Cationic Emulsion Research Articles

Preclinical development of lyophilized self-replicating RNA vaccines for COVID-19 and malaria with improved long-term thermostability.

Messenger RNA (mRNA) vaccines against COVID-19 have demonstrated high efficacy and rapid deployment capability to target emerging infectious diseases. However, the need for ultra-low temperature storage made the distribution of LNP/mRNA vaccines to regions with limited resources impractical. This study explores the use of lyophilization to enhance the stability of self-replicating mRNA (repRNA) vaccines, allowing for their storage at non-freezing temperatures such as 2-8 °C or room temperature (25 °C). We lyophilized repRNA molecules complexed to a novel cationic emulsion delivery system, LION™, with different sugar-based lyoprotectants to identify candidates that provided the best vaccine integrity and effectiveness after being thermally stressed. For screening, we used repRNA encoding the reporter protein secreted embryonic alkaline phosphatase (SEAP) and for proof-of-concept, we used repRNA vaccines encoding SARS-CoV-2 full-length spike (WA-1 isolate) or full-length surface protein circumsporozoite (CS) of Plasmodium yoelii (Py). We found that lyophilization of LION/repRNA with sucrose provided the best colloidal stability, preserved in vitro expression, and induced equivalent antigen-specific antibody responses in mice compared to freshly prepared liquid LION/repRNA. Furthermore, lyophilized vaccines were stable for at least one week at 25 °C and at least one year at 2-8 °C. The cumulative analysis of stability-determining physicochemical data, in vitro potency, and in vivo immunogenicity in mice enabled the selection of a lead lyophilized composition containing 10 % w/v sucrose as the lyoprotectant. The data presented here provide a foundation for the clinical evaluation of next-generation thermostable repRNA vaccines that will enable more equitable vaccine access globally.

Enhancing Vaccine Efficacy with Polyethylenimine-Modified Lovastatin-Loaded Nanoparticle Pickering Emulsion Adjuvant.

Despite the potent immunoadjuvant properties of mevalonate pathway inhibitors, their application is constrained by poor solubility and instability. In this study, we developed a cationic nanoparticle-stabilized Pickering emulsion loaded with lovastatin (Lov-PPE), using polyethylenimine (PEI)-modified PLGA nanoparticles and squalene as carriers. The system was prepared and tested by evaluating the physicochemical properties and adjuvant efficacy of the Lov-PPE. Lov-PPE/O demonstrated good particle size distribution and zeta potential, with an adsorption efficiency of up to 73.07%. The immunization results showed that Lov-PPE/O significantly promoted the production of OVA-specific IgG antibodies, activated CD4+ and CD8+ T cells, and induced a strong mixed Th1/2 immune response. Additionally, safety assessments indicated that Lov-PPE/O has good in vivo safety. This study demonstrates that the PEI-modified lovastatin PLGA nanoparticle Pickering emulsion (Lov-PPE) is an effective vaccine adjuvant capable of significantly enhancing humoral and cellular immune responses while possessing good safety, offering a new strategy for vaccine formulation development.

Enhancing waste asphalt durability through cold recycling and additive integration

The longevity of waste asphalt can be considerably improved through cold recycling techniques combined with various additives. This research investigates the cold regeneration of aged asphalt concrete using Reclaimed Asphalt Pavement (RAP), Portland cement, cationic bitumen emulsion, and additional aggregates. The primary goal is to evaluate the performance enhancements in terms of average density, compressive strength, water resistance, and swelling across different mix compositions. Three distinct mixtures were formulated and assessed. Mix No. 1, composed solely of RAP, showed the lowest average density and highest swelling, indicating poor performance due to the lack of binding agents. Mix No. 2, which incorporated RAP, Portland cement, and water, exhibited the highest density and compressive strength, highlighting the crucial role of Portland cement in improving structural integrity. Mix No. 3, a more complex mixture including RAP, aggregates, Portland cement, water, and bitumen emulsion, displayed balanced properties with enhanced moisture resistance and reduced swelling. The experimental findings emphasize the effectiveness of adding Portland cement and bitumen emulsion to improve the mechanical and durability characteristics of recycled asphalt mixtures. Specifically, Mix No. 2 and Mix No. 3 demonstrated significant performance improvements, making them suitable for road maintenance applications. This study advocates for the widespread use of cold recycling methods with additive integration to achieve sustainable and cost-effective pavement restoration solutions.

Efficacy and Safety of a Preservative-Free Latanoprost Cationic Emulsion in Patients with Open-Angle Glaucoma and Concurrent Ocular Surface Disease: A Randomized Phase 2 Study.

Purpose: To compare intraocular pressure (IOP), ocular surface disease (OSD) parameters, and safety in patients with open-angle glaucoma (OAG)/ocular hypertension (OH) and concurrent OSD treated with preservative-free latanoprost 0.005% cationic emulsion (PF-latanoprost-E) or travoprost-Z 0.004% ophthalmical solution containing a soft preservative system. Methods: Patients with OAG/OH and OSD were randomized to treatment with PF-latanoprost-E or travoprost-Z nightly for 3 months. Outcomes included mean diurnal IOP reduction; OSD endpoints, including symptom improvement, tear break-up time (TBUT), and corneal fluorescein staining (CFS) score; and safety after 1 and 3 months. Results: A total of 105 patients were randomized, 51 to PF-latanoprost-E and 54 to travoprost-Z. IOP reductions (LS mean differences) at 3 months were numerically greater in the PF-latanoprost-E than in the travoprost-Z group at 8AM (7.2 versus 6.0 mmHg), 10AM (6.7 versus 5.9 mmHg), and 4PM (6.0 versus 5.4 mmHg). LS mean changes in IOP from baseline in both groups at 1 and 3 months, however, were comparable. Mean ± SD CFS scores on the Ora scale at month 3 showed significantly greater reductions in the PF-latanoprost-E than in the travoprost-Z group (-1.07 ± 1.863 versus -0.16 ± 2.553 P = 0.0461). The mean TBUT at month 3 showed similar improvements in both groups (1.1 versus 1.0 s, P > 0.05). OSD symptoms improved but did not differ significantly in the two groups. Overall safety was comparable in both groups. Conclusion: PF-latanoprost-E effectively and safely lowered IOP and improved OSD parameters in patients with OAG/OH. These findings provide evidence for the beneficial effects of this new formulation of latanoprost in glaucoma patients with OSD.

Breaking behavior of cationic bitumen emulsions

Breaking behavior of cationic bitumen emulsions

Evaluation of the electrochemical interaction in the asphalt emulsion-aggregate system of cold mix asphalt through zeta potential and surface free energy analysis

ABSTRACT The interaction in the emulsion-aggregate system is well known and influences the Cold Mix Asphalt (CMA) performance. However, the electrochemical interaction indexes for the emulsion-aggregate systems are still not well understood. Therefore, the present investigation focussed on evaluating the electrochemical interaction in the Asphalt Emulsion-Aggregate system (AEA-S) of Cold Mix Asphalt (CMA). Zeta Potential (ZP), X-ray diffraction (XRD), and Surface Free Energy (SFE) analysis were carried out in three slow-setting cationic asphalt emulsions and three common Colombian aggregates (alluvial and quarried) to determine the electrical potential and interaction in the emulsion-aggregate system. Zeta Potential analysis shows both dependence on the chemical compounds of the aggregates and variation in pH conditions. Moreover, Zeta Potential shows negative values for all three aggregates in the entire pH range variation and decreases with asphalt emulsions pH associated with SiO 2 / Al 2 O 3 ratio. Through chemical identification and electrokinetic forces is feasible to conclude that high Zeta Potential (ZP) and Surface Free Energy (SFE) values improve the electrochemical ad of the asphalt emulsion-aggregate system (AEA-S), demonstrating that high polarity is an essential factor in Cold Mix Asphalts (CMA).

Prophylactic Therapy for Long-Term Ocular Discomfort After Cataract Surgery.

The cataract surgery dissatisfaction rate is 20% to 35% due to ocular surface discomfort. We investigate the ocular surface discomfort after surgical failure as a consequence of age-related parainflammation. We also aim to prevent it by immune-modulating prophylactic management. Monocentric clinical trial realized in a teaching hospital. Prospective, randomized, open-label, unmasked clinical trial. One hundred patients diagnosed with cataracts underwent phacoemulsification surgery. Groups A (<65 years; n = 25) and B (>75 years; n = 25) received surgery only. Groups C and D (both >75 years and both n = 25) used cyclosporine A 0.1% cationic emulsion (CE) eye drops or CE lubricating eye drops (both twice daily), respectively, for 30 days before surgery. Patients were followed up 90 days after surgery. The primary outcome was postoperative ocular surface failure; secondary outcomes examined the influence of prophylactic cyclosporine A 0.1% CE therapy on ocular surface outcomes. Group B demonstrated greater severity regarding ocular surface signs and symptoms throughout the study period, versus all other groups. Signs/symptoms were typically lower in Group A. Group C achieved significant reductions in conjunctival Symptom Assessment in Dry Eye values ( P < 0.05), conjunctival hyperemia severity ( P < 0.01), and meibomian gland dysfunction ( P < 0.001) at Day 45, versus Group B, and tear break-up time was increased ( P < 0.001). Ocular surface inflammatory marker transcription (HLADR, intercellular adhesion molecule 1 [ICAM-1], and interleukin 6 [IL-6]) was significantly downregulated in Group C, versus Group B, at 90 days ( P < 0.05). Cataract surgery induced ocular surface system failure with a clinically significant persistent inflammatory status (InflammAging) in patients older than 75 years. Prophylactic cyclosporine A 0.1% CE eye drops were associated with improved ocular surface homeostasis and reductions in inflammatory markers.

Real-world insights and outcomes related to ciclosporin A 0.1% cationic emulsion for the long-term treatment of dry eye disease in Germany: Country-level sub-analysis of the PERSPECTIVE study

PurposeThe PERSPECTIVE study was a real-world European, non-interventional, multicenter, observational study that evaluated the effectiveness, tolerability, and safety of ciclosporin A (CsA) 0.1% cationic emulsion (CE) in routine clinical practice as a treatment for adults with severe keratitis and dry eye disease (DED) that remained insufficiently controlled with artificial tears. This sub-analysis examined data from ophthalmology clinics in Germany to provide more precise insights into treatment patterns, outcomes, and clinical decision-making related to CsA 0.1% CE.MethodsStudy data were collected from adults starting CsA 0.1% CE (one drop in both eyes at bedtime) and followed up at Week 4, 12, and 24, and Month 12. The primary endpoint was mean change from baseline in corneal fluorescein staining (CFS) score (Oxford Grade Scale) at Month 12. Secondary endpoints examined the severity of ocular signs and symptoms, and adverse events (AEs).ResultsA total of 236 patients from 20 ophthalmology clinics in Germany participated in the PERSPECTIVE study (69.9% female; mean age 60.8 years). Following treatment with CsA 0.1% CE, patients experienced significant reductions in CFS score from Week 4, which were maintained through to Month 12 (P < 0.0001). From baseline, 81.6% of patients experienced an improvement in CFS score at Month 12. CsA 0.1% CE provided significant reductions in the severity of eyelid and conjunctival erythema at Month 12 compared with baseline (P < 0.001), as well as significant reductions in the severity of subjective ocular symptoms (all P ≤ 0.015). Safety data were consistent with the known safety profile of CsA 0.1% CE. Tolerability was rated as “satisfactory,” “good,” or “very good” by 97.2% of physicians and 95.7% of patients.ConclusionOutcomes in Germany were similar to those reported for the overall European study population and are indicative of the treatment results that ophthalmologists may expect to see with CsA 0.1% CE treatment in real-life clinical practice. Treatment with CsA 0.1% CE provided long-term improvements over 12 months and was generally well tolerated.

Analysis of road construction waste generation in developing economies: A focus on surfacing and sub-base construction projects in Sri Lanka

The motivation for this study was to develop simplified tools to estimate material wastage during road construction projects. In developing countries, there is a lack of information about material wastage factors (MWFs) in road construction projects. The purpose of this study is to reveal the MWFs of materials used in road construction. To investigate MWFs, statistics were collected from a sample of 58 road contracts concluded in the southern province of Sri Lanka, comprising 245 road construction projects. Of the selected sample, 80% of the road projects utilized wearing course (asphalt concrete), aggregate base course (ABC), cationic slow setting emulsion 1 (CSS1) and sand. The mean MWFs were calculated only for ABC, wearing course and CSS1 as 8.69%, 5.21% and 6.8%, respectively, because the authors could only achieve acceptable precision levels for these three types of materials. The coefficient of variation (CV) for all these three types of materials ranged from 25% to 3%. Based on collected data, this study proposes equations to predict waste generation for CSS1 and wearing course. Implementing the derived equations to predict waste generation can aid in efficient planning and help construction companies to move towards more sustainable practices.

Studies on cationic ocular emulsions containing bipartitioned oil droplets to codeliver cyclosporin A and etodolac.

Background: To prepare ocular emulsions containing bipartitioned oil droplets to entrap cyclosporin A (0.05% w/w) and etodolac (0.2% w/w) by using castor, olive and silicon oils. Methods: The physicochemical characterizations of prepared emulsions were performed. The drug's biodistribution profiles and pharmacokinetic parameters from emulsions were checked using the ultraperformance liquid chromatography-tandemmass spectrometry method in the ocular tissues of the healthy rabbit eye model. Results: The emulsions displayed 365.13±7.21nm size and 26.45±2.09mV zeta potential. The ferrying of two drugs after releasing from emulsions occurred across corneal/conjunctival tissues to enter the vitreous and sclera following a single drop administration into the rabbit's eyes. Conclusion: The dual drug-loaded emulsions weremore likely to produce synergistic anti-inflammatory activity for managing moderate-to-severe dry eye disease.

Synthesis of Cationic Starch Compound Emulsion by Graft Copolymerization with Tea Polyphenols and AEM5700

AbstractAn antibacterial biobased compound emulsion is prepared by modifying cationic oxidized starch grafted styrene‐acrylic emulsion with 3‐(trimethoxysilyl)‐propyldimethyloctadecyl ammonium chloride (AEM5700) and tea polyphenols. The biobased compound emulsion exhibits better stability, chemical properties, and antibacterial properties. The structure and surface morphology of biobased compound emulsion are characterized by Fourier Transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The thermal stability of biobased compound emulsion is improved, which can be concluded from the thermogravimetric analysis (TGA). The surface morphology of film is observed by the atomic force microscope (AFM). The wetting property of emulsion film is tested by contact angle test. When the compound ratio is 1.5, the biobased antibacterial compound emulsion has better stability and antibacterial properties. Compared to a single antibacterial agent, the inhibition zone increases by 4–5.5 mm. In addition, the polymerization mechanism of the biobased antibacterial emulsion is analyzed.

Short-Term Efficacy of Ophthalmic Cyclosporine: A 0.1% Cationic Emulsion in Dry Eye Patients Assessed Under Controlled Environment.

To evaluate the short-term efficacy of cyclosporine A (CsA)-0.1% cationic emulsion (CE) in patients with dry eye disease (DED) and mitigation of the inflammatory flares triggered by desiccating stress environments. A single-center non-randomized clinical trial was performed at a tertiary care setting. Twenty patients with DED treated with CsA 0.1% CE were exposed to a normal controlled environment (NCE) (23°C, 50% relative humidity) and an adverse controlled environment (ACE) (23°C, 10% relative humidity, 0.43m/s localized airflow) during baseline and the 1- and 3-month visits. Patients underwent the following evaluations: conjunctival hyperemia and staining, corneal fluorescein staining (CFS) using the Oxford and Cornea and Contact Lens Research Unit (CCLRU) scale, meibomian gland (MG) secretion quality, Dry Eye Questionnaire-5, Symptom Assessment in Dry Eye (SANDE II), and Change in Dry Eye Symptoms Questionnaire. Multivariate models were adjusted for statistical analysis. Nineteen women and one man (mean age, 58.9 ± 12.3years) completed the study. All symptom questionnaires, CFS, conjunctival hyperemia and staining, and MG secretion quality improved (p ≤ 0.003) with 1month of treatment; improvements were maintained after 3months (p ≤ 0.02), except for SANDE II (p ≥ 0.07). The CFS worsening (total CCLRU) after baseline ACE exposure (from 8.6 to 10.1) was higher, although not significant (p = 0.64), compared with 1month (from 5.4 to 5.8) and 3months (from 5.0 to 5.9) after treatment. Topical CsA-0.1% CE improved DED signs and symptoms after 1month of treatment under controlled environmental conditions. Future studies should confirm the benefit of CsA-0.1% CE in desiccating stress environments. ClinicalTrials.gov identifier, NCT04492878.

Review of clinical outcomes of a cationic emulsion tear substitute in patients with dry eye disease.

First-line options for the treatment of dry eye disease (DED) rely on artificial tears (ATs), among which cationic emulsion (CE)-based ATs have been developed in order to mimic the healthy tear film for an improved restoration of the ocular surface homeostasis. In this review, we describe the outcomes reported in several studies, assessing the mode of action, ocular tolerance and clinical performance of a CE-based AT. Pilot studies have revealed that CE-based ATs can increase the volume and stability of the tear film while limiting its evaporation rate. Larger studies have demonstrated that CE-based ATs play a significant role in the improvement of both objective and subjective DED parameters, including superior efficacy on DED symptoms compared to several other available AT formulation types. Concomitantly, CE-based ATs have been shown to help patients to prevent or recover from corneal defects associated with refractive surgery. These positive outcomes on ocular surface epithelia are likely due to the combination of unique rheological behaviour and intrinsic anti-inflammatory properties. Based on all clinical findings, CE-based ATs represent a valuable treatment option for patients with various etiologies of DED including evaporative forms and would deserve evaluation of benefits in other surgical intervention types triggering DED.

Long‐term results and persistence of topical cyclosporine a 0.1% treatment in patients with dry eye disease in a tertiary eye centre

Aims/Purpose: This study aims to assess clinical effectiveness, outcome and safety of long‐term topical Cyclosporine A 0.1% Cationic Emulsion (CsA 0.1% CE; Ikervis®) treatment in patients with dry eye disease.Methods: Retrospective chart review of 55 patients (110 eyes) with dry eye disease and severe keratitis treated with Ikervis® since 2016 for at least 12 months without interruption was performed. Study outcomes were median change from baseline in corneal fluorescein staining (CFS, Oxford Grade Scale) score, clinical outcome, treatment discontinuation reason, ocular symptom severity and adverse events (AEs) during long follow‐up.Results: The mean age of patients was 65.96 ± 1.9 years, 81.8% women and 18.2% men. The mean follow‐up was 33.8 ± 19.1 (12–80) months. 43.6% eyes had grade III of CFS at baseline and 4.5% had grade I of CFS at the last follow up. The median CFS score reduced from 2 (1–3) at baseline to 0 (0–1) at the last follow up and this reduction was statistically significant (p &lt; 0.001) from the fourth week. Clinical outcome was defined as active/worsening in 1.8%, stabilization in 14.5%, improvement in 69.1% and resolution in 14.5% of the cases. 65.5% of the patients have continued the treatment without interruption during the whole follow‐up, the treatment discontinuation in 35.5% of the cases were due to improvement (14.5%), AEs (5.5%), patient decision (5.5%), treatment failure (3.6%), other reason (5.5%). Ocular symptom severity was significantly reduced from baseline during the follow up (p &lt; 0.001). In 27.3% cases treatment‐related AEs were reported, most of them (64.7%) were mild.Conclusions: This study shows a long‐term clinical effectiveness and persistence of the topical CsA 0.1% CE treatment in patients with dry eye disease. The significantly reduction of the dry eye symptoms severity from the fourth week of the initiated Ikervis® treatment sustains for a long follow up, and thus definitely improves the quality of life of patients.Reference1. Geerling G, Hamada S, Trocmé S, Ræder S, Chen X, Fassari C, Lanzl I; PERSPECTIVE study group. Real‐World Effectiveness, Tolerability and Safety of Cyclosporine A 0.1% Cationic Emulsion in Severe Keratitis and Dry Eye Treatment. Ophthalmol Ther 2022; 11(3): 1101–1117. doi: 10.1007/s40123‐022‐00487‐x.

The place of ciclosporin A cationic emulsion 0.1% in the therapy of xerophthalmia

Dry eye disease (DED) is pathogenetically based on inflammation of the ocular surface. A step-by-step approach to DED treatment involves early initiation of anti-inflammatory therapy, including instillation of cyclosporine A (CsA). However, recommendations for the use of topical CsA in clinical practice are limited. This article presents an expert consensus on practical recommendations for the management of patients with DED, including indications, time of initiation and duration of CsA therapy, comparison of CsA forms currently registered in the Russian Federation, as well as issues of patient education.

Evaluation of the Mechanical Behavior of Soil Stabilized with Asphalt Emulsion Using Multi-Stage Loading

The objective of this research was to assess the mechanical response (resilient and plastic) of soil stabilized with petroleum asphalt concrete using asphalt emulsion under multi-stage loading. To enhance the adhesion of the asphalt film to the soil grains, the stabilized soil underwent air-drying curing for seven days. Dosage was conducted through the indirect tensile strength test using diametral compression. With the optimum content determined in the dosage (2% emulsion), additions and removals of 0.5% asphalt emulsion from this content were performed. Consequently, three specimens were molded with concentrations of 1.5%, 2%, and 2.5% of slow-setting cationic asphalt emulsion. These specimens were then subjected to drained triaxial tests under multi-stage loading, using 5 different stress pairs, totaling 50,000 cycles. Analyzing the regions defined by the total and permanent deformation curves allowed studying the plastic and elastic response, the proportionality between these regions, and the increase in elastic and plastic regions of the soil and stabilized soil in a single test, providing a more accurate interpretation. Regarding the measured deformations, as the deviator stress was increased with each loading cycle, the stabilized samples exhibited an increase in plastic deformations compared to the natural soil (control). It was also observed a proportional increase in the resilient region, indicating that the addition of asphalt made the soil less rigid but provided cohesion that was absent before stabilization. Doi: 10.28991/CEJ-2024-010-01-02 Full Text: PDF

Fabrication of a poly(N-isopropylacrylamide)-grafted alginate composite aerogel for efficient treatment of emulsified oily wastewater

The treatment of emulsion wastewater poses significant challenges. In this study, a novel porous material, namely esterified bagasse/poly(N, N-dimethylacrylamide)/sodium alginate (SBS/PDMAA/Alg) aerogel, was developed for efficient demulsification and oil recovery. By grafting a poly(N-isopropylacrylamide) (PNIPAM) brush onto the SBS/PDMAA/Alg skeleton through free radical polymerization, the resulting aerogel exhibits both surface charge and a molecular brush structure. The aerogel demonstrates remarkable demulsification efficiency for cationic surfactant-stabilized emulsions at various concentrations, achieving a demulsification efficiency of 95.6% even at an oil content of 100 g L−1. Furthermore, the molecular brush structure extends the application range of the aerogel, enabling a demulsification efficiency of 98.3% for anionic and non-ionic surfactant-stabilized emulsions. The interpenetrating polymer network (IPN) structure formed by SBS, PDMAA, and alginate enhances the mechanical stability of the aerogel, enabling a demulsification efficiency of 91.3% even after 20 repeated cycles. The demulsification ability of the composite aerogel is attributed to its surface charge, high interfacial activity, and unique brush-like structure. A demulsification mechanism based on the synergistic effect of surface charge and molecular brush is proposed to elucidate the efficient demulsification process.

FEATURES OF THE MIX TIME OF BITUMEN EMULSIONS WITH CEMENT FOR SLURRY SURFACING TECHNOLOGY

Pavement grade cationic bitumen emulsions formulations were developed for Slurry Surfacing based on orthophosphoric and hydrochloric acids with both all-purpose and specialized emulsifiers used. As a result, there were established relations of mix time upon cement - for Slurry Surfacing based on various acids and emulsifiers. Mix time of Slurry Surfacing mix (having different cement content) with bitumen emulsions on both orthophosphoric and hydrochloric acids is characterized by parabolic relation, branches of the parabola going down. Still, parabola slope steepness for Slurry Surfacing with cement and bitumen emulsions on orthophosphoric acid is higher than for emulsions on hydrochloric acid. The regularity investigated allows affirming that dosing cement for Slurry Surfacing with orthophosphoric-based bitumen emulsions shall be more diligently checked and controlled – so as to avoid the premature mix time.

OVER-STABILIZED BITUMEN EMULSIONS MADE FROM EMULSIFIERS FOR SLOW-SETTING EMULSIONS

Formulations of road over-stabilized cationic bitumen emulsions with orthophosphoric, sulfuric and hydrochloric acids and cationic emulsifiers for slowly disintegrating emulsions have been designed. The physical and mechanical properties of the manufactured over-stabilized bitumen emulsions and their breaking behavior were determined. It has been established that over-stabilised bitumen emulsions demonstrate good storage stability for 180 days. The obtained results of breaking behavior bitumen emulsions indicate that emulsions based on hydrochloric and sulfuric acid have a shorter fines mixing time and greater mixing stability with cement than emulsions based on orthophosphoric acid. For over-stabilized bitumen emulsions on orthophosphoric acid, the method according to DSTU EN 12848:2020 is not effective, due to the high reactivity of emulsions on orthophosphoric acid during interaction with portland cement.

Construction of chitosan modified cationic lipid droplet emulsions for high-value microalgae harvesting

To reduce the risk of microalgae biomass and environmental contamination, a natural cationic lipid droplet emulsion has been constructed for harvesting microalgae. Using three different microalgae strains (Chlorella vulgaris, Scenedesmus quadricauda and Spirulina platensis), the present work studied the influence of lipid droplet dosage, chitosan concentration, pH on harvesting efficiency, and then the flotation behavior was analyzed by zeta potentials, floc size distribution, algal organic matter component, attenuated total reflectance Fourier transform infrared spectrometer and microscopic observation. The XDLVO theory was used to explain the attachment behavior during the flotation process. The experimental results showed that the maximum harvesting efficiency for two green microalgae strains was over 95% at pH 7, while the optimal dosage and ratio of lipid droplet and chitosan were depended on the microalgae species. The maximum harvesting efficiency for Spirulina platensis was less than 70% since the high salinity of growth medium weakened the bridging and netting ability of chitosan. The mechanism of capturing microalgae by the ballasting agents was mainly physical electrostatic attraction, bridging and netting. In addition, the changes of microalgae components before and after harvesting were less than 5%, indicating this method would not affect the downstream application of microalgae biomass.