KHSO4 Research Articles

Titanium dioxide in face powders and eyeshadows: Developing an analytical methodology for accessing customer safety.

Titanium dioxide (TiO2), a white powder, represents the opacifier used in many products, including drugs, foods, cosmetics, paints, and dyes. The Uv-Vis spectrophotometry was a particularly suitable technique to quantify TiO2 in the solutions obtained from cosmetics. In this work, we determined the TiO2 content in a total of 88 samples of eye shadows and face powders of different brands and costs. Before to analyse the samples, we developed the mineralization and analysis method, in fact, fusion with potassium bisulphate would be very laborious because it must be carried out on one sample at a time and requires very long times, instead, the mineralization with the acid mixture and the aid of microwaves allowed us to solubilize six samples at the same time within 45 min. From the results obtained, we can state that the highest concentrations of TiO2 are found in the eyeshadows with a maximum value of 36% in a blue eyeshadow.

Effective of different industrial disinfection in subzero cold-chain environment

Effective disinfection methods are crucial in the cold chain transportation process of food due to the specificity of temperature and the diversity of contaminated flora. The objective of this study was to investigate the sanitizing effect of different disinfectants on various fungi at – 20 °C to achieve accurate disinfection of diverse bacterial populations. Peracetic acid, hydrogen peroxide, and potassium bisulfate were selected as low-temperature disinfectants and were combined with antifreeze. The sanitizing effect of these cryogenic disinfectants on pathogens such as Bacillus subtilis black variant spores (ATCC9372), Staphylococcus aureus (ATCC 6538), Candida albicans (ATCC 10231), Escherichia coli (8099), and poliovirus (PV-1) was sequentially verified by bactericidal and virus inactivation experiments. After a specified time of disinfection, a neutralizing agent was used to halt the sanitizing process. The study demonstrates that different disinfectants exhibit selective effects during the low-temperature disinfection process. Peracetic acid, hydrogen peroxide, and potassium monopersulfate are suitable for the low-temperature environmental disinfection of bacterial propagules, viruses, and fungal contaminants. However, for microorganisms with strong resistance to spores, a low-temperature disinfectant based on peracetic acid should be chosen for effective disinfection treatment. Our results provide a valuable reference for selecting appropriate disinfectants to sanitize various potential pathogens in the future.

Growth, Surface Morphology and Mechanical Properties of Potassium Hydrogen Sulphate Single Crystals for Antimicrobial and Third-Order NLO Applications

A good quality single crystal of potassium hydrogen sulphate (KHS) has been grown and subjected to characterization techniques including single crystal X-ray diffraction, scanning electron microscope, hardness test, Z-scan and antimicrobial test. The single crystal X-ray diffraction study discloses the orthorhombic system of the KHS crystals. The SEM analysis shows the formation of tiny hillocks in the KHS crystal. Vickers microhardness test was utilized for testing the mechanical hardness of the grown KHS crystals. Moreover, the mechanical parameters such as elastic stiffness constant and yield strength were also determined. The nonlinear optical properties such as nonlinear susceptibility, nonlinear refractive index, and nonlinear absorption coefficient were estimated by Z scan analysis. In addition, antimicrobial activity was performed against certain pathogens for medication applications.

Introducing a Concept for Designing an Aqueous Electrolyte with pH Buffer Properties for Zn–MnO2Batteries with Mn2+/MnO2Deposition/Dissolution

For large‐scale energy‐storage systems, the aqueous rechargeable zinc–manganese dioxide battery (ARZMB) attracts increasing attention due to its excellent advantages such as high energy density, high safety, low material cost, and environmental friendliness. Still, the reaction mechanism and its influence on the electrolyte's pH are under debate. Herein, a pH buffer concept for ARZMB electrolytes is introduced. Selection criteria for pH buffer substances are defined. Different buffered electrolytes based on a zinc salt (ZnSO4, Zn(CH3COO)2, Zn(CHOO)2), and pH buffer substances (acetic acid, propionic acid, formic acid, citric acid, 4‐hydrobenzoic acid, potassium bisulfate, potassium dihydrogen citrate, and potassium hydrogen phthalate) are selected and compared to an unbuffered 2 mZnSO4reference electrolyte using titration, galvanostatic cycling with pH tracking, and cyclic voltammetry. By adding buffer substances, the pH changes can be reduced and controlled within the defined operating window, supporting the Mn2+/MnO2deposition/dissolution mechanism. Furthermore, the potential plateau during discharge can be increased from ≈1.3 V (ZnSO4) to ≈1.7 V (ZnSO4 + AA) versus Zn/Zn2+and the energy retention from ≈30% after 268 cycles (ZnSO4) to ≈86% after 494 cycles (ZnSO4 + AA). Herein, this work can serve as a basis for the targeted design of long‐term stable ARZMB electrolytes.

Batch Production of Lead Sulfate from Spent Lead–Acid Batteries via an Oxygen-Free Roasting Route: A Negative-Carbon Strategy

Multicomponent lead compounds, including lead (Pb), lead oxide (PbO), lead dioxide (PbO2), and lead sulfate (PbSO4), in spent lead–acid batteries (LABs), if not properly disposed of and recycled, will cause serious pollution and damage to the ecological environment. Pyrometallurgical smelting performed above 1000 °C often incurs high energy consumption and lead pollution. In this study, a low-temperature (300 °C), oxygen-free roasting process was proposed. With potassium bisulfate (KHSO4) as the roasting reagent, the uniform conversion of multicomponent lead compounds from spent lead paste (SLP) to PbSO4 was successfully realized in one step. We observed that PbO2 species were relatively chemically stable, during the oxygen-free roasting. However, the decomposition of PbO2 into PbO can be achieved by heating to 300 °C, resulting in an effective conversion to PbSO4. The optimal conditions for PbSO4 production were a heating temperature of 300 °C, an SLP/KHSO4 mass ratio of 1:1, and a holding time of 10.0 min. Life cycle assessment results show that the recycling of 1.0 t spent LABs can reduce carbon emissions of 2.45 t CO2 and smog of 0.13 t. Our research provides an emission-free, low-temperature, and negative-carbon strategy for facile and cost-effective recycling of spent LABs, as an alternative to traditional pyrometallurgical smelting.

Comparative study on modifications of pH-adjusted fluorogypsum by potassium carbonate and potassium bicarbonate

In view of the poor hydration activity and difficult utilization of industrial by-product fluorogypsum, the effects of potassium carbonate (K2CO3) and potassium bicarbonate (KHCO3) on the hydration mechanisms of fluorogypsum (pH-adjusted to 7.3) were investigated and compared through hydration rate, hydration heat, solubility and microscopic tests. The results show that both K2CO3 and KHCO3 could significantly increase the hydration rate, hydration heat release rate, and accelerate the hydration process of fluorogypsum. The optimum contents of K2CO3 and KHCO3 were found to be 1% and 0.5%, respectively, and the compressive strength of the fluorogypsum increased from 3.5 MPa (control group) to 20.3 MPa (increase by 480%) and 18.5 MPa (increase by 429%) after curing for 3 days. Both of the two increased the solubility of fluorogypsum, supersaturation of dihydrate gypsum, the nucleation and growth rate of dihydrate gypsum, and inhibited the dissolution of dihydrate gypsum. The compactness of the hardened fluorogypsum was improved and the porosity was reduced. K2CO3 was found to be more effective than KHCO3, resulting in a higher early strength. The acceleration mechanisms of the two were also found to be different: K2CO3 increased the hydration of fluorogypsum by forming an unstable double salt syngenite; while KHCO3 mainly promoted the formation of dihydrate gypsum through a ‘catalysis effect’ by unstable potassium bisulfate. With the addition of any of these two modifiers, the crystal morphology of dihydrate gypsum was changed from plate to column or needle, which was beneficial for the strength development.

Simultaneous degradation of trace antibiotics in water by adsorption and catalytic oxidation induced by N-doped reduced graphene oxide (N-rGO): synergistic mechanism

Aimed at current difficulties in the treatment of trace antibiotics in water, an adsorption-catalytic oxidation system was established by combining persulfate and graphene, which have the dual functions of adsorption and catalysis, for simultaneous enrichment and degradation of trace antibiotics in water. The experimental results showed that over 90% sulfamethoxazole could be degraded by the proposed system. The activation energy of the proposed system was 7.9 kJ mol−1, which was significantly lower than those of typical Co catalysts and some carbon-based catalysts. Synergistic effect analysis revealed that catalytic oxidation was the key degradation kinetic of the proposed system, while adsorption showed a significant enhancement effect. Specifically, a compound with large adsorption capacity tended to be degraded preferably and rapidly. Characterization results indicated that N atoms were doped into the graphene framework, resulting in significant impacts on the activation process of potassium bisulfate by activating the sp2 C system. Quenching and free radical trapping experiments revealed that degradation catalyzed by the proposed system was a non-free radical oxidation reaction dominated by singlet oxygen. In summary, the proposed design was rational, N-rGO surface provided good adsorption and catalysis sites, the synergistic effect of adsorption and catalytic oxidation led to rapid and effective enrichment and in situ degradation of trace antibiotics in water.

Investigation on the solubility, growth, vibrational characteristics and linear optical constants of potassium bisulphate single crystals

The present research report describes on the characterization of potassium bisulfate or potassium hydrogen sulphate (KHS) single crystals grown using slow evaporation method at room temperature. The KHS crystal was found to be crystallizing in centrosymmetric orthorhombic structure. The existence of different functional groups in the crystal was assured by FTIR investigation. The optical transmittance of the KHS crystal was investigated using the UV visible spectrum. Moreover, the band gap energy as well as optical constants including dielectric constant, reflectance, extinction coefficient, optical conductivity, refractive index, and electrical conductivity was reported.

From hazardous waste to fertilizer: Recovery of high-value metals from smelter slags

This work proposes a method to valorize lead slag for fertilizer purposes. The research concept was to selectively recover valuable microelements (Cu(II), Fe(II), Zn(II) in an amount of at least 0.2% m/v of each) by chemical leaching while retaining toxic elements in the slag (i.e. As and Pb). Among acids, hydroxides, salts and their mixtures tested for slag treatment, it was potassium hydrogen sulfate and ammonia liquor under strongly oxidizing conditions (in the presence of hydrogen peroxide) that proved to be the most effective leaching agents. Response Surface Methodology applied to optimize the slag leaching conditions set the most favorable process parameters (concentration of leaching agents, slag to reagent weight ratio, and temperature). As a result, the concentration of Cu(II) in the extract was 3751 mg/L (for ammonia liquor) and Fe(II) and Zn(II) concentrations in potassium hydrogen sulfate were 4738 mg/L and 6102 mg/L, respectively. To close the life cycle of the waste, immobilization in polyethylene and binding to cement were indicated as methods to manage the solid waste material after leaching. The mixed extracts rich in Cu(II), Fe(II) and Zn(II) ions were tested in germination tests on cucumber. No phytotoxic effect was observed, which raises the possibility of utilizing the solutions after chemical leaching of slag as an alternative source of micronutrients for the production of multicomponent fertilizers. The results are promising and fit in the assumptions of circular economy.

Photoluminescence, Impedance, Thermal Characteristics and Hirshfeld Surface Analysis of Potassium Bisulphate Single Crystals for Third Order NLO Applications

Good quality potassium bisulphate (KHS) single crystals have been grown by slow evaporation method at room temperature. The KHS crystal was found to be crystallizing in orthorhombic crystal structure with Pbca space group. The photoluminescence behaviour of the crystal was analysed in the visible region. This study disclosed that the grown KHS crystal has intense blue emission peak at 490 nm. Impedance analysis was performed to investigate the frequency dependent electrical characteristics at various temperatures. From the impedance studies the bulk resistance, grain boundary resistance and DC conductivity values of the grown crystal were found out. The KHS crystal was subjected to TGA/DTA and the results have been investigated. The electrical parameters like Fermi energy and average energy gap of KHS crystal have been determined. The evaluated values are used to estimate the electronic polarizability. The intermolecular interactions were predicted using Hirshfeld surface analysis. This analysis exhibited that the utmost contribution to the crystal structure was the K⋯O (46.7%) interaction. The 2D fingerprint plot provides the percentage contribution of each atom-to-atom interaction. Since KHS material is a centrosymmetric crystal, it could be used for third order nonlinear optical (NLO) applications.

Exploring the Additive Effects of Aluminium and Potassium Sulfates in Enhancing the Charge Cycle of Lead Acid Batteries

The adoption of aluminium sulfate and potassium sulfate as electrolyte additives were investigated to determine the possibility of enhancing the charge cycle of 2V/ 20AH lead acid battery with reference to the conventional dilute sulfuric acid electrolyte. The duration and efficiency of lead acid batteries have been a challenge for industries over time due to weak electrolyte and insufficient charge cycle leading to sulfation. This has affected the long-term production output in manufacturing companies that depend on lead acid batteries as alternative power source. Hence there is need to explore the use of specific sulfate additives that can possibly address this gap. The electrolyte solutions were in three separate charge and discharge cycles involving dilute sulfuric acid electrolyte, dilute sulfuric acid-aluminium sulfate mixed electrolyte and dilute sulfuric acid-potassium sulfate mixed electrolyte for one hour each. The total voltage after 30 minutes charge cycle was 2.3V, 2.35V and 5.10V for dilute sulfuric acid, aluminium sulfate additive and potassium sulfate additive respectively. The cell efficiency for dilute sulfuric acid, aluminium sulfate additive and potassium sulfate additive electrolytes are 77%, 77% and 33% respectively. The electrolyte sulfate additives were of no positive impact to the conventional dilute sulfuric acid electrolyte of a typical lead acid battery due to the low difference in potentials between the terminals.

Evaluation of the effect of the fluxing agent over the purification of Columbite-Tantalite ore for the synthesis of Nb,Ta mixed oxides

In this paper, the effect of alkaline fusion associated with acid leaching for the purification process of tantalum-niobium ore (Fe,Mn)(Ta1−xNbx)2O6 was investigated. The milled, screened, and sieved ore was melted upon the use of alkaline fluxing agents: potassium pyrosulfate, an equimolar mixture of potassium pyrosulfate and potassium bisulfite, and potassium bisulfate. The fused and crushed samples were subject to hot HCl leaching under several experimental conditions. The retrieved solid was then washed with DI water and dried so that XRF analysis could be performed to assess the attained purification of the ore. It was found that the use of potassium bisulfate as an alkaline fluxing agent was the most efficient of the three, and that total purification (>97 %wt. of Nb and Ta) was attained after the 15th round of acid leaching with HCl producing a nanoscale mixed and amorphous Nb,Ta oxide powder as the final product.

Propyl Gallate

The title compound, propyl gallate (III), is an important substance popularly used in the food, cosmetic and pharmaceutical industries. Current chemical syntheses of this compound are based on the acylation supported by thionyl chloride, DIC/DMAP or Fischer esterification using a range of homogenous and heterogenous catalysts. In this paper, an efficient, green, straightforward, and economical method for synthesizing propyl gallate using potassium hydrogen sulfate, KHSO4, as the heterogenous acidic catalyst has been developed for the first time. In addition, this paper provides a comprehensive spectral dataset for the title compound, especially the new data on DEPT and 2D NMR (HSQC and HMBC) spectra which are not currently available in the literature.

Potassium hydrogen sulfate mediated kinetics and mechanism of oxidation of certain polyols by Quinolinium bound Cr(VI) reagents

Potassium hydrogen sulfate (KHSO4) mediated oxidation of certain alcohols (Polyols) has been studied by quinolinium bound Cr(VI) reagents like quinolinium dichromate (QDC) and quinolinium chlorochromate (QCC) at different temperatures. Reaction kinetics revealed second order kinetics with a first order in [Alcohol] and [Cr(VI) reagent] at constant bisulfate concentration. Ten fold variation of added [KHSO4] enhanced the observed rateconstant (k′) by ten fold, showing first order dependence on [KHSO4]. Most plausible mechanisms for QDC oxidation and QCC oxidation of polyols are proposed on the basis of observed kinetic features.

Uranium removal from tin smelter slag by bisulfate fusion and acidic leaching

Slag as secondary product (waste) of tin smelter still contains not only valuable elements e.g. Ti, Nb, Ta, Zr, Hf and rare earth elements, but also radioactives such as Th and U, wich are accumulated in the slag phase during the smelting. Due to valuable element content, the slag becomes major of interest in mineral processing industries, hence the slag needs to be decontaminated before it could be processed further.Common approach to reduce U content from the slag using leaching process is considered ineffective due to association of U with refractory elements e.g. Si and Ti in the slag. To break down the refractory phases, the fusion approach by using fusing agent is required in order to release U so that they could be leached out using mild lixiviant.In this research, potassium hydrogen sulfate (KHSO4) and sulfuric acid was used as fusing agent and lixiviant, respectively. The parameters studied includes molar ratio between fusing agent and refractory elements in slag, fusion temperature, fusion time, sulfuric acid concentration in lixiviant and pulp density during leaching stage. The studies so far demonstrated that optimum condition in U removal occurred at fusion temperature 400 °C, fusion time 2 hours, molar ratio of potassium hydrogen sulfate to tin slag 5, sulfuric acid concentration 2 M and pulp density 15 ml/gr. The maximum recovery of U was 85.6%, which was significant compared to the results using direct leaching without fusion (0.1%).

Platinum Group Elements Recovery from Used Catalytic Converters by Acidic Fusion and Leaching

The recovery of platinum group elements (PGE (platinum group element coating); Pd, Pt, and Rh) from used catalytic converters, using low energy and fewer chemicals, was developed using potassium bisulfate fusion pretreatment, and subsequently leached using hydrochloric acid. In the fusion pre-treatment, potassium bisulfate alone (without the addition of an oxidant) proved to be an effective and selective fusing agent. It altered PGE into a more soluble species and did not react with the cordierite support, based on X-Ray Diffraction (XRD) and metallographic characterization results. The fusion efficacy was due to the transformation of bisulfate into pyrosulfate, which is capable of oxidizing PGE. However, the introduction of potassium through the fusing agent proved to be detrimental, in general, since potassium formed insoluble potassium PGE chloro-complexes during leaching (decreasing the recovery) and required higher HCl concentration and a higher leaching temperature to restore the solubility. Optimization on the fusion and leaching parameter resulted in 106% ± 1.7%, 93.3% ± 0.6%, and 94.3% ± 3.9% recovery for Pd, Pt, and Rh, respectively. These results were achieved at fusion conditions: temperature 550 °C, potassium bisulfate/raw material mass ratio 2.5, and fusion time within 30 min. The leaching conditions were: HCl concentration 5 M, temperature 80 °C, and time within 20 min.

Carbonization of oriented poly(vinyl alcohol) fibers impregnated with potassium bisulfate

The structural transformationss of oriented poly(vinyl alcohol) (PVA) fibers impregnated with potassium bisulfate (PBS) were studied in detail on the way from PVA precursor fibers till carbonized at a temperature of 1000 °C fibers. It has been shown that the impregnation of PVA fibers with a sulfur-containing compound (PBS) is an efficient technique to decrease the thermoplasticity of PVA fibers during heat treatment at high temperatures in air and argon and contributes to a high yield of coke residue after heat treatment up to 1000 °C. TMA, TGA, DSC, mass spectrometry, FTIR, Raman spectroscopy, SEM, WAXS and SAXS were used to study the structural transformations of oriented PVA fibers impregnated with PBS at the stages of their preliminary thermal stabilization (215 °C), thermal stabilization (215–400 °C) and carbonization (400–1000 °C). A reaction scheme has been proposed that fully describes carbonization chemistry in the entire studied temperature range. The processing temperature of 215 °C was found to be optimal for preliminary thermal stabilization of PVA fibers impregnated with PBS. The heat treatment in an inert medium can be recommended as the optimal for thermal stabilization of fibers impregnated with PBS. The characteristics of the carbonized PVA fibers, such as strength, modulus and electrical conductivity, were close to the characteristics of commercial cellulose-based carbon fibers yarns.

Development of poly (acrylamide-co-diallyldimethylammoniumchloride) nanogels and study of their ability as drug delivery devices

Bio-degradable polymers have attracted much attention and been familiar to be the most promising drug carrier materials for the last several years due to their wonderful virtues such as easily existing, non-toxic, bio-compatible, and can be modified easily. Herein, we report the synthesis of new drug carrier poly (acrylamide-co-diallyldimethylammoniumchloride) nanogels (PAD-NG) by dispersion polymerization technique using free radical initiator potassium persulphate (KPS), potassium hydrogen sulphate (KHSO4) as a co-initiator and chemical cross-linker N, N-methylene bisacrylamide (NN-MBA). The developed nanogels are characterized for their structure, size and morphology. The average size of the nanogels was about 100 nm. These nanogels were used as intracellular drug delivery vehicle by encapsulating 5-fluorouracil (5-FU) with efficiency of 76.34%. Further, placebo nanogels showed negligible hemolytic activity and cytotoxicity against neuroblastoma cells.

Alumina Extraction from Coal Fly Ash via Low-Temperature Potassium Bisulfate Calcination

Owing to the depletion of bauxite and increasing demand for alumina, calcination methods for extracting alumina from coal fly ash (CFA) were developed. However, these methods have disadvantages such as the need for high temperatures and the emission of toxic gases. Hence, in this study, Al2O3 was extracted from CFA via low-temperature potassium bisulfate calcination technology. Effects of the potassium bisulfate amount, calcination temperature, and calcination time on the alumina extraction efficiency were investigated using X-ray diffraction, thermal gravimetry, scanning electron microscopy, differential scanning calorimetry, and energy-dispersive spectroscopy. It was found that this technique could recover alumina efficiently, and potassium bisulfate significantly contributed to the degradation of mullite and corundum phases. Al2O3 in CFA was converted into soluble K3Al(SO4)3. With a KHSO4/Al2O3 molar ratio of 7:1, calcining temperature of 230 °C, and calcining time of 3 h, the alumina extraction efficiency reached a maximum of 92.8%. The Avrami–Erofeev equation showed the best fit with the kinetic data for the low-temperature calcination of CFA with KHSO4. The activation energy was 28.36 kJ/mol.

Direct Amination of Arenes with Azodicarboxylates Catalyzed by Bisulfate Salt/HFIP Association.

A mild and efficient amination of arenes with azodicarboxylates using potassium bisulfate (KHSO4) as the catalyst in 1,1,1,3,3,3-hexafluoro-2-propanol has been developed. This protocol allowed the amination of a broad range of arenes leading to corresponding hydrazides in good to excellent yields.