Alkaline Range Research Articles

Analysis and Quantification of Selected Heavy Metals and Paraphenylenediamine in Commercially Available Herbal Black Hair Dyes in Sri Lanka

Currently, the use of henna-based herbal black hair dyes is widespread in the community. However, it is important to note that these dyes cannot be classified as completely natural due to the addition of various ingredients to enhance their effectiveness. Most black hair dyes use paraphenylenediamine (PPD) to get a black hue, however, PPD is widely recognized as a contact sensitizer. The toxicity of heavy metals is also prevalent in the cosmetics sector. These metallic elements can permeate the skin and provide widespread exposure throughout the body. Hair dye requires an alkaline pH value because of reactions that occur during the dyeing process, which is incompatible with scalp pH. The varying concentrations of these chemicals and their frequency of usage can result in diverse health issues. The present research implemented High-Performance Liquid Chromatography and Atomic Absorption Spectrometry to quantify the concentrations of PPD and heavy metals (Pb, Cd, and Fe) in seven frequently used brands in Sri Lanka. The lead content in the examined samples exhibited variability, ranging from 0.04 ± 0.01 ppm to 0.28 ± 0.14 ppm. However, all the samples remained below the allowed level of 2 ppm according to the BVL standard. Regarding Cd, certain examined materials surpassed the acceptable thresholds, while others did not and varied between 0 ppm and 2.33 ± 1.92 ppm. Iron was found at a significantly higher concentration compared to the other two heavy metals. A significant quantity of PPD was detected, exceeding the allowable threshold of 6% according to the European Union legislation. All the samples that were analyzed had a pH value within the alkaline range. The study indicates that herbal dyes generated from natural materials may contain harmful compounds, such as a high concentration of PPD in herbal black hair color potentially inducing sensitization.

ATM kinase phosphorylates Ser15 of p53 in a pH-dependent manner

The phosphorylation of Ser15 in the transactivation domain (TAD) of the tumor suppressor protein 53 (p53) by ataxia-telangiectasia mutated (ATM) kinase is a crucial step in the tumor suppressor function of p53. An understanding of the factors that affect the rate of Ser15 phosphorylation may provide new strategies for the manipulation of the ATM-p53 pathway in cancer therapy. In this study, the effect of electrostatic interactions between ATM and p53 was investigated by measuring the phosphorylation of Ser15 at varying pH ranges from 5 to 9. To achieve this, two different kinase assay methods were utilized: the ELISA technique, which directly quantifies the phosphorylated Ser15, and the Universal Kinase Assay, which assesses the formation of ADP. The results revealed that Ser15 phosphorylation was pH-dependent, with higher phosphorylation rates observed in the alkaline range. To ascertain whether the lower phosphorylation rates observed at acidic pH were due to protein denaturation, a pH-dependent solubility profile was generated using the CamSol server. The obtained results demonstrated comparable solubility rates within the pH range of the kinase assays performed. Furthermore, the significance of negatively charged residues in TAD1-39 was evaluated by substituting Asp and Glu residues with hydrophobic and uncharged hydrophilic residues in TAD1-39 using ChimeraX and subsequently comparing their interactions with the ATM using the protein-protein docking server HADDOCK2.4. The results of the docking simulations indicated that the alteration of negatively charged residues with uncharged ones resulted in a reduction in the efficiency of the interaction between the ATM and TAD1-39. In conclusion, it can be stated that electrostatic interactions between the ATM and TAD are important for optimal Ser15 phosphorylation.

Development of a Superhydrophobic Protection Mechanism and Coating Materials for Cement Concrete Surfaces.

In order to further enhance the erosion resistance of cement concrete pavement materials, this study constructed an apparent rough hydrophobic structure layer by spraying a micro-nano substrate coating on the surface layer of the cement concrete pavement. This was followed by a secondary spray of a hydroxy-silicone oil-modified epoxy resin and a low surface energy-modified substance paste, which combine to form a superhydrophobic coating. The hydrophobic mechanism of the coating was then analysed. Firstly, the effects of different types and ratios of micro-nano substrates on the apparent morphology and hydrophobic performance of the rough structure layer were explored through contact angle testing and scanning electron microscopy (SEM). Subsequently, Fourier transform infrared spectroscopy and permeation gel chromatography were employed to ascertain the optimal modification ratio, temperature, and reaction mechanism of hydroxy-silicone oil with E51 type epoxy resin. Additionally, the mechanical properties of the modified epoxy resin-low surface energy-modified substance paste were evaluated through tensile tests. Finally, the erosion resistance of the superhydrophobic coating was tested under a range of conditions, including acidic, alkaline, de-icer, UV ageing, freeze-thaw cycles and wet wheel wear. The results demonstrate that relying solely on the rough structure of the concrete surface makes it challenging to achieve superhydrophobic performance. A rough structure layer constructed with diamond micropowder and hydrophobic nano-silica is less prone to cracking and can form more "air chamber" structures on the surface, with better wear resistance and hydrophobic performance. The ring-opening reaction products that occur during the preparation of modified epoxy resin will severely affect its mechanical strength after curing. Controlling the reaction temperature and reactant ratio can effectively push the modification reaction of epoxy resin through dehydration condensation, which produces more grafted polymer. It is noteworthy that the grafted polymer content is positively correlated with the hydrophobicity of the modified epoxy resin. The superhydrophobic coating exhibited enhanced erosion resistance (based on hydrochloric acid), UV ageing resistance, abrasion resistance, and freeze-thaw damage resistance to de-icers by 19.41%, 18.36%, 43.17% and 87.47%, respectively, in comparison to the conventional silane-based surface treatment.

Study on gastric digestion behavior of phytase-treated soybean protein: A semi-dynamic digestion method

The digestive characteristics of plant proteins are crucial for their nutritional value and utilization efficiency. In this study, an in vitro semi-dynamic digestion model was employed to investigate the gastric digestion process of soybean protein after treatment with phytase. The results found that phytase treatment reduced the phytate content in soybean proteins (22.83 ± 0.09 to 8.72 ± 0.07 mg/g), shifted its isoelectric point towards the alkaline range by 1 pH unit, and significantly improved its solubility at pH 4.0. Particularly for protein sample treated with phytase after acid precipitation, the formation of aggregates during digestion was weakened, resulting in a significantly higher digestion rate compared to untreated SPI, with digestion being at least 15 min faster than SPI. This study provides a strategy for preparing soybean protein with faster digestion and weaker clot-forming ability during digestion, which offers insights for the application of soybean protein in clinical nutrition products and specialized medical foods.

Alkaline range pH sensor based on chitosan hydrogel: A novel approach to pH sensing

Monitoring of pH under extreme alkaline range is still a challenge due to the lack of accuracy and validity. This research developed a novel pH sensor (hydrogel/BTB) based on the transition of bromothymol blue from the hydrogel matrix into the pH-examining sample solution. The hydrogel/BTB sensor was synthesized through the solvent casting of chitosan, citric acid as the crosslinker, and bromothymol blue as a pH-sensitive dye. The structure of hydrogel/BTB was characterized using Fourier-transform infrared spectroscopy (FT-IR), Energy-dispersive X-ray spectroscopy (EDS), Field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET) analysis, and thermogravimetric analysis (TGA). The effect of various parameters on pH determination was investigated. The developed pH sensor demonstrated a linear detection range validated from pH 10 to 14 using the gravimetric method, and from pH 11 to 14 using the colorimetric method. The sensor successfully detected pH in alkaline tap water, carbonate buffer, and ethanol amine buffer. The transition of bromothymol blue is described by the Peppas-Korsmeyer kinetic model. The activation and Gibbs free energy were obtained as 357.1 J/mol and 260 J/mol, respectively. This work furnished a new mechanism for pH detection, and it has excellent potential for developing novel sensors in this field.

Electropsun non-woven luminescent two-dye pH sensors: Effect of morphology on the sensing performance

Electrospun (ES) non-woven matrices are regarded as promising platforms for the development of miniaturized sensing systems with improved detection capacity. Their high specific surface area and void-to-volume ratio are expected to promote higher and faster interaction of the sensing molecular probes with the target stimuli increasing sensor sensitivity and response time. However, the poor light transparency of ES non-woven mats appears as the main limiting effect regarding their use as optical sensor platforms being important to determine to what extent it affects the sensor prediction accuracy. This work addresses this question providing a comparative analysis of the performance of flat cast and ES non-woven cellulose acetate luminescent platforms loaded with a pH sensitive dye-pair, i.e. fluorescein isothiocyanate (FITC) and rhodamine 6 G (R6G). This study follows a comprehensive approach aiming at clarifying the effect of the platform morphology on the sensitivity of their spectral properties to pH and to understand about the advantages of using dual dye systems for pH detection. The presence of R6G improved remarkably the sensitivity of these ES matrices extending the analytical capacity of the probes to the alkaline range. The emission of ES matrices showed stronger sensitivity to pH. However, pH prediction accuracy was found to depend crucially on a synergistic effect from the platform morphology and the signal analysis methodology. ES non-woven matrices allows for accurate pH prediction, characterized by determination errors < 10 % for pH < 10, by exponential analysis of the dye-pair emission at λExc of 450 nm and λEm of 519 nm. Furthermore, it shows a strong reduction of the determination errors, at extremely acidic conditions, resulting in values comparable to that obtained by analysis of the emission signal from flat cast platforms with more complex Förster Resonance Energy Transfer (FRET) methodologies.

Thiophene desulfurization: Effects of dendritic silica and PEG as surface modifier on ZnO photocatalyst

This work focused on desulfurizing thiophene using a photocatalyst comprising zinc oxide (ZnO) and fibrous silica nanospheres (KCC-1) to exploit the photocatalytic process. Six photocatalyst samples (commercial ZnO, KCC-1, ZnO/1.5KCC-1, ZnO/2.0KCC-1, ZnO/2.5KCC-1 and ZnO/PEG) were characterized using field-emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffractometry (XRD). It was found that the properties of ZnO were altered by incorporating KCC-1 to enhance the efficiency of thiophene desulfurization. Desulfurization performances were investigated using three parameters, which were initial pH, initial thiophene concentration, and photocatalyst loading. Each parameter was validated using thiophene desulfurization percentage and turbidity removal percentage. This work discovered that ZnO/2.0KCC-1 was the optimum photocatalyst with 83 % thiophene desulfurization. No clear trend was observed for turbidity removal percentage, yet the ZnO/KCC-1 photocatalyst was able to reduce turbidity significantly. The pH of the permeation rose from neutral to alkaline range due to the hydroxyl radicals (•OH) produced during the desulfurization process.

A new species of Metadiaptomus Wang & Wang, 2024 from the Qinghai-Tibetan Plateau, China (Copepoda, Calanoida, Diaptomidae)

A new copepod species Metadiaptomus aliensis sp. nov., collected from lakes in the Qinghai-Tibetan Plateau, is described. M. aliensis sp. nov. is differentiated by total length of both sexes, the fifth leg of both sexes, and the right antennule of the male, compared with the similar species M. asiaticus Ul'yanin, 1875 and M. chevreuxi Guerne & Richard, 1894. The low temperature species M. aliensis sp. nov. survives in a wide salinity range from fresh to polyhaline water, and a wide alkalinity range from 6.12 to 40.39 mmol/L. The first generic record of M. aliensis sp. nov. in the Qinghai-Tibetan Plateau contributes to our understanding of the global biogeography of the subfamily Paradiaptominae.

Mild alkaline conditions affect digester performance and community dynamics during long-term exposure

This paper examines the adaptive responses of microbial communities to gradual shifts in pH toward the mild alkaline range in anaerobic digestion (AD) systems. The results indicate that a pH of 8.0 serves as a critical upper limit for stable AD operation, beyond which microbial efficiency declines, underscoring the importance of microbial resilience against elevated pH stress. Specifically, hydrolysis genera, e.g. Eubacterium and Anaerobacterium, and syntrophic bacteria were crucial for reactor stability. Fibrobacter had also been shown to play a key role in the accumulation of propionate, thus leading to its dominance in the volatile fatty acid profile throughout the experimental phases. Overall, this investigation revealed the potential adaptability of microbial communities in AD systems to mild alkaline pH shifts, emphasizing the hydrolysis bacteria and syntrophic bacteria as key factors for maintaining metabolic function in elevated pH conditions.

DISPERSION OF AQUEOUS Y2O3 NANO-SUSPENSION AND FABRICATION OF TRANSPARENT CERAMICS BY COLLOIDAL PROCESSING

In the present study, transparent Y2O3 ceramics were successfully fabricated via colloidal processing, employing polyethylenimine (PEI) as an effective dispersant. The effect of PEI on nanosized Y2O3 suspensions was characterized by zeta-potential, adsorption behavior, rheological properties, and sedimentation test. The addition of PEI shifted the IEP of the Y2O3 powder towards a more alkaline pH range, and the adsorption of PEI on the Y2O3 surfaces gradually increased with the amount of PEI until reaching the saturation adsorption at 1.5 w/%. The PEI amount of 1.5 w/% was superior for the preparation of Y2O3 suspension as a result of a lower viscosity or sedimentation behavior. The viscosity of the suspension depended on the solids loading, increasing with the amount of powder. The optimal rheological behavior was achieved with 29 /% Y2O3 in the suspension, enabling the centrifugal slip casting of complex-shaped green bodies with a packing density of 43 %. Including an additional CIP treatment boosted the packing density of the green compacts, achieving above 50 %. Vacuum sintering the compacts at 1700 °C for 5 h yielded high-density ceramics exhibiting an in-line transmittance of approximately 73 % at a wavelength of 1100 nm.

Alloyed Trimetallic Nanocomposite as an Efficient and Recyclable Solid Matrix for Ideonella sakaiensis Lipase Immobilization.

In this work, a trimetallic (Ni/Co/Zn) organic framework (tMOF), synthesized by a solvothermal method, was calcinated at 400 and 600 °C and the final products were used as a support for lipase immobilization. The material annealed at 400 °C (Ni-Co-Zn@400) had an improved surface area (66.01 m2/g) and pore volume (0.194 cm3/g), which showed the highest enzyme loading capacity (301 mg/g) with a specific activity of 0.196 U/mg, and could protect the enzyme against thermal denaturation at 65 °C. The optimal pH and temperature for the lipase were 8.0 and 45 °C but could tolerate pH levels 7.0-8.0 and temperatures 40-60 °C. Moreover, the immobilized enzyme (Ni-Co-Zn@Lipase, Ni-Co-Zn@400@Lipase, or Ni-Co-Zn@600@Lipase) could be recovered and reused for over seven cycles maintaining 80, 90, and 11% of its original activity and maintained a residual activity >90% after 40 storage days. The remarkable thermostability and storage stability of the immobilized lipase suggest that the rigid structure of the support acted as a protective shield against denaturation, while the improved pH tolerance toward the alkaline range indicates a shift in the ionization state attributed to unequal partitioning of hydroxyl and hydrogen ions within the microenvironment of the active site, suggesting that acidic residues may have been involved in forming an enzyme-support bond. The high enzyme loading capacity, specific activity, encouraging stability, and high recoverability of the tMOF@Lipase indicate that a multimetallic MOF could be a better platform for efficient enzyme immobilization.

Evaluation of Gastric pH and Gastrin Concentrations in Horses Subjected to General Inhalation Anesthesia in Dorsal Recumbency.

The prevalence of gastric disorders in high-performance horses, especially gastric ulceration, ranges from 50 to 90%. These pathological conditions have negative impacts on athletic performance and health. This study was designed to evaluate changes in gastric pH during a 24 h period and to compare gastrin concentrations at different time points in horses undergoing general inhalation anesthesia and dorsal recumbency. Twenty-two mixed-breed mares weighing 400 ± 50 kg and aged 8 ± 2 years were used. Of these, eight were fasted for 8 h and submitted to 90 min of general inhalation anesthesia in dorsal recumbency. Gastric juice samples were collected prior to anesthesia (T0), and then at 15 min intervals during anesthesia (T15-T90). After recovery from anesthesia (45 ± 1 min), samples were collected every hour for 24 h (T1 to T24) for gastric juice pH measurement. During this period, mares had free access to Bermuda grass hay and water and were fed a commercial concentrate twice (T4 and T16). In a second group (control), four non-anesthetized mares were submitted to 8 h of fasting followed by nasogastric intubation. Gastric juice samples were then collected at T0, T15, T30, T45, T60, T75, and T90. During this period, mares did not receive food or water. After 45 min, mares had free access to Bermuda grass hay and water, and gastric juice samples were collected every hour for four hours (T1 to T4). In a third group comprising ten non-fasted, non-anesthetized mares with free access to Bermuda grass hay and water, gastric juice samples were collected 30 min after concentrate intake (T0). In anesthetized mares, blood gastrin levels were measured prior to anesthesia (8 h fasting; baseline), during recovery from anesthesia, and 4 months after the anesthetic procedure, 90 min after the morning meal. Mean values of gastric juice pH remained acidic during general anesthesia. Mean pH values were within the physiological range (4.52 ± 1.69) and did not differ significantly between time points (T15-T90; p > 0.05). After recovery from anesthesia, mean gastric pH values increased and remained in the alkaline range throughout the 24 h period of evaluation. Significant differences were observed between T0 (4.88 ± 2.38), T5 (7.08 ± 0.89), T8 (7.43 ± 0.22), T9 (7.28 ± 0.36), T11 (7.26 ± 0.71), T13 (6.74 ± 0.90), and T17 (6.94 ± 1.04) (p < 0.05). The mean gastric juice pH ranged from weakly acidic to neutral or weakly alkaline in all groups, regardless of food and water intake (i.e., in the fasted, non-fasted, and fed states). Mean gastric pH measured in the control group did not differ from values measured during the 24 h post-anesthesia period or in the non-fasted group. Gastrin concentrations increased significantly during the post-anesthetic period compared to baseline (20.15 ± 7.65 pg/mL and 15.15 ± 3.82 pg/mL respectively; p < 0.05). General inhalation anesthesia and dorsal recumbency did not affect gastric juice pH, which remained acidic and within the physiological range. Gastric juice pH was weakly alkaline after recovery from anesthesia and in the fasted and fed states. Serum gastrin levels increased in response to general inhalation anesthesia in dorsal recumbency and were not influenced by fasting. Preventive pharmacological measures are not required in horses submitted to general anesthesia and dorsal recumbency.

Research Progress of Small Plant Peptides on the Regulation of Plant Growth, Development, and Abiotic Stress.

Small peptides in plants are typically characterized as being shorter than 120 amino acids, with their biologically active variants comprising fewer than 20 amino acids. These peptides are instrumental in regulating plant growth, development, and physiological processes, even at minimal concentrations. They play a critical role in long-distance signal transduction within plants and act as primary responders to a range of stress conditions, including salinity, alkalinity, drought, high temperatures, and cold. This review highlights the crucial roles of various small peptides in plant growth and development, plant resistance to abiotic stress, and their involvement in long-distance transport. Furthermore, it elaborates their roles in the regulation of plant hormone biosynthesis. Special emphasis is given to the functions and mechanisms of small peptides in plants responding to abiotic stress conditions, aiming to provide valuable insights for researchers working on the comprehensive study and practical application of small peptides.

A biodegradable pH-response packaging film with blueberry extract: Blown-extrusion fabrication, multifunctional activity, and kinetic investigation

This work proposed a novel strategy for manufacturing biodegradable pH-response packaging. Briefly, to minimize the amount and thermal processing times of blueberry extract (BE), ethanol-dissolved BE (≤ 3‰ w/w) was sprayed onto the starch/poly(butylene adipate-co-terephthalate) (PBAT) pellets before extrusion blowing. BE was well-integrated into the matrix, forming uniformly colored films. The films with BE exhibited superior mechanical (7.85 MPa of strength, 606.53% of elongation) and enhanced barrier capabilities against ultraviolet light, moisture, and gas. Additionally, they exhibited good antioxidant capacity (68.69%), antibacterial activity (72.40%), and maintained color stability. The film with 3‰ w/w BE presented excellent color responsiveness (ΔE⁎ ≥ 15) in the alkaline range, and successfully monitored the spoilage of shrimp. The pigments in the film had the maximum migration degree (≥ 70%) and rate in 50% ethanol simulation, following a first-order kinetic behavior dominated by Fickian diffusion. Findings supported the application of this strategy in the fabrication of starch/PBAT/BE films for pH-response intelligent packaging.

Hydrogeochemical and microbial constituents of groundwater in Lephalale municipality, Limpopo province, South Africa

This study assessed the hydrogeochemical characteristics and microbial constituents of groundwater in Lephalale Municipality, South Africa. A total of 71 borehole water samples were collected from 15 villages within the Lephalale Municipality between April 2019 and October 2020. The results of the parameters such pH, EC, TDS, and alkalinity range from 6.69 to 7.87, 620.30 to 1937.00 μS/cm, 330.35 to1035.50 mg/L and 50.00-390.00 mg/L, respectively. The mean values of major cations and anions were found to be in the order of Na+>Ca2+>Mg2+>K+ and HCO3−>Cl−>NO3−>SO42−>F−, respectively. About 35 % of the tested samples had F− concentrations above 1.5 mg/L recommended by the world health organization (WHO) to eliminate the risk of fluorosis. The hydrogeochemical facies determined using a piper diagram revealed the dominance of mixed CaMgCl and CaHCO3 water types. The Gibbs plot analysis revealed that the main composition-controlling hydrogeochemical processes in the study area is the rock-water interaction. The microbial constituent's analysis showed that faecal coliform in groundwater samples were ranging between 0 and 71 CFU/ 100 mL with an average of 0.56 CFU/100 mL, while total coliform (TC) counts were between 0 and 360.5 CFU/100mL with the average of 30.81 CFU/100mL, respectively. This study revealed that groundwater in some boreholes from Lephalale Municipality poses risk of fluorosis and pathogen related diseases. Therefore, the study recommends improving of water quality within the study area prior to consumption.

Physicochemical Analysis of Surface Water in Rohri Canal from Sukkur Barrage to Mehrabpur

The purpose of this study was to assess the effect of domestic and industrial waste discharge on the surface water quality of Rohri Canal in the stretch of the canal from Sukkur Barrage to Mehrabpur town. Eight sampling points were selected along the canal focusing on canal locations near major settlements. The parameters studied were temperature, pH, turbidity, hardness, alkalinity, total dissolved solids and suspended solids, chlorides, biochemical oxygen demand (BOD), chemical oxygen demand (COD) and E-coli. The average value of BOD and COD at the sampling stations were recorded as 212 mg/L and 423 mg/L respectively, which exceed the permissible surface water limits for drinking and irrigation purposes. The results indicate significantly higher value of BOD in sampling locations where there are major settlements and there is a continuous inflow of untreated sewage into the canal. The pH values at all the sampling sites were found within the drinking and irrigation water quality standards whereas the TDS values at only sampling stations (3 and 4) exceeded these limits. The turbidity values of the samples ranged from 237 to 821 NTU, exceeding the WHO drinking water quality standards for this parameter. The values of the water quality parameters including hardness (range 146 to 300 mg/L), chlorides (range 36 to 103 mg/L) and alkalinity (range 120 to 230 mg/L) were found well below the limits of WHO drinking water quality standards. The turbidity values of the samples ranged from 237 to 821 NTU and exceeded the WHO drinking water quality standards for this parameter. At all the sampling sites located near major settlements low levels of dissolved oxygen and the presence of E.coli were recorded. The results revealed that the continuous inflowing of untreated or un-treated sewage and industrial effluents into the canal has changed its physicochemical and biological characteristics, which make it unfit for human consumption and can have long-term irrevocable ecological threats if left unmanaged

Comparison of antimicrobial properties of inorganic peroxide polymer composites

AbstractWound healing and prevention of bacterial infections are critical aspects of modern medical care. In this work, antibacterial films were produced by creating composites of polycaprolactone with inorganic peroxides. Calcium, magnesium, and zinc peroxide were incorporated in a biocompatible polymeric film. Iron oxide, sodium bicarbonate, and calcium phosphate were added to reduce hydrogen peroxide and to maintain pH in a less alkaline range, allowing for optimization of the material's antibacterial efficacy while minimizing cytotoxicity toward human fibroblasts. Experiments with common wound pathogens, Staphylococcus aureus and Pseudomonas aerugonisa, confirmed significant and prolonged antibacterial effects of peroxide‐doped films. Findings showed that the addition of CaO2 and MgO2 within the film increased cytotoxicity toward human fibroblasts after 48 h (30%–40% decrease compared to control), whereas ZnO2‐based films exhibited a minimal cytotoxicity consistently maintaining over 70% cell viability throughout the course of the experiment. We examined the materials’ sustained release of reactive oxygen species and oxygen, and pH variation correlated with antibacterial activity. Given the unique combination of antibacterial efficacy and mammalian biocompatibility, these peroxides have value as components to sustain hydrogen peroxide release when appropriately compounded to reduce pH variation and avoid excessive hydrogen peroxide levels.

Assessment of water quality from selected borehole locations in Ado Ekiti, Ekiti State, Southwest Nigeria.

Borehole water is commonly believed to be pure and safe to drink. The present study assessed the quality of ten selected borehole locations within Ado -Ekiti. This was carried out by assessing the physicochemical parameters, microbial and heavy metal contamination using standard procedures. The physicochemical parameter results showed that Temperature range between 25.99 oC - 26.60 oC, Electrical conductivity range between 41.62 µs/cm - 202.54 µs/cm, pH range between 6.81-7.57, Total dissolved solids range between 28.15 mg/L - 116.22 mg/L, Total suspended solids range between 0.09 mgl -1.27 mgl, Turbidity range between 0.12 NTU-0.71 NTU, Total Hardness range between 29.64 mg/l -80.61 mg/l, Total Alkalinity range between 20.97 mg/l - 65.42 mg/l and all values were within World Health Organisation (WHO) permissible limits. The bacteria count of borehole water sample range from 10.66 ± 0.03 Cfu/ml to 12.56 ± 0.03 Cfu/ml. Highest fungi count of the borehole water sample was in the value range from 8.27 ± 0.00 Sfu/ml to 9.63 ± 0.02 Sfu/ml. The highest coliform detected in the borehole sample range from 5.33 ± 0.58 Cfu/ml to 8.67 ± 8.56 Cfu/ml. The bacteria, fungi and coliform count result observed in this study was higher than the WHO recommended limits. The metals occurred in the samples in this order Cr &gt;Fe &gt; Pb &gt; As &gt; Cd. The heavy metals were present in quantities higher than WHO recommended limit in some of the samples which is an indication of potential health hazards through the water consumption.

Sub-Supercritical Hydrothermal Liquefaction of Lignocellulose and Protein-Containing Biomass

Hydrothermal liquefaction (HTL) is an emerging technology for bio-crude production but faces challenges in determining the optimal temperature for feedstocks depending on the process mode. In this study, three feedstocks—wood, microalgae spirulina (Algae Sp.), and hydrolysis lignin were tested for sub-supercritical HTL at 350 and 400 °C through six batch-scale experiments. An alkali catalyst (K2CO3) was used with wood and hydrolysis lignin, while e (Algae Sp.) was liquefied without catalyst. Further, two experiments were conducted on wood in a Continuous Stirred Tank Reactor (CSTR) at 350 and 400 °C which provided a batch versus continuous comparison. Results showed Algae Sp. had higher bio-crude yields, followed by wood and lignin. The subcritical temperature of 350 °C yielded more biocrude from all feedstocks than the supercritical range. At 400 °C, a significant change occurred in lignin, with the maximum percentage of solids. Additionally, the supercritical state gave higher values for Higher Heating Values (HHVs) and a greater amount of volatile matter in bio-crude. Gas Chromatography and Mass Spectrometry (GCMS) analysis revealed that phenols dominated the composition of bio-crude derived from wood and hydrolysis lignin, whereas Algae Sp. bio-crude exhibited higher percentages of N-heterocycles and amides. The aqueous phase analysis showed a Total Organic Carbon (TOC) range from 7 to 22 g/L, with Algae Sp. displaying a higher Total Nitrogen (TN) content, ranging from 11 to 13 g/L. The pH levels of all samples were consistently within the alkaline range, except for Wood Cont. 350. In a broader perspective, the subcritical temperature range proved to be advantageous for enhancing bio-crude yield, while the supercritical state improved the quality of the bio-crude.

Magnesite everywhere: Formation of carbonates in the alkaline lakes and playas of the Cariboo Plateau, British Columbia, Canada

The Cariboo Plateau in central British Columbia, Canada, hosts the largest aerial extent of low temperature lacustrine magnesite in the world. Magnesite was the most abundant carbonate mineral in 21 of 33 sampled alkaline lakes and 20 of 22 sampled playas. Calcite, hydromagnesite and very high magnesium calcite (VHMC, also called disordered dolomite) were also found in closed basin alkaline lakes on the plateau. Carbonate mineralogy was strongly associated with lake water geochemistry, particularly total alkalinity. VHMC was the dominant carbonate mineral in lakes with the highest alkalinities (>1000 mEq/kg), magnesite was the dominant carbonate mineral in lakes in the middle range of alkalinities (generally 70 to 800 mEq/kg) and hydromagnesite with minor amounts of magnesite was the phase assemblage in lakes with lower relative alkalinities (<110 mEq/kg). The geochemical trends for the activity of CO32−, Ca2+ and Mg2+ suggest that these constituents in all Cariboo water bodies are controlled by the precipitation of Ca- and/or Mg‑carbonate minerals. The waters are near equilibrium with metastable crystalline Ca‑carbonate and Mg‑carbonate minerals. We hypothesize that carbonates present in the lakes likely formed via non-classical crystallization pathways based on the relationship between aqueous geochemistry and mineralogy and the chemical composition of the Ca-bearing magnesites. Non-classical crystallization offers new models for thinking about magnesite formation in lacustrine environments.