Solution pH Research Articles

Control system and process optimization for electroless nickel plating

A novel method based on mid-frequency vibration is proposed to eliminate coating defects such as bubbles during electroless nickel plating. An automated control system for the plating, enabling precise and stable measurements and adjustments of critical parameters such as plating solution temperature, pH, and nickel ion concentration, is also established, which significantly improves process efficiency and coating quality. Experimental results indicate that the system is capable of realizing stable operation over extended periods. A nonporous nickel–phosphorus coating with a thickness greater than 200 μm is successfully obtained, with high phosphorus content, robust adhesion, and superior machinability.

An Investigation of the Batch Adsorption Capacity for the Removal of Phosphate from Wastewater Using Both Unmodified and Functional Nanoparticle-Modified Biochars

One of the most widely employed methods for adsorption is the utilization of biochar produced during pyrolysis. Biochar has attracted considerable attention due to its oxygen-containing functional groups and relatively high specific surface area. In alignment with the principles of cleaner production, the sludge generated from sewage treatment plants is typically classified as waste. However, it can be effectively repurposed as an adsorbent following pyrolysis and subsequent nanoparticle modification. This environmentally friendly approach presents an ecological alternative to conventional water treatment methods. The objective of this study is to evaluate the efficiency of batch adsorption for the removal of phosphate from wastewater using both unmodified and modified sewage sludge biochars (SSBs) that were produced at various temperatures (300 °C, 400 °C, 500 °C, and 600 °C) and modified with zero-valent iron nanoparticles (nZVI-SSB300, nZVI-SSB400, nZVI-SSB500, and nZVI-SSB600). The findings indicate that biochar modified with functional nanoparticles is a highly effective adsorbent for the removal of phosphate from wastewater. As demonstrated by the research results, the adsorption capacity of modified biochar is approximately 3 to 3.5 times greater than that of the unmodified variants. The phosphate removal efficiency with modified biochars was optimal with nZVI-SSB600. In experiments with a phosphate concentration (25 mg/L), the modified sorbent biochar exhibited an equilibrium adsorption capacity of 23.74 mg/g, translating to a phosphate removal efficiency of 60%. Under similar test conditions, at an initial phosphate concentration of 50 mg/L, the adsorption capacity improved to 25.67 mg/g (75% efficiency); at 75 mg/L, it reached 27.97 mg/g (80%); at 100 mg/L, it was 28.44 mg/g (85%); and at 125 mg/L, it achieved 29.48 mg/g (89%). The models confirmed the observed adsorption behavior, yielding a maximum phosphate adsorption capacity (qe) of 19.00 mg/g for the 600 °C pyrolysis of modified biochar at the primary phosphate concentration (25 mg/L). Furthermore, this study indicates that the influence of solution pH on phosphate adsorption remains stable and maximal (nZVI-SSB600, ranging from 16.87 to 20.46 mg/g) within the pH range of 3 to 8. On average, the modified biochar (nZVI-SSB) demonstrated 20 to 30% superior adsorption performance compared to the unmodified biochar (SSB). Additionally, significant differences were noted between various ambient temperatures, ranging from 5 °C to 25 °C. As the ambient temperature increased, the sorption capacity of the adsorbent exhibited a considerable improvement. With a primary concentration of phosphate (100 mg/g) at 5 °C, the adsorption capacity of nZVI-SSB600 was measured at 7.99 mg/g; this increased to 14.33 mg/g at 10 °C, 21.79 mg/g at 20 °C, and 28.44 mg/g at 25 °C. This research highlights the potential application of biochar in wastewater treatment for phosphate removal, simultaneously enabling the effective utilization of generated sewage sludge waste through pyrolysis and coating with zero-iron nanoparticles, resulting in a sustainable solution.

Reduction of hexavalent chromium by compost-derived dissolved organic matter.

Compost-derived dissolved organic matter (DOMC) is a heterogeneous assemblage of different redox-active organic molecules. We hypothesize that DOMC can interact with Cr(VI) and reduce it to Cr(III), thereby influencing the dynamics of Cr(VI) in soil and aquatic environments. Here, DOMC, along with soil humic substances isolated from red soil and black soil, were fractionated into humic acid fractions (i.e., HAC, HAB, and HAR) and fulvic acid fractions (i.e., FAC, FAB, and FAR), respectively. The reduction and interaction between Cr(VI) and the six organic matter fractions were investigated. The results showed that the total Cr(VI) reduction capacity (TRC) of the six organic matter fractions was 26.77-49.34 μM Cr(VI) per mg OM. The TRC of HA fractions was 35.54-49.34 μM Cr(VI) per mg OM, which exceeded that of FA fractions (26.77-31.29 μM Cr(VI) per mg OM). DOMC had a HA/FA ratio of 0.64, which was higher than that of black soil humic substance (0.59) and red soil humic substance (0.20). The sum of the TRC of DOMC was 35.57 μM Cr(VI) per mg OM, which was larger than that of black soil humic substance (32.87 μM Cr(VI) per mg OM) and red soil humic substance (33.01 μM Cr(VI) per mg OM). The TRC was positively correlated with TOC, TN, phenol C, alkyl C, and aromatic C contents and negatively correlated with E2/E3, O-alkyl C, and carboxyl C contents. The reduction of Cr(VI) at pH 6 was negligible, whereas 32-67% Cr(VI) was reduced at pH 2. The Cr(VI) reduction capacities (RC2, RC2, and RC6) at pH 2-6 were positively correlated (R2 > 0.71) with phenol C. Spectral analysis showed that there was no obvious complexation between Cr(VI) and the six organic matter fractions at pH 6, and thus the reduction of Cr(VI) was negligible, but solution pH could affect the accessibility of organic molecules to Cr(VI) and thus influence Cr(VI) reduction.

Mn3O4-MnOOH nanocomposites for the adsorption-based removal of nickel ions from wastewater.

The removal of nickel from wastewater is a significant environmental concern because of its potential hazards to environment. Adsorption is known as an efficient water treatment strategy and there is a growing interest in the development of new adsorbent materials providing rapid adsorption kinetics, cost-effectiveness, and high adsorption capacity. In this study, the feasibility of Mn3O4-MnOOH nanocomposites was evaluated as the adsorbent material for the removal of nickel ions from wastewater. The nanocomposites were prepared using a modified sonochemical method and characterized by XRD analysis and SEM images. Batch adsorption experiments were carried out under different experimental conditions obtained by varying solution pH, adsorbent amount, and contact period. Under the optimum adsorption conditions, the %RE value was recorded around 80% for 10mg/L Ni(II) ions. The adsorption characteristics were investigated with respect to adsorption isotherms and kinetics. Langmuir and Freundlich isotherm models were used to fit the adsorption data and the results indicated that adsorption of nickel ions onto nanocomposite could be complex and obey both monolayer adsorption and heterogeneous surface. Accordingly, maximum adsorption capacity of nanocomposites were calculated as 12.387mg/g. Research works comparing the kinetic models of pseudo-first-order, pseudo-second-order, and Elovich revealed that chemical sorption plays an important role as the rate-limiting step in the adsorption of nickel ions.

Engineering Charge Transfer Characteristics in ZnO NRs/Ag2O NPs p-n Heterojunctions: Toward Highly Efficient and Recyclable Photocatalysts.

Staggered gap p-n heterojunction ZnO nanorods/Ag2O nanoparticles, a paradigm of photocatalysts, were developed via engineering the hydrothermal and coprecipitation method. Under simulated sunlight, the photocatalytic characteristics of ZnO/Ag2O(Zn/A) heterojunctions with varying mole ratios (from 8:1 to 8:4, named Zn/A-1-Zn/A-4) were systematically evaluated through the degradation of methylene blue (MB). The influence of key experimental variables, including photocatalyst concentration, MB concentration, and solution pH, on the photocatalyst performance was further analyzed. The incorporation of Ag2O enhanced visible-light absorption, improved electron-hole separation efficiency, and significantly improved the photocatalytic recyclability of the Zn/A heterojunctions. Additionally, metallic Ag generated during photodegradation was found to enhance the photocatalytic activity further. Kinetic studies indicated that the photocatalytic degradation of MB followed pseudo-first-order kinetics, with the Zn/A-3 heterojunction showing the highest photocatalytic activity, achieving a degradation rate constant (k) of 0.028 min-1. Scavenger experiments confirmed that •OH radicals, holes (h+), and superoxide radicals (•O2-) were the primary reactive species involved in the degradation process. The photocatalytic mechanism was identified as a Z-scheme charge transfer system, facilitating efficient charge separation. Moreover, the Zn/A-3 heterojunction exhibited remarkable recyclability, retaining >91% of the photocatalytic activity after five cycles. This study demonstrates the potential of Zn/A heterojunctions for practical applications in industrial wastewater treatment using solar energy.

Aggregation, Not Micellization: Perfluorooctanoic Acid, Perfluorobutanesulfonic Acid, and Potassium Perfluorooctanesulfonate Behavior in Aqueous Solution.

Surface tension, conductivity, and dynamic light scattering (DLS) measurements were used to examine the surface and bulk solution behaviors of three members of the PFAS family, perfluorooctanoic acid (PFOA), perfluorobutanesulfonic acid (PFBS), and the potassium salt of perfluorooctanesulfonic acid (PFOS). Measurements were carried out in solutions having variable (acidic) pH and in solutions buffered to pH = 8.0. Surface tension data show traditional soluble surfactant behavior, and results illustrate that PFOA, PFBS, and PFOS surface activity depends sensitively on solution phase pH. The tightly packed monolayers formed by PFOA in mildly acidic solutions imply that the surface pH of PFOA solutions is several units lower than bulk. Results from conductivity experiments generally show increasing conductivity with increasing bulk solution surfactant concentration. In pH = 8.0 solutions, changes in conductivity slope with surfactant concentration suggest the onset of micelle formation at concentrations <1 mM, markedly lower than reported in literature. In general, apparent critical micelle concentrations (CMCs) determined from conductivity data agree with similar predictions made from surface tension results. DLS measurements show that at concentrations close to the predicted PFAS CMCs, objects with diameters ≤10 nm start to form. However, unlike micelles, these objects continue to grow with increasing bulk solute concentration. These aggregates form structures having diameters of 50-150 nm. Aggregate size shrinks modestly as solution phase temperature increases, and this behavior is reversible. Cryo-EM images of PFOA solutions confirm a broad distribution of particles, supporting the DLS measurements. Findings reported in this work represent the first evidence that these three EPA-regulated PFAS surfactants form aggregates rather than micelles in solution. Findings also begin to reconcile differences in reported surface behaviors that have led to CMC predictions in the literature varying by more than an order of magnitude.

Removal of Cr(VI) from aqueous phase using dimethylaminopropylamine anchored polystyrene‐co‐divinylbenzene polymer as adsorbent

AbstractThe current investigation delves into the effectiveness of dimethylaminopropylamine tethered onto polystyrene‐co‐divinylbenzene polymer for the proficient elimination of hexavalent chromium from simulated wastewater. The resin was characterized using SEM, FT‐IR spectroscopy, EDX, elemental analysis, thermogravimetry, and solid state 13C NMR spectroscopy. The experimental investigation into sorption dynamics involved varying process parameters, including initial Cr(VI) concentration, amount of adsorbent used, solution pH, temperature, and contact between phases. The binding modes of chromate ions, either bidentate or monodentate, were observed, with their manifestation influenced by the solution's pH. Sorption capacity was found to be pH‐dependent, with removal efficiencies of 98.27%, 96.38%, and 85.52% observed at pH levels of 3, 6, and 9, respectively. PS‐DMAPA resin demonstrated robust regeneration capabilities, throughout five consecutive adsorption–desorption cycles. The Langmuir adsorption model exhibited excellent agreement with the experimental findings (R2 = 0.9994), revealing a maximum adsorption capacity of 70.15 mg g−1 at 298 K. Additionally, the experimental findings closely matched the second‐order kinetic model. The kinetics of sorption and the thermodynamic parameters were also investigated. Performance evaluating of the PS‐DMAPA resin under dynamic conditions included analyzing the Cr(VI) breakthrough curve. The 10% sodium chloride solution was employed to effectively recover the extracted Cr(VI) quantitatively.

A Heterogeneous Phosphomolybdate Nanocatalyst Utilizes Vitamin B1 to Promote Solvent‐Free H2O2 Sulfoxidation Selectivity

ABSTRACTCatalyst design and fabrication with safe and affordable components and methods is a high‐value‐added business. In this work, a vitamin‐based hybrid nanomaterial (PMoB1) is prepared by simple stirring of thiamine hydrochloride (vitamin B1, VB1) as an inexpensive commercially available biologically active compound with phosphomolybdic acid (PMo12) in acidic aqueous solution to catalyze selective oxidation of sulfides using aqueous H2O2. A small amount of this heterogeneous catalyst drives rapidly the sulfoxidation reaction under mild and solvent‐free conditions facilitating the product separation and reducing significantly the environmental impacts. The main factors of the catalytic reaction were optimized by the central composite design (CCD) method. The solid catalyst tolerates a wide range of pH and retained its structural integrity even at alkaline solution (pH = 11). PMoB1 composed of two VB1 and one PMo12 was found to be partially reduced based on 13P NMR and UV–Vis spectra. An amorphous structure with aggregated nanoparticles with sizes ranging between 50 and 70 nm and a specific surface area of 35 m2/g are important reasons for enhanced catalytic activity and selectivity. Nevertheless, non‐covalent interactions such as hydrogen bonding and the π–π stacking can also significantly affect the catalyst performance. Given the scavenging tests and spectral evidences, a non‐radical mechanism involving peroxo species is postulated. The catalysis is shown to be truly heterogeneous while the solid catalyst largely maintains its structural integrity during the recycling test.

Development of Alginate Hydrogels Incorporating Essential Oils Loaded in Chitosan Nanoparticles for Biomedical Applications

A hybrid alginate hydrogel–chitosan nanoparticle system suitable for biomedical applications was prepared. Chitosan (CS) was used as a matrix for the encapsulation of lavender (Lavandula angustifolia) essential oil (LEO) and Mentha (Mentha arvensis) essential oil (MEO). An aqueous solution of an acidic Natural Deep Eutectic Solvent (NADES), namely choline chloride/ascorbic acid in a 2:1 molar ratio, was used to achieve the acidic environment for the dissolution of chitosan and also played the role of the ionic gelator for the preparation of the chitosan nanoparticles (CS-NPs). The hydrodynamic diameter of the CS-MEO NPs was 130.7 nm, and the size of the CS-LEO NPs was 143.4 nm (as determined using Nanoparticle Tracking Analysis). The CS-NPs were incorporated into alginate hydrogels crosslinked with CaCl2. The hydrogels showed significant water retention capacity (&gt;80%) even after the swollen sample was kept in the aqueous HCl solution (pH 1.2) for 4 h, indicating a good stability of the network. The hydrogels were tested (a) for their ability to absorb dietary lipids and (b) for their antimicrobial activity against Gram-positive and Gram-negative foodborne pathogens. The antimicrobial activity of the hybrid hydrogels was comparable to that of the widely used food preservative sodium benzoate 5% w/v.

Chromatographic analysis of ponatinib and its impurities: method development, validation, and identification of new degradation product

BackgroundPonatinib, a third-generation tyrosine kinase inhibitor, is employed in the management of adult chronic myeloid leukemia. Nevertheless, the presence of process impurities and degradation impurities linked to ponatinib may potentially influence its effectiveness and safety. Therefore, the objective of this research was to establish a robust liquid chromatography method and systematically validate it for the detection of substances related to ponatinib.MethodsThe separation of ponatinib and its impurities was conducted using an Agilent 5HC-C18 chromatographic column (4.6 mm × 250 mm, 5 μm). The mobile phase A comprised a mixture of water and acetonitrile in a 9:1 ratio, with an aqueous solution of pH 2.4 containing 2 mM potassium dihydrogen phosphate and 0.4% triethylamine. Mobile phase B, consisting of acetonitrile, was eluted in a gradient fashion. The flow rate was set at 1.0 mL/min, detection wavelength at 250 nm, column temperature at 40°C, and injection volume at 10 μL.ResultsThe method demonstrated high specificity, sensitivity, solution stability, linearity, precision, accuracy, and robustness. Additionally, this research unveiled a novel compound, imp-B, generated via the oxidative degradation of ponatinib. The molecular structure of the newly discovered product was elucidated through the utilization of nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS).ConclusionIn conclusion, the chromatographic method developed in this study has the potential to be utilized for the detection of ponatinib and its impurities, thereby offering significant insights for quality assessment in ponatinib research.

Ultrasound-assisted bisphenol AF degradation using in situ generated hydrogen peroxide

Bisphenol AF (BPAF) is degraded through the ultrasound-assisted in situ generation and activation of hydrogen peroxide (H2O2) by the copper(II) catalysed oxidation of hydroxylamine (NH2OH) with dioxygen (O2). Compared to added H2O2, in situ generated H2O2 significantly improves the degradation of BPAF from 46.7% to 94.8% in ∼15 min. The reaction follows a pseudo-first-order kinetic model. This study examines the influence of solution pH, anions, humic acid, and different concentrations of the reactants on BPAF degradation. Mass spectrometry was used to identify the BPAF degradation products, and a degradation pathway is proposed. This work advances the understanding of in situ hydrogen peroxide generation and activation in advanced oxidation (Fenton-like) processes (AOPs).

Application of a magnetic graphene nanocomposite modified with 5-aminoisophthalic acid amine group for chromium (VI) adsorption from aqueous solutions: kinetic and thermodynamic studies

ABSTRACT Polymer nanocomposites are composite materials that incorporate nanomaterials, such as magnetic graphene oxide (mGO), into a polymer matrix. To enhance its adsorption capacity, the surface of mGO nanoparticles was polymerised by a 5-aminoisophthalic acid amine group (mGO-AIPA) through a simplified co-precipitation method. The structural and morphological characteristics of the synthesised nanoparticles were evaluated through techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Thermogravimetric analysis (TGA), and Vibrating sample magnetometer (VSM). Response surface method (RSM) was used to evaluate the effectiveness of mGO-AIPA nanocomposite in removing chromium (VI) ions by examining variables such as solution of pH, contact time, adsorbent dose and initial concentration. Also, the study of kinetic models, adsorption isotherms and thermodynamic modelling of the process were evaluated. The results found that the mGO-AIPA nanocomposite has the maximum removal of chromium (VI) ions from the aqueous solution by 83.11% in optimal conditions including pH 3.5, contact time of 35 min, an adsorbent dosage of 25 mg g−1 and an initial concentration of 55 mg L−1. The pseudo-second-order kinetic and Langmuir isotherm models had a better fit with the experimental data of adsorption and the maximum adsorption capacity of chromium (VI) the base of the Langmuir model was 90.91 mg g−1. Moreover, the thermodynamic analysis indicated that the process was exothermic and nonspontaneous process, implying that it was energetically unfavourable. These findings suggest that the mGO-AIPA nanocomposite has a high performance as an effectual adsorbent to eliminate chromium heavy metal from an aqueous medium.

Synthesis of bagasse-derived magnetic biochar for the removal of fluoride from water solution

ABSTRACT Fluoride levels in drinking water pose a significant environmental threat, and adsorption is a common technique. However, many adsorbent materials have drawbacks such as poor adsorption capabilities, extended contact times, high pH levels, and large dosages. A biochar-based magnetic composite adsorbent has been developed for water defluoridation using a chemical co-precipitation process to immobilize iron particles on the biochar surface. X-ray diffraction analysis, Fourier transformed infrared spectroscopy, Brunauer–Emmett–Teller, and scanning electron microscopy were used to analyse the composite. The central composite design was used to design laboratory tests, which included four input variables: solution pH, dosage, contact time, and initial concentration. The adsorbent dosage was 5.92 g/L, the aqueous pH was 5.79, the contact time was 66.48 min, and the initial fluoride concentration was 12.38 mg/L. The removal efficiency was predicted to be 98.61%, with a 98.55% removal efficiency at optimum conditions. The study concluded that the composite adsorbent can be a reliable and sustainable solution for fluoride removal from water.

Influence of the Angle of Periodontal Intrabony Defects on Blood Clots: A Confocal Microscopy Study

Intrabony defects can be the result of parodontitis. In this study we aimed to examine how clot stability is affected by different infrabony defect angles and superficial treatments in regenerative surgery. Methods: Thirty single-root extracted teeth were cut to obtain a section from each tooth. This section was placed in an artificial model containing an infrabony defect with three walls in order to achieve 10 models at angles of 25°, 37°, and 50°. Five root samples for every angle were not subjected any treatment (NT) and five were subjected to root conditioning with a neutral pH solution of ethylenediaminetetraacetic acid (EDTA) at 24%, applied for 2 min. Venous blood was put into the artificial models containing the root sections, and these were placed in an incubator at a constant temperature of 37 °C for 2 h. Samples were analyzed by laser confocal microscopy. Results: All samples exhibited signs of retraction. The EDTA group exhibited a plateau trend for infrabony defects, while in the NT group, there was a statistically significant difference between clot retraction and the increase in defect amplitude. Conclusion: The greater the angle of the infraosseous defect, the higher the rate of clot retraction. This showed that EDTA could reduce the influence of the angle of the infraosseous defect.

Closed-Loop Process of Extracting and Separating Zinc Impurities from Industrial Cobalt Products—Pilot Test Study

The cobalt-containing products of an enterprise were selected as the object of this study. The separation effect of Cyanex 272 on Zn and Co was studied through a pilot test. The results showed that Cyanex 272 had a high extraction rate for Zn at pH 3–3.4, up to 99.8%. The extracted Zn2+ was enriched in the organic phase, and the Zn2+ in the organic phase was extracted back into the aqueous phase in the stripping stage by adding strong acid. Addition amounts of strong acid of 50 g·L−1, 80 g·L−1, and 100 g·L−1 were set. The results showed that the addition amounts of 80 g·L−1 and 100 g·L−1 could significantly reduce the pH of the back-extraction solution and effectively enrich Zn2+ in the solution. There was a large amount of Zn2+ in the back-extraction solution, which could be used twice to prepare zinc carbonate products through neutralization and precipitation. By comparing the extraction effect, economic cost, and resource loss under different strong acid addition amounts, it was found that the 80 g·L−1 strong acid addition amount was more suitable for the actual production process. This study provides data support and practical evidence for the selection of industrial extraction process parameters for Zn2+ separation in actual cobalt products.

Boosting Electrochemical Degradation of Water Pollutants Using Sulfur‐Rich Porous Polyimide‐Derived Laser‐Induced Graphene Catalytic Membrane

Water pollution is an inevitable concern associated with technological advancement. To address this problem, it is necessary to significantly shorten the manufacturing process of porous materials while enabling effective pollutant removal. Herein, a facile, rapid, and scalable approach is reported to obtain sulfur‐doped hierarchically porous laser‐induced graphene (S‐LIG) as a catalytic membrane with three‐dimensional networks by localized laser irradiation, along with possible adsorption and electrochemical degradation mechanisms for pollutant removal. S‐LIG is derived from sulfur‐containing porous polyimide film which is prepared via thermally induced phase separation followed by stepwise thermal imidization. Methylene blue (MB) adsorption behavior on the S‐LIG membrane closely fits the pseudo‐second‐order and Freundlich isotherm models, suggesting a complex sorption mechanism, including both strong chemical interaction and physical adsorption. Furthermore, S‐doping enhances catalytic activity for generating reactive oxygen species (ROS), aiding MB degradation via indirect oxidation, and improves direct oxidation on the anode by accelerating electron transfer at the electrodes. This results in a stable 93% MB degradation at a low 1.5 V after 24 h. Additionally, the impact of solution pH reveals that electrostatic attraction forces under basic conditions and the high generation of ROS under acidic conditions favor adsorption and electrochemical oxidation.

Nanofiltration Membranes Containing a Metal–Polyphenol Network Layer: Using Casting Solution pH as a Tool to Tailor the Separation Performance

Nanofiltration Membranes Containing a Metal–Polyphenol Network Layer: Using Casting Solution pH as a Tool to Tailor the Separation Performance

Optimization of Bromelain extraction from green papaya (Carica papaya) peel waste and its application in the recovery of silver from waste of X-ray photographic films.

As bromelain is a proteolytic enzyme present in many fruits, this study utilises the bromelain content present in unripe papaya (Carica papaya L.) by extraction and characterisation of bromelain extract from the unripe papaya peel waste. The extracted bromelain was utilised in the recovery of silver from waste of X-ray films, since the toxicity of silver directly impacts on the environment to treat and recover silver bromelain enzyme was used as a biocatalyst in this study. Response surface methodology with Box-Behnken design was used to optimise both the parameters included in the recovery of bromelain from papaya waste and silver from X-ray waste. Parameters involved in the recovery of bromelain include incubation time, pH of solution, temperature of solution and concentration of solution; for silver recovery along with the parameters selected for bromelain, recovery weight of X-rays is also considered in the study. Characterisation techniques like XRD, SEM, TGA, BET, FTIR and GC/MS were performed for the samples of bromelain and recovered silver from X-rays. At 30min of incubation time, pH of 8, with 15mL of bromelain solution maintained at 80 ℃ with 0.6g of X-rays gives optimum silver recovery. The optimum recovery of silver was observed to be 96.6%.

N‐ZrS3/p‐ZrOS Photoanodes with NiOOH/FeOOH Oxygen Evolution Catalysts for Photoelectrochemical Water Oxidation

AbstractPhotoelectrochemical water splitting offers a promising approach for carbon neutrality, but its commercial prospects are still hampered by a lack of efficient and stable photoelectrodes with earth‐abundant materials. Here, we report a strategy to construct an efficient photoanode with a coaxial nanobelt structure, comprising a buried‐ZrS3/ZrOS n−p junction, for photoelectrochemical water splitting. The p‐type ZrOS layer, formed on the surface of the n‐type ZrS3 nanobelt through a pulsed‐ozone‐treatment method, acts as a hole collection layer for hole extraction and a protective layer to shield the photoanode from photocorrosion. The resulting ZrS3/ZrOS photoanode exhibits light harvesting with good photo‐to‐current efficiencies across the whole visible region to over 650 nm. By further employing NiOOH/FeOOH as the oxygen evolution reaction cocatalyst, the ZrS3/ZrOS/NiOOH/FeOOH photoanode yields a photocurrent density of ~9.3 mA cm−2 at 1.23 V versus the reversible hydrogen electrode with an applied bias photon‐to‐current efficiency of ~3.2 % under simulated sunlight irradiation in an alkaline solution (pH=13.6). The conformal ZrOS layer enables ZrS3/ZrOS/NiOOH/FeOOH photoanode operation over 1000 hours in an alkaline solution without obvious performance degradation. This study, offering a promising approach to fabricate efficient and durable photoelectrodes with earth‐abundant materials, advances the frontiers of photoelectrochemical water splitting.

Comparative Dissolution Study of Ciprofloxacin Hydrochloride-sustained Release Tablets by Using Carbopol-934 and Guar Gum Polymers

Aims: This study aimed to identify the potential release of the drug from the tablet dosage form using Carbopol-934 and Guar Gum polymers at different concentration ratios. Objective: The objective of this study was to determine the cumulative percentage of ciprofloxacin hydrochloride released from different polymers. Method: We formulated ciprofloxacin hydrochloride sustained-release tablets with Carbopol-934 and Guar gum using the wet granulation method. For the formulation of sustained-release ciprofloxacin hydrochloride tablets, both polymers were mixed in varying ratios. The tablets were examined for pre-formulation studies, including the angle of repose, bulk density, compressibility index, and physiological properties, such as variations in weight, friability, and drug content. For postformulation studies, such as the in vitro study, the in vitro release of the drugs was evaluated in a phosphate buffer solution (pH 7.4) for 8 h. However, the physiological properties of ciprofloxacin hydrochloride tablets were limited due to their liberality. Results: The tablets containing guar gum (Batches B-I and B-II) showed better drug content than other polymer-based batches, such as Carbopol-934 (Batch A-I, A-II) and a mixture of both polymer Carbopol-934 and Guar gum (Batch C-I, C-II). Sustained drug release was observed in the guar gum polymer-based tablets (Batch B-II). It was observed that the dissolution profile of ciprofloxacin hydrochloride tablets formed using different polymers showed an increase in the polymer ratio, which can be related to the increase in drug release. Conclusion: From this study, we can conclude that the ciprofloxacin hydrochloride drug release percentage was maximum when guar gum polymer was used in the tablet dosage form.