pH Levels Research Articles

A Comparative Study on the Stability and Coagulation Removal of Aged vs. Non-Aged Nanoplastics in Surface Water

Nanoplastics (NPs) are released into surface water due to the widespread use of plastics, undergoing aging from environmental and human factors that alter their physical and chemical characteristics. However, detecting NPs remains challenging, resulting in limited research on their behavior in surface water and their removal efficiency by drinking water treatment. This study utilizes palladium-doped polystyrene nanoplastics (PSNPs) as tracers to enable precise detection and quantification through ICP-MS, thereby overcoming the limitations of conventional detection methods. PSNPs are aged using solar irradiation and ozone to simulate both natural and artificial aging processes, affecting the physical and chemical properties of NPs, which in turn influence their behavior in water treatment systems. Moreover, the study investigates the impact of various coagulation conditions, including different coagulants (AlCl3 and PACl), pH levels (4-9), and humic acid (HA) concentrations (0-10mg/L), on the of both aged and nonaged NPs. The results demonstrate solar aging triggers significant morphological changes in PSNPs, while ozone aging induces more oxygen functional groups on PSNPs (CIozone=20.99; CIsolar=0.70), increasing sensitivity to HA concentrations and resulting in reduced removal efficiencies for ozone aged PSNPs by AlCl3 (68.68%) and PACl (74.74%). In addition, PACl achieves higher PSNPs removal efficiencies (REmin=88.59%) than that of AlCl3 (REmin=85.57%) under varied pH levels. This research fills a gap in understanding aged NPs behavior in surface water and offers practical solutions for optimizing coagulation for NPs removal, enhancing our ability to predict NPs environmental fate and manage NPs pollution to ensure drinking water safety.

Dual-mode sensing with L-phenylalanine-stabilized copper nanoparticles: Real-time detection of Fe3+ and pH monitoring

Water-soluble copper nanoparticles stabilized with L-Phenylalanine (L-PCuNPs) were synthesized and characterized for dual sensing of Fe3+ ions and pH levels. These nanoparticles exhibited green fluorescence at 486 nm, which was quenched by Fe3+ ions, resulting in a color shift from colorless to yellow. Additionally, L-PCuNPs showed pH responsiveness, with increased fluorescence intensity as the pH shifted from acidic to basic. Their effectiveness was further validated through analysis of environmental, biological, and food samples, demonstrating their practical utility across diverse real-world applications.

Exploring the feasibility of using fluidized bed homogeneous crystallization technology to recover sulfate ions from briny water as calcium sulfate pellets

The increasing salinity of water sources poses significant operational and environmental challenges, highlighting the importance of developing efficient methods for recovering [SO42−] ions from briny wastewater. In this study, the potential of fluidized bed homogeneous crystallization (FBHC) technology for recovering [SO42−] ions from briny water is explored. FBHC is an innovative technique that enhances scalability and separation efficiency by promoting the growth of crystalline particles in a fluidized state. To achieve maximum [SO42−] recovery and maintain stable fluidized bed conditions, a pH of 8 is recommended. A removal ratio (RR) of 71 % was recorded at a [SO42−] concentration of 0.14 M. Various [SO42−] concentrations exhibited a molar ratio (MR) of [Ca2+]/[SO42−] = 1.5. Smaller particles, which are more soluble and exhibit less nucleation, are typically formed under conditions with lower pH and [Ca2+] levels. Intermediate-sized particles are favored at neutral to slightly alkaline pH levels and near-stoichiometric [Ca2+]/[SO42−] MR. Greater calcium content and higher pH values promote the development and agglomeration of larger particles, with 50 % of the particles exceeding an average size of 0.38 mm. In the XPS study of CaSO4 crystals (gypsum), the Ca 2p1/2 and Ca 2p3/2 peaks are observed at binding energies of 351.5 eV and 347.7 eV, respectively. Gypsum is identifiable due to the presence of clear and distinct peaks in XRD patterns. SEM analysis reveals the coexistence of amorphous patches and tiny crystalline domains on the surface. These gypsum crystals resemble stacked needle-like structures accompanied by small, powdery crystals. In an acidic environment, the primary phase is CaSO4·2H2O, which generates well-formed, elongated, or tabular crystals that are characteristic of gypsum. The FBHC process, characterized by a high crystallization ratio (CR = 68 %) and the recovery of crystal pellets (>0.3 mm), significantly reduces sludge production compared to traditional chemical precipitation methods. Its cost-effectiveness and recoverability make FBHC a promising technology for the recovery of sulfate ions from briny wastewater.

Seawater boosts oxytetracycline (OTC) residues in struvite via hydroxyapatite (HAP) and dissolved organic matter (DOM) co-precipitation.

Seawater, as an alternative magnesium (Mg) source, has the potential to improve the overall economic and environmental footprint of struvite production compared to the use of pure Mg salts. However, the presence of other ions in seawater may affect the migration of tetracyclines (TCs), commonly found in wastewater, potentially reducing the quality of the recovered product, and posing environmental risks. But these effect has not been illustrated before. This study investigated the impact of seawater on oxytetracycline (OTC) migration during struvite recovery from swine wastewater. Under varying pH levels and Mg/P molar ratios, the OTC content in recovered struvite was ranged from 19 to 103μg/g, which was 6 to 43μg/g when using MgCl2 as Mg source. The key factor influencing OTC content was identified as Ca2+ in seawater. The co-precipitation of hydroxyapatite (HAP) and the incorporation of dissolved organic matter (DOM) were the primary reasons for increased OTC content. Interactions between Ca2+ on HAP surfaces and the carbonyl oxygen of OTC, along with ternary complex formations involving Ca2+, DOM, and OTC, facilitated OTC migration through adsorption onto struvite. Notably, increasing the Mg/P molar ratio reduced OTC enrichment due to the competition between Ca2+ and Mg2+. Density functional theory (DFT) calculations supported these interfacial interactions. These findings enhanced the understanding of antibiotic migration during phosphorus (P) recovery using seawater as alternative Mg source and suggested solutions for reducing P recovery contamination in the future.

Coagulative removal of polyethylene microplastics using polyaluminum chloride in conjunction with laminarin

As emerging pollutants in water, microplastics pose potential risks to aquatic organisms and human health. Previous studies have shown that traditional metal coagulants are effective in removing microplastics from water, but they come with drawbacks such as high chemical dosage and metal residues. Therefore, it is important to explore more efficient coagulation systems. This study utilized laminarin (LA) as a coagulant aid in combination with polyaluminum chloride (PAC) to investigate its enhanced coagulation performance on polyethylene microplastics in water. The performance of coagulation systems for the removal of microplastics was evaluated for different agent dosages, pH, anion and HA content. Experimental results demonstrated that the compounded system (PAC-LA) significantly improved the removal efficiency of PE microplastics compared to the single PAC system, achieving a removal rate of 91.5% while reducing the dosage of PAC. The enhanced coagulation mechanism of LA was analyzed using various techniques including scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and zeta potential analysis. The results indicated that charge neutralization and sweep flocculation were the primary coagulation mechanisms in the presence of PAC alone. The effect of charge neutralization and adsorption was strengthened with the introduction of LA. The coagulation system of PAC-LA showed higher removal rates of PE microplastics under different environmental conditions such as varying pH levels, co-existing anions, and humic acid, suggesting a promising application for microplastic control in water.

Genomic signals of adaptation to a natural CO2 gradient over a striking microgeographic scale

Our study explores genomic signs of adaptation in A. lixula to different water pH conditions. To achieve this, we analysed the genomics variation of A. lixula individuals living across a natural pH gradient in Canary Islands, Spain. We use a 2b-RADseq protocol with 74 samples from sites with varying pH levels (from 7.3 to 7.9 during low tide) and included a control site. We identified 14,883 SNPs, with 432 identified as candidate SNPs under selection to pH variations through redundancy analysis. While all SNPs indicated genomic homogeneity, the 432 candidate SNPs under selection displayed genomic differences among sites and along the pH gradient. Out of these 432 loci, 17 were annotated using published A. lixula transcriptomes, involved in biological functions such as growth. Therefore, our findings suggest local adaptation in A. lixula populations to acidification in CO2 vents, even over short distances of 75 m, underscoring their potential resistance to future Ocean Acidification.

Development and characterization of advanced nano-coating with CeO₂, Al₂O₃, ZnO, and TiO₂ nanoparticles fWor enhanced durability and corrosion resistance

This study introduces an innovative sol-gel nano-coating designed to address silica scaling and corrosion in hydrothermal and high-stimulation environments. By incorporating CeO₂, Al₂O₃, ZnO, and TiO₂ nanoparticles into a polymer matrix through precise sonication techniques, the coating achieves uniform dispersion and enhanced functional performance. The meticulous characterization of nanoparticle integration optimizes mechanical strength, thermal stability, and chemical resistance. Applied via a directional supplying device, the nano-coating is mechanically deposited onto the cemented walls of wells, providing robust protection against scaling and corrosion across diverse conditions, including varying temperatures and pH levels. Laboratory testing demonstrates significant reductions in silica scaling and corrosion rates, confirming the coating's efficacy in maintaining production efficiency in both hydrothermal projects and fracking operations. This paper details the synthesis process and molecular chemistry involved in nanoparticle integration, alongside the resultant structural properties of the coating. Thermogravimetric analysis (TGA) assesses thermal stability, while kinetic models such as Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) evaluate activation energy without assuming specific reaction models. The findings highlight the potential of this advanced nano-coating as a robust solution for enhancing operational longevity and efficiency in challenging industrial applications.

Effects of Mineral and Almond Oil Administration on Transepidermal Water Loss and Skin Acidity in Chronic Renal Failure Patients Undergoing Hemodialysis

Introduction: Patients undergoing hemodialysis experience decreased moisture content in the dermis due to fluid transfer during the dialysis process, causing xerosis, pruritus, and damage to the skin barrier. Almond oil and mineral oil are well-known moisturizers used in skin care products. Objectives: To compare the effect of almond oil with mineral oil on transepidermal water loss (TEWL) and skin acidity in hemodialyzed chronic renal failure (CRF) patients. Methods: An experimental study was conducted on patients with chronic renal failure (CRF) undergoing hemodialysis at Dr. Moewardi Hospital in Indonesia. The study involved applying mineral and almond oils twice daily on the right and left forearms for four weeks. We measured TEWL and pH levels before and after the treatment. Results: There is a significant difference in TEWL between before and after mineral oil application (p=0.036), but not in the almond oil arm (p=0.394). Subsequently, the change of TEWL value significantly differed between mineral oil and almond oil (p=0.043). However, the effects of mineral oil and almond oil on pH were insignificant (p=0.574 and 0.268, respectively). Conclusion: After undergoing hemodialysis, CRF patients experienced a statistically significant reduction in transepidermal water loss (TEWL) when using mineral oil compared to both baseline and almond oil.

Comparison of Effects between Nasal Bi-Level Positive Airway Pressure and Nasal Synchronized Intermittent Mandatory Ventilation in Neonatal Respiratory Distress Syndrome

Aims/Background Neonatal respiratory distress syndrome (NRDS) is characterized by progressive aggravation and rapid progression of respiratory distress, with a high incidence rate among premature infants. If left untreated, NRDS results in a poor prognosis. In recent years, various respiratory support modalities have received extensive attention in clinical practice. The therapeutic effect of different respiratory support modes on NRDS has gradually become the focus of clinical research. The aim of this study was to explore the therapeutic effects of nasal bi-level positive airway pressure (nBiPAP) and nasal synchronized intermittent mandatory ventilation (nSIMV) on NRDS. Methods This study retrospectively analyzed the clinical data of 157 newborns with NRDS in the Mudanjiang Medical University Affiliated Second Hospital from January 2021 to December 2023, finally including 153 cases after excluding 4 cases with missing clinical data. According to the non-invasive ventilation method, these newborns were categorized into a nBiPAP group (receiving nBiPAP treatment, n = 77) and an nSIMV group (receiving nSIMV treatment, n = 76). The blood gas indices, using time of ventilator, hospitalization time, therapeutic effects, and incidence of complications were compared between the two groups. Results The PaCO2, PaO2, and pH levels in the nBiPAP group were basically consistent with those in the nSIMV group before and after treatment (p > 0.05). The use time of ventilator, hospitalization time, and therapeutic effects in the nBiPAP group were similar to those in the nSIMV group (p > 0.05). Additionally, both groups demonstrated no significant difference in the incidence of complications such as intraventricular hemorrhage, apnea, necrotizing enterocolitis, and feeding intolerance (p > 0.05). The incidence rates of ventilator-associated lung injury and neonatal bronchopulmonary dysplasia in the nBiPAP group were lower than those in the nSIMV group, with a significant difference (p < 0.05). Conclusion Both nBiPAP and nSIMV have shown good effects in treating NRDS, with nBiPAP showing a significant advantage in reducing the incidence rates of complications such as ventilator-associated lung injury and neonatal bronchopulmonary dysplasia.

Investigating pH Swings at Denver Water

Denver Water used a variety of water treatment and chemistry approaches to resolve fluctuating pH levels and meet its Lead and Copper Rule variance requirements.

Growth dynamics, antagonistic activity and acid production of Lactiplantibacillus (=Lactobacillus) plantarum KT-L18/1 and Bacillus subtilis BPT-B1 inoculants in alfalfa silage

Aim. To study growth dynamics, antagonistic activity and acid formation of two inoculant strains, Lactiplantibacillus (=Lactobacillus) plantarum КТ-L18/1 and Ваcillus subtilis ВРТ-В1, that were introduced into alfalfa silage, up to 30 days of fermentation. Methods. A streptomycin-resistant strain of both above-mentioned organisms, obtained in earlier research, was used to achieve the research aims. Alfalfa was artificially wilted and dried to a dry matter content of 39–40 %. Fermentation was conducted under anaerobic conditions in polyethylene bags. Inoculant was added at a concentration of 108 CFU/kg alfalfa. The resulting 12 × 3 = 36 bags were kept at room temperature in a dark place for 30 days. At each examination date one sample per treatment was used and examined after cultivation of the two inoculants on elective De Man-Rogosa-Sharpe (MRS) agar and meat infusion agar (MIA), containing streptomycin. The antibacterial (ABA) and antifungal activities (AFA) were studied by the agar diffusion method. Results. After 30 days of ensiling the alfalfa samples, L. plantarum КТ-L18/1str and В. subtilis ВРТ-В1str were still present at levels of 9.2 lg CFU/g and 6.9 lg CFU/g respectively. In the natural population of LAB, L. plantarum КТ-L18/1str had a dominant position. After 30 days of the alfalfa fermentation L. plantarum КТ-L18/1str and В. subtilis ВРТ-В1str maintained ABA and AFA to the PPB strains (S. aureus, P. aeruginosa, S. typhimurium) and fungal strains tested. However, the antagonistic activities of the two inoculant strains decreased during the fermentation, for L. plantarum КТ-L18/1str from 7–21 %, and for В. subtilis ВРТ-В1str from 16–21 %. Compared to the uninoculated control treatment, the inoculated silage treatments had a lower pH level (5.2–5.3), an increased number of lactic acid bacteria (LAB) (by 32 %), and clostridia were no longer detected. The inoculation impacted fungi down to a level of 102–103 CFU/g that can ensure the aerobic stability of the feed. Conclusions. The inoculant strains and L. plantarum КТ-L18/1str and Ваcillus subtilis ВРТ-В1str showed a high competitiveness with background microbiota in an ensiling experiment with alfalfa. The antagonistic activity of the two strains to PPB after fermentation was preserved at a high level, albeit with a decrease of 7–21 %. Ваcillus subtilis ВРТ-В1str kept its AFA against all three fungal strains tested during the 30 days of fermentation. For L. plantarum КТ-L18/1str this was true for a strain of the Penicillium chrysogenum only. The inoculation of and L. plantarum КТ-L18/1str and Ваcillus subtilis ВРТ-В1str caused a decrease in pH of 8–9 % at the end of the fermentation period, an accumulation of LAB with 32 %, and the inhibition of the growth of clostridia up to undetectability in the fermented alfalfa. For both inoculants, compared to uninoculated control variant, fungi decreased down to 102–103 CFU/g of the feed, which can ensure the aerobic stability of the feed.

An Assessment of Drinking Water Quality in the Chief Albert Luthuli Local Municipality, South Africa: A Case Study of the Elukwatini Water Supply Scheme

This study analysed the water quality of 156 samples collected from 13 different points within the Chief Albert Luthuli Local Municipality between January and December 2021, focusing on compliance with the South African National Standard 241 (SANS 241). Microbiological assessments revealed widespread contamination, with heterotrophic plate counts (HPCs) exceeding the recommended range in nearly all samples. The median HPC levels were particularly concerning, with the untreated source (RE000) exhibiting a median of 2555 CFU/mL. Total coliforms and Escherichia coli were present at alarming levels, indicating significant faecal contamination; the highest total coliform count, 2420 CFU/100 mL, was recorded at RE000. Physically, while all samples complied with electrical conductivity standards (0–70 µS/cm), turbidity levels showed variability, with nine samples exceeding the acceptable threshold of 1 NTU. The highest turbidity, 7.55 NTU, was recorded at the untreated source (RE000). Chemically, pH levels fell within safe ranges (6.0–9.0), with all samples being compliant with standards. However, only one sample (E001) met the free chlorine standard of 0.3–0.6 mg/L, suggesting inadequate disinfection practices. The untreated source was classified as ‘Unsuitable for drinking’ (WQI = 207.27). These findings highlight the critical need for enhanced monitoring and remediation strategies to improve drinking water safety in the region.

Effect of Various pH Levels on the Growth and Sporulation of Trichoderma viride Isolates and Assessing their Antagonistic Activity against Soil-borne Pathogens

Trichoderma viride strains, which are filamentous fungi commonly found in soil, possess the ability to parasitize various fungi harmful to plants. In this study, ten strains of T. viride were isolated from different locations in Uttar Pradesh, India, and examined for their cultural, physiological, morphological, and antagonistic characteristics against soil-borne pathogens. The T. viride isolates were assessed at different pH levels for their growth, sporulation, and antagonistic efficacy under in vitro conditions using the dual culture technique against five major soil-borne pathogens that cause significant diseases in cereal and pulse crops. Among the ten isolates tested, the 49CP isolate from Sultanpur exhibited the maximum growth and sporulation at a pH of 6.5 as well as the highest inhibition percentages of mycelial growth in the pathogens: 63.23% against Fusarium oxysporum f. sp. ciceri, 65.85% against Sclerotium rolfsii, 53.33% against Sclerotinia sclerotiorum, 53.84% against Pythium sp., and 48.00% against Rhizoctonia bataticola. Trichoderma viride is also recognized for its effectiveness as a biocontrol agent against soil-borne pathogens, which are responsible for significant crop losses.

Adaptive Agronomic Strategies for Enhancing Cereal Yield Resilience Under Changing Climate in Poland

Climate-driven changes have raised concerns about their long-term impacts on the yield resilience of cereal crops. This issue is critical in Poland as it affects major cereal crops like winter triticale, spring wheat, winter wheat, spring barley, and winter barley. This study investigates how soil nutrient profiles, fertilization practices, and crop management conditions influence the yield resilience of key cereal crops over a thirteen-year period (2009–2022) in the context of changing climate expressed as varying Climatic Water Balance. Data from 47 locations provided by the Research Centre for Cultivar Testing were analyzed to assess the combined effects of agronomic practices and climate-related water availability on crop performance. Yield outcomes under moderate and enhanced management practices were contrasted using Classification and Regression Trees to evaluate the relationships between yield variations and agronomic factors, including soil pH, nitrogen, phosphorus, potassium fertilization, and levels of phosphorus, potassium, and magnesium in the soil. The study found a downward trend in Climatic Water Balance, highlighting the increasing influence of climate change on regional water resources. Crop yields responded positively to increased agricultural inputs, especially nitrogen. Optimal soil pH and medium phosphorus levels were identified as crucial for maximizing yield. The findings underscore the importance of tailored nutrient management and adaptive strategies to mitigate the adverse effects of climate variability on cereal production. The results provide insights for field crop research and practical approaches to sustain cereal production in changing climatic conditions.

Antibacterial efficacy of berry juices against Bacillus cereus relative to their phytochemical composition and antioxidant properties.

Ensuring the safety and stability of minimally processed foods using natural preservatives is of great scientific and commercial interest in modern biotechnology. Berry juice supplementation is increasingly recognized within this field. This study investigated the effectiveness of juices from four berry species Aronia melanocarpa, Ribes nigrum, Vaccinium macrocarpon, and Sambucus nigra, against the food pathogen Bacillus cereus. Overall, the antibacterial potency of juice supplements (up to 10% v/v in tryptic soy broth) followed the order of chokeberry > blackcurrant > cranberry > elderberry, with the latter showing no inhibitory effects. Notably, chokeberry and elderberry juices presented lower acidity and significantly greater phenolic contents (p < 0.05) than blackcurrant and cranberry juices did, suggesting that B. cereus susceptibility is not strictly dependent upon low extracellular pH or elevated anthocyanin levels. Instead, it is inferred to correlate with pro-oxidative effects induced directly at the intracellular level. Accordingly, this paper discusses the antioxidative, acidic, and lipophilic attributes of juices and their constituent fractions, including anthocyanins, to elucidate their biopreservative potential. The results of this study increase our understanding of the antibacterial susceptibility of B. cereus.

Characterization and genomic analysis of bacteriophage VT223 infecting Salmonella enterica subsp enterica serovar Enteritidis

Bacteriophages are increasingly considered a promising alternative to antibiotics for treating bacterial infections. For the bacteriophage VT223, which was isolated from shrimp pond wastewater, a thorough analysis of its host range, morphology, and genome sequencing was performed. Bacteriophage VT223 exhibits high specificity towards Salmonella spp. strains, highlighting its potential as a targeted therapy for Salmonella spp. infections. Electron microscopy revealed that VT223 belongs to the Caudoviricetes, Jerseyvirus, with an icosahedral head and a non-contractile tail. This phage can infect three species within the Salmonella spp., with a short latent period of 30 minutes and a burst size of 446 PFU/infected cells. Genome sequencing revealed a 43,062 bp double-stranded DNA genome with a GC content of 49.6%. Stability tests showed that VT223 is stable over various temperatures and pH levels. Biofilm formation inhibition testing revealed that phage VT223 reduced biofilm by up to 57.7% after a four-hour treatment. In vitro studies demonstrated the lytic activity of VT223 against Salmonella enterica subsp enterica serovar Enteritidis ATCC 49223. These findings provide valuable insights into the biological properties of bacteriophage VT223 and its potential use as a biocontrol agent in livestock production and aquaculture to combat bacterial growth. Published on November 15, 2024

Comparison of Luting Cement Solubility: A Narrative Review

Background: Dental restoration success relies on the physical properties of luting cements. Luting cements fill the space between teeth and the restoration, provide retention and protection from occlusal forces, and act as a barrier to microleakages in the oral environment. Objective: This review aims to evaluate and compare the solubility of the three most used dental luting cements: glass ionomer (GI), resin-modified glass ionomer (RMGI), and resin cement (RC). Methods: The studies selected for review compared the solubilities of combinations of GI, RMGI, and RC in solutions with different pH levels to replicate acidic oral pH. Results: A review of the studies concluded that resin cement had the overall lowest degree of solubility at all pH values and all storage periods, followed by RMGI and GI cement. Conclusion: The success of the restoration is dependent upon the choice of luting cement. The results of the studies reviewed show that all dental luting cements showed some degree of dissolution. Resin cement overall demonstrated the least amount of solubility, followed by RMGI and GI cement.

Factors Influencing the Protective Effect of Salivary Pellicle Against Dental Erosion: A Concise Review

Dental erosion is the irreversible loss of dental hard tissue caused by chemical processes without bacteria involvement. Dental erosion prevalence has increased due to extensive consumption of acidic foods and drinks or suffering from gastrointestinal diseases. Salivary pellicle acts as a physical barrier that impedes direct contact between the tooth surface and erosive acids. Furthermore, it is a selectively permeable membrane that controls the diffusion of erosive acids to the tooth surface. Therefore, salivary pellicle can protect the tooth surface from erosive demineralization. The protective effect of salivary pellicle depends on the intraoral location, tooth substrate, thickness, formation time, composition, the pH level of erosive acids, and exposure time. This concise review aimed to provide an overview on factors influencing the protective effect of salivary pellicle against dental erosion.

In vivo biodegradation rates of domestic membranes for guided tissue regeneration

Background: Experimental research is required to provide guidelines for the use of domestic biodegradable membranes. Aim: To assess the swelling index and biodegradation rate of barrier membranes (non-collagen and collagen) for guided tissue regeneration in vitro, as well as their biocompatibility in vivo. Materials and Methods: The swelling index of two types of membranes was assessed after 24 h of exposure to phosphate-buffered saline (PBS) at different pH levels (6.50 and 7.37). The spontaneous degradation rate of the two types of membranes was assessed; changes in their weight following exposure to PBS at different pH levels (6.50 and 7.37) were measured at predetermined time points. Moreover, the biocompatibility of two membrane samples following subcutaneous implantation in B/D male mice was assessed. Results: The swelling index of non-collagen membranes was higher at neutral pH compared to acidic pH: 7.7 for pH 7.37 vs 7.2 for pH 6.50. For collagen membranes, the swelling index was pH-independent. There were no differences in membrane weight loss following exposure to PBS at pH 6.5 during 8 weeks. During the first two weeks, collagen membranes had a higher resorption rate at pH 7.37 than non-collagen membranes. Following subcutaneous implantation of both membranes, histopathological specimens collected two weeks after surgery revealed the formation of foreign body granulomas with well-defined boundaries around the implants. Macrophages, monocytes, single giant cells of foreign bodies, and Pirogov–Langhans giant cells were detected, with the number gradually increasing over time. Conclusion: Non-collagen membranes had a larger swelling index than collagen membranes, which depended on pH. At pH 7.37, collagen membranes had a higher resorption rate during the first two weeks compared to non-collagen membranes. In vitro weight loss after 8 weeks was 20–30% for both membranes, regardless of pH. Subcutaneous implantation in mice confirmed the biocompatibility of the membranes. The biodegradation rate of non-collagen membranes was higher than that of collagen membranes.

From Waste to Wealth: Entrepreneurial Ventures in Chitosan Extraction for Environmental Sustainability

The degradation of water quality in the environment can be attributed to the discharge of wastewater from shrimp ponds. Conversely, solid waste in the form of shrimp shells presents an entrepreneurial opportunity through the extraction of chitosan, a substance with the potential to enhance water quality while contributing to environmental sustainability. Sampling for this study was conducted at the Vannamei Nusantara Gemilang pond, located in Tambakrejo Village, Malang Regency, East Java. The research employed an experimental methodology with a quantitative approach, supplemented by a literature review. Various doses of chitosan solutions were tested on shrimp pond wastewater. The optimal results were obtained at a dosage of 80 mg/L, significantly outperforming the untreated water. The test outcomes for the 80 mg/L dosage included: BOD (Biochemical Oxygen Demand) at 4.62 mg/L, Nitrite concentration at 0.045 mg/L, turbidity at 3.55 NTU (Nephelometric Turbidity Units), TSS (Total Suspended Solids) at 14.6 mg/L, TDS (Total Dissolved Solids) at 2974 mg/L, pH level at 6.31, and temperature at 31.40°C. Notably, the Total Dissolved Solids (TDS) levels did not meet quality standards, highlighting the need for further process optimization. These findings emphasize the potential of chitosan extraction as a sustainable solution, while also underscoring the importance of continued research into the economic feasibility of this waste-to-wealth approach. Further studies are necessary to refine the wastewater treatment process, quantify the economic benefits, and ensure the long-term viability of this entrepreneurial venture in environmental sustainability.