals from a facility, especially, power plants and companies in shore line. The primary objective is to find a reasonable method to make standards related in discharging industrial wastewater.

Эффективность действия пеногасителей для однокомпонентной полиуретановой системы

Чурикова Татьяна Николаевна – ведущий инженер сектора химико-технологических исследований отдела ПИТСиП, ОАО «РосНИТИ».454139, г. Челябинск, ул. Новороссийская, 30. E-mail:churikova@rosniti.ru Самкова Нина Петровна – начальник сектора химико-технологических исследований отдела ПИТСиП, ОАО «РосНИТИ». 454139, г. Челябинск, ул. Новороссийская, 30. E-mail: samkovanp@rosniti.ru Авдин Вячеслав Викторович – декан Химического факультета, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: avdinvv@susu.ru T.N. Churikova1, churikova@rosniti.ru N.P. Samkova1, samkovanp@rosniti.ru V.V. Avdin2, avdinvv@susu.ru 1 The Russian Research Institute of the Tube & Pipe Industries Joint Stock Company, Chelyabinsk, Russian Federation 2 South Ural State University, Chelyabinsk, Russian Federation