Acid Solution Treatment Research Articles

(Invited) Insights from Cyclic Voltammetry into Active Sites on Carbon Electrodes and Their Importance in Vanadium Flow Batteries and Other Electrochemical Applications

Flow battery technology is uniquely positioned to fill the niche of long duration energy storage that will be needed to enhance grid reliability and power quality. Vanadium Flow Batteries (VFBs) and other flow battery technologies use carbon as their electrodes. The behaviour of carbon as an electrode is complex and there is considerable variation in the literature regarding the kinetics of flow battery reactions at carbon electrodes.The electrochemical response of a carbon electrode towards redox reactions is known to be improved after electrochemical treatments. For the past decade we have investigated the effect of electrochemical treatment on the electrode activity of carbon towards vanadium redox reactions. We have reported that cathodic treatment in acidic solution enhances the kinetics of the positive (VIV-VV) electrode in VFBs but inhibits the kinetics of the negative (VII-VIII) electrode, while anodic treatment inhibits the kinetics of the positive electrode but enhances the kinetics of the negative electrode1-3. We also showed that the activity of carbon-based material is strongly dependent on the surface history, and in particular on the most positive and the most negative potential used to treat an electrode4.In this presentation, we report some interesting results from our investigations of carbon electrode pretreatment in H2SO4. The cyclic voltammetry behavior which we observe shows a remarkable correlation with kinetics measurements in vanadium-containing electrolytes. We believe that our results provide a novel method of investigating the behavior of active sites on carbon electrodes. This is particularly important in the context of flow battery electrodes but may also, in a much broader context, provide a route to understanding the electrocatalytic behavior of carbon electrodes in many other applications.References. A. Bourke, M. A. Miller, R. P. Lynch, X. Gao, J. Landon, J. S. Wainright, R. F. Savinell and D. N. Buckley, J. Electrochem. Soc. 163, A5097 (2016). A. Bourke, M. A. Miller, R. P. Lynch, J. S. Wainright, R. F. Savinell and D. N. Buckley, J. Electrochem. Soc., 162, A1547 (2015). M. A. Miller, A. Bourke, N. Quill, J. S. Wainright, R. P. Lynch, D. N. Buckley and R. F. Savinell, J. Electrochem. Soc., 163, A2095 (2016). M. Al Hajji Safi, A. Bourke, D. N. Buckley, R. P. Lynch, ECS Trans., 109, 67-84 (2022).

Evaluation the Efficacy of Microneedling with Topical Metformin Solution Compared with Microneedling with Topical Tranexemic Acid Solution in Treatment of Melasma

Evaluation the Efficacy of Microneedling with Topical Metformin Solution Compared with Microneedling with Topical Tranexemic Acid Solution in Treatment of Melasma

Study on the performance of ground melon vine straw fiber modified asphalt

In order to reduce the waste of resources and the pollution of ecological environment caused by the large amount of waste crop straw accumulation or incineration, and to realize the high-value utilization of waste straw resources, this paper adopts the mechanical crushing method, acid and alkali solution treatment method to prepare the groundnut seedling straw fibers, and compares and analyzes the micro-morphology and chemical composition and thermal stability of the groundnut seedling straw fibers prepared by the physical method, the NaOH solution method, and the HCL solution method, through the scanning electron microscope, infrared spectroscope and the thermogravimetric analysis test; secondly, the optimal blending range of the groundnut seedling straw fibers is preferred. Secondly, the optimal dosage range of ground melon vine straw fiber was selected, the preparation process of ground melon vine straw fiber modified asphalt was proposed, five different dosages of ground melon vine straw fiber modified asphalt were prepared, and the basic properties, viscosity and temperature characteristics, and storage stability of ground melon vine straw fiber modified asphalt were analyzed; and then, a dynamic shear rheometer was used. Dynamic Shear Rheometer and Bending Beam Rheometer tests were used to study the high and low temperature rheological properties and resistance to permanent deformation of ground melon vine straw fiber modified asphalt, and the optimal dosage of groundnut seedling straw fibers was determined; finally, through Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy tests, the chemical components of ground melon vine straw fiber modified asphalt were clarified, and the chemical components of ground melon vine straw fiber modified asphalt were revealed to be the most important. The toughening mechanism of ground melon vine straw fiber modified asphalt was revealed. The results showed that the chemical alkali treatment method was the best preparation process for groundnut straw fiber, and the process flow was to use NaOH solution with a mass fraction of 3 % to treat the ground melon vine straw fiber for 50 min at a temperature of 60 °C; compared with the matrix asphalt, the needle penetration and elongation of the ground melon vine straw fiber modified asphalt decreased with the increase of the blending amount, and the softening point, the equivalent softening point, and the temperature sensitivity of the asphalt increased. Sensitivity enhancement, softening point difference in line with the specification requirements, but the ductility in the low dosage improved; with the increase in the dosage of ground melon vine straw fiber, ground melon vine straw fiber modified asphalt rutting factor, creep modulus, 0.4 %–1 % dosage of the creep rate and creep recovery rate increased, while 1.3 %–1.6 % dosage of the creep rate and the amount of unrecoverable creep flexibility decreased The results show that 0.4 %–1.6 % dosage of melaleuca alternifolia straw fiber modified asphalt high temperature performance and resistance to permanent deformation performance, and 0.4 %–1 % dosage of melaleuca alternifolia straw fiber low temperature performance has also been improved, the overall consideration, to determine the optimal dosage of melaleuca alternifolia straw fiber 1 %; melaleuca alternifolia straw fibers (NaOH) and the asphalt combined with the production of new functional groups, and melaleuca alternifolia straw fibers with each other. Lap cross to form a fiber skeleton grid structure, can play a role in the entire material to transfer stress and crack resistance, asphalt to play the role of enhanced toughening effect.

The efficacy of 20% salicylic acid solution versus intralesional MMR vaccine combination with 20% salicylic acid solution in treatment of plane wart

Background and objectives: Plane wart treatment is challenging; modalities such as cauterization and cryotherapy having a great probability to recur, as well as the risk of scarring, discomfort, and expensive costs. The goal of this study is to compare the efficacy of salicylic acid 20% superficial chemical peel alone to topical salicylic acid solution 20% combined with intralesional measles mumps rubella vaccine. Methods: A therapeutic clinical trial conducted in outpatient department of “Shahid Nabaz Dermatology Teaching Center” a period from March to September of 2022.Fifty participants with plane wart were enrolled in this study, 27 female and 23 male. The participants were randomly divided into two groups, group­- A 25 patients, received topical 20% salicylic acid solution with intralesional measles-mumps- rubella vaccine. Group B, received topical 20% salicylic acid solution alone. The total number of therapeutic sessions was six, and the solution was applied every two weeks and the measles-mumps-rubella vaccine was injected every fortnightly. Every two weeks, the effectiveness of the treatment was assessed by counting the number of lesions. Result: Group A patients who were treated with intralesional measles mumps-rubella-vaccine combined with topical 20% salicylic acid solution showed complete clearance (24/25) with six sessions .group B patients treated with topical 20% salicylic acid solutions showed clearance (14/25) with six sessions. Lesions were significantly fewer in Group-A, which was statistically significant. Conclusion: The intralesional measles mumps-rubella-vaccine combination with 20% topical salicylic acid solution and the 20% salicylic acid solution alone were both effective in clearing plane warts, however, intralesional measles mumps-rubella-vaccine combination with 20% topical salicylic acid solution can achieve higher response with fewer sessions .

Protonated Z-scheme CdS-covalent organic framework heterojunction with highly efficient photocatalytic hydrogen evolution

The low efficiency of photocatalytic hydrogen production from water is mainly suffer from limited light absorption, charge separation and water delivery to the active centers. Herein, an inorganic–organic Z-scheme heterojunction (CdS-COF-Ni) is constructed by in-situ growth of CdS nanosheets on the porphyrin-based covalent organic framework with nickel ions (COF-Ni) in the porphyrin centers. A built-in electric field is formed at the interface, which accelerates the separation and transfer of photogenerated charges. Moreover, through the surface protonation treatment in ascorbic acid (AC) solution, the hydrophilicity of the obtained composite is obviously increased and facilitates the transport of water molecules to the photocatalytic centers. Under the synergistic effect of the interfacial interaction and surface protonation treatment, the photocatalytic hydrogen production rate is optimized to be 18.23 mmol h−1 g−1 without adding any cocatalysts, which is 21 times that of CdS. After a series of photoelectrochemical measurements, in situ X-ray photoelectron spectroscopy (XPS) analysis, and density functional theory (DFT) calculations, it is found that the photocatalytic charge transfer pathway conforms to the Z-scheme mechanism, which not only greatly accelerates the separation and transfer of photogenerated charges, but also retains a high reduction capacity for water splitting. This work offers a good strategy for constructing highly efficient organic–inorganic heterojunctions for water splitting.

Evaluation of Micro-Needling Followed by Metformin Solution versus Micro-Needling Followed by Tranexamic Acid Solution in Treatment of Melasma: A Comparative Split Face Study

Abstract Background Melasma is a common acquired pigmentary disorder that manifests as symmetric hyperpigmented macules and patches on the face, more frequently affecting women of reproductive age. Various underling risk factors have been implicated in the etiology of melasma including; Genetic factors, pregnancy, oral contraceptives, endocrine dysfunction, hormone treatments, cosmetic contact sensitivity and exposure to ultraviolet (UV) light. Management of melasma is a frustrating experience both for the treating doctors and patients because of its recurrent and often recalcitrant nature. Numerous therapeutic modalities have been tried for this condition such as hydroquinone, kligman’s formula (hydroquinone + steroid + tretinoin), kojic acid, azelaic acid, arbutin, ascorbic acid, chemical peels, lasers, tranexamic acid, rucinol, oligopeptides, silymarin, orchid extracts, and various botanical extracts with variable success rates. Objectives Our aim was to assess and compare the therapeutic effects of topical metformin solution 30% with microneedling versus topical tranexamic acid (4mg\ml) solution with microneedling in treating patients with facial melasma. Patients and Methods This is a split-face study included 35 patients with facial melasma. The patients recruited from the Outpatient Dermatology Clinic at Ain Shams University Hospitals. Topical metformin 30% solution with microneedling sessions were done for the right side of the face (4sessions - two weeks apart), and topical tranexamic acid solution (4mg/ml) with microneedling on the left side of the face (4 sessions – two weeks apart). The patients were followed up for 3 months. The response of treatment was evaluated by Hemi MASI score and Antera 3D camera. Results Our study revealed that both microneedling followed by topical metformin solution and microneedling followed by topical TXA solution were efficient in treatment of facial melasma as shown by significant decrease in h-MASI score and average melanin level assessed by Antera camera. Although statistically insignificant, the percentage of change in h- MASI score was more evident with TXA treatment than metformin treatment. The side effects were limited and transient in the form of erythema, burning sensation, and xerosis. The main problem with either treatment was the high relapse rate. Conclusion Both metformin and tranexamic acid applied topically following microneedling sessions led to statistically significant improvement of melasma according to Hemi MASI scores. Topical metformin appears to be a promising therapeutic option in the treatment of melasma without serious adverse effects.

The fabrication and research of pH-responsive cement-based materials with switchable wettability

Recently, intelligent responsive materials have received increasing attention due to the controllability of their wettability. However, research has primarily focused on the surface properties of materials such as sponges and copper meshes, with a notable lack of investigation into cement-based materials in this regard. Currently, multi-functionality has become an inevitable trend in the development of cement-based materials. The controllable and adjustable wettability of cement-based materials can further expand their application scope. In this article, saturated fatty acids and dicarboxylic acids were selected to modify cement-based materials, fully utilizing their rich hydroxyl characteristics. Firstly, the feasibility of developing pH-stimuli-responsive surfaces on cement-based substrates with chosen raw materials was rapidly verified using the immersion method. When the mass fraction of dicarboxylic acid in the modifier is between 60 % and 80 %, the modified substrate surface exhibits hydrophobicity towards neutral liquids and hydrophilicity towards alkaline liquids. Based on this, the corresponding sodium salts of organic acid were synthesized and used as additives, which were then mixed with cement to prepare modified cement-based materials with switchable wettability. Through acid solution treatment, the modified hardened cement paste can transform from initially hydrophilic to hydrophobic, and the conversion angle can reach 90°. This study broadens the application field of intelligent response surfaces and enriches the functionality of cement-based materials.

Surface Chemistry Modulation of BaGd0.8La0.2Co2O6-δ As Active Air Electrode for Solid Oxide Cells.

Modulation of the surface chemistry of air electrodes makes it possible to significantly improve the electrocatalytic performance of solid oxide cells (SOCs). Here, the surface chemistry of BaGd0.8La0.2Co2O6-δ (BGLC) double perovskite is modulated by treatment in an acidic citric acid solution. The treatment leads to corrosion on the surface of BGLC particles, and the effect is dependent on the acidity of the solution. As the acidity of solution is low, Ba cations are selectively dissolved out of the BGLC surface, while as the acidity increases, the corrosion becomes more homogeneous. The Ba surface deficiency remarkably increases the concentration of surface oxygen vacancies and electrocatalytic activity of BGLC. To avoid the loss of Ba-deficient surface during the conventional high temperature sintering process, a sintering-free fabrication route is utilized to directly assemble the Ba-deficient BGLC powder into an air electrode. A single cell with the surface Ba-deficient BGLC electrode shows a peak power density of 1.04 W cm-2 at 750 °C and an electrolysis current density of 1.48 A cm-2 at 1.3 V, much greater than 0.64 W cm-2 and 1.02 A cm-2 of the cell with the pristine BGLC, respectively. This work provides a simple and effective surface chemistry modulation strategy for the development of an efficient air electrode for SOCs.

Preparation of novel zwitterionic polysulfone ultrafiltration membranes for the dual-enhanced antifouling and antibacterial properties by in-situ one pot crosslinking reaction

Zwitterionic polysulfone (PSf) ultrafiltration membranes were fabricated by non-solvent phase separation (NIPS) method. Herein, a casting solution at 45 °C was developed by using chloromethylated polysulfone (CMPSf), N, N-dimethylacetamide (DMAc) as a solvent, 4-amino-benzenesulfonic acid monosodium salt (ABS) as a cross-linking agent, and Na2CO3 as an acid binder. Simultaneously, the occurrence of the electrophilic substitution reaction between ABS and CMPSf caused the formation of ABS grafting CMPSf (CMPSf-g-ABS). After a specific reaction time, the casting solution was applied to cast membranes, which were subsequently submerged in coagulation bath. A zwitterionic ultrafiltration (ZUF) membrane was obtained using NIPS following the treatment of hydrochloric acid (HCl) solution (1 M mol). Because of the formation of cross-linked CMPSf-g-ABS, the results revealed that the casting solution's viscosity increased sharply from 425.4 mPa s at the initial stage (0 h) to 4810.8 mPa s (22 h). Interestingly, the morphology of the membranes with an asymmetric finger-like structure at 0 h gradually transformed to a gradient sponge-like structure after 22 h. Specifically, the ZUF membrane (M22-H) with the gel fraction of 72.1% procured after the reaction of 22 h demonstrated a low water contact angle (40.17°) and a high pure water permeance (420.4 L m−2 h−1 bar−1). The M22-H also exhibited a high flux recovery rate (FRR) (90.2%), bovine serum albumin (BSA) rejection (>95%), and Escherichia coli (E. coli) antibacterial rate (96.2%). The surface of the ZUF membrane with numerous zwitterionic groups enhances the hydration layer's energy (i region <16 nm) and creates a thick hydration layer (ii region >16 nm), causing a significant improvement in the antifouling performance. This research opens new avenues for preparing zwitterionic functional membranes.

Polystyrene Waste-ZnO nanocomposite film for energy harvesting via hydrophobic triboelectric nanogenerator: Transforming waste into energy

This research aimed to generate electricity from polystyrene waste materials combined with zinc oxide (ZnO) nanomaterials. Developing alternative polystyrene waste materials for generating electricity in triboelectric nanogenerator (TENG) could be beneficial in a circular economy and sustainable development. With the motivation to reduce environmental pollution by using polystyrene waste, a recycled polystyrene-ZnO nanocomposite film (rPS-ZnO NF) was synthesized and served as a triboelectric material for energy harvesting applications. ZnO nanopowder was produced by a low-temperature solution immersion method in conjunction with a simple film-casting method to prepare the rPS-ZnO NF. The effects of varying amounts of toluene as a solvent medium and the immersion time in stearic acid (SA) solution treatment on the structural properties, wettability behavior, surface morphology, chemical bonding properties, surface characteristics, and TENG performance were investigated. In this work, rPS film, rPS-ZnO NF, and SA-treated rPS-ZnO NF were paired with Kapton film as the opposite triboelectric material in constructing the vertical contact-separation mode TENG. Compared to rPS TENG, the rPS-ZnO TENG exhibited a two-fold enhancement in performance (8.2 V) in output voltage and ∼4.5 fold enhancement (28.1 μW/cm2) in power density. Furthermore, following SA treatment, the triboelectric performance further improved, reaching the highest open circuit voltage of ∼8.8 V and the highest power density of 32.0 μW/cm2 for repeated 2 N-solenoid tapping force. The hydrophobic behavior was also improved with the highest water contact angle of 134.7 (when the SA treatment immersion time was 1 h). These findings demonstrate that SA-treated rPS-ZnO NF could be a promising candidate for efficient mechanical energy harvesting with high electrical output and excellent surface wettability. This research not only exhibits an excellent output performance of SA-treated rPS-ZnO TENG, but it also sheds new light on the sustainable approach of converting polystyrene waste into energy-harvesting material.

Chemical Instability-Induced Wettability Patterns on Superhydrophobic Surfaces.

Chemical instability of liquid-repellent surfaces is one of the nontrivial hurdles that hinders their real-world applications. Although much effort has been made to prepare chemically durable liquid-repellent surfaces, little attention has been paid to exploit the instability for versatile use. Herein, we propose to create hydrophilic patterns on a superhydrophobic surface by taking advantage of its chemical instability induced by acid solution treatment. A superhydrophobic Cu(OH)2 nanoneedle-covered Cu plate that shows poor stability towards HCl solution (1.0 M) is taken as an example. The results show that 2.5 min of HCl solution exposure leads to the etching of Cu(OH)2 nanoneedles and the partial removal of the self-assembled fluoroalkyl silane molecular layer, resulting in the wettability transition from superhydrophobocity to hydrophilicity, and the water contact angle decreases from ~160° to ~30°. Hydrophilic dimples with different diameters are then created on the superhydrophobic surfaces by depositing HCl droplets with different volumes. Afterwards, the hydrophilic dimple-patterned superhydrophobic surfaces are used for water droplet manipulations, including controlled transfer, merging, and nanoliter droplet deposition. The results thereby verify the feasibility of creating wettability patterns on superhydrophobic surfaces by using their chemical instability towards corrosive solutions, which broadens the fabrication methods and applications of functional liquid-repellent surfaces.

Sorption Treatment of Nitric Acid Solutions to Remove Tributyl Phosphate and Hexachlorobutadiene

Sorption Treatment of Nitric Acid Solutions to Remove Tributyl Phosphate and Hexachlorobutadiene

Nano-protrusions in intercalated graphite: understanding the structural and electronic effects through DFT.

Complex phenomena characterize the intercalation of ions inside stratified crystals. Their comprehension is crucial in view of exploiting the intercalation mechanism to change the transport properties of the crystal or obtaining a fine control of crystal delamination. In particular, the relationship between the concentration and nature of intercalated ions and surface structural modifications of the host stratified crystal is still under debate. Here, we discuss a theoretical effort to provide a rationale for some structural changes observed on the highly oriented pyrolytic graphite (HOPG) surface after electrochemical treatment in perchloric and sulphuric acid solutions. The formation of the so-called nano-protrusions on the basal plane of intercalated graphite was previously observed with scanning tunneling microscopy (STM). In this work, we employed both STM and density functional theory (DFT) simulations to elucidate the physical and chemical mechanisms driving the emergence of these nano-protrusions. The DFT results show that, in a bilayer graphene system, the presence of a single ion can generate a nano-protrusion with 2.49 Å height and 21.27 Å width. In the deformed area, the C-C bond length is stretched by about 2.5% more than the normal graphene bond. These values are of the same dimensional scale as those reported in previous STM experimental results.25 However, the simulated STM images obtained by increasing the amount of intercalated ions per area suggest that the presence of more than one ion is needed for the deformation of the uppermost graphite layer during the early stages of intercalation. In contrast, in a multilayer graphene system, no significant surface deformation is detected when ions are intercalated between the third and fourth layers. Charge analysis indicates an altered distribution of the charges as a consequence of the intercalation. The charge transfer from graphene layers to the intercalated ions results in a surface layer more prone to oxidation.

Mechanical properties of fracture-grouted prefabricated sandstone after thermal-acid coupling treatment: An experimental study

Grouting reinforcement is an efficient approach to increase the stability of engineered fractured rock masses that may be subjected to high temperatures and acidic groundwater in complex geological environments. To reveal the mechanical properties and failure characteristics of the grout-reinforced fractured rock masses under thermal-acid coupling conditions, prefabricated fractured red sandstone specimens with different inclination angles (IAs) were firstly grouted using a new high-strength fast anchoring agent (HSFAA). Then, the grout-reinforced specimens (GRSs) were then immersed in hydrochloric acid (HCl) solutions with different temperatures (varying from 25 to 300 °C). Finally, the macroscopic mechanical properties, microscopic morphology, and crack evolution characteristics of the GRSs after thermal and acid solution treatments were investigated by the uniaxial compression test, X-ray computed tomography (CT) and scanning electron microscopes (SEM). The results confirmed that the HSFAA featured with high fluidity, rapid setting, excellent early strength, and micro-expansion, was an ideal grouted reinforcement material for fractured rock masses. The compressive and tensile strengths of the HSFAA material at a 1-day curing were 2.01 and 1.64 times those of the ordinary Portland cement 42.5 (P.O 42.5), respectively. The fractured IA, thermal-acid coupling method and temperature affected the mass loss, strength parameters, and failure modes of the GRSs to different degrees. The thermal-acid coupling treatment affected the initiation location and extension direction of cracks within the GRSs. The increasing temperature led to the larger and more varied internal cracks, as well as the more complex 3D spatial morphology within the GRSs.

Synthesis, Structure, and Energetic Characteristics of Perovskite Photocatalyst SrTiO3: an Experimental and DFT Study

SrTiO3-based photocatalysts have become widely used due to their excellent properties such as high thermal stability, photocorrosion resistance, and stable structure that can be modified by doping and making composites. In this work, SrTiO3 powder was prepared from Sr(NO3)2 and TiO2 precursors by a simple chemical precipitation method followed by calcination. It was determined that calcination at 900 °C followed by treatment in nitric acid solution produced cubic SrTiO3 particles without the presence of any impurities. In addition, structural, morphology, and energetic characterization using experimental and theoretical aspects are presented. Within the framework of density functional theory, the electronic properties of SrTiO3 have been investigated in the Quantum ESPRESSO software package using the PBE functional under the generalized gradient approximation (GGA). The band structure and density of states were obtained, and the width of the bandgap was determined.

Comparison of UV-LED treatments at 255 and 281 nm in continuous-flow on bacterial inactivation, quality, nutrients and electrical efficiency in beverages

Ultraviolet light emitting diodes (UV-LEDs) have emerged as an alternative UV source. We compared the treatment of coconut water (CW), blue lemonade (BL) and ascorbic acid (AA) solution at 255 and 281 nm UV-LEDs in continuous-flow in terms of bacterial inactivation and effects on physical, quality and nutritional parameters and electrical efficiency. A 5-log10 reduction of Escherichia coli was achieved in CW and BL at both wavelengths. At similar fluence levels, a decrease in absorption coefficient (CW and BL), ascorbic acid and antioxidants (CW) was observed at both wavelengths. An increase in colour lightness of BL was observed at 281 nm. Treatment with 281 nm was more electrically efficient at achieving a 5-log10 reduction in beverages compared to 255 nm. This was confirmed in AA solution where 281 nm showed less photo-oxidation compared to 255 nm. Use of UV-LEDs allows for selection of optimal wavelengths to achieve higher microbial and electrical efficiency while maintaining product quality.

ELECTROTRANSPOT CHARACTERISTICS OF POLYANILINE-MODIFIED CATION EXCHANGE MEMBRANES IN SOLUTIONS OF NICKEL AND CHROMIUM SULFATES AND SULFURIC ACID

The electrotranspot and structural characteristics of the MK-40 and MF-4SK sulfocationic membranes modified with polyaniline in an electrodialysis apparatus were studied in solutions of nickel and chromium sulfates and sulfuric acid. The decrease in the conductivity of membranes and the increase in their diffusion permeability in solutions of all electrolytes after modification with polyaniline were estimated. The key effect of the charge of the counterion on the electrical conductivity of the initial and modified membranes was confirmed, and an unusual effect of reducing the electrical conductivity of the MF-4SK/PANI membrane with an increase in the concentration of a solution containing multi-charged counter-ion was found. The information on the effect of multi-charged ions on the structure of a homogeneous and heterogeneous membranes, obtained by the method of standard contact porometry, is supplemented by the estimation of transport and structural parameters of microheterogeneous model. Based on the analysis of the parameters of current-voltage curves in solutions of nickel and chromium sulfates and sulfuric acid, the prospects of using the polyaniline-modified membranes in the processes of electrodialysis treatment of acid solutions containing multi-charged ions are evaluated.

Synthesis of boron- free titanosilicate zeolite by TiCl4/HCl treatment of pure silicon MWW as an epoxidation catalyst

The pure silicon MWW were synthesized for the first time by means of a dry-gel conversion method utilizing N, N, N-trimethyl-1-adamantyl ammonium hydroxide and hexamethyleneimine as the structural directing agents. A vapor transport assisted crystallization method for obtaining complete crystallinity was developed to replace the traditional dry-gel conversion methods. TiCl4 acid solution treatment was cleverly used for the implantation of titanium in MWW. Compared with Ti-ERB-1, the Ti content of boron- free Ti-MWW is only 20% of the former, the conversion rate of 1-hexene epoxidation is 2.3 times of the former and nearly 100% of H2O2 efficiency.

The Effect of Various Concentrations of Both Lime Juice and Synthetic Citric Acid Solutions to Protect Capsicum frutescens L. against Yellow Leaf Curl Disease

The yellow leaf curl (YLC) disease is one of plant disease generally found in chili pepper. The aim of the research was to know various concentrations of lime juice and synthetic citric acids to protect chili pepper (Capsicum frutescens L.) against YLC disease. The research used a randomized completely block design using seven treatments and three replications. The treatments tested were spraying lime juice of 0.1%, 0.2%, and 0.3% volume per volume (v/v); citric acid solution of 0.1%, 0.2%, and 0.3 % weight per volume (w/v). Control was used water only. The data result were analyzed using the honestly significant different test at the 95% confidence level. The treatment of both lime juice and citric acid solutions 0.2% and 0.3% could decreased whitefly population on chili pepper compared with control. The lime juice and citric acid solutions 0.3% was able to reduce the incidence and intensity of YLC disease. Lime juice and citric acid solution of 0.2% and 0.3% increased fruit numbers and fruit weights compared with control. The lower whitefly population decreased disease incidence of YLC (with regression Y = 5.7505x – 48.029). Intensity of YLC disease decreased fruit numbers and fruit weight (correlation value of -0.949 and -0.912). Keywords: Citric acid, Chili pepper, Gemini virus diseases, Whitefly.

Protective and water-repellent properties of alkylcarboxylic and alkylphosphonic acid films on technically pure magnesium

The formation of superhydrophobic coatings using low‑toxicity corrosion inhibitors is a promising method for corrosion protection of metals and alloys. In this study, the effects of surface roughness and the of the adsorbed substance structure on wettability and corrosion resistance of commercially pure magnesium were investigated. Surface roughness was created by three different methods: paper grinding, etching in nitric acid solution and laser treatment. Oleic, stearic and octadecylphosphonic acids were investigated as potential surface modifiers for the formation of corrosion resistant superhydrophobic coatings. It has been shown that the protective and hydrophobic properties of acid films on magnesium, as well as their stability, are determined by both the initial surface morphology and the nature of the inhibitors. Experimentally, the laser treatment was found to be preferable to mechanical and chemical surface preparation and the best hydrophobic agent among the studied acids is phosphonic acid. The most stable films with excellent superhydrophobic and protective properties in atmospheres of high humidity and salt spray clamber are formed in a solution of 0.001 M octadecylphosphonic acid on the surface of magnesium with high roughness. In addition, the effect of vinyltrimethoxysilane on the protective and hydrophobic properties of stearic acid and octadecylphosphonic acid films was investigated. The results of direct corrosion tests and wetting contact angle degradation kinetics studies showed that the protective and hydrophobic properties of stearic acid can be enhanced by its layer-by-layer adsorption with silane. They practically reach the parameters of octadecylphosphonic acid.