Chemical Cleaning Research Articles

Newer New Jersey work-based learning teachers during the COVID-19 pandemic: school safety regarding ventilation, trainings, and awareness of government agencies resources

ABSTRACT New Jersey (NJ) Safe Schools Program (NJSS) provides code-required trainings for NJ teachers supervising students in work-based learning (WBL) experiences. During the COVID-19 pandemic, increased use of chemical cleaning, sanitization, and disinfectant products (CSDPs) led to ventilation and other health concerns. NJSS conducted two surveys of newer NJ WBL teachers between October 2021 and June 2023, with a follow-up in fall 2022 for those who completed initial surveys before summer 2022. This study focused on questions regarding workspace ventilation; respirator and CSDPs trainings; awareness of government resources for safety and health (S&H); and demographics. Over 65% of participant classrooms have operable windows or ventilation systems, while 13% of school salons have ceiling fans. Half of participants didn’t receive training on handling CSDPs, although 90% were aware of government S&H resources. Data suggested teachers have well-ventilated workspaces and are aware of different resources available, which is important to continue post COVID-19.

Effect of different MoS2 morphologies on the formation and performance of adsorptive-catalytic nanocomposite membranes

This study synthesized three MoS₂ morphologies—nanospheres, nanoplatelets, and nanosheets—under varied conditions and incorporated them into chitosan membranes. TEM confirmed unique morphologies and crystallinity. Clean water flux showed that the nanoplatelet (P-CM) membrane had the highest flux due to higher porosity. The P-CM membrane excelled in removing Mn²⁺ and Zn²⁺ ions, achieving 93.0 ± 0.5% and 90.4 ± 1.5% removal, outperforming membranes with nanospheres (S-CM) and nanosheets (T-CM). Its superior performance is attributed to thicker nanoplatelets forming more water channels. The MoS₂‘s tri-layered structure generated reactive oxygen species (ROS) via H₂O₂ catalysis, contributing to enhanced heavy metal removal. These adsorptive-catalytic membranes combine adsorption with catalytic decomposition of heavy metals, highlighting the work’s novelty and superior performance. The membranes demonstrated excellent flux recovery and reusability (96.0 ± 0.5% for P-CM) after chemical cleaning. The findings emphasize the impact of nanomaterial morphologies on membrane performance in water treatment and environmental remediation.

Sustainable control of organic-inorganic combined fouling of electroactive ultrafiltration membrane during electrocatalytic-driven self-cleaning process: Mechanism and implications

Organic-inorganic combined fouling of membrane is a tough problem that restrained its application in water treatment, which was insufficient and non-sustainable to be alleviated by conventional chemical cleaning. Herein, a facile and sustainable control strategy was developed to mitigate biopolymer-Ca2+ combined fouling for an electroactive metal-organic framework ultrafiltration membrane. Bovine serum albumin (BSA) and sodium alginate (SA) were selected as model biopolymer. The results showed BSA and SA fouling both accelerated with increasing Ca2+ concentration (0–1.0 mM) via calcium bridging action and hydraulic cleaning was insufficient to restore flux (flux recovery < 7 %). By comparison, flux can be fully recovered by applying electricity to all combined fouling, suggesting membrane presented outstanding self-cleaning performance. According to the free radical quenching test and physicochemical property of biopolymer, fouling control mechanism was revealed because in-situ electro-generated OH and O2− free radicals caused decomplexation of biopolymer and Ca2+, and then degraded biopolymer into smaller and less hydrophobic fragments that repulsed membrane. Extended Derjaguin–Landau–Verwey–Overbeek theory further unveiled the foulants-membrane interaction shifted from attraction to repulsion after self-cleaning. This strategy has the advantages of low chemical cleaning reagents and energy consumption, which may provide the guidance for sustainable control of organic-inorganic combined membrane fouling.

Studies on Recovery of Performance of Fouled Nanocomposite Ultrafiltration Membranes on Cleaning after Treatment of Oil–Water Emulsions

Herein, we discussed the pure water flux recovery of carbon based nanofillers embedded polyvinyl chloride nanocomposite membranes after physical cleaning through backwashing &amp; flushing with flow reversal and after chemical cleaning using hydrochloric acid and caustic soda. The water flux recovery by backwashing is more than that by forward flushing for all the membrane but it is more effective in carbon black (CB) &amp; graphitized carbon black (GCB) carbon-based membranes than relatively hydrophilic multiwalled carbon-nanotube (MWCNT) &amp; carboxylated multiwalled carbon-nanotube (CMWCNT) based nanocomposite membranes. The highest water flux recovery was found ~96% for nanocomposite membranes by backwashing and caustic soda cleaning. The combination of backwashing and caustic soda cleaning could be the most effective method of cleaning of oil-water fouled membranes to restore the maximum water flux.

Alleviation of RO membrane fouling in wastewater reclamation plants using an enhanced acid-base chemical cleaning method

Membrane fouling has always been a critical constraint in the operation of the reverse osmosis (RO) process, and chemical cleaning is essential for mitigating membrane fouling and ensuring smooth operation of the membrane system. This paper presents an optimized chemical cleaning method for the efficient cleaning of RO membranes in full-scale applications. Compared to the regular cleaning method (cleaning with 0.1 % NaOH + 1 % ethylenediaminetetraacetic acid + 0.025 % sodium dodecyl benzene sulfonate followed by 0.2 % HCl), the optimized cleaning method improves the cleaning efficiency by adding sodium chloride to the alkaline cleaning solution and citric acid to the acid cleaning solution. Notably, the membrane flux recovery rate with the optimized cleaning method is 45.74 %, and it improves the cleaning efficiency by 1.65 times compared to the regular cleaning method. Additionally, the optimized cleaning method removes 30.46 % of total foulants (organic and inorganic), which is 2.11 times higher than the regular cleaning method. The removal of inorganic ions such as Fe, Ca, and Mg is significantly improved with the optimized cleaning method. For organic matter removal, the optimized cleaning method effectively removes more polysaccharides, proteins, and microbial metabolites by disrupting the complex structures of organic matter. Furthermore, it also changes the microbial community structure on the RO membrane surface by eliminating microorganisms that cannot withstand strong acids, bases, and high salt environments. However, Mycobacterium can adapt to these harsh conditions, showing a relative abundance of up to 84.13 % after cleaning. Overall, our results provide a new chemical cleaning method for RO membranes in full-scale applications. This method effectively removes membrane foulants and enhances the understanding of the removal characteristics of foulants on RO membrane surfaces by chemical cleaning.

Innovative perspective for the cleaning of historical iron heritage: novel bio-organogel for the combined removal of undesired organic coatings and corrosion

An innovative green organogel was designed to simultaneously tackle inorganic compounds (i.e., iron corrosion) and organic substances (i.e., acrylic coatings) as undesired materials possibly present on the surface of altered indoor metal artworks. Poly-3-hydroxybutyrate (PHB), ethyl lactate (EL), and deferoxamine B (DFO) were employed in the formulation as thickening agent, organic solvent, and complexing agent, respectively, aiming to propose a sustainable and less harmful chemical cleaning method for metal care. The components were selected because they are bio-sourced, renewable, biodegradable, and non- or low-toxic materials. A multi-modal protocol of analysis was carried out to characterise the newly designed PHB-EL-DFO organogel. The cleaning performance of the novel formulation was assessed on mild steel mock-ups presenting both corrosion and organic coating to be removed. The conducted multi-analytical approach verified that the PHB-EL-DFO gel was able to tackle the two undesired materials simultaneously in an adjustable and easy-to-use way thanks to a modular application.

Optimizing sustainability in hybrid cooling towers: Investigating fouling resistance, water quality correlations, modeling, and cleaning strategies for thermal power plants

This research explored the intricacies of water consumption and energy requirements within cooling systems designed for concentrated solar power plants. In the present work, an innovative hybrid cooling tower was presented and studied, aiming at reducing water consumption and preserving power generation efficiency. Experimental cooling towers were studied with four different cooling water qualities, elucidating that, compared to kaolinite, calcium carbonate has a substantial influence on fouling behavior as an additive to the cooling water. Through the establishment of correlations between water quality and critical fouling parameters such as fouling resistance Rf, deposition rates mf, and fouling thickness εf, the study provided valuable insights for predicting fouling behavior in similar operating conditions. Furthermore, the development and validation of a numerical code with both literature and experimental work was helpful in predicting the thermal performance of hybrid cooling along one-year operation. The assessment of three cleaning methods; water jet, air jet, and chemical cleaning, revealed distinct impacts on heat transfer and associated costs. Particularly noteworthy were the substantial improvements in heat transfer efficiency, especially with air jet cleaning, which enhanced heat transfer of the polymer bundles by 6.1% with no water consumption. These findings not only portend cost-effective maintenance practices but also endorse environmentally friendly approaches by significantly curtailing water usage, a pivotal progression in the sustainability of hybrids cooling systems.

A comparative analysis of particulate bovine bone substitutes for oral regeneration: a narrative review.

Particulate bovine bone substitutes (BS) are commonly used in oral regeneration. However, more literature is needed focusing on comparative analyses among various particulate bovine BS. This study evaluates pre-clinical and clinical data of different particulate bovine BS in oral regeneration. A narrative review was conducted by screening the PubMed database Included in the review were pre-clinical and clinical studies until 2024 comparing a minimum of two distinct particulate bovine BS. In addition to examining general data concerning manufacturing and treatment processes, biological safety, physical and chemical characteristics, and graft resorption, particular emphasis was placed on assessing pre-clinical and clinical data related to ridge preservation, sinus floor elevation, peri-implant defects, and various forms of alveolar ridge augmentation utilizing particulate bovine BS. Various treatment temperatures ranging from 300 to 1,250°C and the employment of chemical cleaning steps were identified for the manufacturing process of particulate bovine BS deemed to possess biosecurity. A notable heterogeneity was observed in the physical and chemical characteristics of particulate bovine BS, with minimal or negligible graft resorption. Variations were evident in particle and pore sizes and the porosity of particulate bovine BS. Pre-clinical assessments noted a marginal inclination towards favorable outcomes for particulate bovine BS subjected to higher treatment temperatures. However, clinical data are insufficient. No distinctions were observed regarding ridge preservation, while slight advantages were noted for high-temperature treated particulate bovine BS in sinus floor elevation. Subtle variances in both pre-clinical and clinical outcomes were observed in across various particulate bovine BS. Due to inadequate data, numerous considerations related to diverse particulate bovine BS, including peri-implant defects, must be more conclusive. Additional clinical studies are imperative to address these knowledge gaps effectively.

Femtosecond laser-induced nanoparticle implantation into flexible substrate for sensitive and reusable microfluidics SERS detection

Surface-enhanced Raman spectroscopy (SERS) microfluidic system, which enables rapid detection of chemical and biological analytes, offers an effective platform to monitor various food contaminants and disease diagnoses. The efficacy of SERS microfluidic systems is greatly dependent on the sensitivity and reusability of SERS detection substrates to ensure repeated use for prolonged periods. This study proposed a novel process of femtosecond laser nanoparticle array (NPA) implantation to achieve homogeneous forward transfer of gold NPA on a flexible polymer film and accurately integrated it within microfluidic chips for SERS detection. The implanted Au-NPA strips show a remarkable electromagnetic field enhancement with the factor of 9 × 108 during SERS detection of malachite green (MG) solution, achieving a detection limit lower than 10 ppt, far better than most laser-prepared SERS substrates. Furthermore, Au-NPA strips show excellent reusability after several physical and chemical cleaning, because of the robust embedment of laser-implanted NPA in flexible substrates. To demonstrate the performance of Au-NPA, a SERS microfluidic system is built to monitor the online oxidation reaction between MG/NaClO reactants, which helps infer the reaction path. The proposed method of nanoparticle implantation is more effective than the direct laser structuring technique. It provides better performance for SERS detection, robustness of detection, and substrate flexibility and has a wider range of applications for microfluidic systems without any negative impact.

Enhancement of waterborne pathogen removal by functionalized biochar with ε-polylysine ″dynamic arms″: Potential application in ultrafiltration system

Widespread outbreaks of threatening infections caused by unknown pathogens and water transmission have spawned the development of adsorption methods for pathogen elimination. We proposed a biochar functionalization strategy involving ε-polylysine (PLL), a bio-macromolecular poly(amino acid)s with variable folding conformations, as a "pathogen gripper" on biochar. PLL was successfully bridged onto biochar via polydopamine (PDA) crosslinking. The extension of electropositive side chains within PLL enables the capture of both nanoscale viruses and micrometer-scale bacteria in water, achieving excellent removal performances. This functionalized biochar was tentatively incorporated into ultrafiltration (UF) system, to achieve effective and controllable adsorption and retention of pathogens, and to realize the transfer of pathogens from membrane surface/pore to biochar surface as well as flushing water. The biochar-amended UF systems presents complete retention (∼7 LRV) and hydraulic elution of pathogens into membrane flushing water. Improvements in removal of organics and anti-fouling capability were observed, indicating the broken trade-off in UF pathogen removal dependent on irreversible fouling. Chemical characterizations revealed adsorption mechanisms encompassing electrostatic/hydrophobic interactions, pore filling, electron transfer, chemical bonding and secondary structure transitions. Microscopic and mechanical analyses validated the mechanisms for rapid adsorption and pathogen lysis. Low-concentration alkaline solution for used biochar regeneration, facilitated the deprotonation and transformation of PLL side chain to folded structures (α-helix/β-sheet). Biochar regeneration process also promoted the effective detachment/inactivation of pathogens and protection of functional groups on biochar, corroborated by physicochemical inspection and molecular dynamics simulation. The foldability of poly(amino acid)s acting like dynamic arms, significantly contributed to pathogen capture/desorption/inactivation and biochar regeneration. This study also inspires future investigation for performances of UF systems amended by poly(amino acid)s-functionalized biochar under diverse pressure, temperature, reactive oxygen species of feeds and chemical cleaning solutions, with far-reaching implications for public health, environmental applications of biochar, and UF process improvement.

Pit-formation in germanium homoepitaxial layers

With increasing importance of germanium (Ge) for semiconductor quantum technologies, the necessity of growing defect-free Ge films has become crucial. Here, Ge homoepitaxial growth experiments were conducted using molecular beam epitaxy (MBE). This requires a smooth (σrms≤10 Å) and contamination-free substrate surface. We have shown that common ex-situ wet chemical cleaning methods are not sufficient. Foreign atoms like carbon stick to the substrate surface and tend to form clusters which results in macroscopic growth defects which are referred here as pits. The density of such pits is in the range of 106 to 109 cm−2. The formation and characteristics of the pits have been investigated. Pits emerge after a growth at 370 °C with a thickness of above 5 nm . At growth temperatures lower than 300 °C, the density of pits increases, while it decreases at temperatures higher than 400 °C. Pits can be faceted with the main facets being {1 1 3} and {3 15 23}.Furthermore, a procedure is presented involving a Ge buffer growth at room temperature with a high growth rate (0.02 nm/s). This leads to a coverage of present contamination and the formation of a new substrate surface which prevent pit formation.

New mechanistic insight into the microbial responses to on-line chemical cleaning of UF membranes with NaClO

On-line membrane cleaning with NaClO is frequently implemented during membrane-based water treatment, where diverse aqueous microorganisms inevitably react with NaClO, leading to a significant impact on the next-round operation. This study filled the knowledge gap to explore the respective response of bacteria, algae and fungi to NaClO exposure. The results indicated that the three types of microorganisms exhibited distinct behaviors to NaClO attack. Specifically, E. coli showed stronger adaptation to NaClO by releasing more EPS and agglomeration behavior to resist chemical attack, thereby maintaining a higher survival rate. In contrast, M. aeruginosa and Aspergillus might experience significant cell death caused by substantial production of ROS. During subsequent ultrafiltration, accelerated biofouling development with a thinner biofilm layer was found for all three microorganisms exposed to NaClO, especially for M. aeruginosa and Aspergillus who formed the biofilms with remarkable stratified structures. The biofilm formed by E. coli was strongly correlated with EPS secretion, while excessive production of ROS and attachment of survived cells on membrane were considered as crucial factors controlling the biofilm development for M. aeruginosa and Aspergillus. Detailed responding mechanisms to NaClO cleaning were eventually proposed for the respective three microorganisms, which offered new insight into UF system operation for water treatment.

Humidity Diode Sensors Based on 1D Nanosized Silicon Structures

Introduction. Humidity measurement is essential in microelectronics, aerospace, biomedical, and food industries, as well as in households for climate control. Currently, various types of devices have been used as humidity sensors: capacitive, resistive, diode, gravimetric, optical structures, field-effect transistors and devices based on surface acoustic waves.Problem Statement. Today, there is a need to develop IC-compatible humidity sensors that have high sensitivityand low cost. To this end, silicon nanowires have been successfully used in resistive and capacitive humidity sensors. However, there is a lack of research on the nanowire effect on device parameters of diode-type humidity sensors.Purpose. To develop diode sensors based on silicon nanowires and to determine the effect of process parameters of synthesis and structural features of nanowires on the performance of humidity sensors.Materials and Methods. The process of sensor fabrication includes several steps: chemical cleaning of silicon wafer, synthesis of silicon nanowires using standard or modified metal-assisted chemical etching, phosphorus diffusion to create a p-n junction, front and back metallization. The surface morphology of the nanostructures has been studied by scanning electron microscopy. The humidity-sensitive characteristics have been studied with theuse of salt hygrostats.Results. It has been shown that the addition of one-dimensional silicon nanostructures to the diode-type sensor signifi cantly improves its characteristics. The rectification ratio increases from 161 to 1807, the response ups from 4.5 to 25, the sensitivity grows from 1.6 to 4.02 (%RH)–1, while the response time and recovery time are reduced from 85/90 to 25/30 s, the hysteresis value goes down from 75 to 16%, the signal deviation after cycling drops from 15to 3%, and the signal fluctuation during continuous device operation decreases from 17 to 15%.Conclusions. The results have shown that the use of a simple and cheap nanowire synthesis technology is effective to produce humidity sensors.

Experimental evaluation of atmospheric plasma treatment effects on different textures of CFRP composite for aircraft applications

This article examines the impact of Atmospheric Plasma Treatment (APL) on the chemical composition and fracture properties of various textured surfaces (tool and bag side) of carbon fiber/epoxy (CFRP) composites utilized in aircraft applications. For this purpose, parameters of atmospheric plasma (APL) surface treatment were evaluated in comparison to chemical cleaning and peel-ply applications, taking into account its effects on surface properties and adhesive bond strength. A comprehensive variety of surface characterization techniques were utilized to analyze surface modifications, including water and diiodomethane contact angle measurements for assessing surface hydrophilicity, Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR) and X-ray Photoelectron Spectroscopy (XPS) for analyzing chemical composition and functional groups, and Profilometry, Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) for evaluating surface topography and morphology. Experimental results indicated that the reduction in the contact angle following plasma treatment correlated with the elevated oxygen concentration and the presence of polar functional groups (e.g. -OH, -NH2, -NH3, C=O, O-C=O) on the composite surface. Plasma treatment, especially at low nozzle speeds, increased surface roughness on the bag side surfaces. This prevented adhesive penetration and led to gas entrapment, resulting in adhesive failure mode and reduced single lap shear strength for the bag side. In contrast, on the tool side surfaces, the plasma treatment led to a remarkable 19.7% enhancement in shear strength, highlighting its effectiveness.

La0·8Mn0·2FeO3 impregnated ceramic membrane for membrane fouling elimination via peroxymonosulfate activation

To endow SiC ceramic membranes a catalytic self-cleaning capability, a pore-functionalized SiC ceramic membrane with impregnated a perovskite-type catalyst La0·8Mn0·2FeO3 was fabricated by a urea-assisted one-step combustion method. Diffraction of X-ray (XRD), canning electronic microscopy (SEM) with an energy dispersion X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were employed to investigate the effects of the impregnating of La0·8Mn0·2FeO3 on SiC membrane pore-structure (La0·8Mn0·2FeO3-CM). The catalytic self-cleaning performance of the as-prepared membranes was assessed through peroxymonosulfate (PMS) activation under a cross-flow filtration mode. Results indicate that La0·8Mn0·2FeO3 has been successfully impregnated into the macropores of SiC membranes without pore blocking, and 92.4 % of the flux recovery rate (FRR) was achieved when the PMS concentration was 70 mM and catalytic flushing time was 45 min. Therefore, the La0·8Mn0·2FeO3 impregnated SiC membrane exhibited excellent catalytic self-cleaning property, which can effectively avoid the environmental pollution and the deterioration of membrane materials caused by chemical cleaning for membrane fouling. In addition, the radical quenching experiment and electron spin resonance (EPR) tests were conducted in the catalytic self-cleaning process, and the results suggested that the hydroxyl radical (⋅OH) and sulfate radical (SO4•‾) are simultaneously captured and ⋅OH is the dominant active species. This study embarks on a novel and environmental friendly membrane cleaning approach for irreversible fouling eliminates in diverse membrane separation applications.

Off-line chemical cleaning reduces the spatial heterogeneity of membrane fouling in full-scale membrane bioreactors: A case study

Full-scale membrane bioreactors (MBRs) are widely employed for wastewater treatment. Nevertheless, the spatial heterogeneity of membrane fouling within full-scale MBR modules has received limited attention, especially regarding the impact of off-line chemical cleaning on this spatial heterogeneity. This study, based on 192 hollow fiber samples collected from two full-scale MBRs, investigated the spatial fouling heterogeneity before and after off-line chemical cleaning. The membrane samples were categorized into different groups based on sampling locations, and statistical tools were employed to analyze spatial fouling heterogeneity. The results of foulant mass and filtration resistance of samples confirmed the presence of spatial fouling heterogeneity within the MBR modules after 5 months of operation. The off-line chemical cleaning removed organic foulants more effectively than inorganic foulants, and interestingly, it effectively reduced the spatial fouling heterogeneity. Computational fluid dynamics analysis in the cleaning tank and the chlorine concentration distribution indicated that chemical cleaning occurred without mass transfer or reaction limitations. We further offer insights into the reduction of spatial fouling heterogeneity by clarifying the fouling layer structure and the role of off-line chemical cleaning. Our findings suggest that with an appropriate cleaning strategy, the hollow fiber filtration performance can be rebalanced before a new operation cycle.

Long-term trial of a community-scale decentralized point-of-use drinking water treatment system

Two billion people lack access to safely managed drinking water services, many of these are in low/middle income countries where centralised systems are impractical. Decentralised point-of-use drinking water treatment systems offer alternative solutions in remote or resource constrained settings. The main aim of this study was to assess the long-term (3 year) operation and performance of a point-of-use drinking water treatment system (POU-DWTS). A biologically contaminated urban drainage pond was used as a water source and the quality of the produced drinking water was assessed over two independent trials. The decentralised POU-DWTS combined ultrafiltration membranes with disinfection from electrochemically generated hypochlorous acid (HOCl). The operational parameters, such as flow rate, free available chlorine and transmembrane pressure, were monitored in real-time and recorded via a remote monitoring system. Water quality from the source and treated water was assessed over two trial periods within the 3-year operational trial: an 11-week period at the start and a 22-week trial at the end. All water samples were assessed for a range of basic, chemical, microbiological and metal water quality parameters. The results demonstrate that the decentralised POU-DWTS is capable of continuously producing high quality drinking water when HOCl is continuously used to dose water prior to entering the ultrafiltration [UF] membranes. Over the 3-year operational study, the continuous dosing of HOCl pre-UF membranes resulted in stable permeability, indicating no occurrences of irreversible biofouling within the UF membranes and that good membrane ‘health’ was maintained throughout. As such, there was no need to replace the UF membranes nor undertake acid/alkaline chemical cleans at any point throughput the three-year study. The POU-DWTS continuously produced high quality drinking water, resulting in 6453 m3 of drinking water produced over the trial period, that met international water quality standards, at a community scale within the location studied.

Effectiveness biduri leaf extract (Calotropis gigantea) as a denture cleanser in acrylic immersion against the growth of Candida albicans: an experimental laboratory

ABSTRACTIntroduction: The high number of cases of tooth loss in Indonesia has led to the emergence of dentures. Dentures not appropriately kept clean can trigger cases of denture stomatitis due to Candida albicans. C. albicans is often detected on denture plates and causes denture stomatitis. Cleaning the dentures can prevent denture stomatitis, and chemical cleaning often uses synthetic materials such as alkaline peroxide. However, alkaline peroxide can cause side effects in the form of increased porosity on the surface of the acrylic plate, so an alternative natural ingredient, namely biduri leaves (Calotropis gigantea), is needed because it has various active compounds such as alkaloids, flavonoids, phenols, saponins, terpenoids and tannins which have antifungal effects. This study aimed to determine the effective inhibitory power of biduri leaf extract as a denture cleanser in acrylic immersion against the growth of C. albicans. Methods: Biduri leaves were extracted using the maceration method with 70% ethanol solvent to produce varying concentrations of 20, 30, 40, and 50%. The sample used in this research was an acrylic plate measuring 10x10x1 mm, soaked in artificial sterile saliva for 1 hour, then soaked in each sample group for 8 hours, after that it was placed in 10 ml of Sabouraud Dextrose Broth (SDB) media, and vibrated for 30 seconds using a mixing vortex, spreading 0,1ml SDB on Saboraud Dextrose Agar (SDA) and incubated for 48 hours. The growth of C. albicans was observed and counted using the colony counting method. Result: This research showed an inhibitory power of biduri leaf extract in concentrations of 20, 30, 40, and 50% on the growth of C. albicans, with a concentration of 50%, having the most significant inhibitory power. Conclusion: Biduri leaf extract as a denture cleanser has an inhibitory power on the growth of C. albicans.KEYWORDS Biduri leaves, Calotropis gigantea, heat cured acrylic, Candida albicans

Су беттерін және кәсіпорындардың ағынды суларын биоремедиациялау мәселесі бойынша

The problem of environmental protection from pollution by oil, petroleum products and industrial wastewater, as well as their disposal, is becoming increasingly acute due to the limited possibilities, and sometimes environmental insecurity, of using mechanical, physical and chemical cleaning methods for these purposes. In this regard, the possibility of using microorganisms capable of growing and displaying active biochemical activity in an environment with a high content of oil, petroleum products and industrial waste capable of biodegradation of these substances for purification purposes is relevant. The article analyzes the existing modern technologies for cleaning water surfaces and wastewater of industrial enterprises from oil and petroleum products pollution. Indicates the urgent need for the introduction of modern cleaning technologies, as well as the improvement of existing technologies. The article proposes modern methods of biological purification of water surfaces, bioremediation is a set of measures for cleaning soils and waters using the metabolic potential of biological objects. The use of microorganisms, insects, plants, algae, fungi is considered one of the most environmentally friendly and cost-effective technologies for cleaning at this stage

CONSERVATION OF A PAINTED WOODEN COFFIN AT DAHSHUR ARCHAEOLOGICAL AREA

This paper aims to document the conservation processes of a polychrome wooden coffin in the Dahshur archaeological area dating back to the late period. The exterior part of the coffin is decorated with a painted layer. Visual observation, 2D Program, and Optical Microscopy (OM) were used. wood identification. The coffin was in a bad condition. It was covered with a thick layer of dust, losing parts of the painted and gesso layers, as well as other parts of these layers, were lost. Some parts were missing from the head area of the lid coffin. The conservation processes of the wooden coffin included mechanical and chemical cleaning, reattachment of the separated parts of the ground layer and painted layers, filling the edge of the painted layer, and consolidating the painted layer. The conservation process included mechanical cleaning using soft brushes, chemical cleaning using ethyl alcohol and distilled water for painting, stabilization of the separated gesso layer using Paraloid B72, filling cracks of the gesso layers using glass microballoon with Paraloid B72 and consolidating the painted layer with calcium oxide nanoparticles with Klucel G (hydroxypropyl cellulose) 0. 5%