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The antiscale magnetic treatment (ASMT) claims to utilize magnetic field to combat scaling. However, its underlying mechanism, effectiveness, and reliability remain controversial. To address these contentious aspects, we analyze the influence of a magnetic field on the different stages of typical scale formation, using as a model scale. For simplification, we consider the working fluid, such as in domestic and industrial settings, as a homogeneous mixture of a supersaturated, multi-ionic solution and a suspension of neutral multiphase contaminants, a fraction of which is magnetic. We argue that the combined effects of pH variation and catalytic role of magnetic contaminants are crucial factors affecting the properties of the resultant scale. Based on these considerations, we clarify the controversy by showing that each side holds a valid piece of the overall picture of the ASMT process. Indeed, the two viewpoints on magnetic field’s influence on scaling can be explained along the following scenarios: (i) Within a non-contaminated, supersaturated solution, there is no significant field influence because, under typical laboratory conditions, the Lorentz force does not practically affect the scaling process. (ii) Within a high-pH, magnetically-contaminated, supersaturated solution, the field does have an influence: Here, gradient-force-driven agglomerated particulates can act as templates for heterogeneous nucleation and growth.

pH plays a pivotal role in influencing various aspects of proton-coupled electron transfer (PCET) reactions in electrochemical systems. These reactions are affected by pH in terms of mass transport, electrochemical double layer (EDL) structure, and surface adsorption energy, all of which impact the overall electrochemical processes. This review article aims to provide a comprehensive understanding of the research progress made in elucidating the effects of pH on different electrochemical reactions, the hydrogen evolution reaction/hydrogen oxidation reaction (HER/HOR), oxygen reduction reaction/oxygen evolution reaction (ORR/OER), and carbon dioxide reduction reaction (CO 2 RR). To embark on this endeavor, we have conducted a bibliometric analysis to clearly outline of the research trends and advancements in the field concerning the pH effects. Subsequently, we present a systematic overview of the mechanisms governing these reactions, with a special focus on pH’s influence on both the proton and electron aspects. We conclude by discussing the current challenges in this area and suggesting future research avenues that could further our understanding of pH's role in electrochemical reactions. Graphical abstract

PurposeTo describe a stepwise approach to evaluate the pH effect for a weakly basic drug by in vitro, in vivo and in silico techniques and identify a viable mitigation strategy that addresses the risk.MethodsClinical studies included assessment of the pH effect with famotidine. In vitro dissolution was evaluated in various biorelevant media and in a pH-shift test. PK studies in dogs were conducted under pentagastrin or famotidine pre-treatment and GastroPlus was employed to model human and dog PK data and simulate the performance in human.ResultsClinical data indicated considerable pH dependent absorption of the drug when dosed in the presence of H2-antagonists. In vitro dissolution and in vivo dog data confirmed that the observed pH effect was due to reduced dissolution rate and lower solubility at increased gastric and intestinal pH. A salt form was identified to overcome the effect by providing fast dissolution and prolonged supersaturation. GastroPlus simulations predicted a mitigation of the pH effect by the salt.ConclusionsThe drug exhibited a strong pH-effect in humans. The in vitro, in vivo and modeling approach provides a systematic workflow to evaluate the risk of a new drug and identify a strategy able to mitigate the risk.

Ovotransferrin (OVT) is a multi-functional protein showing over 50% homology with Bovine lactoferrin (BLF) and human lactoferrin (HLF), which have the potential to be a substitute for lactoferrin (LF) due to the limited production of LF. To explore the substitutability of OVT, the molecular properties and thermal stability of OVT, BLF and HLF were characterized because these properties will affect the processing quality and biological activities of protein products when exposed to different processing conditions (e.g., temperature, pH, ion strength). The results showed that although obviously different isoelectric point (5.31, 9.12 and 8.75 for OVT, BLF and HLF, respectively), particle size distribution and hydrophobicity were found, they exhibited good dispersity because of high potential value. They showed an endothermic peak at 80.64 °C, 65.71 °C and 90.01 °C, respectively, and the denaturation temperature varied at different pH and ionic strength. OVT and BLF were more susceptible to heating at pH 5.0 as reflected by the decline of denaturation temperature (21.78 °C shift for OVT and 5.81 °C shift for BLF), while HLF could remain stable. Compared with BLF, OVT showed higher secondary structure stability at pH 7.0 and 9.0 with heating. For example, the α-helix content of OVT changed from 20.35% to 15.4% at pH 7.0 after heating, while that of BLF changed from 20.05% to 6.65%. The increase on fluorescence intensity and redshifts on the maximum wavelength after heating indicated the changes of tertiary structure of them. The turbidity measurements showed that the thermal aggregation degree of OVT was lower than BLF and HLF at pH 7.0 (30.98%, 59.53% and 35.66%, respectively) and pH 9.0 (4.83%, 12.80% and 39.87%, respectively). This work demonstrated the similar molecular properties and comparable thermal stability of OVT to BLF and HLF, which can offer a useful reference for the substitute of LF by OVT.

Removing toxic metal ions arising from contaminated wastewaters caused by industrial effluents with a cost-effective method tackles a serious concern worldwide. The adsorption process onto metal oxide and carbon-based materials offers one of the most efficient technologies adopted for metal ion removal. In this study, mesoporous MgO/g-C3N4 sorbent is fabricated by ultrasonication method for the uptake Pb (II) and Cd (II) heavy metal ions from an aqueous solution. The optimum conditions for maximum uptake: initial concentration of metal ions 250 mg g−1, pH = 5 and pH = 3 for Pb++ and Cd++, and a 60 mg dose of adsorbent. In less than 50 min, the equilibrium is reached with a good adsorption capacity of 114 and 90 mg g−1 corresponding to Pb++ and Cd++, respectively. Moreover, the adsorption isotherm models fit well with the Langmuir isotherm, while the kinetics model fitting study manifest a perfect fit with the pseudo-second order. The as fabricated mesoporous MgO/g-C3N4 sorbent exhibit excellent Pb++ and Cd++ ions uptake and can be utilized as a potential adsorbent in wastewater purification.

Uranium is a naturally occurring trace element and radionuclide. Uranium is introduced in the environment during industrial activities and nuclear energy accidents involving nuclear power plants, nuclear weapons tests, ore mining, and manufacturing, which may lead to the contamination of groundwater and soil. Hydroxyapatite (HAP) is a natural mineral with a high affinity for uranium in water. Groundwater often contains high carbonate concentrations that may affect uranium removal due to the formation of uranyl carbonate complexes. In order to understand the process of uranium removal, uranium adsorptions on three nano-HAPs were conducted under various biogeochemical conditions. Results showed that the fastest U adsorption occurred onto nano-HAP and U adsorption was strongly affected by biogeochemical conditions such as pH and the presence of carbonates, but less affected by temperature. The current study indicates that the presence of carbonates at pH’s above the neutral range in groundwater may inhibit U removal with nanohydroxyapatites.

The mechanism of byproduct formation and oxidation pathway of bisphenol A (BPA) during ozonation process have been compared under acidic, neutral and alkaline conditions at an applied ozone dose of 5.3 mg·L−1 min−1. Alkaline conditions promoted the fastest removal and the pseudo first-order reaction rate constant was calculated as 0.15 min−1. Complete removal under alkaline conditions (after 30 minutes of reaction time) was achieved with 1.59 mg ozone per mg BPA and 52% mineralization was achieved at 6.04 mg ozone application per mg total organic carbon (after 90 minutes of reaction time). Hydroxyl radical dominated degradation pathway (pH 10) resulted with opening of ring-structured products into Heptanoic acid, methyl ester. Sixty per cent BPA removal occurred under acidic conditions where the ozone was dominant and formation of Cyclohexene-1-carboxylic acid, ethyl ester, Benzaldehyde, 4-hydroxy-3,5-dimethyl- and 2-Phenylbenzoquinone were evidenced. Despite the fact that complete removal was achieved under neutral conditions, mineralization was not remarkable and both hydroxyl radical and ozone-based degradation pattern was evidenced after the treatment.

Hydroxyapatite (HAp) is a natural hard tissue constituent widely used for bone and tooth replacement engineering. In the present work, synthetic HAp was obtained from calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) and ammonium phosphate dibasic (NH4)2HPO4 following an optimized microwave assisted hydrothermal method. The effect of pH was evaluated by the addition of ammonium hydroxide (NH4OH). Hence, different characterization techniques were used to determine its influence on the resulted HAp powders’ size, shape, and crystallinity. By Transmission Electron Microscopy (TEM), it was observed that the reaction pH environment modifies the morphology of HAp, and a shape evolution, from sub-hedral particles at pH = 7 to rod-like nanosized HAp at pH = 10, was confirmed. Using the X-ray Diffraction (XRD) technique, the characteristic diffraction peaks of the monoclinic phase were identified. Even if the performed Rietveld analysis indicated the presence of both phases (hexagonal and monoclinic), monoclinic HAp prevails in 95% with an average crystallite size of about 23 nm. The infrared spectra (FTIR) showed absorption bands at 3468 cm−1 and 630 cm−1 associated with OH− of hydroxyapatite, and bands at 584 cm−1, 960 cm−1, and 1090 cm−1 that correspond to the PO43− and CO32− characteristic groups. In summary, this work contributes to obtaining nanosized rod-like monoclinic HAp by a simple and soft method that has not been previously reported.

Introduction24-hour catheter-based pH monitoring is a routine test in the diagnosis of gastro-oesophageal reflux disease (GORD). An alternative test used for the diagnosis of GORD is a 96-hour BravoTM capsule test, this study aims to assess if there is a clinical need for a BravoTM on patients who have had a normal 24-Hour pH study.MethodsThe total acid exposure time (AET) was compared for 39 patients who had both previously completed both a 24-hour catheter-based pH study and 96-hour BravoTM capsule study for the investigation of GORD. The data was collected from Sheffield Teaching Hospital’s Gastrointestinal Physiology department. A two-tailed t-test was used to assess if a significant difference in total AET exists between the two groups.ResultsThere was a significant difference (p<0.05) in total AET between both groups with total AET significantly higher in the BravoTM study (4.5±3.6%) compared to the 24-hour catheter-based study (1.6±1.1%). Consequently, the BravoTM had a 38.5% increase in the diagnostic yield of GORD versus the 24-hour catheter-based test.ConclusionsDespite the BravoTM capsules study’s higher diagnostic yield of GORD which is possibly attributed to its prolonged test time and therefore higher sensitivity it remains valuable as a 2nd line of investigation following the more routine catheter-based study due to the cost and personnel requirements of the BravoTM capsule procedure.

There has been increasing interest in using biochar for nutrient removal from water, and its application for anionic nutrient removal such as in phosphate (PO43−) necessitates surface modifications of raw biochar. This study produced avocado seed biochar (AB), impregnated Fe- or Mg-(hydr)oxide onto biochar (post-pyrolysis), and tested their performance for aqueous phosphate removal. The Fe- or Mg-loaded biochar was prepared in either high (1:8 of biochar to metal salt in terms of mass ratio) or low (1:2) loading rates via the co-precipitation method. A total of 5 biochar materials (unmodified AB, AB + High Fe, AB + Low Fe, AB + High Mg, and AB + Low Mg) were characterized according to their selected physicochemical properties, and their phosphate adsorption performance was tested through pH effect and adsorption isotherm experiments. Fe-loaded AB contained Fe3O4, while Mg-loaded AB contained Mg(OH)2. The metal (hydr)oxide inclusion was higher in Fe-loaded AB. Mg-loaded AB showed a unique free O–H functional group, while Fe-loaded AB showed an increase in its specific surface area more than 10-times compared to unmodified AB (1.8 m2 g−1). The effect of the initial pH on phosphate adsorption was not consistent between Fe-(anion adsorption envelope) vs. Mg-loaded AB. The phosphate adsorption capacity was higher with Fe-loaded AB in low concentration ranges (≤50 mg L−1), while Mg-loaded AB outperformed Fe-loaded AB in high concentration ranges (75–500 mg L−1). The phosphate adsorption isotherm by Fe-loaded AB fit well with the Langmuir model (R2 = 0.91–0.96), indicating the adsorptive surfaces were relatively homogeneous. Mg-loaded biochar, however, fit much better with Freundlich model (R2 = 0.94–0.96), indicating the presence of heterogenous adsorptive surfaces. No substantial benefit of high loading rates in metal impregnation was found for phosphate adsorption. The enhanced phosphate removal by Mg-loaded biochar in high concentration ranges highlights the important role of the chemical precipitation of phosphate associated with dissolved Mg2+.