Efficient elimination of amoxicillin and methylene blue dye from wastewater by ultrasonic-assisted adsorption using walnut shells-derived sulfonated adsorbent: Optimization by response surface methodology.

Short-chain chlorinated paraffins (SCCPs) are commonly employed as flame retardants and plasticizing agents in carpet manufacturing to improve the flame retardancy and durability of carpet products. However, the application of SCCPs in carpets poses potential exposure risks to humans and the environment. Due to the complex structure of carpets, a reliable and sensitive method for the analysis of SCCPs in carpets has yet to be established to date. Consequently, a novel analytical method was developed for the quantitative determination of SCCPs in carpets using gas chromatography-electron capture negative ionization mass spectrometry (GC-ECNI-MS) coupled with ultrasonic extraction, filtration through a 0.45 µm organic-phase membrane, and purification with concentrated sulfuric acid. Prior to determination by GC-ECNI-MS, all key parameters, including the extraction solvent, extraction conditions and purification methods, were carefully optimised, resulting in high detection sensitivity. Following the optimisation study, detection limit, precision and trueness tests were conducted. The detection limit of this method is 5.76 mg kg-1, the relative standard deviation for precision is between 1.9% and 5.0%, and accuracy is expressed as spiked recovery, which ranges from 97.2% to 102.8%. This method features simple sample pretreatment, low cost, high repeatability, and excellent accuracy, enabling the accurate quantification of SCCPs in carpets.

ABSTRACT Low-grade brucite is a promising magnesium-silicon resource, but its complex composition and high impurity content severely limit its application. This study developed an integrated ammonia distillation-acid leaching process to achieve the synergistic recovery of high-purity magnesium hydroxide and amorphous silica from low-grade brucite. The optimal ammonia distillation conditions were determined as an ammonia-to-magnesium molar ratio of 3:1, reaction temperature of 105 °C and duration of 4 h, enabling efficient Mg²+ leaching with a concentration of 0.9 mol/L. Ammonia precipitation at 50 °C yielded hexagonal flake magnesium hydroxide with uniform particle size and high purity, whose growth mechanism was clarified by BFDH model simulation. The silicon-rich residue was treated by acid leaching under optimised parameters (stirring rate 500 r/min, sulfuric acid concentration 4 mol/L, temperature 353 K), producing amorphous silica with purity ≥98%, specific surface area ≥300 m²/g and particle size ≤45 μm. Kinetic analysis indicated that the acid leaching process followed a chemical reaction mixed-control model with an apparent activation energy of 59.66 kJ/mol. This process realises the high-value utilisation of low-grade brucite, providing a sustainable solution for similar mineral resources and conforming to the principles of circular economy.

Mannose constitutes a principal component in numerous biomass hemicelluloses; however, its utilization by the cellulose-producing bacterium Komagataeibacter xylinus is inefficient. Consequently, during biorefinery and the transformation of biomass rich in mannose for the production of the high-value biological product, bacterial cellulose (BC), the biomass components cannot be fully utilized, leading to resource wastage. Moreover, inappropriate discharge of the fermentation effluent may also result in environmental pollution. This study addressed the underutilization of mannose in spent coffee grounds (SCGs) by introducing a fusion vector expressing mannokinase and phosphomannose isomerase into K. xylinus ATCC 23770, thereby enhancing mannose utilization in this strain model. SCG was pretreated with concentrated sulfuric acid to disrupt crystalline structures, followed by enzymatic hydrolysis to extract saccharides. When culturing in SCG hydrolysate, BC pellicle-derived inoculum achieved 1.2-fold higher BC yield than broth inoculum, attributed to BC matrix protection. The engineered strain K. xylinus CGMCC 31806 demonstrated superior mannose assimilation, yielding 1.5-fold more BC than wild type in simulated SCG medium. In authentic SCG medium without extra nitrogen addition, BC production reached 3.80 g/L, a 1.2- to 2.5-fold increase. The obtained BC exhibited enhanced mechanical properties with 40-84% higher tensile strength and 20-75% increased Young's modulus. This study validates a dual strategy combining agro-waste valorization and targeted strain modification, establishing a collaborative optimization framework linking biomass feedstocks, microbial engineering, and bioprocessing for cost-effective BC production. Future research would utilize existing commercial high-yield strains to replicate the expression strategy of this fusion protein, in order to achieve truly efficient industrial production.IMPORTANCEThe inefficient utilization of mannose, a major hemicellulose component prevalent in biomass by Komagataeibacter xylinus represents a significant bottleneck in the sustainable, cost-effective bioproduction of bacterial cellulose (BC). This underutilization would lead to wasted resources and potential environmental pollution from fermentation effluents. The study directly addresses this critical challenge by pioneering a synergistic "Feedstock-Strain-Process" integration strategy in advancing BC industrialization. We demonstrate the significant impact of engineering K. xylinus for enhanced mannose assimilation coupled with optimized biorefinery of agro-industrial waste, taking mannose-rich spent coffee grounds, as the representative raw material. This integrated approach not only valorizes abundant agricultural waste streams significantly boosting BC yields under nutrient-limited conditions but also generates BC with superior mechanical properties. The study establishes an actionable blueprint for advancing BC industrialization through collaborative optimization of biomass feedstocks, targeted microbial engineering, and process innovation, aligning with the goals of the circular bioeconomy and sustainable material production.

Biofuel production from biomass sources remains a key area of research, aimed at reducing reliance on fossil fuels and promoting environmental sustainability. This study investigates the conversion of used cooking oil (UCO) into biogasoline via catalytic hydrocracking, employing sulfated mesoporous silica dispersed with nickel as the catalyst. Mesoporous silica was synthesized using tetraethyl orthosilicate (TEOS) and NaHCO₃ as the template, followed by a hydrothermal method to introduce sulfate groups and nickel metal. Among the synthesized catalysts, SMS-2 exhibited the highest acidity across varying sulfuric acid concentrations, while 1 Ni/SMS-2 demonstrated superior acidity compared to other nickel loadings. The SiO₂, SMS-2, and 1 Ni/SMS-2 catalysts were evaluated for UCO hydrocracking in a semi-batch double-furnace reactor operated at an optimum temperature of 550 °C for 2 h, with a hydrogen flow rate of 20 mL min⁻¹ under atmospheric pressure. Modifying mesoporous silica with sulfuric acid and nickel significantly enhanced its catalytic performance, with the 1 Ni/SMS-2 catalyst achieving the highest liquid product yield (66.10%) and gasoline fraction (35.47%) at an optimum catalyst-to-feed ratio of 1:100 (w/w). Notably, the resulting biogasoline exhibited a calorific value comparable to commercial gasoline and was free of aromatic hydrocarbons, indicating the potential for cleaner combustion. This study provides valuable insights into the effectiveness of mesoporous silica-based catalysts, highlighting their acid site modulation capabilities for efficiently transforming waste into high-value fuels. Copyright © 2026 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Abstract BACKGROUND The mercury (Hg) content in technical concentrated sulfuric acid must be strictly controlled for industrial applications, particularly in water treatment, fertilizer production, etc. This study explores the removal of Hg(II) ions directly from concentrated sulfuric acid (93–98%) using granular activated carbon. While adsorption processes are well established in aqueous systems, their application in concentrated sulfuric acid matrices has received limited attention due to the highly aggressive chemical media. RESULTS Adsorption performance was evaluated through equilibrium studies, kinetic modeling and continuous‐flow fixed‐bed column experiments. Scanning electron microscopy, Fourier transform infrared spectroscopy and X‐ray fluorescence spectroscopy with energy‐dispersive X‐ray analysis confirmed the chemical stability of activated carbon under strongly acidic conditions and the adsorption of Hg(II) on the activated carbon. The Sips isotherm model provided the best description of equilibrium data ( R 2 = 0.996), while Avrami kinetics adequately fitted the adsorption process ( R 2 = 0.968). CONCLUSION Fixed‐bed column results further demonstrated practical feasibility, suggesting that the use of granular activated carbon offers a promising approach for Hg control in sulfuric acid production. © 2026 Society of Chemical Industry (SCI).

Seaweed bioactive extraction generates de-extracted residual solids that remain carbohydrate-rich but are often underutilized. This study developed an integrated valorization route for Gracilaria fisheri spent biomass to produce fermentable sugars for β-carotene production by Rhodotorula paludigena CM33. Reducing sugar production was optimized using response surface methodology (Box–Behnken design) by varying reaction time, sulfuric acid concentration, and biomass loading at 90 °C. The predicted optimum (47.39 min, 2.50% (w/v) H2SO4, and 7.13% (w/v) biomass) yielded 22.41 g/L reducing sugars and was validated experimentally at 22.22 ± 0.19 g/L, indicating that the model reliably predicted reducing sugar production. The optimized condition was scaled up in a 22 L bioreactor with sequential acid hydrolysis followed by enzyme-assisted hydrolysis, increasing reducing sugars from ~30 to ~40 g/L. FTIR and SEM analyses indicated progressive modification of the carbohydrate matrix across processing stages. Batch cultivation of R. paludigena on the hydrolysate showed that ammonium sulfate supplementation significantly increased biomass, whereas β-carotene titers were not significantly different. Repeated-batch operation on non-supplemented hydrolysate sustained production over four cycles with β-carotene titers of 13.75–17.27 mg/L, demonstrating the operational feasibility of the hydrolysate-based system. Overall, this work demonstrates a practical seaweed biorefinery approach to upgrade G. fisheri spent biomass into sugars and carotenoid-rich yeast biomass.

This work addresses the preparation of V3.5+ electrolyte for vanadium redox flow batteries (VRFBs) by proposing an efficient paired electrosynthesis strategy, combining it with the synthesis of the high-value-added chemical p-chlorobenzaldehyde (PCAD). Traditional methods for preparing V3.5+ electrolyte suffer from issues like impurity introducing and low energy utilizing, while the hydrogen reduction reaction at the cathode in PCAD synthesis has low value. To solve these problems, this work designed and constructed a paired electrosynthesis system based on an electrochemical microchannel reactor: precisely reducing VOSO4 to V3.5+ electrolyte at the cathode, while simultaneously electro-oxidizing Mn2+ to Mn3+ at the anode, which subsequently oxidizing p-chlorotoluene (PCT) to synthesize PCAD. The effects of current density, sulfuric acid concentration, and reactant ratio on reaction efficiency were systematically investigated. Results show that the total vanadium valence state of the cathodically prepared V3.5+ electrolyte stabilized at 3.50 ± 0.02, the yield of anodically synthesized PCAD was 35.51%, the total current efficiency of the paired electrosynthesis system reached 178.8%, and the system demonstrated good repeatability and stability. This study provides a new approach for the green and efficient preparation of VRFB electrolytes and the electrosynthesis of high-value chemicals.

Abstract This study presents a sustainable “waste‐to‐resource” approach by converting sugar beet pulp into a high‐performance sulfonated biochar (CSBP) through a streamlined chemical carbonization route. By utilizing concentrated sulfuric acid, simultaneous carbonization and surface functionalization were achieved under mild conditions, eliminating the need for high‐temperature pyrolysis. Comprehensive physicochemical characterization revealed a highly porous carbonaceous framework enriched with sulfonic acid groups, yielding a fine‐grained adsorbent (<20 μm) with high thermal stability and a carbon content of approximately 85 wt%. Batch adsorption experiments were systematically performed to evaluate the effects of adsorbent dosage, solution pH, initial dye concentration, contact time, and temperature. The adsorption process exhibited high removal efficiency (>90%) at the natural pH of the dye solution, eliminating the need for pH adjustment. Kinetic analysis demonstrated that the adsorption behavior followed a pseudo‐second‐order model, indicating that chemisorption governs the rate‐controlling step, with an activation energy of 9.01 kJ/mol. Equilibrium data were best described by the Langmuir isotherm, confirming monolayer adsorption on a homogeneous surface, with a maximum adsorption capacity of 2.70 mmol/g at 55°C. Thermodynamic parameters (Δ H ° = +9.301 kJ/mol and negative Δ G ° values) indicated that the adsorption process is endothermic and spontaneous. The adsorption mechanism was attributed to the synergistic contribution of electrostatic interactions, π–π stacking, surface complexation involving sulfonic and oxygen‐containing functional groups, and pore‐filling effects. Overall, this study demonstrates that sulfuric acid‐carbonized sugar beet pulp is a highly effective and environmentally benign adsorbent for cationic dye removal.

In this study, cellulose nanofibers (CNFs) were isolated from Eucalyptus wood pulp (WP) using a chemo-mechanical method that involved sulfuric acid treatment, cryocrushing, and ultrasonication. To minimize environmental impact and reduce chemical usage, a low concentration of sulfuric acid was employed to isolate nanofibers. The isolation process was optimized using 5% and 10% (w/w) sulfuric acid solutions, followed by varying durations of cryocrushing and ultrasonication to produce CNFs. The resulting CNFs were characterized using light microscopy, scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray diffraction (XRD) to evaluate their morphology, chemical composition, and crystallinity. The FTIR results showed that lignin and hemicellulose were effectively removed from the isolated cellulose nanofibrils. XRD analysis revealed that the crystallinity index (CrI) was increased from wood pulp (WP) to bleached wood pulp (BWP), but the decrease observed for CNFs might due to break down of the hydrogen bonds. All treatments successfully produced CNFs, which exhibited diameters ranging from 9.23 to 47.51 nm. The findings of this study suggest that the combination of acid hydrolysis, liquid nitrogen-assisted cryocrushing, and ultrasonication is an effective chemo-mechanical process to disrupt the cellulose matrix to produce nanofibers.

ABSTRACT This study aims to develop an economical, facile, and efficient approach for the recovery and reuse of Fenton sludge (FS) by proposing an in-situ reutilisation strategy that integrates acid leaching with micron-sized zero-valent iron (mZVI) reduction. Given the high iron content of FS (50.68%), single-factor experiments were performed to investigate the influence of critical parameters in acid leaching (liquid-to-solid ratio, sulfuric acid concentration, and acid leaching time) and mZVI reduction (mZVI/Fe3+ (mol/mol), reaction time, and stirring speed). Furthermore, response surface methodology was applied to optimise the process parameters. The optimisation results showed that the optimal acid leaching conditions were a liquid-to-solid ratio of 2.1, a sulfuric acid concentration of 6.2 mol/L, and an acid leaching time of 32 min, achieving a total iron leaching efficiency of 94.24%. For mZVI reduction, the optimal conditions were an mZVI/Fe3+ of 2.15, a reaction time of 134.4 min, and a stirring speed of 156.7 r/min, resulting in an Fe3+ reduction efficiency of 99.32%. Comparative experiments confirmed that the TOC removal efficiency of the FS-derived reduction solution was comparable to that of commercial FeSO4 in treating aniline-containing wastewater, achieving 44.11% and 44.36%, respectively. Economic analysis showed that the treatment cost using FS decreased from 0.63 $/kg-FS to 0.32 $/kg-FS. This study provides a feasible pathway for energy conservation and emission reduction in the Fenton process by minimising FS generation and enabling its in-situ resource recovery.

Life as we know it depends on peptide and nucleic acid polymers built from a limited set of backbone residues, yet planetary environments beyond Earth motivate consideration of alternative chemical frameworks for genetic- and protein-like polymers. In this context, we synthesize four azatide dipeptide analogs (Alaa-Glya (1), Glya-Alaa (2), Glya-Glya (3), and Alaa-Alaa (4)) as candidate backbone motifs for non-standard biologically relevant polymers. We then systematically assess their stability and reactivity in 98% w/w sulfuric acid, a solvent relevant to Venusian cloud chemistry. We assess the stability of the azatides via 1H and 13C NMR spectroscopy supported with ELSD-LCMS. We monitor the stability of the compounds over periods from hours to two weeks at room temperature and at elevated temperatures (50-80 °C). All four azatides readily dissolve in 98% w/w D2SO4 and are generally stable at room temperature. Glya-Alaa (2) shows no detectable degradation over a two-week incubation in 98% w/w sulfuric acid. The other three azatide analogs display only minor decomposition. ELSD-LCMS measurements qualitatively confirm the NMR results, revealing only minor-to-moderate loss of parent compounds after two weeks at room temperature. At higher temperatures, representative of the lower Venusian cloud deck, the stability of the azatides decreases dramatically. All four compounds undergo significant decomposition at 50 °C and completely degrade within one to two weeks at 80 °C. Our findings indicate that azatides, despite being generally stable in concentrated sulfuric acid at room temperature, lack the thermal stability that might be required to serve as viable backbone motifs for biological polymers in environments spanning the full temperature range of Venusian clouds.

Abstract Zinc ferrite, a by-product of zinc hydrometallurgy, is a typical secondary resource. This paper focuses on investigating the factors influencing the sulfuric acid leaching process of zinc ferrite and analyzes the leaching kinetics. The research indicates that the zinc leaching rates of both pure zinc ferrite and zinc ferrite within zinc calcine exhibit positive correlations with individual influencing factors. Moreover, a strong positive synergistic effect exists between leaching temperature and leaching time. The differential impact of various factors on the two zinc leaching rates lies in the interaction involving sulfuric acid concentration, where sulfuric acid concentration acts as a limiting factor for the zinc leaching rate from zinc calcine. Kinetic studies on zinc leaching revealed that the rate-controlling step for zinc leaching from pure zinc ferrite is the surface chemical reaction, with an apparent activation energy of 54.22 kJ/mol. At leaching temperatures of 55 °C, 85 °C, and 95 °C, the zinc leaching rate from zinc ferrite in zinc calcine showed high conformity with both the diffusion model and the surface chemical reaction model, suggesting that the leaching process may be influenced by both kinetic mechanisms at these temperatures.

The elevation of creatinine in the blood is a typical indicator of renal dysfunction, and persistent renal insufficiency can eventually develop into kidney failure, requiring patients to rely on dialysis or kidney transplantation to maintain their lives. This study focuses on the preparation and performance evaluation of a molecularly imprinted membrane, PVA@CS-MIPs, designed for selective adsorption of creatinine. The PVA@CS-MIPs membrane was fabricated using PVA/CScomposite base membrane prepared via solution casting, with α-methylacrylic acid (MAA) as the functional monomer, N,N′-methylenebisacrylamide (MBA) as the crosslinker, and cerium ammonium sulfate (ACS) and concentrated sulfuric acid as initiators. The PVA@CS-MIPs membrane was characterized using FT–IR, SEM, and XPS. The adsorption and permeation behaviors of PVA@CS-MIPs were investigated, and the underlying mechanisms were discussed. The results demonstrate that PVA@CS-MIPs exhibit a high adsorption capacity of 322.5 mg/g for creatinine and good adsorption selectivity. Moreover, the membrane exhibits excellent reusability. These findings suggest that the prepared PVA@CS-MIPs possesses specific recognition ability forcreatinine and hold promise for applications in hemodialysis-related fields.

The corrosion resistance of ferrosilides of the Fe-Si-Cr-Ni-Mo-Mn system in concentrated sulfuric acid in the temperature range of 25-200°C was investigated. The corrosion rate was calculated based on electrochemical parameters using passivation and temperature dependence models of the Arrhenius type. It was confirmed that the main factor determining corrosion resistance is the silicon content. The existence of a critical Si content threshold was shown, upon reaching which a continuous passive SiO₂ film is formed, which provides a reduction in the corrosion rate by 1-2 orders of magnitude. Characteristic temperature ranges of the corrosion process were identified: stable passivation (25-80°C), transitional regime (80-150°C) and degradation of the passive state (150-200°C). It has been shown that Cr and Mo in Fe-Si alloys enhance the stability of the passivated state, particularly at high sulfuric acid temperatures, whereas Ni primarily affects the electrochemical characteristics, and Mn reduces the effectiveness of passivation. The effectiveness of adding chromium to Fe-Si alloys increases proportionally with the Si content; molybdenum stabilizes passivation at acid temperatures above 150°C and reduces the rate of localized corrosion; nickel is not a determining factor at high acid temperatures. The influence of operational factors (turbulence, erosion, impurities) on the corrosion rate has been determined. The expected corrosion rates for the studied alloys in sulfuric acid have been calculated, taking into account industrial operating conditions. The experimental data obtained can be used to develop new corrosion-resistant materials and optimize the composition of Fe-Si alloys for operation in high-temperature aggressive environments of concentrated sulfuric acid.

Lead cake forms from dust as a result of the gas cleaning process during copper smelting. The objective of this study was to develop equipment and technology for a continuous hydrometallurgical method for extracting osmium from the lead cake. In this method, leaching is carried out using an aqueous solution of hydrogen peroxide and sulfuric acid. During the leaching, rhenium is converted into an acidic solution from which rhenium can be easily extracted into a marketable product. Osmium is predominantly converted into a solution, the processing of which, including the extraction of osmium into a marketable product, will be published later. A unit for leaching osmium–rhenium-containing cake with continuous loading for leaching, continuous feeding of leaching solutions, and continuous discharge of the leaching slurry was created. Using the simplex experimental design method, the dependence of osmium recovery on the consumption rates of hydrogen peroxide and sulfuric acid and the leaching duration was studied. Near-optimal leaching conditions were as follows: 68–70 mL of 30% hydrogen peroxide and 7 mL of concentrated sulfuric acid per 100 g of cake, 55 min of leaching, and a specific column throughput of 100 g of cake per 55 min. Nine experiments achieved 96.5% osmium recovery.

ABSTRACT As an organic extractant in kerosene, Acorga OR25 was used to study the selective removal of Cr6+, V5+, and Fe3+ contaminants from the sulfate leach liquid of ilmenite. Purifying titanium-rich fluids and facilitating the manufacturing of high-purity titanium dioxide were the goals of the study. Sulfuric acid concentration, extractant dosage, contact time, organic-to-aqueous phase ratio (O/A), and temperature were among the important extraction parameters that were tuned. The findings showed that extraction efficiency rose as acid concentration rose, peaking at 1 M H2SO4. 10% Acorga OR25 was used to obtain maximum removal efficiency of 99.5% for Cr6+, 98.5% for Fe3+, and 81% for V5+. Equilibrium was attained in a mere 15 minutes. The ideal O/A ratio for economic viability and efficiency was 1:1. The complexation of metal ions with Acorga OR25 was verified by FTIR analysis, and thermodynamic analyses showed that the extraction procedure was exothermic and spontaneous. These results show that Acorga OR25 can effectively purify ilmenite leachates, providing a workable method for producing high-grade TiO2 for industrial uses.

We synthesized seven carbocyclic nucleoside analogs featuring a cyclopentane ring in place of the (deoxy)ribose sugar, which serves as a linker in DNA/RNA nucleosides. We assessed the stability of cyclopentane nucleosides in 98% w/w sulfuric acid at room temperature via 1H and 13C NMR spectroscopy. We observe that adenine (A1, A4), guanine (G1) and thymine (T1) cyclopentane nucleoside analogs remain stable for at least two weeks at room temperature, with only minor (~4%) degradation in A1. In contrast, the cytosine analog (C1) rapidly degrades to release a soluble cytosine. Methyl-substituted adenine analogs mimicking polymer backbone attachments at positions prone to tertiary carbocation formation (A2, A3) prove unstable and release soluble adenine. Only the 3,3-dimethylcyclopentyl adenine analog (A4) exhibits sufficient stability. Our findings reveal that cyclopentane serves as a viable stable linker in concentrated sulfuric acid for select nucleic acid bases, provided that the backbone connections avoid tertiary carbons susceptible to carbocation-mediated cleavage. We thus identify one potential key structural feature for engineering examples of genetic-like polymers that could potentially persist in Venus's concentrated sulfuric acid cloud environment.

Recent findings demonstrate that concentrated sulfuric acid supports rich organic chemistry, including the stability of the canonical DNA bases adenine, thymine, guanine and cytosine. Yet, due to full protonation in concentrated sulfuric acid, these bases may not pair as effectively as they do in water. We are therefore motivated to study nucleic acid bases that pair via hydrophobic and van der Waals interactions instead of canonical hydrogen bonding. Here, we investigate the stability of 14 selected, commercially available alternative nucleobases in concentrated sulfuric acid to evaluate their potential for forming DNA-like polymers in this solvent. The reactivity of compounds 1-14 have not been previously investigated in concentrated sulfuric acid. We incubate the selected compounds in 98% and 81% w/w sulfuric acid and monitor their stability using 1H and 13C NMR spectroscopy over 3 weeks at room temperature. In 98% w/w sulfuric acid, six bases-benzo[c][1,2,5]thiadiazole (1), 2,2'-bipyridine (2), 1,1'-biphenyl (3), 1-methoxy-3-methylbenzene (MMO2) (7) and 1-chloro-3-methoxybenzene (ClMO) (13), and 2,4-difluorotoluene (14)-remain soluble and stable with no detectable degradation. A few compounds show non-destructive reactivity, like sulfonation (compound 3) or H/D exchange (compounds 7, 13, 14). The other compounds react rapidly or are insoluble in 98% w/w sulfuric acid. In 81% w/w sulfuric acid, only compounds 1 and 2 remain stable and soluble, while other selected compounds are insoluble or unstable. Our findings identify a subset of alternative bases stable in concentrated sulfuric acid, advancing efforts towards the design of an example genetic-like polymer in this unusual solvent. Our work further highlights sulfuric acid's potential for supporting complex organic chemistry, with implications for astrobiology, planetary science of Venus and synthetic biology.

Comprehensive extraction of valuable metals from lepidolite by mechanical activation and low temperature sulfation roasting