Concentrated Sulfuric Acid Solution Research Articles

Complex Protection of Some Steels in Sulfuric Acid Solutions by 1,2,4-Triazole Derivatives.

The corrosion behavior of steels of various grades in sulfuric acid solutions with the addition of nitrogen-containing corrosion inhibitors has been studied. Compounds containing the 1,2,4-triazole moiety effectively protect low-carbon (St3, St20, 08PS), high-strength (70S2KhA), and stainless steels (1Kh18N9T) not only from corrosion but also from the hydrogen penetration into the metals in concentrated sulfuric acid solutions. In some cases, the degree of steel protection from corrosion by these compounds exceeded 99%. The possibility of creating mixed inhibitors for steel protection containing triazole derivatives and KI has been shown. The rate constants for the main steps of cathodic evolution and hydrogen penetration into steel in sulfuric acid solutions have been determined, and the subsurface concentrations of hydrogen in the metals have been calculated. Triazole derivatives were found to act as inhibitors of hydrogen absorption by steel in H2SO4 solution. The degree of protection of steel from hydrogen absorption can reach 97%. It has been shown that triazole derivatives act as complex inhibitors of steel corrosion in sulfuric acid solutions because, along with strong inhibition of metal corrosion, they prevent hydrogen absorption by steel.

TEAK SEEDS (Tectona grandis L.f.) GERMINATION BASED ON DIFFERENT CONCENTRATION AND SOAKING TIME LENGTH USING SULFURIC ACID SOLUTION (H2SO4)

Teak (Tectona grandis L.f.) is a plant that produces raw materials for the wood industry, which is very popular due to its high quality and selling value. Procurement of teak seeds can be done in two ways: generatively and vegetatively. One problem in cultivating this plant is the inhibition of seed germination due to dormancy. Teak roots experience physical inactivity, namely tough skin. One technique that can be used to break seed dormancy is through chemical treatment. This study aims to determine the concentration of sulfuric acid (H2SO4) and the appropriate soaking time to break the teak seeds dormancy. This research was conducted for two months in the Permanent Nursery of the Department of Forestry, State Agricultural Polytechnic of Kupang, from 15 November 2022 until 15 January 2023. This study used a Completely Randomized Design (CRD) with two factors. The first factor was the concentration of a sulfuric acid solution (control: K0, 75% H2SO4: K1, 80% H2SO4: K2, and 85% H2SO4: K3). The second factor was the soaking time (T1: 45 minutes, T2: 50 minutes, and T3: 55 minutes). The two factors was combined to produce 12 treatment combinations as a whole. Each treatment was repeated three times and used ten seeds, so the total seeds used were 360 seeds. The results showed that there was an interaction between the concentration of sulfuric acid solution (H2SO4) with soaking time length, where the combination of 75% sulfuric acid (H2SO4) concentration and 45 minutes of soaking time gave higher results than other treatments, so it can be said that this combination is better at breaking teak seed dormancy.

Production of boric acid from colemanite ore in the semi-batch reactor: Investigation of product yield and impurity control

Boric acid is produced by the reaction between colemanite ore and sulfuric acid in industrial processes. Since colemanite ore is not pure, various side reactions, including partial clay decomposition, can occur in the reactor medium. These reactions also lead to the presence of impurities, specifically sulfate salts. In this context, semi-batch reactors (SBR) provide selectivity, and the rate of side reactions is reduced. However, batch reactors (BR) and continuous stirred tank reactors (CSTR) have been used for boric acid production both on an industrial scale and on a laboratory scale, and the semi-batch reactor has never been used for this area. This study used SBR to minimize the side reactions rate and impurities for boric acid production. In the experimental process, a specific concentration of sulfuric acid solution was fed to the reactor at varying flow rates. The yield in the SBR increased up to 99.6%, depending on the sulfuric acid feed rate. When the same conditions were applied in the BR experiment, the yield was calculated to be 90.8%. Compared with the batch reactor results, it was observed that the impurity concentration in the boric acid solution produced within the SBR decreased by 41.7% to 45.3%, depending on the feed rate. Consequently, the utilization of SBR demonstrated clear advantages over the BR in terms of both yield and impurity control. Furthermore, this study serves as a compelling illustration of the practical applications of solid–liquid heterogeneous phase reactions within the context of SBR technology.

Convenient preparation of expanded graphite and graphite nanosheets as well as improvement of electrical conductivity of polyurethane by filling graphite nanosheets

Expandable graphite precursors were firstly prepared by the oxidative intercalation of natural flake graphite powders with mean lateral particle sizes of 25–100 μm in concentrated sulfuric acid solutions using Ca(ClO)2 as an oxidant. Higher oxidative intercalation extent increased the thermal expansion of expandable graphite to obtain expanded graphite with a larger volume ratio of 162 mL⋅g−1. Graphite nanosheet samples were facilely and eco-friendly prepared by sand milling of expanded graphite in an aqueous solution. The thicknesses of as-prepared graphite nanosheets could be decreased from 15–20 to 4.8–5.5 nm with the prolonging of sand milling time from 4 to 12 h. As compared with polyurethane/natural flake graphite composite films, the electric conductivity of polyurethane/graphite nanosheet composite films was increased by 6 orders of magnitude at a lower filler content of 5 wt%. The filling of graphite nanosheets endows polyurethane with good electrical conductivity.

One Pot Synthesis of Calcium Sulfate Hemihydrate from Fishbone-derived Carbon

Calcium Sulfate Hemihydrate (CSH) with uniform morphology and high crystallinity were successfully prepared by a precipitation-hydrolysis method in a concentrated sulfuric acid solution containing fishbone-derived carbon. The CSH was produced by carbonization of fishbone powder at 500 °C for 2 h, followed by sulfonation with concentrated sulfuric acid for 3 h. The solid mixture was washed until the pH of 2, then left at room temperature for 3 days. Physical properties of synthesized CSH were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF), Scanning Electron Microscope (SEM), nitrogen adsorption-desorption isotherm, and melting point test. It is concluded that the CSH were formed due to hydrolysis of fishbone-derived carbon in a moderately concentrated sulfuric acid solution of carbon-derived fishbone and crystallization into a fibrous octa calcium phosphate (OCP) form. In this research, effect of crystal growth time, effect of pH during the crystal growth, and effect of volume of the solution were also investigated. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Inhibition of Steel Corrosion Rate in Sulfuric Acid Solution with Various Concentrations Using Soursop (Annona muricata L.) Leaf Extract Inhibitor

Exploration of soursop leaf extract (Annona muricata L.) as one of the natural inhibitors against the corrosion process. The objective of this research is to determine the effect of the extract on inhibiting the corrosion rate of steel. The corrosion rate is determined by the decrease in the mass of the steel during immersion in various concentrations of sulfuric acid solutions, namely 0.01, 0.05, and 0.1 M, and optical microscopy will be used to analyze the corroded steel samples. This study consists of several stages: soursop leaf extraction, steel sample preparation, inhibitor solution and corrosive media preparation, immersion, and characterization. The extraction method is performed by maceration for 168 hours to obtain the extract. The highest corrosion inhibition efficiency obtained is 63.1% with the presence of 600 ppm inhibitor in 0.01 M sulfuric acid solution, while the lowest corrosion inhibition efficiency obtained is 14.8% with the use of 200 ppm inhibitor in 0.1 M sulfuric acid solution. The types of corrosion that occur on the steel surface are uniform corrosion and pitting corrosion.

DYNAMICS OF DECOMPOSITION OF SOLID HOUSEHOLD WASTE IN THE PRESENCE OF SULFURIC ACID

The article is devoted to the development of technology for obtaining organic-mineral fertilizers and chemical meliorants on the basis of solid waste (SW). The presented article mainly describes the physico-chemical basis of decomposition of solid waste with solutions of different percentages of sulfuric acid, which is the first stage of the study. The purpose of the research is to study the physico-chemical basis of decomposition of solid waste depending on the concentration of sulfuric acid solution, its initial temperature, time and intensity of mixing during the development of technology for obtaining organic-mineral fertilizers and ameliorative substances. During the study, the concentration of sulfuric acid solution from 5% to 70, decomposition dynamics of samples within 36-80 minutes, It was studied under mixing conditions at an intensity of 40 per/min to 180 per/min. It was established that each factor has a great influence on the percentage of decomposition of solid household waste, therefore, the optimal parameters for each factor were determined and clarified as a result of experimental experiments. As a result of the conducted research, it was determined that solid waste from the point of view of the richness of macro-and microelements contained in it is a fully usable raw material for fertilizer production, it has been observed that the extraction of food-repellent elements from the composition of solid household waste with 10-20% sulfuric acid solution is appropriate and in this case, along with the decomposition, the process of neutralization of microorganisms in it takes place. 40-600C optimum temperature of technological process for transition of moisture-repellent elements into solution, it has been proved that the concentration of acid solution is between 10-20% and the mixing intensity is 60-140 per/min., in the end, it is recommended to enrich the composition of the obtained fertilizer with nutritive substances after the completion of the technological process in order to improve the quality of the composition of the obtained liquid fertilizer. As a result of the conducted studies, it was found that during the decomposition of solid waste in the presence of weak acid solutions, about 80-85% of the nutrient elements contained in it can be extracted and used in fertilizer production. Keywords: fertilizer, solid waste, sulfuric acid, ameliorant, salinity, salinization.

Microplastic quantification of nylon and polyethylene terephthalate by chromic acid wet oxidation and ultraviolet spectrometry

Microplastics are ubiquitous and their quantification in an environmental sample is important. This study modified the Walkley–Black titration method to measure the organic content of a synthetic sample containing polyethylene terephthalate (PET) or/and Nylon66 (NY) dissolved in a concentrated sulfuric acid solution, which was further converted to mass by incorporating the factors of carbon mass ratios by their molecular structures. The PET mass in concentrated sulfuric acid was also measured using UV/VIS spectrophotometer. The experimental results from the chromic acid wet oxidation showed that almost-complete oxidation of PET and NY by dichromate was achieved at the elevated temperature of 135 ∼ 140 °C, and the organic carbon resulting from existing PET and NY can be determined accurately. This study is a pioneer investigation using wet oxidation for PET and NY quantification. A step-by-step protocol was proposed to delineate the operating procedure of the modified chromic acid wet oxidation. By incorporating the UV/VIS spectrometry with chromic acid wet oxidation, the PET and NY content in a synthetic sample can be quantified. • Chromic acid wet oxidation was applied to quantifying PET and NY accurately. • UV/VIS spectrophotometer was found capable of measuring PET. • A heating system was introduced to improve the accuracy of wet oxidation analysis. • PET and NY can be measured by combining titrimetric and optical methods.

Development of MoO3-Based Proton Batteries

Aqueous rocking chair batteries have attracted attention as highly safe and inexpensive secondary batteries. Lithium and sodium ions have mostly been used as the mobile ions, whereas proton systems with potentially the highest mobility have rarely been reported. Recently, research on proton batteries has been conducted using concentrated sulfuric acid solutions as the electrolyte that can assist high-rate performance.[1] Stability under concentrated acidic conditions is required for the electrode materials, as well as the capability of proton accommodation. MoO3 has been reported as a stable negative electrode material for aqueous proton batteries,[2] while few positive electrode materials are known except for bulky organic[3] and Prussian-blue materials[4]. For achieving high energy density and long life, oxide positive electrode materials are desirable. Here we propose the application of MoO3 as the positive electrode material by optimizing the operating composition range. The potential values shown below are all shown versus SHE (actually measured with Ag/AgCl).MoO3 showed a discharge profile at around 0.5 V with the maximum capacity of ca. 100 mAh g-1, as shown in the figure. This potential is sufficiently more positive than the redox potential of protonated MoO3 of around -0.3 V as the negative electrode. With the aid of operando X-ray diffraction analysis, it turned out that the discharge regions at 0.5 V and 0.4 V are respectively associated with a biphasic transition of MoO3/phase I (ca. 0 < x < 0.3 in H x MoO3) and a single-phase reaction of phase I (ca. 0.3 < x < 0.5 in H x MoO3). Deep discharging beyond this range results in the coexistence of phase I and phase III (ca. 0.5 < x < 1.5 in H x MoO3) and the proton extraction from phase III leads to the formation of phase II or phase IIa with its discharging potential of 0.0 V. Structural calculation based on the density function theory is employed to clarify the origin of this irreversible phase transition behavior. Different proton sites between these phases seem to be responsible.An aqueous proton battery with a 7 mol dm–3 sulfuric acid electrolyte was constructed with H-inserted MoO3 and MoO3as the negative and positive electrodes, respectively, and was successfully discharged and charged repeatedly, with the operating voltage of ca. 0.6 V, indicating the launch of aqueous proton battery composed of oxide active materials. Reference s : [1] J. Li, H. Yan, C. Xu, Y. Liu, X. Zhang, M. Xia, L. Zhang, J. Shu, Nano Energy, 89 (2021) 106400.[2] X. Wang, Y. Xie, K. Tang, C. Wang, C. Yan, Angew. Chem. Int. Ed., 57 (2018) 11569.[3] X. Wang, J. Zhou, W. Tang, Energy Storage Mater., 36 (2021) 1.[4] X. Wu, J. J. Hong, W. Shin, L. Ma, T. Liu, X. Bi, Y. Yuan, Y. Qi, T. W. Surta, W. Huang, J. Neuefeind, T. Wu, P. A. Greaney, J. Lu, X. Ji, Nat. Energy, 4 (2019) 123. Figure 1

Origin of the Second-Order Proton Catalysis of Ferriin Reduction in Belousov-Zhabotinsky Reactions: Density Functional Studies of Ferroin and Ferriin Aggregates with Outer Sphere Ligands Sulfate, Bisulfate, and Sulfuric Acid.

The detailed mechanisms of Belousov-Zhabotinsky oscillating reactions continue to present grand challenges, even after half a century of study. The origin of the pH dependence of the oscillation pattern had never been rigorously identified. In our recent kinetic study of one of the key Belousov-Zhabotinsky reactions, the iron-catalyzed bromate oxidation of malonic acid, compelling agreement between experiments and kinetic simulations was achieved only with the inclusion of second-order proton catalysis of the reduction of the [Fe(phen)3]3+ species. After exhausting all other avenues in search of an explanation of this proton catalysis, we considered the possibility that the parent iron-phenanthroline complexes could aggregate with neutral and anionic outer sphere ligands (OSLs) in the highly concentrated sulfuric acid solution, and we hypothesized that OSL protonation would increase the capacity of the aggregated complex to oxidize the organic fuel. We performed potential energy surface analyses at the SMD(APFD/6-311G*) level of complexes of the types [Fe(phen)3(SO42-)m(HSO4-)n(H2SO4)o](c-2m-n)+ for ferriin (c = 3) and ferroin (c = 2) aggregated with m sulfate, n bisulfate, and o sulfuric acid OSLs. We present structures of the OSL aggregates, develop a nomenclature for their description, and characterize their electronic structure. The structural chemistry provides the foundation to discuss the ferroin/ferriin redox couple with emphasis on the relationship between the vertical electron affinities of ferriin aggregates and their OSL protonation states. For proton catalysis to manifest itself, double-protonation paths that are slightly endergonic should be present, and proton affinities of aggregated OSLs allow the identification of such double-protonation chains. As a first test of our mechanistic proposal for the second-order proton catalysis of the Belousov-Zhabotinsky reaction, the results presented here provide compelling evidence in support of the importance of outer sphere ligation of the iron catalyst.

The Role of Medium Condition for Uranium Separation from Central Kyzylkum’s Low-grade Phosphorite after Sulfuric Acid Treatment

This article presents the results of separating radioactive elements, particularly uranium, from low-grade phosphorites of the Central Kyzylkum by low concentrated sulfuric acid solution, which is practically feasible at the Kyzylkum phosphorite combine (KPC). In world practice, uranium was extracted from phosphorite ore in the countries of the Middle East (Syria, Morocco, Algeria, Egypt) at the final stages of obtaining phosphorus fertilizers at metallurgical and chemical plants. The extraction of uranium from phosphorite ore is not practiced in Uzbekistan. The proposed method is fundamentally different from the above and is recommended to be applied at the initial stage of enrichment phosphorite ores in the enrichment plants. Studies have shown that the uranium completely passed into solution by treating phosphorite ore with weak concentrated sulfuric acid solution. Analyses of solution and sediment composition showed that the useful component, P2O5, remained in the sediment, increasing from 8.69% to 10.3%, while uranium passed into the solution with alkaline salts alkaline-earth elements. To obtain a finished product, the resulting enriched solution was added to the richer phosphorite ore. When performing the above processes, the pH of the medium was kept at the neutral level, which is of great practical importance for the implementation of this method with minimal economic costs using conventional inventory, corrosion resistance, and environmentally friendly phosphorus fertilizer.

Copper Layer on an Aluminum Door Frame to Prevent Spread of Bacteria

The spread of disease by bacteria and viruses is very susceptible to outbreaks in public facilities through direct and indirect contact. Indirect contact occurs through intermediate such as housing equipment made of aluminum. One thing that people touch the most is door handles and frames. Aluminum frames are generally anodized to give a color effect because painted directly is difficult. Anodized products generally have a pore structure so that they can easily become an ideal place to grow and colonize bacteria and viruses. To overcome this, the coating process is carried out by electroplating. In this study, aluminum was treated with anodization and non-anodization. The concentration of sulfuric acid solution used was 0.5 M; 1M and 2M. The current used is 0.6A; 0.9A and 1.2M. Increasing the sulfuric acid concentration will increase the efficiency of the cathodic current and increase the mass of the deposit per unit area. Observation of the microstructure with an optical microscope shows the structure formed is dendritic in which the nucleus is continuous. The smooth and flat surface makes aluminum safe to be used and does not become a medium for bacteria or viruses to stick at aluminum surfaces.

Acid-resistant hierarchical mordenite for gas dehydration

In this study, mesoporous zeolite mordenite (MOR-S2) was prepared as a solid desiccant for drying a wet gas model. The synthesized zeolite could dehydrate the nitrogen gas with an initial water content of 53 ppmv down to ca. 3 ppmv in only 60 s with a breakthrough capacity of 7.55 g/g. Five dehydration cycles indicated no changes in the adsorption behavior of the desiccant. Moreover, the retained structural properties of the synthesized zeolite after immersing in concentrated (97 %) sulfuric acid solution declared that it could be utilized as a desiccant for drying moist corrosive gases on an industrial scale.

Development and validation of standardization methods of aqueous sapropel extract

Methodological bases and uniform standardization criteria of humic compounds as substances for drug products have not been developed yet. This is due to the structural complexity of humic compounds, the variety of ways to extract them from natural objects, the impossibility of using many classical methods of analytical chemistry to identify and quantify humic substances (HS), the lack of standard samples. The identification of humic acids (HA) in the aqueous sapropel extract (ASE) is identified after extracting from ASE by alkaline hydrolysis by the quantification method. After further precipitation with a concentrated sulfuric acid solution characteristic dark brown color is appeared. It was carried out the HA extraction from the sample of ASE, the precipitation of HA, the oxidation of HA and Mohr’s salt titration in accordance with the methodology developed on the basis of SSTU 7083:2009. It was determined that the total mass fraction of HA in the ASE sample was 83.8 mg/g± 0.12%. The methods of identification and quantification of the total mass of HA in ASE have been developed and validated. The ASE has been standardized.

Preparation of Expanded Graphite and Graphite Nanosheets for Improving Electrical Conductivity of Polyester Coating Films.

Expanded graphite and graphite nanosheets were facilely prepared by the thermal expansion of expandable graphite at 800 °C and sand milling of expanded graphite in water, respectively. When the expandable graphite precursor was prepared by the oxidation and intercalation of natural graphite (5 g) using KMnO₄ (6 g) as an oxidant in a concentrated sulfuric acid solution (120 mL) at room temperature (25 °C) for 8 h, the expanded graphite with a maximum volumetric rate of 317 mL g-1 was prepared after the thermal expansion of the expandable graphite precursor at 800 °C for 60 s. The oxidation extent of natural graphite with KMnO₄ is crucial for the preparation of expanded graphite. The thicknesses of graphite nanosheets decreased from 8.9 to 3.2 nm when the sand milling time of the expanded graphite in deionized water was prolonged from 6 to 24 h. The prolonging of the sand milling time not only decreased the layer number of the graphite nanosheet but also increased the d002 spacing due to the shocking and shearing forces. The addition of the expanded graphite powder and graphite nanosheets in a polyester paint efficiently improved the electrical conductivity of the resultant polyester coating films.

Carbon dots with polarity-tunable characteristics for the selective detection of sodium copper chlorophyllin and copper ions

Compared to water-soluble carbon dots (CDs) the properties and applications of hydrophobic CDs are rarely addressed. In this study, a one-pot, simple chemical oxidation approach has been applied to synthesize hydrophobic carbon dots (TO-CDs) at room temperature from triolein (TO) in concentrated sulfuric acid solution. Sodium copper chlorophyllin (SCC) quenches the fluorescence of TO-CDs by a photoinduced electron transfer process. Upon excitation at 400 nm, the fluorescence intensity of TO-CDs probe at 500 nm shows a linear response against the SCC concentration ranging from 1.0 to 10 μM, with a limit of detection (LOD) of 0.61 μM. Quantitation of SCC in flavored drinks shows percentage recovery (%R) vaues of 98–103% and relative standard deviation (RSD) values less than 6.5%. The hydrophobic TO-CDs can be converted into hydrophilic TO-CDs through hydrolysis in NaOH solution. The presence of sulfonyl groups on the hydrophilic TO-CDs enhances the coordination ability of the CDs toward Cu2+ ions, leading to fluorescence quenching which allows for the detection of Cu2+ ions with LOD of 0.21 μM and a linear range of 0.5–10 μM. The hydrophilic TO-CD probe possesses high selectivity toward Cu2+ ions (tolerance at least ten-fold comparative to other metal ions). The assay has been validated with the analysis of spiked soil samples, with %R values of Cu concentration of 97.8–99.0% and RSDs below 2.0%. The surface tunable CD probes demonstrate their potential for the rapid screening of Cu2+ ions in environmental samples and SCC in foods.

Thermal analysis of a heat pump-based liquid gap membrane distillation H2SO4 system

This paper presents a new type of circulation system combining heat pump and liquid gap membrane distillation (LGMD) for the concentration of sulfuric acid solution. The proposed hybrid system not only has a simpler flow configuration, but it also demonstrates significant thermal performance advantages. Based on the principle of conservation of mass and energy, a mathematical model is established in Aspen Plus to simulate working conditions. Through varying the relevant parameters, the solution with low boiling point elevation to achieve the maximum water production gain to output ratio (GOR) value was obtained, which is approximately 33 times that of the conventional system under the given condition in this research. Given the temperature difference between the condenser and the evaporator in the heat pump cycle, the higher membrane flux and the maximal value of GOR are obtained at the high feed temperature. However, increasing the molar fraction of the feed solution sharply decreases both the membrane flux and GOR, especially at high feed solution temperatures. Additionally, it was found that the high GOR are obtained when selecting the high boiling point working fluids. Therefore, these results can provide significant references for the further implementation and optimization of the proposed system.

The first result in the determination of the percentage concentration of sulfuric acid solution based on the gamma transmission technique with an energy of 662 ke

In this study, we propose an approach using the gamma transmission technique based on the combination of the experimental and simulated data for determining the percentage concentration of the acid solution. The experiment consists of a collimated 137Cs radioactive source emitting a narrow gamma beam of 662 keV and a NaI(Tl) detector. Monte Carlo simulation data is used to construct the calibration curve of lnR versus the percentage concentration of acid solution at different temperatures (R is the ratio of the area under a transmission peak for an acid solution relative to that for water). The percentage concentration of the acid solution is determined based on the calibration curve and the experimental ratio R. The obtained results showed that this approach was feasible in which the percent concentration of 7 in total 8 samples of the sulfuric acid solution are less than 5% in comparison with one of the reference samples. There is only one sample with a relative deviation of 7.6%. These preliminary results suggest that it is possible to develop nondestructive testing for the rapid determination of the percentage concentration of acid solutions based on the gamma transmission technique.

Separation and recovery of valuable metals from spent lithium-ion batteries via concentrated sulfuric acid leaching and regeneration of LiNi1/3Co1/3Mn1/3O2

Recycling of spent lithium ion batteries (LIBs) is an urgent task in the view of environmental protection, resources reuse and sustainable development of battery industry. Our work presents a new method for recovery of Al foils and cathode materials from LIBs via a simple process. The concentrated sulfuric acid (18.4 M H2SO4) solution are used as both separation and leaching agent. The complete separation of cathode materials from Al foils and the complete leaching of Li are achieved simultaneously after leaching for 1 h at 80 °C and solid/liquid ratio of 800 g L−1. Under these conditions, the leaching efficiencies of Ni, Co and Mn reached 25.6%, 23.2% and 18.3%, respectively, and the polyvinylidene fluoride (PVDF) binder is partially decomposed. The concentrated sulfuric acid destroys the structures of cathode materials and PVDF but prevents the Al dissolution by formation of the passivation film, which contributes to the separation of cathode materials from Al foils and no loss of Al foil. After removal of Al foils and adding the 4.5 vol% H2O2 solution to further leach the remaining suspension for 70 min at 70 °C, and the metals of Ni, Co and Mn in the cathode materials are totally leached into the solution. The amount of H2SO4 consumed by leaching 1 kg cathode pieces was 23 mol, which is less than the required acid consumption for the traditional acid leaching process. The leaching solution is precipitated step by step to obtain high purity Ni1/3Co1/3Mn1/3(OH)2 and Li2CO3. The obtained Ni1/3Co1/3Mn1/3(OH)2 and Li2CO3 are regenerated to LiNi1/3Co1/3Mn1/3O2 materials with excellent electrochemical performance.

Synthesis And Characterization Of Adsorbent From Solid Waste Of Ceramics Industry

At present, the adsorbents generally use bentonite and activated carbon, but the availability of bentonite is less so that other alternatives are needed for substitution of bentonite as an adsorbent. One of the materials that have the potential as an adsorbent is the ceramic industry waste (ceramic clay). Ceramics clay containing feldspar which before being activated using sulfuric acid has a ratio of concentration between silica and alumina (silica/alumina) of 3.6, so a process is needed to increase the ratio of silica and alumina. One such process is by activating ceramic clay using sulfuric acid. The characterization and adsorption performance of adsorbent from ceramic clay were studied with various acid concentration. Ceramic clay powder was activated with sulfuric acid. The adsorbent particles were characterized by IR Spectra, X-Ray Diffraction, X-Ray Fluorescence, and BET. Various concentrations of sulfuric acid solutions for activation have a significant effect on the characteristics and performance adsorbent. This is indicated by XRD analysis where the characteristics of the adsorbent have feldspar (Ca-KAl2SiO3) content with the ratio between silica and alumina increasing around 4.3-4.8 with an increase in sulfuric acid concentration from 10-30% and adsorbents in the form of mesoporous crystalline structure. The characteristics of adsorbent with IR Spectra analysis showed that the presence of silicate alumina groups, so the products have the potential as a bleaching agent. The best surface area is produced at a concentration of 15 % sulfuric acid solution with one hour activation time which is equal to 117.44 m2/g.