HCl Aqueous Solution Research Articles

Effect of Electrochemical Anodization on the Hardness of Grade 2 Titanium Using Aqueous HCl as Electrolytic Solution

Currently, there are different synthesis techniques to obtain new materials, however, one of the most used is electrochemical anodizing, which, by means of oxide-reduction reactions, allows modifying the surface of a metal, thus generating an oxide layer that protects the material in such a way that it improves its hardness values. In this research work, an electrochemical anodizing process was carried out on titanium grade 2, using HCl in aqueous solution with a concentration of 0.15 M and with voltage variation of 10V, 11V, 12V, 13V, and 14V as electrolyte. Subsequently, an annealing process was carried out at 550°C for 4h to obtain a crystalline titanium oxide coating. For the analysis of the oxide layer obtained, Vickers hardness tests were carried out with an applied load of 50g. The presence of a titanium oxide layer improved the hardness values ​​from 2.07 GPa to 4.12 GPa.

Some regularities in the process of anthocyanin extraction from vegetable sources

This work investigates regularities in the process of extracting anthocyanins from various plant sources in the medium of extractants. For extraction, fresh plant samples were used, including the roots of purple carrots, roots of purple potatoes of the Amethyst variety, fresh fruits of Michurin's aronia, fruits of the garden nightshade, cornelian cherries, blueberries and red cabbage, as well as dried peony petals. The extraction was carried out by infusing the plant material under study in a selected extractant (left overnight). The concentration of anthocyanins was determined spectrophotometrically. It was shown that a 0.1 M aqueous solution of HCl is an effective and environmentally friendly extractant allowing for the extraction of anthocyanins from various sources. Provided that the medium acidity is greater than 1, significant losses of anthocyanins are possible: 5-45% at pH = 2; 33-88% at pH = 3; 41-92% when extracted with distilled water. Acylation does not contribute to an increase in the degree of anthocyanin extraction. The addition of organic solvents (ethanol, acetonitrile and glycerin) can significantly accelerate the anthocyanin extraction in some cases, which is particularly true for cornelian cherries. When using crushed material, the influence of the extractant on the degree of extraction is minimal. Information is presented on the solvatochromic effect, which affects the spectral characteristics of some anthocyanin solutions. It was shown that the shift of the absorption band maximum is the greatest for non-acylated anthocyanins, while decreasing for acylated compounds. The latter is most likely to be associated with the intramolecular copigmentation of acylated anthocyanins in aqueous solutions. When determining the concentration of anthocyanins in solvents with different concentrations of organic additives, the solvatochromic effect should be taken into account. The addition of an organic solvent leads not only to a shift in the absorption band maxima, but also to significant hyperchromic effects. If this effect is ignored, errors in determination of anthocyanins can exceed 70%. This paper proposes a simple and effective approach to considering these effects using a cross-dilution scheme. Therefore, the choice of extractants for efficient anthocyanin extraction from various plant raw materials was experimentally substantiated, and a method for evaluating solvatochromic effects was proposed.

Corrosion Resistance Evaluation of a Stainless-Steel Brazed Joint in HCl Solution

To clarify the effect of the acid solution type on corrosion resistance, the corrosion behavior of stainless steel brazed joints in HCl aqueous solution was evaluated through electrochemical measurements. Anodic polarization curves of a ferritic stainless-steel base metal, Ni-based brazing filler metals, and a brazed joint were recorded. In addition, in situ observations were conducted to observe the corrosion behavior of each structure of the brazed joint. Corrosion potentials of the brazing filler metal were lower than that of the base metal. In situ observations of the brazed joint revealed the order of corrosion in aqueous hydrochloric acid. According to the electrochemical measurements, under an actual corrosive environment, the brazing filler metal can function as an anode and selectively corrode. In addition, the anodic polarization curve of the brazed joint showed values between those of the polarization curves of the brazing filler metal and the base metal, indicating that the corrosion resistance could be electrochemically evaluated in HCl aqueous solution.

Volumetric and Acoustic Properties of D(+) Glucosamine·HCl and L-Lysine·HCl in Aqueous Solutions at Different Temperatures

In present work, density and speed of sound of aqueous binary mixtures of biologically important amino acid derivatives namely D(+) glucosamine·HCl and L-lysine·HCl have been measured at three different temperatures i.e. (278.15, 288.15 and 298.15) K and in the concentration range of 0.0-0.2 mol kg-1. Using density and speed of sound data, different thermodynamic and acoustic parameters like apparent molar volume (Vφ) and apparent molar isentropic compression (Kφ) of solute have been computed at different temperatures. Speed of sound data have also been used to calculate hydration number (nH) of solute. The temperature dependence of the limiting apparent molar volume of solute has been used to calculate thermal expansion coefficient (α*), apparent molar expansivity (E0 φ) of solute and Hepler’s constant (∂2V0 φ/∂T2). The final outcome of the study has been discussed in terms of various interactions among solute and solvent molecules.

Study on Kinetics of GD Hydrolysis in HCl aqueous

Organophosphate neurotoxic agents like Sarin (GB) and Soman (GD) are lethal to person. Except various kinds of decontaminants, they can be also decomposed in natural environment through nucleophilic reaction, where acidic or alkaline substance was to accelerate their hydrolysis. Most of the papers were about GB hydrolysis. Information on GD hydrolysis was relatively small, especially about kinetics of GD in acidic solution. In view of possible effect of positive ion and negative ion on hydrolysis reaction, a relatively simple composes solution, HCl aqueous solutions, was selected to investigate the factors affecting GD hydrolysis rate. Results showed that GD hydrolysis was accorded with the first-order kinetics equation if pH value was kept constant. Its rate constant was independent of GD initial concentration when the amount of H+ was excess than its requested amount. The apparent hydrolysis rate constant (kobs) in pH of 0.90 was about 0.202 min-1 at 20°C, no matter what initial concentration of GD was. The concentration of H+ was the most important factor affecting its rate. The rate constant (kobs) in HCl aqueous as a function of pH value (0.90~2.80) obeyed an equation in 25°C, that is kobs =0.17×10-0.82×pH. Reaction temperature had an obvious effect on hydrolysis rate of GD. Every 10°C increase in temperature, kobs of GD hydrolysis was improved about 2.5 times. The activation energy value (Ea) of GD hydrolysis in HCl aqueous with a pH value of 0.90 was approximately 64.25 kJ/mol.

Molten salt synthesis of TiB2 nanopowder by reduction of TiO2 with MgB2

This research work presents the preparation of TiB2 nanopowders by molten-salt synthesis (MSS) technique from TiO2 and MgB2 as starting active materials and MgCl2 as a molten salt. The pure TiB2 nanopowders were finally prepared using 2M HCl aqueous solution to leach the synthesized samples. The effects of the firing temperature, firing time and reactants to salt ratio on the TiB2 nanopowders formation were examined. The results demonstrated that the TiB2 formation was completed even with reactants to salt mass ratio of 1:2 at 1000 ?C for 4 h. The TiB2 nanopowders synthesized with 1:2, 1:5 and 1:10 reactants to salt mass ratios have different particle sizes. Thus, the average particle sizes estimated from BET surface areas were 59, 55 and 46 nm for the samples synthesized with 1:2, 1:5 and 1:10 reactants to salts mass ratios, respectively. These results illustrated that the high concentration of MgCl2 plays a key role in the particles? size reduction. The above results assured that this research study presents a new low-temperature synthesis route for nano-sized metal diboride powders.

COMPETITION BETWEEN METHANOL AND WATER MOLECULES UPON THE FORMATION AND SOLVATION OF IONS IN THE CH3OH–H2O–HCl SYSTEM

IR spectroscopy and density functional theory (B3LYP/6-31++G(d, p)) are used to study the competition between methanol and water molecules during the formation of (CH3(H)O∙∙∙H∙∙∙O(H)CH3)+, (CH3(H)O∙∙∙H∙∙∙OH2)+, and (H2O∙∙∙H∙∙∙OH2)+ ions with strong quasi-symmetrical H-bonds and their solvation in the CH3OH–H2O–HCl system. When water is added to a solution of HCl in methanol, H2O molecules substitute CH3OH molecules in (CH3(H)O∙∙∙H∙∙∙O(H)CH3)+ ions to form mixed disolvates. Conversely, when methanol is added to an aqueous solution of HCl, (H2O∙∙∙H∙∙∙OH2)+ ions are maintained and CH3OH molecules are involved in their solvation. Provided that the fractions of methanol and water are commensurate, the solutions contain simultaneously (CH3(H)O∙∙∙H∙∙∙OH2)+ and (H2O∙∙∙H∙∙∙OH2)+ ions. The ratio between their concentrations depends on the content of HCl in the system. It is shown that the energy of the hydrogen bond system per one dissociated HCl molecule is the main factor determining the structure of CH3OH–H2O–HCl solutions, in particular, the composition of proton disolvates.

One-step fabrication of transparent superhydrophobic surface

A self-cleaning, transparent superhydrophobic silica-based surface with water contact angle (CA)/sliding angle (SA) 168°/2° was fabricated by simple one-step thermal oxidation of silicone grease. Microstructural studies (FESEM/TEM) confirmed the presence of a sponge-like pore structure of amorphous silica nanoparticle having a diameter of around 20 ± 2.2 nm. EDS analysis confirms the presence of C, Si, and O in coated substrates. Also, phase and thermal studies (XRD, FTIR, and TG-DSC) analysis showed the thermo-oxidative decomposition of silicone grease results in superhydrophobic –H2C-Si-O-Si-CH2- network structure at 400 °C followed by thermally stable superhydrophilic HO-Si-O-Si-OH network structure at 500 °C. The coated surface showed excellent stability towards corrosive liquids (1 M NaCl, NaOH, HCl aqueous solution, and hot water) and exposed temperature up to 400 °C. The maximum visible light transparency of the superhydrophobic glass was 92.4% compared to the uncoated glass (93.3%). Thus, making transparent superhydrophobic surfaces by a simple and straightforward process can be potentially used in self-cleaning glasses for various engineering applications.

Influence of the morphology of Co2O3 particles on the dissolution kinetics in electrolytes

Establishment of criteria for optimizing technological processes for dissolving transition metal oxides, separating metal compounds from depleted ores, removing oxide deposits from thermotechnical equipment, and methods for cleaning compounds are of practical significance. Cobalt and its compounds are important in the production of hard and heat-resistant alloys as organic synthesis catalysts, as a component of trace elements, fertilizers and drugs. Cobalt isotopes are used as radioactive labels in medicine, as fuel in spacecraft batteries. To solve the technological issues of replenishing the deficit of cobalt by processing cobalt raw materials and its regeneration from industrial waste, it is necessary to conduct targeted research, study the regularities of its behavior during chemical processes (leaching of ores and concentrates) and during electrochemical dissolution (obtaining cobaltcontaining intermediate products for further alloy smelting). One of the important factors affecting the kinetic parameters of the dissolution of cobalt oxides is the characterization of surface properties of the solid phase. The surface structure of powdery Co2O3 oxide was studied by X-ray phase analysis and electron microscopy. The chemical dissolution of the oxide in aqueous solutions of HCl was studied. The sizes and shapes of cobalt oxide particles, the nature of their surface distribution were determined, and kinetic curves of the chemical dissolution of Co2O3 were constructed. The independence of the oxide dissolution mechanism on the acid concentration was established. The kinetic parameters of the process were calculated (specific dissolution rate, reaction order with respect to hydrogen ion). A comparative analysis of the correspondence between the obtained experimental and available literature data was carried out. The obtained experimental and calculated results are of interest in studying the regularities of the dissolution of solid oxide phases of cobalt in various electrolyte compositions.The work was carried out with funding by D. Mendeleev Chemical Technical University of Russia, Project No. X-2020-011.

Bactericidal Pectin/Chitosan/Glycerol Films for Food Pack Coatings: A Critical Viewpoint.

Pectin and chitosan films containing glycerol (Gly) at 5, 10, 15, 20, 30, and 40 wt % were prepared in an aqueous HCl solution (0.10 M) by the solvent evaporation method. The unwashed film (UF) containing 40 wt % Gly (UF40) had elongation at break (ε, %) of 19%. Washed films (WFs) had high tensile strength (σ > 46 MPa) and low elongation at break (ε, <5.0%), enabling their use in food packaging applications. The polymers’ self-assembling occurred during the washing, increasing the stiffness. The XPS analysis suggests that some HCl is lost during the drying process, resulting in a low acid content on the UF surfaces. The UF40 (at 5.0 mg/mL) exhibits cytocompatibility toward mammalian cells and antimicrobial and anti-adhesive properties against Escherichia coli. The remaining HCl in the UF40 can be a disadvantage for food packaging applications; the UF40 (∅ = 8.5 mm; 55 μm thickness) releases H3O+/HCl, reducing the pH to approximately 3.0 when kept in 200 mL distilled water for approximately 30 min. Therefore, we propose the use of UF40 to coat commercial food packaging. The UF40 has low permeability to water vapor and oxygen and works as a barrier against ultraviolet light. The UF40 is also colorless and completely transparent. The UF40 maintained tomatoes’ structural integrity for 18 days at room temperature with no oxidation or microorganism contamination. This paper presents a critical viewpoint concerning chitosan-based films with antimicrobial activities.

Highly efficient extraction separation of La3+ and Ce3+ with N, N, N′, N′-tetraisobutyl-3-oxadiglycolamide from mixed REEs

The extraction and selective separation of Ln3+ with N, N, N′, N′-tetraisobutyl-3-oxadiglycolamide (TiBDGA) from the aqueous HCl solution was studied. The extraction temperature, diluent, salting-out agent, hydrochloric acid concentration, and extractant concentration were investigated to evaluate the effect on the extraction distribution ratio. The extraction mechanism was established based on the FT-IR spectra, XPS analysis, and crystal structure, which ascertains that the stoichiometry of the complex is La(TiBDGA)2Cl3·4H2O. The complex crystallizes in the orthorhombic space group Pbca and La3+ ions coordinate with ten oxygen donor atoms. The extraction results showed that TiBDGA has good selectivity of La3+ and Ce3+ from the other Ln3+. The presence of both NaCl and HCl showed a significant enhancement of extraction and separation. When the concentrations of both HCl and NaCl solution were 2.0 M, the separation factors of La3+ and Ce3+ from adjacent Pr3+ were as high as 133.7 and 136.5, respectively.

Adsorption studies of Cibacron Blue onto both untreated and chemically treated pistachio shell powder from aqueous solutions

ABSTRACT In order to enhance its adsorption properties, pistachio shell powder was modified first with aqueous HCl solution and then with aqueous NaOH solution. The adsorption of Cibacron Blue dye onto both untreated and chemically treated pistachio shell powder was investigated using a batch adsorption technique. The parameters affecting the adsorption process, namely contact time, pH, adsorbent dose, and initial dye concentration were examined. For both adsorbents, the dye adsorption was favored under acidic conditions (pH 2–3). Equilibrium adsorption isotherm and kinetic studies showed that Langmuir isotherm and the pseudo-second-order kinetic model fitted well to the experimental data.

Uranium extraction from different acidic media using a novel solvent-impregnated resin

In present study, uranium (VI) extraction from different acidic media (e.g. H2SO4, HCl and HNO3 aqueous solutions) using tri-n-octylamine (TOA) impregnated into Siplite LX-16 polymeric resin has been investigated using batch experiments. The extraction parameters including aqueous pH, free acidity, salting-out agent addition, initial uranium concentration, volume of aqueous solution to weight of the impregnated resin (v/w) ratio and the phases contact time have been studied. Batch adsorption studies reveal that the prepared TOA/Siplite LX-16 has a significant capacity for the adsorption of U(VI) from aqueous solutions. The maximum sorption capacity of U(VI) from sulfate solution onto the working resin was 92.74 mg/g at an optimum pH range from 1.4 to 1.6. Quantitative desorption of the extracted uranium has successfully been achieved using 0.75 M NaCl acidified with 0.15 M HCl solution. Finally, a complete precipitation of uranium from the eluate solution was attained by hydrogen peroxide precipitation at pH 2.

Easy and environmentally friendly synthesis method for T8 H (HSiO3/2)8

Environmentally friendly methods for the synthesis of T8 H were developed. A combination of triethoxysilane (TES), concentrated HCl aqueous solution, and FeCl3 produced T8 H with almost the same yield as the previously known methods. We also found that HNO3 could be used instead of HCl, resulting in a similar yield. No toxic gases were generated during the reaction with HNO3. Additionally, the synthesis of T8 H based on TES did not generate dangerous substances such as hydrogen chloride and methanol, unlike when trichlorosilane or trimethoxysilane are used. Therefore, our new method for the synthesis of T8 H is considered to be safer, although the yield is the same as the conventional methods.

Development of High Corrosion- and Wear-Resistant Al-Si Alloy Coating on AZ80 Mg Alloy by Hot Extrusion

Mg alloys have been known as the lightest metal materials. However, their practical use is strictly limited due to their poor corrosion and wear resistances. To improve those resistances simultaneously, the present authors have fabricated an Al-Si alloy coating on a Mg alloy substrate by hot extrusion. The Al-Si alloy for coating material was prepared by powder metallurgy and casting processes. An AZ80 Mg alloy billet, a compacted Al-Si alloy plate or a cast Al-Si alloy plate, a die and rams were put in bottom of an extrusion container, and the Mg alloy and the Al-Si alloy were indirectly extruded together. By the hot extrusion, the Mg alloy was successfully coated with the Al-Si alloys prepared in both the powder metallurgy and the casting. The Al-Si alloy-coated Mg alloys showed a high corrosion resistance in a 1.0 mol/L HCl aqueous solution. Also, the wear resistance of the Mg alloy was significantly improved by the Al-Si alloy coating layers. The highest wear resistance was obtained with a cast Al-20 vol.%Si alloy coating layer. The coating improved the wear resistance by 50% compared with the AZ80 Mg alloy.

Evaluation of the Global S-Entropy Production in Membrane Transport of Aqueous Solutions of Hydrochloric Acid and Ammonia.

The results of experimental studies of volume osmotic fluxes () and fluxes of dissolved substances () in a system containing a synthetic Nephrophan® membrane (Orwo VEB Filmfabrik, Wolfen, Germany) set in a horizontal plane are presented. The membrane separated water and aqueous HCl or ammonia solutions or aqueous ammonia and HCl solutions. It was found that for the homogeneity conditions of the solutions and depend only on the concentration and composition of the solutions. For concentration polarization conditions (where concentration boundary layers are created on both sides), and depend on both the concentration and composition of the solutions and the configuration of the membrane system. The obtained results of the and flux studies were used to assess the global production of entropy for the conditions of homogeneity of solutions (), while and —to assess the global production of entropy for concentration polarization conditions ). In addition, the diffusion-convective effects and the convection effect in the global source of entropy were calculated. The concentration polarization coefficient was related to modified concentration Rayleigh number, e.g., the parameter controlling the transition from non-convective (diffusive) to convective state. This number acts as a switch between two states of the concentration field: convective (with a higher entropy source value) and non-convective (with a lower entropy source value). The operation of this switch indicates the regulatory role of earthly gravity in relation to membrane transport.

Clay Minerals Functionalized by Magnetite (Fe3O4) Nanoparticles as Solid Platform for Removal of Chromium (VI) from Water: Characterization, Kinetics, Thermodynamics, Analytical Utility and Reusability Studies

A new protocol for the extraction of chromium (VI) from water is proposed. The established method was based upon retention of chromium (VI) species from aqueous HCl solution (pH = 0.0-2.0) as ion associate of chlorochromate [CrO3Cl]- aq anions onto the clay minerals (CMs) functionalized by magnetite (Fe3O4) nanoparticles (NPs) as solid platform (Fe3O4NPs/CMs). The nanocomposite Fe3O4NPs/CMs was characterized using various instrumental techniques. The nanocomposite enhanced chromium (VI) uptake via the synergic effect of the modified surface area and surface-modified groups, solvent extraction based ion exchange, and electrostatic adsorption. Chromium (VI) sorption was fast and fitted with pseudo-second order with a rate constant of 0.078 min-1 and half-life time (t1/2) of 1.2±0.04 min. The positive and negative values of the enthalpy (ΔH =3.08 kJmol-1) and the Gibbs free energy (ΔG = -5.539 KJmol-1) indicate endothermic, spontaneous, and physical in nature of chromium (VI) uptake and the binding of the [CrO3Cl]- aq onto the nanocomposites was proceeded via electrostatic interactions. Sorbent packed column was tested for chromium (VI) uptake from water, subsequently recovered with NaOH (1.0 mol L-1), and analyzed. Sorbent packed column was reused 3-4 times towards chromium (VI) in water. The sorbent could easily be regenerated with NaOH.

Image analysis data for the study of the reactivity of the phases in Nd-Fe-B magnets etched with HCl-saturated Cyphos IL 101.

Three phases can be distinguished in Nd‒Fe‒B permanent magnets: a Nd2Fe14B matrix grain phase, a Nd-rich grain boundary phase and a Nd-oxide phases. Common reaction models for leaching, such as the shrinking-particle model, cannot simply be applied to composite Nd‒Fe‒B permanent magnets because of the different chemical reactivities of the crystalline phases mentioned above. Etching the surface of a Nd‒Fe‒B magnet to expose its microstructure to electron microscopy is a necessary practice to correlate the microstructure itself to the specific properties of the magnets. Aqueous solutions of mineral acids are often used for etching purposes. However, these solutions are too low viscous to easily control the etching front and they show little selectivity in the etching process. In our work, the ionic liquid Cyphos IL 101 was used to etch bulk magnets instead of aqueous HCl solutions. The bulk Nd‒Fe‒B magnets were first polished, then exposed to a solution of 3 M HCl in Cyphos IL 101 for different times and at different temperatures. Afterwards, the etched Nd‒Fe‒B magnets were washed with ethanol and acetone. The results were examined via scanning-electron microscopy and image analysis. A commercial software, ImageJ®, was employed for image analysis. The latter technique was used to correlate the etched area (%area) or the grain and oxide size to the etching temperature or the etching time. The grain or the oxide size were calculated as Feret diameter. Image analysis revealed to be a necessary tool to support and correct the findings first suggested by the simple scanning-electron microscopy. The data presented in this article might be reused to corroborate a new reactivity order of the three Nd‒Fe‒B phases, different from that traditionally reported in literature, which is – from the most to the least reactive – grain boundary > oxides > the Nd2Fe14B grain phase.

Novel one‐dimensional polymeric Cu(II) complexes via Cu(II)‐assisted hydrolysis of the 2,4‐bis(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐6‐methoxy‐1,3,5‐triazine pincer ligand: Synthesis, structure, and antimicrobial activities

Two unexpected one‐dimensional coordination polymers, [Cu(PT)(H2O)Cl]n 1 and [Cu2(BPT)(ClO4)3(H2O)4]n·2nH2O 2, of symmetrical triazine‐based ligands were synthesized by Cu(II)‐mediated hydrolysis of the 2,4‐bis(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐6‐methoxy‐1,3,5‐triazine (MBPT) pincer ligand. The reaction of Cu(ClO4)2·6H2O with MBPT proceeded via hydrolysis of the methoxy group to produce the dicompartmental 4,6‐bis(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐1,3,5‐triazin‐2(1H)‐one ligand (HBPT) that then undergoes in situ complexation with Cu(II) to afford 2. In case of CuCl2, the reaction proceeds further with C–N cleavage of one pyrazolyl unit leading to the formation of 6‐(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐1,3,5‐triazine‐2,4(1H,3H)‐dione ligand (HPT) that also undergoes in situ complexation with Cu(II) affording 1. The role of Cu(II) is to increase the Lewis acid reactivity of the water molecule where similar hydrolytic reactions for MBPT were observed in acidic medium in presence of an aqueous HCl (1:1 v/v) solution. The molecular and supramolecular structures of complexes 1 and 2 were investigated using X‐ray diffraction of single crystal, Hirshfeld analysis, and density functional theory calculations. The Cl…H (11.7%) and O…H (24.7%) contacts are the most important in 1, whereas the molecular packing of 2 is controlled mainly by the O…H (58.7%) hydrogen bonds. Complex 2 showed better activity against Escherichia coli, Bacillus subtilis, and Candida albicans compared with the standard antibiotics amoxicillin, tetracycline, and ampicillin. In general, complexes 1 and 2 showed good antimicrobial activity than these antibiotics and have the advantage to be used as both antibacterial and antifungal agents.

Protonation-Driven Aqueous Lyotropic Self-Assembly of Synthetic Six-Tail Lipidoids.

We report the aqueous lyotropic mesophase behaviors of protonated amine-based "lipidoids," a class of synthetic lipid-like molecules that mirrors essential structural features of the multitail bacterial amphiphile lipid A. Small-angle X-ray scattering (SAXS) studies demonstrate that the protonation of the tetra(amine) headgroups of six-tail lipidoids in aqueous HCl, HNO3, H2SO4, and H3PO4 solutions variably drives their self-assembly into lamellar (Lα) and inverse micellar (III) lyotropic liquid crystals (LLCs), depending on acid identity and concentration, amphiphile tail length, and temperature. Lipidoid assemblies formed in H2SO4(aq) exhibit rare inverse body-centered cubic (BCC) and inverse face-centered cubic (FCC) micellar morphologies, the latter of which unexpectedly coexists with zero mean curvature Lα phases. Complementary atomistic molecular dynamics (MD) simulations furnish detailed insights into this unusual self-assembly behavior. The unique aqueous lyotropic mesophase behaviors of ammonium lipidoids originate in their dichotomous ability to adopt both inverse conical and chain-extended molecular conformations depending on the number of counterions and their identity, which lead to coexisting supramolecular assemblies with remarkably different mean interfacial curvatures.