Search Results (16)

As surface-active functional compounds, defoamers play a pivotal role in seawater desalination processes. In this study, a polyether-modified silicone compound was synthesized, and its structure was confirmed through FITR and ¹H-NMR characterization. Using this compound as the main component, a more effective and stable composite defoamer product was obtained through a co-optimization method. The particle size of the defoamer ranged from 600 to 700 nm in aqueous systems, and the surface tension could be reduced to 27.46 mN/m, thereby exhibiting superior defoaming and antifoaming properties. Additionally, the defoamer demonstrated good compatibility with commonly used scale inhibitors and was non-corrosive to equipment. Industrial testing further confirmed its efficacy in controlling foam during seawater desalination effectively. Full article

The selection of an optimal antifoam is critical for efficient fermentation, as industrial agents often have detrimental side effects like growth inhibition, while some can enhance productivity. We studied the efficacy of novel silicone–polyol antifoam emulsions for use in fermentation as defoamers. Except for agent 3L10, all antifoams tested did not show inhibition on six bacterial and one fungal culture. Interestingly, agent 3L10 strongly inhibited Gram-positive bacteria (especially Corynebacterium glutamicum) but not Gram-negative strains. A comprehensive evaluation protocol—combining chemical design, cytotoxicity screening across diverse microorganisms, the determination of minimum effective concentrations (MECs), and validation in model bioreactor fermentations—was established. Through this process, 6T80 was identified as a promising antifoam agent for fermentation. It exhibited a low MEC, high emulsion stability, and no cytotoxicity and did not impair growth or recombinant protein production in Bacillus subtilis or Pseudomonas putida fermentations. This study concludes that agent 6T80 is suitable for further application in processes involving Gram-negative and certain Gram-positive hosts. The developed methodology enables the targeted selection of highly efficient and biocompatible antifoams for specific biotechnological processes. Full article

Suspension fertilizers offer high concentration, excellent fluidity, an eco-friendly production process, and ease of precise and even application, making them ideal for modern fertigation systems. However, stability remains a significant challenge. This study aims to develop an organic value-added suspension fertilizer (VSuF) based on the filtrate of acid–base-treated soybean residue, which can ensure stability during transportation and storage while promoting efficient nutrient utilization in agriculture. The stabilizers were optimized by comparing the effects of various types and dosages on particle size, zeta potential, viscosity, and thixotropy of the suspension fertilizer. Meanwhile, the stability and agricultural effects of the fertilizer were evaluated. Results showed that with 0.40% sodium lignosulfonate, 0.40% xanthan gum, and 0.20% organic silicon defoamer, VSuF remained stable during centrifugation (2000 r·min⁻¹, 30 min) and storage at 0 °C and 50 °C for 14 days. Additionally, agricultural evaluation indicated that VSuF significantly increased the dry weight and phosphorus uptake of crop shoots by 17.40% and 21.00%, respectively, relative to the solid fertilizer without the value-added compound. Meanwhile, VSuF enhanced the fresh weight, length, and surface area of crop roots by 83.10%, 74.47%, and 69.34%, respectively, along with shoots’ phosphorus uptake by 19.80%, compared to the glucose value-added solid fertilizers. Full article

In natural gas gathering and transportation projects, efficient gas-liquid separation equipment is crucial to ensuring the stable operation of subsequent processes. Conventional separation units often have problems such as low efficiency, high energy consumption and poor resistance to load fluctuations when dealing with foam-containing gas-liquid mixtures. For this purpose, numerical simulation and structural optimization of multi-stage foam separation units were carried out in this study. Based on FLUENT software fluid analysis software, a three-dimensional, multi-physics coupled model incorporating cyclonic defoaming components and axial-flow separation tubes was developed. The volume of fluid (VOF) multiphase flow model was used to capture the dynamic characteristics of the gas-liquid interface, and the population balance model was used to simulate the coalescence and fragmentation of the foam. The results show that in the non-working fluid stage, the optimal operating pressure is 5.0–5.5 MPa, and the droplet concentration should be maintained below 50 × 10⁻⁵. The system performance during the working fluid stage is significantly influenced by foam size. The efficiency of millimeter-sized foams is stable above 88% in the 5.0–6.0 MPa range, while the efficiency of micrometer-sized foams is optimal in the 5.3–5.7 MPa range. It is recommended to control the foam proportion below 35% and add a pre-defoaming unit to improve overall performance. Full article

A modular strategy for the molecular design of silicone-based antifoaming agents was developed by precisely controlling the architecture of poly (methylhydrosiloxane) (PMHS). Sixteen PMHS variants were synthesized by systematically varying the siloxane chain length (L1–L4), backbone composition (D₃T₁ vs. D₃₀T₁), and terminal group chemistry (H- vs. M-type). These structural modifications resulted in a broad range of Si-H functionalities, which were quantitatively analyzed and correlated with defoaming performance. The PMHS matrices were integrated with high-viscosity PDMS, a nonionic surfactant, and covalently grafted fumed silica—which was chemically matched to each PMHS backbone—to construct formulation-specific defoaming systems with enhanced interfacial compatibility and colloidal stability. Comprehensive physicochemical characterization via FT-IR, ¹H NMR, GPC, TGA, and surface tension analysis revealed a nonmonotonic relationship between Si-H content and defoaming efficiency. Formulations containing 0.1–0.3 wt% Si-H achieved peak performance, with suppression efficiencies up to 96.6% and surface tensions as low as 18.9 mN/m. Deviations from this optimal range impaired performance due to interfacial over-reactivity or reduced mobility. Furthermore, thermal stability and molecular weight distribution were found to be governed by repeat unit architecture and terminal group selection. Compared with conventional EO/PO-modified commercial defoamers, the PMHS-based systems exhibited markedly improved suppression durability and formulation stability in high-viscosity environments. These results establish a predictive structure–property framework for tailoring antifoaming agents and highlight PMHS-based formulations as advanced foam suppressors with improved functionality. This study provides actionable design criteria for high-performance silicone materials with strong potential for application in thermally and mechanically demanding environments such as coating, bioprocessing, and polymer manufacturing. Full article

Accurately detecting coal slime water concentration during coal washing is crucial for optimizing dosing systems and improving separation efficiency. Traditional concentration detection methods are often affected by flow field disturbances. To address these limitations, this paper proposes a pressure differential concentration detection system utilizing interference rectification for a stabilized flow field and improved measurement accuracy. The experimental system comprises a circulating slurry tank, a defoamer, and a turbulence removal measuring tank. Numerical simulations and experimental studies investigated the effects of slurry concentration and inflow velocity on detection accuracy. Through dynamic measurement of pressure difference data under different concentrations and flow rates, the characteristics of a solid–liquid two-phase flow field are simulated using Fluent software. The results demonstrate that for low-concentration (C = 10%) and high-concentration (C = 30%) slurries, a flow velocity of ≥0.7 m/s significantly improves flow uniformity and achieves a stable particle suspension state, maintaining a measurement error within 1% for a flow rate of 0.7 m/s. However, flow rates exceeding 0.7 m/s decrease flow stability, increasing errors. Notably, the combination of sensors at positions No. 2 and No. 4 yields the lowest measurement errors, which verifies the influence of sensor layout on detection accuracy. A 0.7 m/s velocity is identified as the key threshold for flow field stability, and the nonlinear influence of the synergistic effect of flow rate and concentration on the detection stability is revealed. These findings provide valuable insights for optimizing pulp concentration detection systems and enhancing industrial dosing precision. Full article

During the acidic leaching of flotation zinc oxide concentrates, CO₂ released from carbonate decomposition generates viscous foams that disrupt process stability. This study introduces an innovative synergistic defoaming process combining air flotation and mechanical methods. Fine air bubbles destabilize the foam, while mechanical defoaming enhances the removal of residual bubbles. The results indicate that the defoaming process combining air flotation with mechanical stirring effectively reduces foam generation during the acid leaching of zinc oxide concentrates, enhances leaching efficiency, and improves process stability. This method provides an effective solution for foam control and offers a new approach for the treatment of zinc oxide concentrates. Full article

In many practical applications involving surfactants, achieving defoaming without affecting interfacial activity is a challenge. In this study, the antifoaming performance of REP-type block polymer nonionic surfactant C12EOmPOn was determined, and molecular dynamics simulation method was employed to investigate the molecular behaviors of surfactants at a gas/water interface, the detailed arrangement information of the different structural segments of the surfactant molecules and the inter-/intra-interactions between all the structural motifs in the interfacial layer were analyzed systematically, by which the antifoaming mechanisms of the surfactants were revealed. The results show that the EO and PO groups of REP-type polyether molecules are located in the aqueous phase near the interface, and the hydrophobic tails distribute separately, lying almost flat on the gas/water interface. The interaction between the same groups of EOs and POs is significantly stronger than with water. REP block polyethers with high polymerization degrees of EO and PO are more inclined to overlap into dense layers, resulting in the formation of aggregates resembling “oil lenses” spreading on the gas/water interface, which exerts a stronger antifoaming effect. This study provides a smart approach to obtaining efficient antifoaming performance at room temperature without adding other antifoam ingredients. Full article

Chemical mechanical polishing/planarization (CMP) is an essential manufacturing process in semiconductor technologies. This method combines chemical and mechanical forces to smooth the surfaces of wafers. The effectiveness of CMP relies on a carefully chosen slurry, demanding a sophisticated manufacturing technology. This technology must seamlessly integrate both chemical composition and mechanical elements, highlighting the intricate synergy required for successful semiconductor fabrication. Particularly in milling processes, if agglomerated particles due to slurry particle corrosion are present during polishing, uneven polishing, numerous fine scratches occur, leading to an increase in roughness and a deterioration in the quality of the finished surface. In this study, to overcome the issue of particle agglomeration and uneven polishing in commonly used ceria nanoparticle slurries during CMP processes, we investigated the ceria nanoparticle behavior based on styrene–maleic acid (SMA) dispersant polymer applied with three types of defoaming polymers. The investigations are expected to open up the possibility of utilizing ceria nanoparticles with applied defoaming polymer as an abrasive for advanced CMP applications. All samples were characterized by DLS (dynamic light scattering), SEM-EDX (scanning electron microscopy–energy dispersive X-ray spectroscopy), pH, conductivity, viscosity, a 10-day stability test at 60 °C, the AF4 test, and the polishing rate efficiency test. Our research demonstrates a significant improvement achieved through the use of SMA dispersant polymer, resulting in a polishing selection ratio exceeding 80 for oxide and nitride films. The G-336 defoaming polymer utilized here is expected to serve as a viable alternative in CMP processes by providing stable uniformity. Full article

Operating time series data collected and stored in historian must be managed to extract their full potential. Part 1 of this paper proposed a structured way (a sophisticated approach) to process industrial data; this first part explains in detail the data processing framework used as the basis for the costing analysis present in the second part of this series. The framework considers the analysis scope definition, data management steps, and operating regimes detection and identification. The added value of this proposed framework is demonstrated in Part 2 via the use of cost accounting for operational problem-solving (debottlenecking), i.e., its practicality is validated via its application alongside a cost analysis on the brownstock washing department of a kraft pulp mill. The traditional debottlenecking approach assumes a single operating condition considering that operating regimes allow for a much more sophisticated debottlenecking study of the washing department. With the use of operations-driven cost modeling (contingent on activity-based costing concepts) and processed time series data corresponding to steady-state operation, incremental profit can be assigned to each operating regime in order to identify the most cost-efficient one. The overall objective of this two-part series is to convert processed industrial steady-state data and cost information into knowledge that can be used to optimize the washing department of a chemical pulp mill. More specifically, different operating regimes are assessed, and the most suitable operating strategy is defined. The application of activity-based costing on a large amount of historically processed industrial data led to the improvement in the operation. The identified optimal way to operate (pulp throughput, pulp conductivity, defoamer and bleaching chemical quantity, etc.) led to a profit of CAD 49 M per year. Lastly, a contribution analysis of the regimes based on PCA highlighted how the process was operated when the preferred performances happened. Full article

Poultry slaughterhouse wastewater (PSW) is laden with fats, oil, and grease (FOG), as well as proteins. As such, PSW promotes the proliferation of filamentous organisms, which cause foam formation. In this study, the production of biological defoamers (biodefoamers) uses a consortium with antagonistic properties, i.e., 1.39 L of wastewater/mL defoamers, as reported in our previous study, toward foam formers and their application in the treatment of PSW using a bench-scale activated sludge (AS)-supported treatment system consisting of an aeration and clarification tank. The foam produced was slimy, brown, and thick, suggesting the presence of Nocardia, Microthrix, and Type 1863 species in the PSW/AS wastewater treatment system. The bio (Bio-AS) and synthetic-defoamers (Syn-AS, positive control) supplementation, i.e., at 4% v/v in the PSW/AS primary treatment stage (aeration tank) operated over ten days, resulted in 94% and 98% FOG and protein removal for the biodefoamers, respectively, when compared to 50% and 92% for a synthetic defoamer, respectively. Similarly, the Bio-AS treatment achieved 85.4% COD removal, while a lowly 51% was observed for the Syn-AS PSW treatment regime. Overall, the biodefoamers performed vehemently compared to synthetic defoamers, improving the PSW/AS system’s performance. It was prudent to hypothesize that the biodefoamers might have had FOG solubilization attributes, an assertion that needs further research in future studies. It was concluded that Bio-AS was more efficient in the removal of FOG, proteins, TSS, and COD in comparison to Syn-AS and negative control without supplementation (CAS). Full article

Activated sludge (AS) treatment systems’ major limitation is the nuisance foaming at the surface of the aeration basin in wastewater treatment plants (WWTPs). This foam can be stabilized by biofoamers and surfactants in the wastewater to be treated. In order to control foam, synthetic defoamers are used; however, these defoamers are toxic to the environment. This study aimed to optimize the production of biodefoamers by quantifying foam reduction efficiency and foam collapse by the isolate pervasive to poultry slaughterhouse wastewater (PSW). Before their identification and characterization, nine bacterial isolates were isolated and assessed for foam reduction efficiency. These organisms produced minute biodefoamers under various conditions generated on the response surface methodology (RSM). The isolates that produced biodefoamers with high foam reduction efficiency and at a lower foam collapse rate were Bacillus, Aeromonas, Klebsiella, and Commamonas spp. consortia. At 4% (v defoamer/v PSW), the crude defoamers produced by the consortium had 96% foam reduction efficiency at 1.7 mm/s foam collapse rate, which was comparable to 96% foam reduction efficiency and 2.5 mm/s foam collapse rate for active silicone polymer antifoam A/defoamer by Sigma-Aldrich, a synthetic defoamer. At 2.5 mm/s, all of which were achieved at pH 7 and in less than 50 s. The application of the biodefoamer resulted in sludge compacted flocs, with filament protruding flocs observed when a synthetic defoamer was used. The biodefoamer showed the presence of alkane, amine, carboxyl and hydroxyl groups, which indicated a polysaccharide core structure. The ¹H NMR analysis further confirmed that the biodefoamers were carbohydrate polymers. This study reports for the first time on the efficiency and comparability of a biodefoamer to a synthetic defoamer. Full article

With the oilfield developed to a later stage and its heterogeneity gradually becoming more serious, the adaptability of conventional profile control technologies for the reservoir becomes worse and worse. Therefore, the fitness of compatibility between combined patterns of profile control and target reservoir becomes an important factor for the efficient development of the oil field. Due to the importance of compatibility between the profile control and reservoir property, research on the remaining oil recovery with combined patterns of profile control and foam flooding were carried out. The experimental results showed that the combined profile control is highly consistent with the target reservoir. With a little lower initial viscosity (28.3–40.9 mPa·s), the channel plugging system is easy to inject. Due to the addition of a polymer, the reinforced foam is not easy to defoam when transporting in the pore throats of the core sample, and its spontaneous adaptability makes it match with the porous media of the formation automatically, which effectively prolongs the transporting distance for the foam in the deep part of the core sample. The segment plug with a gel-type profile control agent injected at the front stage is of great significance to the non-homogeneous reservoir, so it is necessary to inject a sufficient gel-type profile control agent into the high permeability layer to make it produce a seal. When the permeability differential was equal to 10, the maximum increase of oil recovery degree was 29.69%, and the development effect became worse after increasing or decreasing the permeability differential. Full article

Foam is essential in the flotation process. However, the gas–liquid–solid three-phase froth produced in the flotation process has very strong stability and is difficult to burst spontaneously. The existence of these froths will reduce the transport capacity of the pulp and affect the working efficiency of subsequent processes, such as filtration of the flotation concentrate. In this study, a new defoaming device is designed by combining mechanical impact with depressurized defoaming and its defoaming mechanism is analyzed theoretically. In addition, the liquid level height and pulp overflow method are applied to characterize the defoaming efficiency of the new defoaming device. The effects of impeller structure, pressure drop, impeller rotation frequency, and aeration rate on defoaming efficiency were studied. The results show that when increasing the pressure drop, the defoaming increases, but it will also enhance the generation of bubbles. The efficiency of combined mechanical–vacuum defoaming technology is superior under low-pressure drop using an SC impeller. Under −1 kpa vacuum condition, it only takes 168 s to eliminate 20 cm flotation froth height with combined mechanical impact, while it takes 453 s under ambient pressure, indicating that under vacuum conditions, the mechanical-defoaming method can significantly improve the defoaming efficiency, and the two have a certain synergistic effect. Full article

In recent years, with the goal of “carbon peaking and carbon neutralization”, the CO₂ flooding technology in carbon capture, utilization, and storage (CCUs) has been paid great attention to the oil fields. However, the CO₂ flooding of crude oil may produce foams in the oil and gas separation process. In addition, the precipitation of wax components in crude oil might enhance the stability characteristics of these foams and lower the separator’s efficiency. Based on a crude oil depressurization foaming device, the influence of wax crystals on the bursting of oil foam was studied using simulated oil, and the microstructure of the wax crystal and foam liquid film was observed using freeze-etching and microscopic observation. In addition, the gas–liquid interface model of the wax oil was established by a molecular dynamics (MD) simulation to analyze the influence mechanism of wax crystals on foam drainage and gas diffusion among foams in the microlayer. The results show that the precipitation of wax crystals overall reduces the rate of defoaming and drainage and increases the grain diameter of the foam. The formation and growth of the wax crystal-shaped network impede the flow of liquid in the drainage channel and stabilize the foam. Moreover, it impedes the diffusion of CO₂ among foams, inhibiting the bursting of the foams. The results of the combined experiments and MD simulation verify the accuracy and applicability of the molecular model, which further clarifies the effect of wax crystals on foam stability and its mechanism of action on foam film. These findings are a benchmark for the enhancement of defoaming and separation efficiency and a theoretical framework for future study and modeling. Full article